REFRACTORY METAL COATINGS BY CHEMICAL VAPOR DEPOSITION

The basic processes necessary to manufacture refractory metal coatings using chemical vapor deposition technology were investigated. The processes developed were demonstrated on a typical oxidation resistant coating of titanium-chromium-silicon but would have general applicability to other similar coatings. The processes utilized both two-stage deposition (metal alloy coating followed by silicon deposition) and a new method developed for the rapid (10 minute) deposition of all three elements in a single step. The processes were used for deposition of metallic coatings and for controlled variation of the composition of titanium and chromium alloys. Substrate property degradation and interaction were minimal for all types of coatings. Performance of the coatings was evaluated by oxidation testing in air and was found to be nominally comparable to coatings by other processes. Reliability and reproducibility, indicated by statistical analysis of results, were high for this initial effort program. The processes have potentials for utilization in rapid and economical manufacturing of a variety of coatings on parts with complex shapes. (Author)