X-Ray Photoelectron Spectroscopy Study of Radiofrequency-Sputtered Titanium Carbide, Molybdenum Carbide, and Titanium Boride Coatings and Their Friction Properties.
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER
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Radiofrequency rf sputtered coatings of titanium carbide TiC, molybdenum carbide Mo2C and titanium boride TiB2 were tested as wear resistant coatings on 440-C stainless steel in a pin on disk apparatus. X-ray photoelectron spectroscopy XPS was used to analyze the sputtered films with regard to both bulk and interface composition in order to obtain maximum film performance. Significant improvements in friction behavior were obtained when properly biased films were deposited on deliberately preoxidized substrates. XPS depth profile data showed thick graded interfaces 2500 A for bias deposited films even when adherence is poor. The addition of 10 percent hydrogen to the sputtering gas produced coatings with Thin poorly adherent interfaces. The results suggest that some of the common practices in the field of sputtering may be detrimental to achieving maximum adherence and optimum composition for these refractory compounds.
- Coatings, Colorants and Finishes
- Atomic and Molecular Physics and Spectroscopy