| abstract |
In the coating of a graphite article, e.g. a rocket tube, with a refractory material, e.g. tungsten, molybdenum, tantalum, zirconium, hafnium, niobium or titanium, or their carbides, nitrides or borides, an intermediate coating comprising a mixture of the refractory coating material with one or more of the metals ruthenium, rhodium, palladium, osmium, indium, and platinum, is applied to the graphite to improve adhesion between the graphite and the refractory coating. The intermediate layer may be applied by covering the graphite with the mixture and heating under vacuum and the outer refractory layer by a plasma jet process. The platinum group metal and the refractory material may be in the proportion of 1 - 50% by weight of the mixture. |