| 摘要 |
<p>1,160,796. Powder metallurgy; coating with metals ; alloys. UNITED AIRCRAFT CORP. Feb.24, 1967 [March 16, 1966], No.8928/67. Headings C7A, C7D and C7F. A metal having a melting point equal to or higher than chromium, e.g. Cr, V, Hf, Nb, Mo, Ta, and W or alloys thereof, is coated with an intermediate layer of a boride, silicide or beryllide of the base metal, and an outer layer comprising Nb, Al, and Sn, and optionally Cr, Ti, or Zn. The outer layer may have a further layer of Sn, Al, Cr, and Ti. After each layer is applied, it may be heated. The intermediate layer may also include Mg, Ca, Ba, Li, and In. All the layers may be applied by a cold spray process, using a slurry including an activating halide, a vapourizable diluent, and a binding agent, e.g. nitrocellulose dissolved in amyl acetate, and then after drying, heating in an argon furnace. The silicide layer may be applied by a fluidized bed or a pack cementation process. The base alloy may be (% by weight) Nb base with 1 Zr, 0À1 C ; 10 W, 0À1 C ; 18 W, 8 Hf; 27 Ta, 10 W, 1 Zr; 10 W, 1 Zr, 0À1 C or Ta base with 9À5 W, 2À5 Hf, 0À1 C; 8 W, 2 Hf or Mo base with 0À5 Ti ; 0À5 Ti, 0À5 Zr, 0À1 C. The outer layer may be 53 Sn, 24 Nb, 10 Al, 7 Ti, 3 Cr, 1À5 Zn and 1À5 LiF. The optional outer layer may be 45 Sn, 30 Cr, 16 Al and 9 Ti.</p> |
