| 摘要 |
1,173,709. Powder metallurgy: Al base alloy bearings. CHRYSLER CORP. June 7, 1968 [June 7, 1967], No. 27288/68. Headings C7A and C7D. A sintered porous metal such as Al, Al alloys, Cu or bronze is made by compacting a powder mixture of the metal with a fatty acid having at least 12 C atoms and a wax having a melting point not exceeding 150‹ C., removing the fatty acid and wax from the compact by heating to a maximum temperature of 345‹ C. in an evacuated chamber in which an inert gas such as N 2 , A or He sweeps away the volatilized acid and wax, and then sintering. The mixture contains 0À2-2% fatty acids and 0À1-1% wax, the metal powder being minus 35 mesh Tyler and preferably 200 to 325 mesh. Suitable fatty acids containing 12-22 C atoms are:- lauric, palmitic, margaric, tridecansic, stearic, oleic, brassidic, arachidic, linoleic, behenic, erucic, linolenic, elaidic, elesstearic, lichemic, ricinoleic, palmitoleic, petroselenic. The suitable waxes are the ester reaction products of fatty acids containing 12-34 C atoms and compounds containing at least one active hydrogen atom e.g. alcohols, amines, amides. Examples of these waxes are carnaulia wax, beeswax and spermaceti. Sintered Al bearings containing Zn, Cu, Mn, Sn, P6, Mg and Si may be formed by compacting at 2-10 T/#", dewaxing at below 3, 500 microns e.g. 50-200 microns in a steam of inert gas and then sintering at above 500‹ C. followed by oil impregnation and coining. Several examples of different Al alloys are given in the range 2-5% Cu, 1-6% Sn, 0-4% P6, 0-1À5% Mg remainder A1. |
