| TIAN Xing-da,LI Yong-quan,WANG Cun-xi,LIANG Guo-dong.High Temperature Oxidation Resistance and Friction Properties of Cr-Al-Y Coating on DZ125 Alloy[J],52(9):170-177 |
| High Temperature Oxidation Resistance and Friction Properties of Cr-Al-Y Coating on DZ125 Alloy |
| Received:September 02, 2022 Revised:November 12, 2022 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.09.013 |
| KeyWord:DZ125 Cr-Al-Y coating high temperature oxidation oxide film wear resistance wear rate |
| Author | Institution |
| TIAN Xing-da |
School of Material Science &Engineering,Yinchuan , China |
| LI Yong-quan |
College of Mechatronic Engineering, North Minzu University, Yinchuan , China |
| WANG Cun-xi |
School of Material Science &Engineering,Yinchuan , China |
| LIANG Guo-dong |
School of Material Science &Engineering,Yinchuan , China |
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| Abstract: |
| In order to improve the high temperature oxidation resistance and wear resistance of DZ125 alloy, Cr-Al-Y coating was prepared on the surface of DZ125 alloy by pack cementation technology. The microstructure and phase composition of Cr-Al-Y coating after high temperature oxidation were analyzed and the friction behavior between the coating and the substrate was compared. The results showed that the prepared Cr-Al-Y coating had a multi-layer structure. The Cr-Al-Y coating of DZ125 prepared by embedding infiltration at 1 050 ℃ for 2 h had a multilayer structure. The outer layer was composed of Ni3Cr2 and Al2O3, the middle layer was composed of Ni3Cr2 and a small amount of Ni3Al, and the inner layer was composed of Ni3Al and the average weight loss of the coating was only 0.85 mg/cm2 after 100 hours of high temperature oxidation. During the high temperature oxidation process, the Cr-Al-Y coating formed continuous and dense Al2O3 and Cr2O3 oxide films. The Al element in the coating was accelerating outward diffusion, forming a new oxide film, and then repairing the oxide film. This process intensified the oxidation rate of the coating surface. With the increase of oxidation temperature, the oxidation rate of the coating surface intensified, resulting in the peeling of oxidation products and surface defects. The friction coefficient of Cr-Al-Y coating was obviously lower than that of DZ125 substrate. The friction coefficient of DZ125 alloy was about 0.45. The friction coefficient of Cr-Al-Y coating was about 0.2. The friction coefficient increased gradually with the wear time. After 15 minutes of wear, the friction coefficient of the coating tended to be stable, and the friction coefficient was about 0.25. Ploughing wear and abrasive wear occurred on DZ125 alloy during the friction process, while abrasive wear occurred on the coating surface. The high temperature oxidation kinetic curve of Cr-Al-Y coating showed a law of weight increase firstly and weight loss later. Cr-Al-Y coating showed a stable oxidation rate. The coating had excellent high temperature oxidation resistance. The continuous and dense Al2O3 oxide film and Cr2O3 oxide film could effectively block the direct contact between the oxidizing atmosphere and the substrate, thus reducing the oxidation rate. The friction coefficient of Cr-Al-Y coating was significantly lower than that of DZ125 substrate, mainly because the oxide film on the coating surface could effectively prevent the direct contact abrasion between GGr15 ball and substrate during the wear process, and the Al2O3 and Cr2O3 formed also acted as lubricating phases, thus reducing the friction coefficient and the wear rate and improving the wear resistance of the alloy. The overall oxidation degree of the coating surface was relatively low, while the iron content was high. The main reason was that during the sliding process, the oxide film could effectively prevent the direct contact between the GGr15 ball and the alloy substrate, and the friction pair only contacted the surface. At the same time, the small protrusions on the surface reduced the contact area of the two friction pairs and the friction coefficient. The wear marks on the surface of DZ125 alloy were oxidized, and the black phase structure was oxidized seriously, thus reducing the wear rate during the friction process and improving the wear resistance of the coating. |
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