AgSnO2 electrical contact materials has excellent resistance to arc erosion and welding resistance. It has partially or completely replaced AgCdO materials in the fields of AC and DC contactors, power relays and low-voltage circuit breakers. The internal oxidation method is a process for manufacturing AgSnO2 electrical contact materials. The most mature and widely used method. This article calculates the thermodynamic condition parameters of internal oxidation of Ag-Sn alloy, discusses the nucleation, growth and coarsening process of SnO2 particles during the internal oxidation process, and prepares SnO2 particles using a new alloy powder forming-internal oxidation-hot extrusion process. AgSnO2 electrical contact materials with fine dispersion and superior performance.

    Research shows:

    ① Prepared by internal oxidation-powder hot extrusion process: in the cross section, fine oxide particles are evenly distributed on the silver matrix, and there is basically no agglomeration of oxide particles. In the longitudinal section, the oxide particles are the largest along the The main deformation direction of extension is fibrous tissue.

    ② Prepared by internal oxidation-hot forging process: There is a black network morphology feature in the sintered billet structure. After hot forging, the powder particles are flattened, and defects such as voids and bubbles in the sintered billet are compacted or welded.

    ③ Hot forging can densify the sintered blank and flatten the powder particles, but it cannot change the complete shape of the powder particles in the sintered blank and obtain a streamlined structure. Therefore, the structure and properties of materials prepared by the internal oxidation-powder hot extrusion process are better than those of the internal oxidation-hot forging process.

——The content of the article comes from the Internet