Copper powder used for electrical carbon products iselectrolytic production, high purity (up to 99.5%), long-grain structure is Carbon steel screw dendritic,after pressing, the products with high mechanical strength. According to differentmanufacturing 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 technicalperformance indicators of copper: copper content is not less than 99.5%; moistureis not more than 0.05%; through nitric acid treated, residue on ignition isless than 0.05%.
Copper is the wear parts of electric industry producing carbonsliding friction, such as one of the important raw materials of metal-graphiteproducts. It can be used for producing copper-graphite brushes, copper-graphitebearing, copper-graphite and copper-graphite electrode contacts. In the copper-graphiteproducts, copper powder as the auxiliary conductor of products, with thecharacteristic of lowering resistivity, increasing the allowable currentdensity, reducing the contact resistance, reducing the contact voltage drop, increasingthe analysis of cokes adhesive, etc.. Copper appearance is pale pink, brown oreven black, should be stored in sealed containers to prevent oxidation. Tin isthe low melting point metal, the melting point is 231.85.The tin powder used for electrical carbon production is the granular structurethat the molten tin liquid prepared by spraying method, the spraying method isby compressing air or other gases to crush the molten metal flow, make it sprayinginto powder. Atomized powder particles are cylindrical spherical form,sometimes also show irregular shape. Tinpowders technical performance indicators: tin content is not less than 99.5%; throughhydrochloric acid treated, the residue is not more than 0.025%. Copper-graphiteproducts by adding tin powder, tin react with copper in the products, obtain tinbronze, it can increase the mechanical strength of products, improved abrasionresistance. Such as bronze-graphite bearing is the eutectic tin bronze formedby tin powder and copper powder role, increase the useful life of the bearing. Leadpowder for electric charcoal production was taken by the molten lead through spraymethod. Different varieties electrical carbon products use different leadpowder particle size, lead powders technical performance indicators: Leadcontent is not less than 99.5%; oxygen content is not more than 0.5%.
Electricalcarbon products produced generally with litharge powder, chemical symbol Pb0.Lead powder monoxide technical performance indicators: a lead oxide content ofnot less than 90%; metallic lead content is not more than 10%; residuesinsoluble in nitric acid is not more than 0.5%. Add leadpowder or oxidized lead powder into electric power brush material ratio canreduce the hardness of the brush raw material, so that the brush can berelatively easy to establish a good contact with the commutator, reducing therectifying sparks. Lead at 200 ~ 250can generate lead oxide film, this film contacts with graphite film, have goodlubricity, can reduce the wear of the brush and the commutator itself. Addingcopper powder in the sliding contact can increase the wear resistance of thecontacts. Silver powder for electric charcoal production is the pure silver powder. Silver powderstechnical 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 lessthan 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 powderis mainly used to manufacture silver-graphite contacts, micro-motor brush,signal relay and the electrical contacts of some electronic equipment and otherspecial occasions using electrical carbon products.
