The tribological behavior of high-velocity oxyfuel sprayed Co-28%Mo-17%Cr-3%Si coatings, both as sprayed and after heat treatments at 200, 400, and 600 °C for 1 h, has been studied. The as-sprayed coating contains oxide stringers and is mostly amorphous. It has low hardness (∼6.7 GPa) and toughness and undergoes adhesive wear against 100Cr6 steel. The friction coefficient increases up to ∼0.9, so the flash temperature reaches a critical oxidation value; then, friction decreases and increases again. This phenomenon occurs periodically. Much adhesive wear occurs in the first stage. Abrasive wear prevails against alumina pin: the coating wear rate is lower because it possesses good plasticity. Thermal effects still occur. The 600 °C treatment causes formation of submicrometric crystals. Hardness increases (∼8.8 GPa), adhesive wear is prevented, the friction coefficient has no peaks. Against the alumina pin, wear rates remain similar to the as-sprayed case. Nevertheless, the friction coefficient has no peaks and its final value is lowered (from 0.84 to0.75).

Heat Treatment Effects on the Tribological Performance of HVOF-Sprayed Co-Mo-Cr-Si Coatings / Bolelli, Giovanni; Lusvarghi, Luca. - In: JOURNAL OF THERMAL SPRAY TECHNOLOGY. - ISSN 1059-9630. - ELETTRONICO. - 15:(2006), pp. 802-810. [10.1361/105996306X146721]

Heat Treatment Effects on the Tribological Performance of HVOF-Sprayed Co-Mo-Cr-Si Coatings

BOLELLI, Giovanni;LUSVARGHI, Luca
2006

Abstract

The tribological behavior of high-velocity oxyfuel sprayed Co-28%Mo-17%Cr-3%Si coatings, both as sprayed and after heat treatments at 200, 400, and 600 °C for 1 h, has been studied. The as-sprayed coating contains oxide stringers and is mostly amorphous. It has low hardness (∼6.7 GPa) and toughness and undergoes adhesive wear against 100Cr6 steel. The friction coefficient increases up to ∼0.9, so the flash temperature reaches a critical oxidation value; then, friction decreases and increases again. This phenomenon occurs periodically. Much adhesive wear occurs in the first stage. Abrasive wear prevails against alumina pin: the coating wear rate is lower because it possesses good plasticity. Thermal effects still occur. The 600 °C treatment causes formation of submicrometric crystals. Hardness increases (∼8.8 GPa), adhesive wear is prevented, the friction coefficient has no peaks. Against the alumina pin, wear rates remain similar to the as-sprayed case. Nevertheless, the friction coefficient has no peaks and its final value is lowered (from 0.84 to0.75).
2006
15
802
810
Heat Treatment Effects on the Tribological Performance of HVOF-Sprayed Co-Mo-Cr-Si Coatings / Bolelli, Giovanni; Lusvarghi, Luca. - In: JOURNAL OF THERMAL SPRAY TECHNOLOGY. - ISSN 1059-9630. - ELETTRONICO. - 15:(2006), pp. 802-810. [10.1361/105996306X146721]
Bolelli, Giovanni; Lusvarghi, Luca
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/593403
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