Metal powder for electrical carbon

Copper powder used for electrical carbon products is electrolytic production, high purity (up to 99.5%), long-grain structure is dendritic, after pressing, the products with high mechanical strength. According to different manufacturing processes, copper powder be divided into saponification (deacidification) copper powder and unsaponifiable copper powder two kinds, electric carbon products production are general use unsaponifiable copper.

The technical performance indicators of copper: copper content is not less than 99.5%; moisture is not more than 0.05%; through nitric acid treated, residue on ignition is less than 0.05%. Copper is the wear parts of electric industry producing carbon sliding friction, such as one of the important raw materials of metal-graphite products. It can be used for producing copper-graphite brushes, copper-graphite bearing, copper-graphite and copper-graphite electrode contacts. In the copper-graphite products, copper powder as the auxiliary conductor of products, with the characteristic of lowering resistivity, increasing the allowable current density, reducing the contact resistance, reducing the contact voltage drop, increasing the analysis of coke’s adhesive, etc.. Copper appearance is pale pink, brown or even black, should be stored in sealed containers to prevent oxidation.

Tin is the low melting point metal, the melting point is 231.85. The tin powder used for electrical carbon production is the granular structure that the molten tin liquid prepared by spraying method, the spraying method is by compressing air or other gases to crush the molten metal flow, make it spraying into powder. Atomized powder particles are cylindrical spherical form, sometimes also show irregular shape.

Tin powder’s technical performance indicators: tin content is not less than 99.5%; through hydrochloric acid treated, the residue is not more than 0.025%. Copper-graphite products by adding tin powder, tin react with copper in the products, obtain tin bronze, it can increase the mechanical strength of products, improved abrasion resistance. Such as bronze-graphite bearing is the eutectic tin bronze formed by tin powder and copper powder role, increase the useful life of the bearing.

Lead powder for electric charcoal production was taken by the molten lead through spray method. Different varieties electrical carbon products use different lead powder particle size, lead powder’s technical performance indicators: Lead content is not less than 99.5%; oxygen content is not more than 0.5%. Electrical carbon products produced generally with litharge powder, chemical symbol Pb0. Lead powder monoxide technical performance indicators: a lead oxide content of not less than 90%; metallic lead content is not more than 10%; residues insoluble in nitric acid is not more than 0.5%.

Add lead powder or oxidized lead powder into electric power brush material ratio can reduce the hardness of the brush raw material, so that the brush can be relatively easy to establish a good contact with the commutator, reducing the rectifying sparks. Lead at 200 ~ 250 can generate lead oxide film, this film contacts with graphite film, have good lubricity, can reduce the wear of the brush and the commutator itself. Adding copper powder in the sliding contact can increase the wear resistance of the contacts.

Silver powder for electric charcoal production is the pure silver powder. Silver powder’s technical performance indicators: silver content is not less than 98.5%; particle size plus 325 mesh is not more than 1.0%, cut 325 mesh is not less than 95%. Silver is a precious metal, its conductivity is the best in metals, so its contact resistance is very low, contact voltage drop is small. Silver powder is mainly used to manufacture silver-graphite contacts, micro-motor brush, signal relay and the electrical contacts of some electronic equipment and other special occasions using electrical carbon products.

Source:http://www.mhcmp.com