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Pejman Zamani, and Zia Valefi, Comparative investigation of microstructure and high-temperature oxidation resistance of high-velocity oxy-fuel sprayed CoNiCrAlY/nano-Al2O3 composite coatings using satellited powders, Int. J. Miner. Metall. Mater., 30(2023), No. 9, pp.1779-1791. https://dx.doi.org/10.1007/s12613-023-2630-9
Pejman Zamani, and Zia Valefi, Comparative investigation of microstructure and high-temperature oxidation resistance of high-velocity oxy-fuel sprayed CoNiCrAlY/nano-Al2O3 composite coatings using satellited powders, Int. J. Miner. Metall. Mater., 30(2023), No. 9, pp.1779-1791. https://dx.doi.org/10.1007/s12613-023-2630-9
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附属粉末高速氧喷涂CoNiCrAlY/纳米Al2O3复合涂层显微组织及高温抗氧化性能对比研究

摘要: 本文采用高速氧燃料工艺在Inconel738高温合金基体上沉积了含有2wt%、4wt%和6wt%氧化物纳米颗粒和纯CoNiCrAlY粉末的附属CoNiCrAlY–Al2O3原料。本研究在1050°C下进行5、50、100、150、200和400 h的氧化试验,分别用扫描电镜和X射线衍射表征粉末和涂层的微观结构和相组成,并对涂层的结合强度进行了评价。结果表明,随着纳米颗粒含量的增加(从2wt%增加到6wt%),涂层的孔隙率(从1vol%增加到4.7vol%)、未熔颗粒和粗糙度(从4.8 µm增加到8.8 µm)增加,结合强度从71 µm下降到48 µm。氧化400 h后,纯涂层和复合涂层(2wt%、4wt%和6wt%)的热生长氧化层厚度分别为6.5、5.5、7.6和8.1 µm。CoNiCrAlY–2wt% Al2O3涂层由于分散良好的纳米颗粒的扩散阻挡效应,表现出最高的抗氧化性。CoNiCrAlY–6wt % Al2O3涂层由于其粗糙的表面形貌和多孔的微观结构而具有最低的抗氧化性。

 

Comparative investigation of microstructure and high-temperature oxidation resistance of high-velocity oxy-fuel sprayed CoNiCrAlY/nano-Al2O3 composite coatings using satellited powders

Abstract: Satellited CoNiCrAlY–Al2O3 feedstocks with 2wt%, 4wt%, and 6wt% oxide nanoparticles and pure CoNiCrAlY powder were deposited by the high-velocity oxy fuel process on an Inconel738 superalloy substrate. The oxidation test was performed at 1050°C for 5, 50, 100, 150, 200, and 400 h. The microstructure and phase composition of powders and coatings were characterized by scanning electron microscopy and X-ray diffraction, respectively. The bonding strength of the coatings was also evaluated. The results proved that with the increase in the percentage of nanoparticles (from 2wt% to 6wt%), the amount of porosity (from 1vol% to 4.7vol%), unmelted particles, and roughness of the coatings (from 4.8 to 8.8 µm) increased, and the bonding strength decreased from 71 to 48 MPa. The thicknesses of the thermally grown oxide layer of pure and composite coatings (2wt%, 4wt%, and 6wt%) after 400 h oxidation were measured as 6.5, 5.5, 7.6, and 8.1 µm, respectively. The CoNiCrAlY–2wt% Al2O3 coating showed the highest oxidation resistance due to the diffusion barrier effect of well-dispersed nanoparticles. The CoNiCrAlY–6wt% Al2O3 coating had the lowest oxidation resistance due to its rough surface morphology and porous microstructure.

 

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