| 摘要 |
<p>The problem of joining silicon nitride to a metal or metal alloy is overcome by bonding a surface of the silicon nitride to a layer of aluminium oxide or an aluminium silicon compound or magnesia or magnesium oxide or mullite, then bonding that first layer to a layer of nickel alumina before joining the nickel alumina to the metal or metal alloy by a conventional brazing or welding process. This has the further advantage of accommodating the widely differing coefficients of thermal expansion between the silicon nitride and the metal by the provision of materials between them which have graded coefficients of thermal expansion between the two extreme coefficients of thermal expansion. The method can be used to produce pistons having silicon nitride crown portions joined to aluminium or aluminium alloy piston bodies or to produce gas turbine blade assemblies having silicon nitride aerofoils joined to a metal root.</p> |
