| 摘要 |
<p>A sintered cermet is produced by subjecting metal wood to a metal diffusion treatment such as chromizing, annealing to homogenize the structure, impregnating with a ceramic, such as an oxide, a silicate or an oxide and/or silicate with a metal or metal carbide and finally sintering the structure. The metal fibres such as steel wool should have a maximum thickness of 0.6 mm. and the length may be 5-50 mm. The steel fibres may either be packed loosely in a mould or compacted and stratified prior to chromizing in granular chromium and gaseous HCl at 1100 DEG C. In a further method the steel fibres are compacted and sintered at 1350 DEG C. in hydrogen prior to chromizing. The chromized fibres are annealed at 1300 DEG C. and in the case of the individual fibres they are mixed with a ceramic, e.g. 95% Al2O3/5% kaolin, compacted and sintered in vacuo at 1550 DEG C. With the precompacted and sintered fibrous body impregnation is effected by dipping into the ceramic slip followed by sintering. A compacting step may be added before the sintering. In a further modification the impregnated body may be coated with a slip of a cermet, e.g. a carbide/ceramic suspension prior to sintering at 1700 DEG C. in vacuo. The preferred composition of the sintered cermet consists of Al2O3 : steel in a volume ratio of 1 : 1.ALSO:A sintered cermet is produced by subjecting metal wool to a metal diffusion treatment such as chromizing, annealing to homogenize the structure, impregnating with a ceramic, such as an oxide, a silicate or an oxide and/or silicate with a metal or metal carbide and finally sintering the structure. The metal fibres such as steel wool should have a maximum thickness of 0.6 mm. and the length may be 5-50 mm. The steel fibres may either be packed loosely in a mould or compacted and stratified prior to chromizing in granular chromium and gaseous HCl at 1100 DEG C. In a further method the steel fibres are compacted and sintered at 1350 DEG C. in hydrogen prior to chromizing. The chromized fibres are annealed at 1300 DEG C. and in the case of the individual fibres they are mixed with a ceramic, e.g. 95% Al2O3/5% kaolin, compacted and sintered in vacuo at 1550 DEG C. With the precompacted and sintered fibrous body impregnation is effected by dipping into the ceramic slip followed by sintering. A compacting step may be added before the sintering. In a further modification the impregnated body may be coated with a slip of a cermet, e.g. a carbide/ceramic suspension, prior to sintering at 1700 DEG C. in vacuo. The preferred composition of the sintered cermet consists of Al2O3:steel in a volume ratio of 1 : 1.</p> |
