| YAN Lv-ying,DONG Zhi-hong,BAO Ze-bin.Effect of Electroless Pt Plating on High Temperature Oxidation Behavior of Multi-arc Ion Plated NiCoCrAlY Coating[J],52(3):228-236 |
| Effect of Electroless Pt Plating on High Temperature Oxidation Behavior of Multi-arc Ion Plated NiCoCrAlY Coating |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.03.020 |
| KeyWord:electroless Pt plating high temperature oxidation microstructure NiCoCrAlY coating α-Al2O3 multi-arc ion plating |
| Author | Institution |
| YAN Lv-ying |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China;University of Science and Technology of China, Hefei , China |
| DONG Zhi-hong |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| BAO Ze-bin |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
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| Abstract: |
| This work aims to improve the oxidation resistance of multi-arc ion plated NiCoCrAlY coatings and explore the effect of electroless Pt plating on the oxidation behavior of NiCoCrAlY coating at high temperature. A 0.5 μm-thick Pt film was prepared on the multi-arc ion plated NiCoCrAlY coating by electroless plating combined with following vacuum annealing treatment. The high temperature oxidation performance of the coatings before and after modification by electroless Pt plating were tested by isothermal temperature oxidation and cyclic oxidation tests at 1 050 ℃ in air, and the phase composition, morphology and element distribution of the coatings were analyzed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe micro-analyzer (EPMA). The results revealed that the NiCoCrAlY coating exhibited a higher oxidation rate in the process of isothermal oxidation for 20 h, and its oxidation weight gain, average thickness of oxide film and oxidation rate constant were 0.78 mg/cm2, 2.31 μm and 6.32×10‒12 g2/(cm4.s), respectively. In contrast, after being modified by electroless Pt plating, the isothermal oxidation rate of the NiCoCrAlY coating was reduced significantly, and its oxidation weight gain, average thickness of oxide film and oxidation rate constant were decreased to 0.47 mg/cm2, 0.83 μm and 2.16×10‒12 g2/(cm4.s), respectively. The modification of electroless Pt plating also effectively improved the cyclic oxidation performance of the NiCoCrAlY coating. After cyclic oxidation for 300 times, the oxidation weight gain was decreased from 1.52 mg/cm2 to 1.05 mg/cm2, the average thickness of oxide film was reduced from about 5.77 μm to 3.62 μm and the oxidation rate constant was decreased from 1.93×10‒12 g2/(cm4.s) to 9.86×10‒13 g2/(cm4.s). The phase composition of the oxide film formed on the NiCoCrAlY coatings before and after modification by electroless Pt plating during the isothermal temperature oxidation and cyclic oxidation were α-Al2O3. However, the α-Al2O3 film formed on the NiCoCrAlY coating under the two oxidation conditions has obvious fluctuations, and also grown into the coating in local areas. It can also be observed that local peeling of the oxide film occurred in the later stage of cyclic oxidation. After modification by electroless Pt plating, the α-Al2O3 film formed on the NiCoCrAlY coating was obviously thinner, with higher compactness and flatness, without cracking and peeling. At the same time, the growth of oxide film into the coating was effectively inhibited. It can be seen that the modification by electroless Pt plating can further improve the high temperature oxidation resistance of the multi-arc ion plated NiCoCrAlY coating. This is mainly due to the following two reasons:(1) The gaps in the NiCoCrAlY coating were effectively filled by electroless Pt plating, which improved the compactness of the coating and inhibited the growth of α-Al2O3 film into the coating. (2) High affinity between Pt element and Al element promoted the rapid diffusion of Al element in the coating to the surface, resulting in the rapid formation of thinner and denser α-Al2O3 film. In short, electroless Pt plating is conducive to further expand the application of multi-arc ion plated NiCoCrAlY coating in the field of high temperature protection. |
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