The hardness, adhesion, and wear resistance of coatings developed for cobalt-base alloys
One potential approach for reducing the level of nuclear plant radiation exposure that results from activated cobalt wear debris is the use of a wear resistant coating. However, large differences in stiffness between a coating/substrate can result in high interfacial stresses that produce coating de-adhesion when a coated substrate is subjected to high stress wear contact. Scratch adhesion and indentation tests have been used to identify four promising coating processes [1,2]: (1) the use of a thin Cr-nitride coating with a hard and less-stiff interlayer, (2) the use of a thick, multilayered Cr-nitride coating with graded layers, (3) use of the duplex approach, or nitriding to harden the material subsurface followed by application of a multilayered Cr-nitride coating, and (4) application of nitriding alone. The processing, characterization, and adhesion of these coating systems are discussed. The wear resistance and performance has been evaluated using laboratory pin-on-disc, 4-ball, and high stress rolling contact tests. Based on the results of these tests, the best coating candidate from the high-stress rolling contact wear test was the thin duplex coating, which consists of ion nitriding followed deposition of a thin Cr-nitride coating, while the thin Cr-nitride coating exhibited the best results in the 4-ball wear test.
- Research Organization:
- Bettis Atomic Power Lab., West Mifflin, PA (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC11-98PN38206
- OSTI ID:
- 770647
- Report Number(s):
- B-T-3294; TRN: AH200131%%389
- Journal Information:
- Journal of Surface and Coating Technology, Other Information: Submitted to Journal of Surface and Coating Technology; PBD: 1 May 2000
- Country of Publication:
- United States
- Language:
- English
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