【摘要】 采用低压等离子喷涂技术在Ni₃Al基单晶高温合金IC21基体上沉积NiCrAlY涂层.将样品在1150℃的恒定温度下进行200 h的静态氧化,利用SEM、EDS、XRD及TEM表征涂层和基体在高温下互扩散后的微观结构和相组成,得到涂层与基体高温下的互扩散规律.结果表明:NiCrAlY涂层/IC21单晶在1150℃下静态氧化5 h时出现了互扩散区（IDZ）和二次反应区（SRZ）;随着氧化时间的延长,IDZ的厚度呈现逐渐增宽趋势,初始0～50 h时IDZ厚度增率攀升较快,50～100 h时增长有放缓趋势,100～200 h时增速下降明显;NiCrAlY涂层/IC21单晶在1150℃下静态氧化后产生了两种不同取向的析出相,分别为针叶状和竹叶状,析出相成分均包含Re,Mo,Cr及Ni元素且成分相近,根据晶面间距计算得出该相为μ-TCP相,出现不同取向的原因为Re和Mo元素易在基体中形成局部过饱和,元素的差异使μ-TCP相优先沿着Re或者Mo含量较高的晶面生长,从而使μ相产生两种不同取向.更多还原

【Abstract】 NiCrAlY is deposited on Ni₃Al-based IC21 single crystal superalloy by low-pressure plasma spraying technology. The coated samples were subjected to static oxidation for 200 h at a constant temperature of 1150℃. SEM, EDS, XRD and TEM were used to characterize the microstructure and phase composition of the coating and substrate after interdiffusion at high temperature. The results show that the inter-diffusion zone（IDZ） and the secondary reaction zone（SRZ） appear when the NiCrAlY coated IC21 single crystal superalloy was oxidized at 1150 ℃ for 5 h. With the extension of the oxidation time, the thickness of IDZ was gradually widened. However, the growth rate of IDZ thickness was increased at the initial of 0-50 h, then the growth rate was slowed down at 50-100 h, and the growth rate was decreased significantly in the final of 100-200 h. NiCrAlY coating/IC21 single crystal statically oxidized at 1150 ℃ produced two different orientations of the precipitated phases were needle-shaped and bamboo leaf-shaped. The components of the precipitated phase included Re, Mo, Cr, Ni and the components were similar. According to the calculation results of the interplanar distance, this phase was μ-TCP phase. The reason for the different orientations is that Re and Mo are easy to be locally supersaturated in the substrate. The difference in elements made the μ-TCP phase preferentially grows along the crystal plane with a higher Re or Mo content, so that the μ-TCP phase produced two different orientations.更多还原