材料期刊网

为提高钛合金的高温抗氧化性能,采用微弧氧化法和有机硅转化法在TA15合金表面制备出微弧氧化/有机硅转化复合涂层.采用XRD、SEM、EDS等方法分析涂层的组织结构,并评价涂层在700℃时的高温氧化行为.结果表明:微弧氧化涂层主要由锐钛矿相和金红石相TiO2组成,涂层表面存在直径约5μm的微孔,但涂层内层致密.微弧氧化涂层表面的有机硅转化层主要由CeO2、SiC、Al和Al2O3相组成,厚度约为20μm;微弧氧化涂层与有机硅转化涂层之间无明显界线,界面结合良好.在700℃长时间高温氧化20 h后,TA15合金的氧化增重为0.5875 mg/cm2,微弧氧化涂层的增重为0.2513 mg/cm2,而复合涂层显著改善抗氧化性能,增重仅为0.0506 mg/cm2.700℃至室温热冲击50循环后,复合涂层没有发现剥落,显示出良好的抗热震性能.

In order to improve the high temperature oxidation resistance of titanium alloy,the microarc oxidation/PHMS-derived ceramic composite coatings were prepared on TA15 titanium alloy by microarc oxidation combined with PHMS-derived ceramic method.The phase composition and microstructure of the coatings were characterized by XRD,SEM and EDS analysis,as well as the high temperature oxidation performance of the coated titanium samples were evaluated at 700 ℃ in air.The results show that the microarc oxidation coatings are mainly composed of anatase TiO2 and rutile TiO2 phase.The diameter of the micropores on the coating surface is about 5 μm,but the inner layer of the coatings is dense.The PHMS-derived ceramic coatings on the surface of microarc oxidation coatings are mainly composed of CeO2,SiC,Al and Al2O3 phases with thickness about 20 μm.No distinct boundary between the microarc oxidation coatings and PHMS-derived ceramic coatings is observed,exhibiting good interface bonding strength.After oxidation at 700 ℃ for 20 h in air,the mass gain of titanium alloy substrate is 0.5875 mg/cm2,and the value of the microarc oxidation coating sample is 0.2513 mg/cm2.While the mass gain of the composite coating sample is as low as 0.0506 mg/cm2,exhibiting the significant improvement of oxidation resistance.The composite coatings show good thermal shock resistance without any peeling after thermal shock from 700 ℃ to room temperature for 50 times.