In this study, the effects of time and temperature of heat treatment on Ni-20 wt.% Al flame spraying coatings were studied. The objectives are to find the optimal sample in terms of microstructure and compare its oxidation resistance with the as-sprayed coating. The coatings were deposited by flame spraying on low carbon (St 37) steel substrate. The specimens were heat-treated in vacuum at 850 °C and 950 °C for 1 h and at 1050 °C for 1, 3, and 6 h. Microstructural characterization and phase analysis were performed by scanning electron microscopy, energy-dispersive spectrometry, and x-ray diffraction, respectively. The results showed that the lowest porosity (0.43 %) and the highest NiAl content were achieved for the sample heat-treated at 1050 °C for 1 h. Optimized heat-treated, as-sprayed, and bare steel specimens were exposed to ambient air at 800 °C in order to evaluate their durability and oxidation resistance. The results showed that their oxidation rate constants were 24.66, 65.06, and 269.42, respectively. Most of the NiAl content in the coating was responsible for covering the coating surface by a protective γ-Al₂O₃ layer during the high-temperature oxidation process.

在这项研究中，研究了热处理时间和温度对Ni-20 wt％Al火焰喷涂涂层的影响。目的是找到最佳的微观结构样品，并将其抗氧化性与喷涂后的涂层进行比较。通过火焰喷涂将涂层沉积在低碳（St 37）钢基材上。将样品在真空中于850°C和950°C热处理1 h，然后在1050°C热处理1、3和6 h。显微结构表征和相分析分别通过扫描电子显微镜，能量分散光谱和X射线衍射进行。结果表明，在1050°C下热处理1 h的样品具有最低的孔隙率（0.43％）和最高的NiAl含量。优化的热处理，喷涂，将裸露的钢试样暴露在800°C的环境空气中，以评估其耐久性和抗氧化性。结果表明，它们的氧化速率常数分别为24.66、65.06和269.42。涂层中的大部分NiAl含量是由保护性γ-Al覆盖涂层表面的原因₂ O ₃层在高温氧化过程中。