| 摘要 |
The surface of the cavity of a graphite die for use in a hot pressing process is coated with a carbide of one of the transition elements in Group IV, V or VI of the Periodic System (i.e. Ti, Zr, Hf, V, Nb, Ta, Cr Mo, W) and the coating then fired on to the surface by heating the die to at least 2000 DEG C. in a protective atmosphere, e.g. hydrogen. The coating may be applied (a) by painting the surface with a suspension of carbide, e.g. titanium carbide, in a medium such as butyl titanate, (b) by contacting the heated surface with a mixture of vaporized or sublimed transition metal tetrachloride and hydrogen, or (c) by contacting the heated surface with a mixture of transition metal carbonyl and hydrogen at reduced pressure. The die may be used for hot pressing borides, diborides or carbides of the said transition elements as disclosed in Specification 877,409. Reference has been directed by the Comptroller to Specification 766,059. |
