Development of wear-resistant coatings for cobalt-base alloys

[摘要] The costs and hazards resulting from nuclear plant radiation exposure with activated cobalt wear debris could potentially be reduced by covering the cobalt-base materials with a wear-resistant coating. However, the hardnesses of many cobalt-base wear alloys are significantly lower than conventional physical vapor deposition (PVD) hard coatings, and mechanical support of the hard coating is a concern. Four approaches have been taken to minimize the hardness differences between the substrate and PVD hard coating: (1) use a thin Cr-nitride hard coating with layers that are graded with respect to hardness; (2) use a thicker, multilayered coating (Cr-nitride or Zr-nitride) with graded layers; (3) use nitriding to harden the alloy subsurface followed by application of a multilayered coating of Cr-nitride; and (4) use of nitriding alone. Since little work has been done on the application of PVD hard coatings to cobalt-base alloys, some details on process development and characterization of the coatings are presented. Scratch testing was used to evaluate the adhesion of the different coatings. A bench-top rolling contact test was used to evaluate the wear resistance of the coatings. The test results are discussed, and the more desirable coating approaches are identified. (C) 1999 Elsevier Science S.A. All rights reserved.

[发布日期] 1999-11-01

[效力级别]  Proceedings Paper

[关键词] chromium-nitride;cobalt-base alloys;wear coatings