| 摘要 |
<p>Sealing elements for use in internal combustion engines, such as piston rings for reciprocating pistons, seals for rotary pistons in engines of the type generally referred to as the Wankel engine, and similar structures in which a sealing element having a hard, wear-resistant bearing surface provides a seal between relatively movable slidable surfaces to prevent or substantially reduce flow therebetween of fluids such as combustion gases, oil films and the like. Such hard, wear and scuff-resistant facings, coatings and the like are preferably provided by the plasma jet application to the peripheral bearing surfaces of the sealing elements of alloy-forming compositions comprising effective proportions of a tungsten carbide-cobalt aggregate; molybdenum; and a nickel-chrome-boron-silicon alloy. For best results the plasma-applied final coating is substantially free from such detrimental components as nickel in its free state and aluminum oxide. If the nickel is present only in a combined form, as it is in nicrome (a nickel-chrome alloy containing about 60% Ni), the nickel has no detrimental effect.</p> |
