Preparation method and system for silver zinc oxide composite powder

Abstract

The invention discloses a preparation method and system for silver zinc oxide composite powder. The preparation method comprises the following steps of: separately weighing a silver raw material and azinc raw material in proportion, dissolving the raw materials to prepare a precursor solution containing silver nitrate and zinc nitrate, performing atomizing treatment on the precursor solution to obtain 0.01-100[mu]m precursor fog drops, and thermally decomposing the precursor fog drops at a temperature being 450-1150 DEG C to obtain the silver oxide composite powder. The system comprises an atomizing device, a thermal treatment device and a cyclone collecting device. According to the method disclosed by the invention, a proper amount of C1-C4 alcohols is added while the precursor solutionis prepared, and sphericity degree of the silver zinc oxide composite powder can be effectively controlled; a proper amount of ammonia water is added, so that the silver zinc oxide composite powder ofa hollow structure can be prepared; and the cyclone collecting device is utilized for effectively grading powder of different grain sizes, the process design is scientific, the process is continuous,the equipment structure is reasonable, raw materials are easily available and are cheap, phases of reaction products are controllable, purity is high, the grain sizes of the particles are controllable, large-scale mass production can be realized, and the application prospect is wide.

Description

technical field [0001] The invention relates to the technical field of preparation of functional powder materials, in particular to a method and system for preparing silver-zinc oxide composite powder. Background technique [0002] At present, the annual demand of silver and silver-based electrical contact materials in the world is about 2900-3000 tons, and the annual demand of my country alone is as high as 900-1000 tons. Silver cadmium oxide, known as "universal electrical contact material", has been gradually banned due to its environmental pollution; silver zinc oxide has become a new generation of environmentally friendly materials due to its excellent arc erosion resistance, wear resistance and fusion welding resistance electrical contact material. [0003] In the prior art, the main methods for preparing silver-zinc oxide electrical contact materials include alloy internal oxidation method, co-precipitation method and powder metallurgy method, among which, alloy inte...

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Problems solved by technology

[0003] In the prior art, the main methods for preparing silver-zinc oxide electrical contact materials include alloy internal oxidation method, co-precipitation method and powder metallurgy method, among which, alloy internal oxidation method is a relatively advanced process for preparing electrical contact materials. This method has simple process, low cost and excellent contact performance, and is widely used at home and abroad. However, the surface and internal structure of the finished material prepared by this method are not uniform, and there is a poor oxide layer in the middle, which leads to inaccurate contact dimensions; Powder metallurgy method is one of the main preparation methods of silver metal oxide composite materials. Powder metallurgy method can obtain electrical contact materials with relatively uniform structure and stable performance, but the finished material has low density, poor processability, low resistivity Higher, poor interfacial wettability between oxide particles and the substrate, and weak interfacial bonding strength; the second phase of the silver-based contact material prepared by the co-precipitation method is dispersed and evenly distributed, and the electrical properties are good, but the powder manufacturing cost is high, and Due to the wet chemical reaction process involved, the stability of each batch of powder quality is difficult to control

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