In the present investigation, the CoCrAlYTa-10%Al2O3and Cr3C2-NiCr coatings were prepared by HVOF thermal spraying. The basic properties of coating were evaluated. Especially the high-temperature sliding wear resistance of two kinds of coatings was evaluated at 3, 6, 9, 12 N. The results could be summarized as follows:
(1) The HVOF sprayed CoCrAlYTa-10%Al2O3and Cr3C2-NiCr coatings had a uniform microstructure. The high-temperature wear resistance of both coatings is much better than that of H13 steel. The wear rate and COF of the CoCrAlYTa-10%Al2O3coating was lower than that of the Cr3C2-NiCr coating under the same load. The CoCrAlYTa-10%Al2O3coating exhibited lower micro-hardness and higher high-temperature wear resistance compared with the Cr3C2-NiCr coating.
(2) When the loads were lower than 9 N, the wear debris formed a smooth tribofilms on the worn track. Some parallel grooves and spalled pits were caused by abrasive wear. While the worn track surface under the load of 12 N, tribofilms was broken. It caused an abrupt intensifying of abrasive wear and adhesive wear, resulting in severe plastic deformation and micro ploughing.
(3) At 3 N, the worn surface of the Cr3C2-NiCr coating exhibited comparatively rough and some spalled pits under the action of abrasive wear. As the loads increasing, the aggravation of abrasive wear made spalled pits and grooves more obvious. Because tribofilms could not be formed on the worn surface. Adhesive wear would also occur in the wear process.
(4) When the load increased from 3N to 9N, the average COF and wear rate of the CoCrAlYTa-10%Al2O3 coatings decreased with increasing loads. When the load increasing to 12N(tribofilms broken), the average COF and wear rate of the CoCrAlYTa-10%Al2O3coatings increased. When the load higher than 3N, the average COF and wear rate of the Cr3C2-NiCr coatings increased with increasing loads. For two kinds of coatings and H13 steel, it shown a positive correlation between wear rate and average COF. When the protective tribofilms formed on the surface of wear track, the average COF and wear rate were negatively correlated with the loads. Without the tribofilms, the average COF and wear rate were positive correlated with the load.
本文由桑尧热喷涂网收集整理。本站文章未经允许不得转载；如欲转载请注明出处，北京桑尧科技开发有限公司网址：http://www.sunspraying.com/
|
