Academic literature on the topic 'Silver-tungsten alloys'

Abstract The manuscript describes the use of anti-galling silver-cobalt alloy as a novel metallic contact finish for connector applications. The purpose of this work was to develop a cost-effective and cyanide-free and self-lubricated silver-cobalt alloy deposited using reversed pulse electrodeposition process for silver-based contact finishes in electrical contacts applications. The manuscript describes a novel silver-cobalt alloy deposited through reversed pulse-electroplating process that provides exceptionally low friction coefficient (similar to hard gold) and outstanding wear resistance compared to standard silver and any commercially available electroplated silver alloys such as silver-tin, silver palladium, silver antimony, silver-bismuth, silver-tellurium, and silver-tungsten.

The nanocrystalline silver powder and the amorphous powders of composition Ni49,5Ti20,5Nb15Zr15 (numbers indicate at%) were prepared by ball milling in the planetary Fritsch mill for 40 hours. TEM studies confirmed almost complete amorphization of milled alloys powders allowed to detect a small fraction of a small intermetallic inclusions within the amorphous matrix. The erosion of composites during contact cycling was similar as in Ag-W composites known as a good contact materials. SEM and TEM studies have shown a low solubility of tungsten in silver after ball milling and no solubility of silver in tungsten. The grain size of silver crystals within powders drastically decreased after milling down to about 30 nm and only a small increase in the grain size up to 200 nm was observed after hot pressing. These results were confirmed using TEM studies of composites after hot pressing. TEM microstructures have shown very narrow transition layer at the amorphous/silver interface (between 10-30 nm thick) containing all elements from the amorphous powders plus silver due to short time of hot pressing. The amorphous part has shown growth of intermetallic phases there, however diffused ring from the amorphous part was still visible. The composites prepared from silver and tungsten have shown presence of coherent tungsten rich precipitates showing typical strain field contrast within fine grains near 100 nm formed most probably during hot pressing of silver solid solution formed during mechanical alloying. The structure of tungsten has shown less defects and consequently less grain refinement than silver particles. SEM studies of the compression tested samples of silver-amorphous composites have shown crack formation at the interfaces of both components most probably due to presence of a brittle transition phase containing all elements.

The results of research on modeling shock-wave loading of metal composites – elkonites, which are sintered refractory materials tungsten, tungsten carbide or molybdenum impregnated with fusible metal silver or copper using thermodynamically equilibrium model TEC are presented. The investigation of the compressibility of such composites are related to the properties of the materials themselves and the possibility of creating samples based on them. Thermodynamic characteristics are calculated for these metals and compared with available data of shock-wave experiments. The model allows us to describe the dynamic loading of solid and porous alloys of various compositions such as Cu–W, Ag–W, Cu–WC, Ag-W. This model allows for targeted selection of material compositions of different porosity values and ratios of their components in order to obtain the specified characteristics for shock-wave loading of samples.

The results of research on modeling shock-wave loading of metal composites – elkonites, which are sintered refractory materials tungsten, tungsten carbide or molybdenum impregnated with fusible metal silver or copper using thermodynamically equilibrium model TEC are presented. The investigation of the compressibility of such composites are related to the properties of the materials themselves and the possibility of creating samples based on them. Thermodynamic characteristics are calculated for these metals and compared with available data of shock-wave experiments. The model allows us to describe the dynamic loading of solid and porous alloys of various compositions such as Cu–W, Ag–W, Cu–WC, Ag-W. This model allows for targeted selection of material compositions of different porosity values and ratios of their components in order to obtain the specified characteristics for shock-wave loading of samples.