等离子喷涂La_(0.8)Ca_(0.2)CrO_3高发射率涂层研究

本文以氧化镧、氧化钙、氧化铬为原料,按分子式La0.8Ca0.2Cr O3进行配料,球磨后,采用固相合成法制备原始粉末,再经喷雾干燥处理,将其制备成团聚体粉末,并将粉末粒度分布范围控制在20~60μm,采用等离子喷涂法在高温合金基体表面制备高发射率涂层。采用IRE-2型红外辐射仪对其全波段发射率进行了测试,利用XRD对涂层的相结构进行了分析,并对涂层的金相、结合强度及抗热震性能进行了测试。结果表明,所制备的La0.8Ca0.2Cr O3涂层结合强度为21MPa,孔隙率为14.8%,在600~800℃高温范围内,其全波段发射率可达0.87~0.88,同时,该涂层试样经1100℃~室温水热震10次后没有发生剥落失效现象,涂层具有良好的抗热震性能。

La0.8Ca0.2CrO3 High Emissivity Coating by Plasma Spraying

High emissivity coating is prepared by the raw materials of chromium oxide,lanthanum oxide and calcium oxide, getting the ingredients in accordance with the molecular formula La0.8Ca0.2CrO3. The raw powder is prepared by solid phase synthesis,then the powder is aggregated by sprat drying. The high emissivity coating is prepared on the super alloy substrate by air plasma spraying. The phase of coating is studied by XRD, while the rate of infrared radiation is tested using IRE-2 infrared radiometer, and the thermal shock resistance of coating is researched as well. The results shown that the prepared La0.8Ca0.2CrO3 coating has high emissivity in full-wave band under 600-800℃, the emission rate can reach to 0.88. The porosity of the coating is about 14.8%, and the bonding strength is 21MPa. Meanwhile, the coating has good resistance on thermal shock. It has no spalling failure after thermal shock testing by water quenching from 1100 degrees to room temperature by 10 times.