Sintered metal parts prodn. - by pressing mixt. of metal powder and binder in die contg. holes, so binder is forced through holes to leave metal compact which is sintered

摘要

A metal powder is mixed with a plastic binder to make a paste which is fed into a mould. The mould contains holes where at least one dimension of the cross-section of the holes is similar to the grain size of the metal powder. Heat and pressure are applied to the mould or die, so the major part of the binder is driven out through the holes while forming a pressed metal compact. The compact is then sintered in a reducing atmos. at above 900 deg.C. The paste is pref. injected into the mould. The metal powder is pref. stainless steel; Ni-steel; Fe; Cu; Ti; Zr; Hf; Ta; W; Rh or Re. The binder is pref. an organic cpd., esp. wax; paraffin wax; polythene; or polymethyl-methacrylate; and may include a solvent. Most of the binder is removed in the pressing operation, so strong green blanks are obtd. and the binder removed from the die can be re-used.