| 摘要 |
1350482 Composite powders SHERRITT GORDON MINES Ltd 19 April 1971 [20 March 1970] 23639/71 Headings C7D and C7F Composite alloy coated powders are made from a powder mixture of 10-850 microns metal coated powders and at least one alloying metal powder by heating the mixture in a non oxidising atmosphere to allow alloying to occur between the coating and the alloying powder without extensive sintering taking place. The core of the composite powders may be graphite, diatomaceous earth, Al 2 O 3 , WC, chromium oxide, BN or CaF 2 ; the metal coating may be Ni, Co, Cu, Mo, Zr, Zn or Al and the alloying powder may be Cr, Al or Si less than 50 microns size. An activator such as the chloride, bromide or fluoride of Cr or NH 4 may be added to the powder mixture. With Cr as the alloying metal, heating is effected at 1500-2300‹ F, and with Al heating is at 1100-1220‹ F, preferably in hydrogen. The alloy coated powder formed may be mixed with another alloying metal powder and the process repeated. The alloyed composite powder formed is crushed and used in flame spraying. |
