Preparation method of nano Ag-SnO2 electric contact composite

Abstract

The invention discloses a preparation method of a nano Ag-SnO2 electric contact composite, which comprises the steps of: preparing a sol solution by using stannous chloride dehydrate as a raw material, adding a silver nitrate solution, controlling Sn<2+> sol particles and Ag<+> ions in the solution to generate a chemical reaction in situ through regulating a pH value so to prepare Ag-SnO2 intermediate composite particles with the content of SnO2 of 10-90 percent; then mixing the Ag-SnO2 intermediate composite particles with pure silver powder, reducing the SnO2 content to 5-30 percent; and pressing, sintering and thermally extruding to obtain the electric contact composite with nano SnO2 reinforced phase particles in a funicular distribution state in a matrix. Sol and gel are combined to generate the chemical reaction; and by the assistance of ultrasonic waves, the particle diameter (nano level) of the Ag particles and the SnO2 particles in the intermediate particles and the dispersion distribution of the Ag particles and the SnO2 particles are controlled effectively, the compatibility of the matrix and the reinforced phase is improved, and the interface binding strength of the matrix and the reinforced phase is improved.

Description

technical field [0001] The invention relates to a preparation method of an electrical contact material, in particular to a nano Ag-SnO 2 Preparation method of electrical contact composite material. Background technique [0002] Ag-SnO 2 It is recognized as the most promising environment-friendly electrical contact functional composite material to replace Ag-CdO. However, SnO 2 It has good thermal stability, and it is not easy to decompose when it is subjected to the action of an arc. In addition, it has poor wettability with molten liquid Ag, and has a large density difference with Ag, so it is easy to float to the surface of the contact to form enrichment. Due to SnO 2 Non-conductive, resulting in an increase in the contact resistance of the contacts, resulting in a rise in temperature and affecting the performance of the electrical appliance. At the same time, Ag-SnO 2 At present, the material still has disadvantages such as low elongation and difficult processing an...

AI Technical Summary

Problems solved by technology

However, these processes also have some deficiencies. For example, tin oxide in the powder metallurgy process is added by external mechanical force, which is likely to cause ball milling medium pollution; internal oxidation and chemical precipitation methods have high requirements for equipment, long production cycle, and high cost. high

[0003] After searching the prior art, it was found that the patent announced in 2009 (200910196285.X, preparation method of silver-doped tin oxide electrical contact material) disclosed a sol-gel method to prepare nano-tin oxide, and then mixed by ball milling A method for preparing silver-tin oxide electrical contact materials. Although this method has solved the nanoscale problem of tin oxide well, the interface problem has not been well solved due to the mechanical blending method.