Development of wear-resistant coatings for cobalt-base alloys
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 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 application of PVD hard coatings to cobalt-base alloys, some details on process development and characterization of the coatings is 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.
- Research Organization:
- Bettis Atomic Power Lab., West Mifflin, PA (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC11-98PN38206
- OSTI ID:
- 755454
- Report Number(s):
- B-T-3237; TRN: US0003873
- Resource Relation:
- Conference: International Conference of Metallurgical Coatings and Thin Films, San Diego, CA (US), 04/12/1999--04/15/1999; Other Information: PBD: 1 Mar 1999
- Country of Publication:
- United States
- Language:
- English
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Wear-resistant coatings for cobalt-base alloys
Development of wear-resistant coatings for cobalt-base alloys