| 摘要 |
A dense cermet article including about 44-93% of a granular first hard phase, about 4-44% of a granular second hard phase, and about 2-20% of a metal phase, all expressed in % by volume. The first hard phase consists essentially of alumina and from 0% to less than 5% of one or more oxides selected from magnesia, zirconia, yttria, hafnia, and silica. The second hard phase consists essentially of a hard refractory carbide, nitride, or boride, or mixture or solid solution thereof. Preferred materials for inclusion in the second hard phase are titanium carbide, hafnium carbide, tantalum carbide, tantalum nitride, tungsten carbide, titanium diboride, and boron carbide. The metal phase consists essentially of a combination of nickel and aluminum having a ratio of nickel to aluminum of from about 85:15 to about 88:12, and 0-5% of an additive selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, cobalt, boron, and/or carbon. The preferred metal phase is substantially of the Ni3Al ordered crystal structure. |
