Journal articles: 'Multi-Layer SIW'

1

Ettorre, Mauro, Ronan Sauleau, and Laurent Le Coq. "Multi-Beam Multi-Layer Leaky-Wave SIW Pillbox Antenna for Millimeter-Wave Applications." IEEE Transactions on Antennas and Propagation 59, no. 4 (April 2011): 1093–100. http://dx.doi.org/10.1109/tap.2011.2109695.

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Wu, Kaimin, Yongjun Huang, Hai Hu, Yao Wang, Jian Li, and Guangjun Wen. "COMPACT MULTI-LAYER FOUR-WAY SIW POWER COMBINERS/DIVIDERS OPERATING AT W-BAND." Progress In Electromagnetics Research C 61 (2016): 185–93. http://dx.doi.org/10.2528/pierc15122301.

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Ma, Jun, Gong Yi Li, Zeng Yong Chu, Tian Jiao Hu, Yi He Li, and Xiao Dong Li. "Continuously Large-Scale Preparation of Multi-Layer Graphene Grown on Polycrystalline SiC Microspheres." Applied Mechanics and Materials 597 (July 2014): 99–102. http://dx.doi.org/10.4028/www.scientific.net/amm.597.99.

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Gram scale multi-layer graphene grown on polycrystalline SiC microspheres were prepared by continuously preparation method in argon through chemical vapor deposition process using liquid polysilacarbosilane as raw material. The observation of products obtained at different temperature confirmed the growth is temperature dependent process. The method could be developed to synthesis hybrid nanostructures based on multi-layer graphene grown on polycrystalline SiC microspheres.

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Smith, P. M. "Dyadic Green's functions for multi-layer SAW substrates." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 48, no. 1 (January 2001): 171–79. http://dx.doi.org/10.1109/58.895928.

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5

Xu, Huiping, Sulei Fu, Rongxuan Su, Junyao Shen, Fei Zeng, Cheng Song, and Feng Pan. "Enhanced Coupling Coefficient in Dual-Mode ZnO/SiC Surface Acoustic Wave Devices with Partially Etched Piezoelectric Layer." Applied Sciences 11, no. 14 (July 10, 2021): 6383. http://dx.doi.org/10.3390/app11146383.

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Surface acoustic wave (SAW) devices based on multi-layer structures have been widely used in filters and sensors. The electromechanical coupling factor (K2), which reflects energy-conversion efficiency, directly determines the bandwidth of the filter and the sensitivity of sensor. In this work, a new configuration of dual-mode (quasi-Rayleigh and quasi-Sezawa) SAW devices on a ZnO/SiC layered structure exhibiting significantly enhanced K2 was studied using the finite element method (FEM), which features in the partial etching of the piezoelectric film between the adjacent interdigitated electrodes (IDTs). The influences of piezoelectric film thickness, etching ratio, top electrodes, bottom electrodes, and the metallization ratio on the K2 were systematically investigated. The optimum K2 for the quasi-Rayleigh mode and quasi-Sezawa mode can exceed 12% and 8%, respectively, which increases by nearly 12 times and 2 times that of the conventional ZnO/SiC structure. Such significantly promoted K2 is of great benefit for better comprehensive performance of SAW devices. More specifically, a quasi-Rayleigh mode with relatively low acoustic velocity (Vp) can be applied into the miniaturization of SAW devices, while a quasi-Sezawa mode exhibiting a Vp value higher than 5000 m/s is suitable for fabricating SAW devices requiring high frequency and large bandwidth. This novel structure has proposed a viable route for fabricating SAW devices with excellent overall performance.

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Tsai, H. Y., W. H. Hsu, Y. K. Yu, and R. Chen. "Using the Effective Surface Permittivity Method to Analyse Multilayer Piezoelectric Substrates for Surface Acoustic Wave Filters." Journal of Mechanics 31, no. 2 (December 1, 2014): 139–45. http://dx.doi.org/10.1017/jmech.2014.59.

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AbstractIn this study, the properties of surface acoustic wave (SAW) filters, including phase velocity and electromechanical coupling coefficient (K2) are investigated. The effective surface permittivity (ESP) method was employed to estimate the K2 of bulk materials (single layer) and multi-layer (double-layer and trilayer) structures. In the cases of bulk materials, the calculation results agree with the experimental data, and the errors are less than 7% for quartz. In the cases of double-layer materials, the phase velocity and K2 of various materials, such as ZnO/Diamond and LiNbO3/Diamond, were acquired, and the results demonstrate that LiNbO3/diamond is the optimal choice for high-frequency SAW devices. For the cases of trilayer, the structure of ZnO/PZT/diamond has relatively high K2 and phase velocity. Therefore, this structure is the optimal trilayer structure for high-frequency SAW devices. The study demonstrates that ESP method can be successfully used for estimating SAW properties in piezoelectric multi-layer structures even though the structures contain nonpiezoelectric film (diamond). The proposed numerical computation has the potential to shorten the developing time of SAW device.

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Miyazawa, Tetsuya, Koji Nakayama, Atsushi Tanaka, Katsunori Asano, Shi Yang Ji, Kazutoshi Kojima, Yuuki Ishida, and Hidekazu Tsuchida. "Growth and Characterization of Thick Multi-Layer 4H-SiC Epiwafer for Very High-Voltage p-Channel IGBTs." Materials Science Forum 821-823 (June 2015): 851–54. http://dx.doi.org/10.4028/www.scientific.net/msf.821-823.851.

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Thick multi-layer 4H-SiC epitaxial growth was investigated for very high-voltage Si-face p-channel insulated gate bipolar transistors (p-IGBTs). The multi-layer included n+ buffer, p+ field stop, and thick p- drift layers. Two processes were employed to enhance the carrier lifetime of the p- drift layer: carbon ion implantation/annealing and hydrogen annealing, and the enhanced carrier lifetime was confirmed by the open-circuit voltage decay measurement. Using the grown thick multi-layer 4H-SiC, simple pin diodes were fabricated instead of p-IGBTs to demonstrate efficient conductivity modulation in the thick p- drift layer. While the on-state voltage was high at room temperature, it decreased significantly at elevated temperatures, and attained 3.5 V at 100 A/cm2 at 200°C for the diode with the carrier lifetime enhancement processes, indicating sufficient conductivity modulation.

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Lai, Zhong Hong, Jae Ho Jeon, Jing Chuan Zhu, and Zhong Da Yin. "Mo-Si-C-N Multi-Layer Anti-Oxidation Coating on C/C Composites." Key Engineering Materials 353-358 (September 2007): 1899–902. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.1899.

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A Mo-Si-C-N multi-layer anti-oxidation coating was in situ fabricated on C/C composites by fused slurry and reaction-sintering method in nitrogen atmosphere using Mo and Si element powders, and characterized by X-ray diffractometry, optical microscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy with energy dispersive spectroscopy. It is shown that the coating contains three distinctive layers, namely, SiC inner-layer, MoSi2/Si middle-layer and Si3N4/SiC/Si thin surface-layer. The MoSi2/Si middle-layer, whose thickness could be controlled by dipping process, is the main portion of coating. Oxidation test reveals that the Mo-Si-C-N multi-layer coating significantly improves the oxidation resistance of the C/C composites. Compared with the Mo-Si-C coating, the oxidation temperature is extended up to 1450°C. After oxidation pre-treating at 1400°C, the anti-oxidizing temperature of the Mo-Si-C-N multi-layer coated C/C composites can be raised to 1500°C and the weight loss is less than 1wt% after 12-hour oxidizing test.

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9

Liu, Xing Fang, Guo Sheng Sun, Yong Mei Zhao, Jin Ning, J. Y. Li, Lei Wang, Wan Shun Zhao, M. C. Luo, and Jin Min Li. "Homoepitaxial Growth of 4H-SiC Multi-Epilayers and its Application to UV Detection." Materials Science Forum 556-557 (September 2007): 109–12. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.109.

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Homoepitaxial growth of 4H-SiC p+/π/n- multi-epilayer on n+ substrate and in-situ doping of p+ and π-epilayer have been achieved in the LPCVD system with SiH4+C2H4+H2. The surface morphologies, homogeneities and doping concentrations of the n--single-epilayers and the p+/π/n- multi-epilayers were investigated by Nomarski, AFM, Raman and SIMS, respectively. AFM and Raman investigation showed that both single- and multi-epilayers have good surface morphologies and homogeneities, and the SIMS analyses indicated the boron concentration in p+ layer was at least 100 times higher than that in π layer. The UV photodetectors fabricated on 4H-SiC p+/π/n- multi-epilayers showed low dark current and high detectivity in the UV range.

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10

Zhang, Xian, Lai Fei Cheng, Li Tong Zhang, Shou Jun Wu, and Yong Dong Xu. "Effect of Yttria Nanopowder on Multi-Layer Coatings of Yttria And CVD SiC/Graphite." Key Engineering Materials 334-335 (March 2007): 653–56. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.653.

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Nano-yttria powder can be synthesized by yttrium citrate-urea precursor, combusted at 600°C in air. The CVD SiC coated on graphite (CVD SiC/Graphite) infiltrated by the yttrium citrate-urea precursor, combusted at of 600°C, and then sintered at 1450°C, the thin yttria film can be achieved. The SEM morphology and EDS result of the thin yttria film show a mass of needle-shaped pining into the CVD SiC layer, which improves the combination of CVD SiC layer and wash yttria coating. Therefore, it is an effective transition layer between CVD SiC coating and wash yttria layer.

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11

Sha, Z. D., Y. Yan, W. X. Qin, X. M. Wu, and L. J. Zhuge. "Structure and optical properties of the SiC/ZnO five-layer multi-layer on Si (111) substrate with a SiC buffer layer." Journal of Physics D: Applied Physics 39, no. 15 (July 21, 2006): 3240–43. http://dx.doi.org/10.1088/0022-3727/39/15/005.

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12

Asaad, Renas Rajab, and Rasan I. Ali. "Back Propagation Neural Network(BPNN) and Sigmoid Activation Function in Multi-Layer Networks." Academic Journal of Nawroz University 8, no. 4 (November 20, 2019): 216. http://dx.doi.org/10.25007/ajnu.v8n4a464.

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Back propagation neural network are known for computing the problems that cannot easily be computed (huge datasets analysis or training) in artificial neural networks. The main idea of this paper is to implement XOR logic gate by ANNs using back propagation neural network for back propagation of errors, and sigmoid activation function. This neural network to map non-linear threshold gate. The non-linear used to classify binary inputs (x1, x2) and passing it through hidden layer for computing coefficient_errors and gradient_errors (Cerrors, Gerrors), after computing errors by (ei = Output_desired- Output_actual) the weights and thetas (ΔWji = (α)(Xj)(gi), Δϴj = (α)(-1)(gi)) are changing according to errors. Sigmoid activation function is = sig(x)=1/(1+e-x) and Derivation of sigmoid is = dsig(x) = sig(x)(1-sig(x)). The sig(x) and Dsig(x) is between 1 to 0.

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13

Wu, Shoujun, Laifei Cheng, Litong Zhang, and Yongdong Xu. "Oxidation behavior of 2D C/SiC with a multi-layer CVD SiC coating." Surface and Coatings Technology 200, no. 14-15 (April 2006): 4489–92. http://dx.doi.org/10.1016/j.surfcoat.2005.03.009.

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14

Shi, Anhong, Xin Yang, Cunqian Fang, Yuanqi Weng, Xiao Luo, Ze Zhang, and Qizhong Huang. "Surface Optimization of ZrC–SiC Inner Layer to Enhance Ablation Property of SiC/ZrC–SiC Multi-Layer Coating for C/C Composites." Coatings 11, no. 4 (March 25, 2021): 378. http://dx.doi.org/10.3390/coatings11040378.

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A ZrC–SiC inner layer was fabricated on carbon/carbon composites by pack cementation at different temperatures, aiming to prepare a transition layer for subsequent deposition of SiC and ZrC–SiC layer by chemical vapor deposition and plasma spray. Results show that the structure and phase composition of the inner layer significantly affected the interface bonding strength and thermal shock resistance of the multilayer, which played a vital role in resisting ablation. The jagged and porous surface of the inner layer led to forming a root-like pinning interface, generating a sawtooth combination between the layers. Moreover, the inner layer with high SiC content decreased the coefficient of thermal expansion mismatch between the inner and outer layers. Therefore, the enhanced ablation resistance of the optimum coating was attributed to the improved interface bonding strength and thermal shock resistance caused by the ZrC–SiC inner layer with rough and porous surface structure.

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15

Miyake, Hidetaka, Nobuyuki Tomita, Yoshiyuki Nakaki, Tomoaki Furusho, Atsushi Itokazu, Takashi Hashimoto, Yoshihiko Toyoda, et al. "Characteristics of a Schottky Barrier Diode and the SiC Wafers Sliced by Wire Electrical Discharge Machining." Materials Science Forum 778-780 (February 2014): 784–87. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.784.

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The multi-wire electrical discharge slicing (multi-wire EDS), which is a brand-new method for fabricating wafers, is expected to considerably reduce the production cost of SiC wafers by decreasing in the width of kerf and kerf loss. We evaluated, for the first time, the influences of a wire electrical discharge machining (WEDM) on the SiC wafers based on experiments using WEDM equipped with a power supply of EDS. Although the analyses by transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) revealed that the WEDM influenced layer consists of a contamination layer including several kinds of metals and a layer having crystal defects was certainly formed near the wafer surfaces, the width of the influenced layers was only 3μm, and the layer could be easily removed by the grinding process. Furthermore, characteristics of Schottky barrier diodes (SBDs) fabricated with removing the influenced layer formed by WEDM are comparable to those fabricated with using conventional wafers.

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16

Wang, L., Z. J. Liang, Z. B. Wang, F. L. Zhao, Z. H. He, and Dihu Chen. "Preparation and photoluminescence of SiC/Si/SiO2 multi-layer structure." Journal of Luminescence 122-123 (January 2007): 179–81. http://dx.doi.org/10.1016/j.jlumin.2006.01.078.

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17

Zhu, Shunwei, Hujun Jia, Xingyu Wang, Yuan Liang, Yibo Tong, Tao Li, and Yintang Yang. "Improved MRD 4H-SiC MESFET with High Power Added Efficiency." Micromachines 10, no. 7 (July 17, 2019): 479. http://dx.doi.org/10.3390/mi10070479.

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An improved multi-recessed double-recessed p-buffer layer 4H–SiC metal semiconductor field effect transistor (IMRD 4H-SiC MESFET) with high power added efficiency is proposed and studied by co-simulation of advanced design system (ADS) and technology computer aided design (TCAD) Sentaurus software in this paper. Based on multi-recessed double-recessed p-buffer layer 4H–SiC metal semiconductor field effect transistor (MRD 4H-SiC MESFET), the recessed area of MRD MESFET on both sides of the gate is optimized, the direct current (DC), radio frequency (RF) parameters and efficiency of the device is balanced, and the IMRD MESFET with a best power-added efficiency (PAE) is finally obtained. The results show that the PAE of the IMRD MESFET is 68.33%, which is 28.66% higher than the MRD MESFET, and DC and RF performance have not dropped significantly. Compared with the MRD MESFET, the IMRD MESFET has a broader prospect in the field of microwave radio frequency.

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18

Taguchi, T., T. Nozawa, N. Igawa, Y. Katoh, S. Jitsukawa, A. Kohyama, T. Hinoki, and L. L. Snead. "Fabrication of advanced SiC fiber/F-CVI SiC matrix composites with SiC/C multi-layer interphase." Journal of Nuclear Materials 329-333 (August 2004): 572–76. http://dx.doi.org/10.1016/j.jnucmat.2004.04.120.

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19

Zhang, Jian, Yulei Zhang, Yanqin Fu, Tao Li, and Jiachen Meng. "Effect of HfC-SiC transition layer on the ablation resistance of SiC/HfC-SiC/HfC multi-layer coating for C/C composites." Vacuum 169 (November 2019): 108886. http://dx.doi.org/10.1016/j.vacuum.2019.108886.

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20

Sun, Yong Qiang, Gan Feng, Zhe Yang Li, Li Ping Lv, Jin Yun Luo, Jin Bo Wu, Yi Yang Li, and Jian Hui Zhang. "50 μm-Thick 100 mm 4H-SiC Epitaxial Layer Growth by Warm-Wall Planetary Reactor." Materials Science Forum 778-780 (February 2014): 163–66. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.163.

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Homo-epitaxial growth of 50 μm-thick 4H-SiC on 4° off-axis 100 mm substrates have been demostrated by using a commercial warm-wall multi-wafer planetary reactor (Aixtron 2800 G4). With optimized process, epitaxial layer with an average thickness of 48.146 μm and doping level of 8.39×1014/cm3are obtained. The thickness uniformity with an edge exclusion of 5 mm are 1.30% (σ/mean) and 2.17% (max-min/max+min), and the doping level uniformity are 4.66% (σ/mean) and 6.95% (max-min/max+min), respectively. Surface roughness of the as-grown 50 μm-thick epitaxial layer has an RMS value of 0.606 nm with one step bunching on the 20×20 μm2areas. This initial effort on thick 4H-SiC homoepitaxial growth indicates that this comercial multi-wafer planetary reactor has the potential for mass production of SiC epiwafers for 5000 V and above power devices.

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Wang, Kai, and Robert R. Reeber. "Thermal Residual Stress Modeling in AlN and GaN Multi Layer Samples." MRS Internet Journal of Nitride Semiconductor Research 4, S1 (1999): 209–14. http://dx.doi.org/10.1557/s1092578300002477.

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Thermal residual stresses can detrimentally affect the electronic and optical properties of epitaxial films thereby shortening device lifetime. Based on our earlier work on thermal expansion of nitrides, we provide a finite element modeling analysis of the residual stress distribution of multilayered GaN and AlN on 6H-SiC. The effects of thickness and growth temperatures are considered in the analysis.

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22

Kawai, Kakisawa, Kubo, Yamaguchi, Yokoi, Akatsu, Kitaoka, and Umeno. "Crack Initiation Criteria in EBC under Thermal Stress." Coatings 9, no. 11 (October 24, 2019): 697. http://dx.doi.org/10.3390/coatings9110697.

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For design of multi-layered environmental barrier coatings (EBCs), it is essential to assure mechanical reliability against interface crack initiation and propagation induced by thermal stress owing to a misfit of the coefficients of thermal expansion between the coating layers and SiC/SiC substrate. We conducted finite element method (FEM) analyses to evaluate energy release rate (ERR) for interface cracks and performed experiment to obtain interface fracture toughness to assess mechanical reliability of an EBC with a function of thermal barrier (T/EBC; SiC/SiAlON/mullite/Yb-silicate gradient composition layer/Yb2SiO5 with porous segment structure) on an SiC/SiC substrate under thermal stress due to cooling in fabrication process. Our FEM analysis revealed that a thinner SiAlON layer and a thicker mullite layer are most suitable to reduce ERRs for crack initiation at the SiC/SiAlON, SiAlON/mullite and mullite/Yb2Si2O7 interfaces. Interface fracture tests of the T/EBC with layer thicknesses within the proposed range exhibited fracture at the SiC/SiAlON and SiAlON/mullite interfaces. We also estimated the approximate fracture toughness for the SiC/SiAlON and SiAlON/mullite interfaces and lower limit of fracture toughness for the mullite/Yb2Si2O7 interface. Comparison between ERR and fracture toughness indicates that the fabricated T/EBC possesses sufficient mechanical reliability against interface crack initiation and propagation.

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23

van der Weerd, Jaap, Ron M. A. Heeren, and Jaap J. Boon. "Preparation Methods and Accessories for the Infrared Spectroscopic Analysis of Multi-Layer Paint Films." Studies in Conservation 49, no. 3 (September 2004): 193–210. http://dx.doi.org/10.1179/sic.2004.49.3.193.

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24

Burk, Albert A., Michael J. O'Loughlin, and S. S. Mani. "SiC Epitaxial Layer Growth in a Novel Multi-Wafer VPE Reactor." Materials Science Forum 264-268 (February 1998): 83–88. http://dx.doi.org/10.4028/www.scientific.net/msf.264-268.83.

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25

Redwan, Renas M. "Neural networks and Sigmoid Activation Function in Multi-Layer Networks." Qubahan Academic Journal 1, no. 2 (November 14, 2020): 29–43. http://dx.doi.org/10.48161/qaj.v1n2a11.

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Back propagation neural networks are known for computing the problems that cannot easily be computed (huge datasets analysis or training) in artificial neural networks. The main idea of this paper is to implement XOR logic gate by ANNs using back propagation neural networks for back propagation of errors, and sigmoid activation function. This neural networks to map non-linear threshold gate. The non-linear used to classify binary inputs ( ) and passing it through hidden layer for computing and ( ), after computing errors by ( ) the weights and thetas ( ) are changing according to errors. Sigmoid activation function is = and Derivation of sigmoid is = . The sig(x) and Dsig(x) is between 1 to 0.

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26

Wang, Dong Sheng, Zong Jun Tian, Bin Yang, and Li Da Shen. "Preparation and Characterization of Nano-SiC_P Strengthened MCrAlY Graded Coating by Laser Multi-Layer Cladding." Advanced Materials Research 557-559 (July 2012): 1937–40. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.1937.

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Nano-SiC/MCrAlY graded coating was prepared by laser multi-layer cladding on TiAl base intermetallic alloy using composite MCrAlY powders with 1%, 2%, and 3% nano-SiC particles (mass fraction) in turn. The microstructure and microhardness of the composite coating were analyzed by means of scanning electron microscope (SEM) and Vickers microhardness tester. The results show that the microstructure of the composite coating was refined and composed of fine equiaxed grains because of addition of nanometer SiC particles, and the crystal size becomes small with increasing the nano-SiC content in the coating. In addition, due to small size and formation heat of the nano-SiC particles, SiC particles decompose and form new carbides in the coating after laser cladding. The hardness of the composite MCrAlY coating is obviously improved due to enhancement of multi-carbide and refinement of structure.

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Hu, Xiao Dong, Qing Kun He, Jian Tao Lv, and Yong Zhang. "Study on the Microstructure and Mechanical Properties of 15CrMoR." Advanced Materials Research 472-475 (February 2012): 2731–35. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.2731.

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The butt weld sample with the material of 15CrMoR has been manufactured with the bonding methods of manual electric arc welding (SMAW) and submerged-arc welding (SAW). The relationship between the microstructure and the mechanical properties has been analyzed in this paper, and the conclusions have been obtained as followed: only the last weld layer has the obvious zones of weld zone, heat-affected zone (HAZ) and fusion area for the multi-layer butt weld, the weld zone and the fusion area will be heat-treated by the next layer welding; the hardness along central intersection shows a W-shaped distribution, and the zone with normalizing organization has the lowest hardness and the surface layer has the highest hardness; the mechanical properties of the multi-layer butt weld are much better than the monolayer weld’s.

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Jacques, Sylvain, and Houssam Fakih. "(SiC/Ti₃SiC₂)_n Multi-Layered Coatings Deposited by CVD." Advances in Science and Technology 45 (October 2006): 1085–90. http://dx.doi.org/10.4028/www.scientific.net/ast.45.1085.

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Thin (SiC/Ti3SiC2)n multi-layered coatings were deposited at 1100°C on ceramic substrates by chemical vapour deposition (CVD) methods. Each SiC sub-layer was classically processed from H2/CH3SiCl3. Each Ti3SiC2 sub-layer was obtained by reactive CVD (RCVD) from a H2/TiCl4 gaseous mixture reacting on each SiC solid sub-layer that was previously deposited. The growth of Ti3SiC2 by RCVD involves partial or total SiC consumption. The H2/TiCl4 ratio was chosen on the basis of a thermodynamic study. Using a sufficiently high H2/TiCl4 ratio and limiting the sub-layer thickness allowed the formation of TiC or binary titanium silicides to be avoided. By using a constant low gas pressure in the CVD reactor, it was possible to obtain nearly pure Ti3SiC2 sub-layers as thin as 0.8 μm. In that case, the ternary compound exhibits basal planes oriented perpendicular to the substrate surface. A way to obtain thinner sub-layers was the use of a pressurepulsed CVD method. In addition, the pressure-pulsed method allowed the preferential orientation to be prevented in the Ti3SiC2 coating.

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Gong, Z. Q., and K. Komvopoulos. "Surface Cracking in Elastic-Plastic Multi-Layered Media Due to Repeated Sliding Contact." Journal of Tribology 126, no. 4 (October 1, 2004): 655–63. http://dx.doi.org/10.1115/1.1757491.

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Surface cracking in a multi-layered medium due to sliding of a rigid asperity was analyzed using linear elastic fracture mechanics and the finite element method. Overlapping of the crack faces and assumptions about the distributions of surface tractions were avoided by using special contact elements. The main objectives of this study were to obtain solutions for the tensile and shear stress intensity factor (SIF) and to determine the crack propagation path in the first layer due to repetitive sliding. The crack propagation direction was predicted based on the maximum (tensile or shear) SIF range. The effects of the crack length, sliding friction, and crack-face friction on the SIF and crack propagation direction are discussed in the context of finite element solutions. Simulation results demonstrate the effects of crack growth in the elastic surface layer on the accumulation of plastic strain in the elastic-plastic underlying layer and the significance of the crack growth increment on the propagation path. It is shown that the surface crack propagates toward the layer interface at an angle of ∼57° from the original crack plane, independent of the crack growth increment, in fair agreement with experimental observations. Based on the obtained results, a general fatigue approach for surface cracking is derived for multi-layered media subjected to repetitive sliding contact.

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Zhang, Zhongwei, Longbiao Li, and Zhaoke Chen. "Damage Evolution and Fracture Behavior of C/SiC Minicomposites with Different Interphases under Uniaxial Tensile Load." Materials 14, no. 6 (March 20, 2021): 1525. http://dx.doi.org/10.3390/ma14061525.

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In this paper, the tensile damage and fracture behavior of carbon fiber reinforced silicon carbide (C/SiC) minicomposites with single- and multiple-layer interphases are investigated. The effect of the interphase on the tensile damage and fracture behavior of C/SiC minicomposites is analyzed. The evolution of matrix cracking under the tensile load of the C/SiC minicomposite with a notch is observed using the digital image correlation (DIC) method. The damage evolution process of the C/SiC minicomposite can be divided into four main stages, namely, (1) an elastic response coupled with partial re-opening of thermal microcracking; (2) multiple matrix microcracking perpendicular to the applied loading; (3) crack opening and related fiber/matrix, bundle/matrix, and inter-bundle debonding; and (4) progressive transfer of the load to the fibers and gradual fiber failure until composite failure/fracture. On the fracture surface, a large number of fibers pulling out of the samples with both single-layer and multi-layer interphases can be clearly observed.

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Hu, Xiao Dong, Yong Zhang, Jian Tao Lv, and Sen Zhang. "Study on the Organization and Mechanical Properties of Q345R Weld-Joint." Advanced Materials Research 562-564 (August 2012): 573–77. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.573.

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The butt weld of Q345R with the thickness of 40mm has been manufactured with the submerged-arc welding (SAW). The mechanical properties of the weld seam have been tested and the metallurgical structures have been analyzed. Conclusions have been obtained as follows: the metallurgical structure of multi-layer butt weld is much more complicated than the monolayer ones; only the last weld layer has the obvious zones of weld zone, heat-affected zone (HAZ) and fusion area; the weld zone and the fusion area will be heat treated with the next layers weld finished; the mechanical property of the multi-layer butt weld is much better than the monolayer weld determined by the corresponding organization.

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Zhang, Yu Feng, Min Rui Li, and Jian Cheng Wang. "Study on Surfacing Technics of 18CrNiWA Engine Crankshaft Surfacing Welding with Flux-Cored Wire." Advanced Materials Research 926-930 (May 2014): 246–49. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.246.

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It discussed repairing the worn engine crankshaft with chromium series metal powder-cored wire. The Mo, Mn, V, Ti metal powder and the SiC ultrafine particles, WC nanopowder added in chromium series metal powder-cored wire. That made the surfacing layer obtained high bonding strength, high hardness, and obtained high fracture toughness. The result indicated the SiC ultrafine particles/WC nanopowder could promotion the in-situ reaction in the surfacing layer, formed the dissemination strengthening, the melting strengthening and so on multi-mechanism strengthening effect. SiC and the metal matrix was not merely the mechanical bond, the partial regions were by the chemical bond. That realized in the structure continuity. And the repaired crankshaft surface wear-resisting disposition enhanced 24% than the original.

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Smith, M., R. A. McMahon, Wolfgang Skorupa, M. Voelskow, and J. Stoemenos. "A Thermal Model for Flash Lamp Annealing of 3C-SiC/Si Multi-Layer Systems (i-FLASiC)." Materials Science Forum 483-485 (May 2005): 217–20. http://dx.doi.org/10.4028/www.scientific.net/msf.483-485.217.

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This paper gives an insight into the thermal modeling of the i-FLASiC process, which is the flash lamp annealing of a 3C-SiC and silicon multilayer system. The model uses a standard heat flow model combined with an advanced multilayer optical model. Results from the model are consistent with experimentally observed phenomenon and have been used to explain diffusion mechanisms for the LPE of SiC.

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Hu, Xiao Dong, Jian Tao Lv, Yong Zhang, Sen Zhang, and Ya Jiang Li. "Study on the Weldability and Metallurgical Structure of 15CrMoR." Advanced Materials Research 562-564 (August 2012): 583–86. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.583.

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The butt weld of 15CrMoR with the thickness of 55mm has been manufactured with the bonding methods of manual electric arc welding (SMAW) and submerged-arc welding (SAW), and the mechanical properties of which have been tested with the corresponding test, and the metallurgical structures have been analyzed with microscope. Conclusions have been obtained as following: the metallurgical structure of multi-layer butt weld is much more complicated than the monolayer ones; only the last weld layer has the obvious zones of weld zone, heat-affected zone (HAZ) and fusion area; the weld zone and the fusion area will be heat treated with the next layers weld finished; the mechanical property of the multi-layer butt weld is much better than the monolayer weld.

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Jia, Hujun, Hang Zhang, Yehui Luo, and Zhihui Yang. "Improved multi-recessed 4H–SiC MESFETs with double-recessed p-buffer layer." Materials Science in Semiconductor Processing 40 (December 2015): 650–54. http://dx.doi.org/10.1016/j.mssp.2015.07.045.

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Guan, Kejie, Leilei Zhang, Feiyan Zhu, Hejun Li, Hongchao Sheng, and Yao Guo. "Multi-layer SiC-graphene oxide-hydroxyapatite bioactive coating for carbon/carbon composites." Journal of Alloys and Compounds 821 (April 2020): 153543. http://dx.doi.org/10.1016/j.jallcom.2019.153543.

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Czarnacka, Karolina, Tomasz N. Koltunowicz, Pawel Zukowski, and Aleksander K. Fedotov. "Dielectric properties of multi-layer nanocomposites SiO /ZrO2 after high temperature annealing." Ceramics International 45, no. 5 (April 2019): 6499–502. http://dx.doi.org/10.1016/j.ceramint.2018.12.139.

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Malik, M. Z. A., M. T. Zainuddin, A. M. Abdullah, and A. Isnin. "Optical and Structural Properties of Multi Deposition Film Derived SiO₂-TiO₂ Systems by Sol-Gel Process." Advanced Materials Research 31 (November 2007): 101–4. http://dx.doi.org/10.4028/www.scientific.net/amr.31.101.

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SiO2-TiO2 systems were extensively investigated in sol-gel process to fabricate passive optical planar waveguides, channel waveguides, interference filters and weather resistant optical memory discs. A high quality, crack free optical thick layer and low processing cost are key success factor for optical applications. Two formulated SiO2-TiO2 systems with 1% and 10% TiO2 were deposited on 20mm x 20mm Si-wafer using multi-spin coating process was investigated on refractive index (n), build-up layer until crack appeared on film. The structure analysis of multi spin was investigated using FTIR. The value of refractive index (n) and thickness of thin films (d) were taken every deposited layer using spectroscopic reflectance and surface morphology of crack thick film by FESEM. SiO2-TiO2 thin film appeared peak ~950cm-1 associated with the Si-O stretching vibrations of Si-OH and Si-O-Ti groups by multi spin coating processes. SiO2-TiO2 system with 10% TiO2 in siloxane structure was found capable on building thick layer up to 2.4 μm at 17 time cycles spins and heat treatments at 680 oC. The value of n was reduced with increasing of number of cycles and believes to form nanoporous zones between interfacial layers during hydrolysis and condensation process of each layer by multi spin coating process.

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Ogawa, Masumi, Kei Mine, Seiki Fuchiyama, Yasuhiro Tawa, and Tomohisa Kato. "Development of Multi-Wire Electric Discharge Machining for SiC Wafer Processing." Materials Science Forum 778-780 (February 2014): 776–79. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.776.

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In order to slice the larger size ingot toward 6 inch of silicon carbide (SiC), we are developing Multi-wire Electric Discharge Machining (EDM). To prevent wire break during slicing, we have developed the electric discharge pulse control system. So far, with 10 multi-wires, we have succeeded in slicing of 4 inch SiC balk single crystal without wire break. High quality slicing surface (e.g. small value of around 10 μm of SORI for 3 inchi wafer) was also achieved. By polishing methode, EDM-sliced wafer was estimated to have the uniform thickness of damaged layer over the entire surface. We confirmed that the wafer sliced by EDM can be processed in the later process, by grinding the 3 inch wafer. And it was confirmed that 6 inch ingot can be sliced with 10 multi-wire EDM, by slicing the boule of SiC poly crystal. For the larger diameter ingot than 4 inch, Multi-wire EDM will be practically used by the effective removal of machining chips from the machining clearance between the wire and work.

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Zhang, Ru, Chuanzhen Huang, Jun Wang, Hongtao Zhu, and Hanlian Liu. "Fabrication of high-aspect-ratio grooves with high surface quality by using femtosecond laser." Industrial Lubrication and Tribology 73, no. 5 (June 10, 2021): 718–26. http://dx.doi.org/10.1108/ilt-11-2020-0432.

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Purpose The purpose of this study is to fabricate high-aspect-ratio grooves with high surface quality by femtosecond laser (FS) to improve the machinability of silicon carbide (SiC) and optimize the process parameters in micromechanical applications. Design/methodology/approach Four contrast experiments are reported to characterize the FS laser grooving process for SiC with polarization direction, crystal orientation, multi-pass scanning and z layer feed, respectively. The effects of different experimental conditions on the groove characteristics, material removal rate (MRR), aspect ratio, heat affected zone (HAZ) and surface roughness Ra are analyzed. Findings The influence of increasing laser fluence and multi-scanning pass on the groove depth is greater than on the groove width. The MRR, aspect ratio, HAZ and Ra increased with the increase of laser fluence and multi-scanning pass. The direction of laser polarization affects the direction of hot electron injection but has little effect on the material characteristics. FS laser ablation is an isotropic process and there is no obvious change in different crystal orientations. The z-layer feed can significantly increase the groove width and depth and reduce HAZ and Ra. The maximum aspect ratio of 82.67% was fabricated. Originality/value The results contribute to the understanding of the removal mechanism and reduce the friction of the microfluidic device and improve the flowability in the FS laser ablation of SiC. This paper provides suggestions for the selection of suitable process parameters and provides a wider possibility for the application of micro-texture on SiC.

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He, Yi Qiang, Bin Qiao, and Li Chao Feng. "Elevated Temperature Mechanical Properties of Al-8.5Fe-1.3V-1.7Si/SiC_P Composite Prepared by Multi-Layer Spray Deposition." Materials Science Forum 694 (July 2011): 708–12. http://dx.doi.org/10.4028/www.scientific.net/msf.694.708.

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Al-8.5Fe-1.3V-1.7Si/SiCP composite prepared by multi-layer spray deposition in different states were investigated. Ultimate tensile strengths of the composite sheets as-rolled tested at 315°C and 400°C are up to 300MPa and 186MPa respectively. The fine dispersoids and fine grains, and homogeneous SiC particles contribute to the excellent mechanical properties of the composite at elevated temperature. Specially, partial dissolution of SiC particles contributes to the stability of Al12(Fe,V)3Si phase.

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Kosugi, Ryoji, Yuuki Sakuma, Kazutoshi Kojima, Sachiko Itoh, Akiyo Nagata, Tsutomu Yatsuo, Yasunori Tanaka, and Hajime Okumura. "Development of SiC Super-Junction (SJ) Devices by Multi-Epitaxial Growth." Materials Science Forum 778-780 (February 2014): 845–50. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.845.

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Super-junction (SJ) devices have been developed to improve the trade-off relationship between the blocking voltage (VBD) and specific on-resistance in unipolar power devices. This SJ structure effect is expected in SiC unipolar devices. Multi-epitaxial growth is a known fabrication method for SJ structures where epitaxial growth and ion implantation are repeated alternately until a certain drift-layer thickness is achieved. In this study, we fabricated two types of test elemental groups with an SJ structure to evaluate the breakdown voltage (VBD) and specific resistivity of the drift layer (Rdrift). Experimental results show that VBDexceeded the theoretical limit of the 4H-SiC by 300V, and Rdriftagreed well with the estimated value from the device simulation. The beneficial effects of the SJ structure in the SiC material on VBDand Rdriftwere confirmed for the first time.

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Abbas, Imran, Yanxiang Wang, Hassan Elahi, Muhammad Ali Siddiqui, Mudaser Ullah, and Faisal Qayyum. "Effect of MoSi2-Si3N4/SiC Multi-Layer Coating on the Oxidation Resistance of Carbon/Carbon Composites above 1770 K." Journal of Composites Science 4, no. 3 (July 3, 2020): 86. http://dx.doi.org/10.3390/jcs4030086.

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To improve the oxidation resistance of carbon/carbon composites at high temperatures (>1770 K), they were coated with MoSi2-Si3N4/SiC. The slurry and pack cementation methods were adopted to deposit the inner SiC layer and outer MoSi2-Si3N4 layer. The phase composition, microstructure, and elemental distributions in the coating were analyzed using SEM, XRD, EDS, and Raman spectroscopy. Oxidation tests show that the deposited multi-layer coating can protect the carbon/carbon matrix from oxidation at high temperatures (>1770 K) for 150h and that the coating can withstand 40 thermal cycles between 1773 and 300 K. It is observed that Si3N4 assists in the formation of a dense SiO2 layer at a high temperature, which plays a vital role in increasing the thermal cyclic and oxidation resistance of the coating itself. The weight loss of coated carbon/carbon composite is attributed to the formation of micro-cracks and diffusion of SiO2, MoO3, and N2 out of the material at high temperatures.

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Convertino, D., A. Rossi, V. Miseikis, V. Piazza, and C. Coletti. "Thermal decomposition and chemical vapor deposition: a comparative study of multi-layer growth of graphene on SiC(000-1)." MRS Advances 1, no. 55 (2016): 3667–72. http://dx.doi.org/10.1557/adv.2016.369.

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ABSTRACTThis work presents a comparison of the structural, chemical and electronic properties of multi-layer graphene grown on SiC(000-1) by using two different growth approaches: thermal decomposition and chemical vapor deposition (CVD). The topography of the samples was investigated by using atomic force microscopy (AFM), and scanning electron microscopy (SEM) was performed to examine the sample on a large scale. Raman spectroscopy was used to assess the crystallinity and electronic behavior of the multi-layer graphene and to estimate its thickness in a non-invasive way. While the crystallinity of the samples obtained with the two different approaches is comparable, our results indicate that the CVD method allows for a better thickness control of the grown graphene.

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Gusev, Alexander, and Irina Kitiashvili. "Spin rotation, Chandler wobble and free core nutation of isolated multi-layer pulsars." Proceedings of the International Astronomical Union 8, S291 (August 2012): 392. http://dx.doi.org/10.1017/s1743921312024246.

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AbstractAt present time there are investigations of precession and nutation for very different celestial multi-layer bodies: the Earth (Getino 1995), Moon (Gusev 2010), planets of Solar system (Gusev 2010) and pulsars (Link et al. 2007). The long-periodic precession phenomenon was detected for few pulsars: PSR B1828-11, PSR B1557-50, PSR 2217+47, PSR 0531+21, PSR B0833-45, and PSR B1642-03. Stairs, Lyne & Shemar (2000) have found that the arrival-time residuals from PSR B1828-11 vary periodically with a different periods. According to our model, the neutron star has the rigid crust (RC), the fluid outer core (FOC) and the solid inner core (SIC). The model explains generation of four modes in the rotation of the pulsar: two modes of Chandler wobble (CW, ICW) and two modes connecting with free core nutation (FCN, FICN) (Gusev & Kitiashvili 2008). We are propose the explanation for all harmonics of Time of Arrival (TOA) pulses variations as precession of a neutron star owing to differential rotation of RC, FOC and crystal SIC of the pulsar PSR B1828-11: 250, 500, 1000 days. We used canonical method for interpretation TOA variations by Chandler Wobble (CW) and Free Core Nutation (FCN) of pulsar.The two - layer model can explain occurrence twin additional fashions in rotation pole motion of a NS: CW and FCN. In the frame of the three-layer model we investigate the free rotation of dynamically-symmetrical PSR by Hamilton methods. Correctly extending theory of SIC-FOC-RC differential rotation for neutron star, we investigated dependence CW, ICW, FCN and FICN periods from flatness of different layers of pulsar.Our investigation showed that interaction between rigid crust, RIC and LOC can be characterized by four modes of periodic variations of rotation pole: CW, retrograde Free Core Nutation (FCN), prograde Free Inner Core Nutation (FICN) and Inner Core Wobble (ICW). In the frame of the three-layer model we proposed the explanation for all pulse fluctuations by differential rotation crust, outer core and inner core of the neutron star and received estimations of dynamical flattening of the pulsar inner and outer cores, including the heat dissipation. We have offered the realistic model of the dynamical pulsar structure and two explanations of the feature of flattened of the crust, the outer core and the inner core of the pulsar.

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Burk, Albert A., Michael J. O'Loughlin, Michael J. Paisley, Adrian R. Powell, M. F. Brady, Stephan G. Müller, and S. T. Allen. "Large Area SiC Epitaxial Layer Growth in a Warm-Wall Planetary VPE Reactor." Materials Science Forum 483-485 (May 2005): 137–40. http://dx.doi.org/10.4028/www.scientific.net/msf.483-485.137.

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Experimental results are presented for SiC epitaxial layer growths employing a largearea, 7x3-inch, warm-wall planetary SiC-VPE reactor. This high-throughput reactor has been optimized for the growth of uniform 0.01 to 30-micron thick, specular, device-quality SiC epitaxial layers with background doping concentrations of <1x1014 cm-3. Multi-layer device profiles such as Schottky, MESFETs, SITs, and BJTs with n-type doping from ~1x1015 cm-3 to >1x1019 cm-3, p-type doping from ~3x1015 cm-3 to >1x1020 cm-3, and abrupt doping transitions (~1 decade/nm) are regularly grown in continuous growth runs. Intrawafer layer thickness and n-type doping uniformities of <1% and <5% s/mean have been achieved. Within a run, wafer-to-wafer thickness and doping variation are ~±1% and ~±5% respectively. Long term run-to-run variations while under process control are approximately ~3% s/mean for thickness and ~5% s/mean for doping. Latest results from an even larger 6x4-inch (100-mm) reactor are also presented.

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47

Sun, Shao Ni, Li Yang Xie, Yi Chen Zhang, and Ying Huang. "Optical Properties of Ta₂O₅/SiO₂ Antireflection Coating System." Advanced Engineering Forum 2-3 (December 2011): 167–71. http://dx.doi.org/10.4028/www.scientific.net/aef.2-3.167.

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The Ta2O5/SiO2 Multi-layer Antireflection Coating Is Prepared on K9 Glass by RF Magnetron Sputtering Technology in the Experiment. the Growth Parameters Are Changed to Get Multi-layer Antireflection Film with Good Optical Properties. in the Technical Research, the Influence of Various Growth Parameters, Including Working Pressure, Oxygen Content, Substrate Temperature, Etc., on the Optical Properties and Structures of the Coatings Are Studied. Optical Properties and Morphological Features such as Surface, Structure Are Investigated by UV-VIS Spectrophotometer and AFM, Respectively. the Detecting Results Further Verify the Important Influences of Proper Growth Parameters on Optical Properties of Antireflection Coating.

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Schmalz, Julius, Anne Kittmann, Phillip Durdaut, Benjamin Spetzler, Franz Faupel, Michael Höft, Eckhard Quandt, and Martina Gerken. "Multi-Mode Love-Wave SAW Magnetic-Field Sensors." Sensors 20, no. 12 (June 17, 2020): 3421. http://dx.doi.org/10.3390/s20123421.

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A surface-acoustic-wave (SAW) magnetic-field sensor utilizing fundamental, first- and second-order Love-wave modes is investigated. A 4.5 μ m SiO2 guiding layer on an ST-cut quartz substrate is coated with a 200 n m (Fe90Co10)78Si12B10 magnetostrictive layer in a delay-line configuration. Love-waves are excited and detected by two interdigital transducers (IDT). The delta-E effect in the magnetostrictive layer causes a phase change with applied magnetic field. A sensitivity of 1250 ° / m T is measured for the fundamental Love mode at 263 M Hz . For the first-order Love mode a value of 45 ° / m T is obtained at 352 M Hz . This result is compared to finite-element-method (FEM) simulations using one-dimensional (1D) and two-and-a-half-dimensional (2.5 D) models. The FEM simulations confirm the large drop in sensitivity as the first-order mode is close to cut-off. For multi-mode operation, we identify as a suitable geometry a guiding layer to wavelength ratio of h GL / λ ≈ 1.5 for an IDT pitch of p = 12 μ m . For this layer configuration, the first three modes are sufficiently far away from cut-off and show good sensitivity.

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Chou, T. C., and T. G. Nieh. "Solid state reactions between Ni3Al and SiC." Journal of Materials Research 5, no. 9 (September 1990): 1985–94. http://dx.doi.org/10.1557/jmr.1990.1985.

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Solid state reactions between SiC and Ni3Al were studied at 1000°C for different times. Multi-reaction-layers were generated in the interdiffusion zone. Cross-sectional views of the reaction zones show the presence of three distinguishable layers. The Ni3Al terminal component is followed by NiAl, Ni5.4Al1Si2, Ni(5.4−x)Al1Si2 + C layers, and the SiC terminal component. The Ni5.4Al1Si2 layer shows carbon precipitation free, while modulated carbon bands were formed in the Ni(5.4−x)Al1Si2 + C layer. The NiAl layer shows dramatic contrast difference with respect to the Ni3Al and Ni5.4Al1Si2 layers, and is bounded by the Ni3Al/NiAl and Ni5.4Al1Si2/NiAl phase boundaries. The kinetics of the NiAl formation is limited by diffusion, and the growth rate constant is measured to be 2 ⊠ 10−10 cm2/s. The thickness of the reaction zone on the SiC side is always thinner than that on the Ni3Al side and no parabolic growth rate is obeyed, suggesting that the decomposition of the SiC may be a rate limiting step for the SiC/Ni3Al reactions. The carbon precipitates were found to exist in either a disordered or partially ordered (graphitic) state, depending upon their locations from the SiC interface. The formation of NiAl phase is discussed based on an Al-rejection model, as a result of a prior formation of Ni–Al–Si ternary phase. A thermodynamic driving force for the SiC/Ni3Al reactions is suggested.

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Feng, Tao, Hejun Li, Xiaohong Shi, Xi Yang, Shaolong Wang, and Zibo He. "Multi-layer CVD-SiC/MoSi2–CrSi2–Si/B-modified SiC oxidation protective coating for carbon/carbon composites." Vacuum 96 (October 2013): 52–58. http://dx.doi.org/10.1016/j.vacuum.2013.03.012.

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Journal articles on the topic 'Multi-Layer SIW'

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