| 摘要 |
A sintered composite metal body such as an electrical contact is made by unilaterally compacting a metal powder such as W,Re,Mo, or their alloys, sintering the compact so as to retain the density variation from one end of the compact to the other and then impregnating the sintered compact with a molten metal such as Cu, Ag or their alloys. The impregnating metal may also contain Ni, Co, Cr, Zn or Sn. Examples are given of the pressing of a powder mixture containing 98.5-93% W, 1-5% Cu and 0.5-2% Ni, a powder mixture containing 89%W, 10% Cu and 1% Ni, sintering at 1150 DEG -1350 DEG C. in vacuo, hydrogen or an inert gas and impregnation with Cu. In a separate embodiment, particularly for shallow compacts the metal powder may be pressed in several layers at the same pressure, or the first layer is pressed at the highest pressure and each succeeding layer is pressed at lower pressures. In this method the powder layers may be of the same or different metals to produce the infiltrated systems M1 -M2 or M1 -M2 -M3 where M1 is W, Re or Mo; M2 is Cu or Ag and M3 is Ni, Co or Cr. |
