Besides copper, there are a rather large rangeof compositions of copper alloy powders available,including the brasses, bronzes, and Cu–Ni.Brass powders are the most widely used forpowder-metallurgy (P/M) structural parts. Conventionalgrades are available with zinc contentsfrom around 10 to 30%. Sintered brassparts have tensile strengths up to around 245and 280 MPa and elongations of from 15 toaround 40% depending on composition, design,and processing. In machinability they are comparableto cost and wrought brass stock of thesame composition. Brass P/M parts are wellsuited for applications requiring good corrosionresistance, and where free machining propertiesare desirable. Cu–Ni, or Ni–Ag, powders contain 10 or18% nickel. Their mechanical properties arerather similar to the brasses, with slightly higherhardness and corrosion resistance. Because theyare easily polished, they find considerable usein decorative applications. Copper and bronze powders are used forfilters, bearings, and electrical and friction products.Bronze powders are relatively hard to pressto densities to give satisfactory strength forstructural parts. Probably the most commonly used bronze contains 10% tin. The strengthproperties are considerably lower than iron-baseand brass powders, usually below 140 MPa.
