|
AgCdO material due to its excellent arc erosion resistance, known as the \Due to the the Cd toxic and, therefore, the development of environmentally friendly electrical performance AgSnO 2 contact material has important application prospect. In But, AgSnO , 2 contact material processing performance, the temperature rise, anti-welding properties and poor. Research on the basis of the papers in AgSnO 2 contact failure analysis, proposed using SnO 2 surface modification method to improve the SnO 2 and Ag wettability, to prepare a high-performance the AgSnO 2 contact material. Firstly, based on the study of electrical contacts mainly with its electrical properties, leading to lack of theoretical guidance novel electrical contact material Institute must present situation, from the point of view of the material, the matrix material, the second phase, additives, material defects electrical contact performance and other factors of various materials, initially built electrical contact material composition, the relationship between organizational structure and performance. Second, using a stereo microscope, scanning electron microscopy, spectroscopy, optical microscopy and other means, the failure of the appearance of the surface of contact organizations, especially contacts around the electrical loss product morphology was investigated. Third, contain trace amounts of additives CuO, Bi 2 O 3 of AgSnO 2 composite powder prepared by electroless plating repression - sintering sintering experiments, using optical microscopy, scanning electron microscopy to study the microstructure of sintered samples and the morphology of the composite powder. Further surface modification of SnO 2 prepared containing of CuO the Bi 2 O 3 the WO 3 additives the AgSnO 2 composite powder, by sintering, hot extrusion, wire drawing prepared the AgSnO 2 wire and rivets, study of SnO 2 Surface Modification AgSnO 2 sintering properties, sintering organization the AgSnO 2 mechanical properties, electrical properties. The analysis of the results of the failure of electrical contacts: electrical contacts arc erosion product appearance and color to its erosion mechanism; arc AgCdO contact erosion the product gray, erosion material splashes loss, while the AgSnO 2 < contacts / sub> arc erosion product is black, erosion mainly material evaporation, the black appearance evaporation formation deposition morphology whisker related. Failure AgSnO 2 contact surface characteristics for the distribution of silver-rich layer at the contact surface, the silver-rich layer below the oxide-rich region. Melting silver and SnO 2 wettability between the differential is caused by the silver and SnO 2 stratification. Trace additives AgSnO 2 the sintering and organizations experiments showed that: the AgSnO of additive-free 2 composite powder sintered density, sintered samples appear SnO 2 was the uneven distribution of network-like morphology, its causes and composite powder SnO 2 silver layer separation phenomenon exists in the calcination process before sintering. Of sintering additives favor of CuO sintering densification better than Bi 2 O 3 good; while Bi 2 O 3 are more conducive to the elimination of the sintered samples SnO 2 network-like distribution; combined addition of CuO the Bi 2 O 3 both conducive to densification, and can also eliminate the sintered sample meshworks, SnO 2 is more uniformly distributed in the Ag matrix. SnO 2 and additives mixed when compared to the chemical silver plating, of SnO , 2 chemical silver plated and then mixed with additives, tissue distribution uniformity better. Using Bi 2 O 3 CuO, and WO 3 SnO 2 surface modification can improve AgSnO 2 powder sintered density and eliminate or the weakened AgSnO 2 organization SnO 2 distribution network because SnO 2 SnO 2 powder with a silver wettability is increased by surface modification, eliminating the AgSnO 2 the composite powder calcination SnO 2 silvered layer separating now
|