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Microstructural and tribological comparison of HVOF-sprayed and post-treated M–Mo–Cr–Si (M = Co, Ni) alloy coatings
High velocity oxygen-fuel (HVOF)-sprayed wear resistant Co–28%Mo–17%Cr–3%Si and Ni–32%Mo–15%Cr–3%Si coatings, both as-sprayed and after heat treatments at 600 °C for 1 h, have been studied. Particularly, their dry sliding wear behaviour has been compared by ball-on-disk tests against different count...
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Published in: | Wear 2007-09, Vol.263 (7), p.1397-1416 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | High velocity oxygen-fuel (HVOF)-sprayed wear resistant Co–28%Mo–17%Cr–3%Si and Ni–32%Mo–15%Cr–3%Si coatings, both as-sprayed and after heat treatments at 600
°C for 1
h, have been studied. Particularly, their dry sliding wear behaviour has been compared by ball-on-disk tests against different counterbodies (100Cr6 steel and sintered alumina), and differences were discussed based on microstructural characteristics and micromechanical properties (Vickers microindentation and scratch test responses). As-sprayed coatings contain oxide stringers, are mostly amorphous and display rather low Vickers microhardness (about 7.4
GPa for the Co-based and 6.2
GPa for the Ni-based), toughness and elastic modulus. Heat-treated ones display sub-micrometric crystalline intermetallics, improving hardness (9.6
GPa and 7.4
GPa, respectively) and elastic modulus. Scratch tests indicate greater brittleness of the Ni-based alloy (higher tendency to cracking). Due to low hardness and toughness, both as-sprayed coatings undergo wear loss against steel and alumina counterparts. The more plastic Co-based alloy undergoes higher adhesive wear against steel and lower abrasive wear against alumina; the situation is reversed for the Ni-based alloy. After heat treatment, the wear loss against steel is very low for both coatings; abrasive wear still occurs against alumina. |
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ISSN: | 0043-1648 1873-2577 |
DOI: | 10.1016/j.wear.2006.12.002 |