摘要
目的研究铪化物含量对激光熔覆CoCrAlYSiHf涂层高温抗氧化性能的影响。方法实验所用激光熔覆粉末为实验室行星式球磨机球磨并真空干燥后所得粉末。采用激光熔覆的方法分别在GH586上制备铪化物含量为x和3x的两种涂层,并在SX2系列高温电阻炉中测试了大气环境下两种涂层的1100℃静态高温氧化性能。利用扫描电子显微镜、X射线衍射仪、能谱仪,对高温氧化过程中的涂层表面形貌、氧化物结构演变进行表征。结果铪化物含量为3x的涂层,其表面出现了大量的孔隙及显微裂纹等缺陷,而铪化物含量为x的涂层表面光整、均匀,无明显缺陷。同时,铪化物含量为x的涂层在1100℃静态高温氧化后,表面形成了一层连续致密的Cr_2O_3氧化膜;而铪化物含量为3x的涂层在1100℃静态高温氧化后,表面氧化物中含有大量的尖晶石氧化物,且氧化膜中存在大量孔隙等缺陷。结论当激光熔覆CoCrAlYSiHf涂层中添加3x的铪化物时,其高温抗氧化性能明显低于含x铪化物的CoCrAlYSiHf涂层。
The work aims to study the influence of hafnium content on high temperature oxidation resistance of CoCrAlYSiHf coatings prepared by laser cladding. The laser cladding powder used in the experiment was milled by laboratory planetary ball mill and dried by vacuum. Laser cladding method was adopted to prepare two coatings with different hafnium content（x and 3 x） on GH586 respectively. The static resistance to high temperature oxidation of these two coatings at 1100 ℃ in atmospheric environment was also tested in SX2 high temperature resistance furnace. The surface morphology and structural evolution of oxidation films on coatings during high temperature oxidation process were characterized by scanning electron microscope（SEM）, X-ray diffractometer（XRD） and energy dispersive spectrometer（EDS）. The coating with 3 x hafnium prepared by laser cladding showed many pores and micro-cracks on the surface, while the coating with x hafnium content was smooth and uniform without visibly defects. A layer of continuous and compacted Cr2O3 oxidation film was formed on the coating by laser cladding with x hafnium content after high temperature oxidation at 1100 ℃, while many spinel and pores were distributed in the oxide on the coating by laser cladding with 3 x hafnium after high temperature oxidation at 1100 ℃. The high temperature oxidation resistance of CoCrAlYSiHf coating by laser cladding with 3 x hafnium is obviously lower than that of coating with x.
作者
雍兆
花银群
YONG Zhao, HUA Yin-qun(Research Institute of New Material, Jiangsu University, Zhenjiang 212000, Chin)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2018年第5期98-103,共6页
Surface Technology
