| 摘要 |
To provide piston rings which are ductile, can be heavily thermally loaded, and are not attacked by corrosive residues occurring upon combustion of residual oil or other sulfur-containing heavy Diesel oils, a powder mixture is sintered in an isostatic hot-pressure sintering process in which a hard metal and a soft filler material are combined; in accordance with one embodiment, the base is a hard metal using nickel or cobalt-based alloys present in 40-80% by weight, the remainder filler which, for example, is unrefined or galvanically coated graphite; in a second embodiment, the base is a soft material such as a high-copper content bronze, and the filler is a nickel or cobalt-based alloy, with the base metal being present in 60-80%, the filler being the remainder (all percentages by weight). Isostatic hot compression results in piston rings which can operate, under emergency conditions, without, or with only insufficient lubrication, have high strength, resistance to attack by corrosive substances, and have sufficient ductility for simple assembly and long wear. |
