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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Ti O2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Ce O2、Si C、Al和Al_2O_3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, micro-arc oxidation / silicone conversion coating was prepared on the surface of TA15 alloy by micro-arc oxidation and silicone conversion. The microstructure of the coating was analyzed by XRD, SEM and EDS. The oxidation behavior of the coating at 700 ℃ was also evaluated. The results show that the micro-arc oxidation coating mainly consists of anatase phase and rutile phase Ti O2. The surface of the coating has micropores with a diameter of about 5 μm, but the inner layer of the coating is dense. The organic silicon conversion layer on the surface of MAO coating mainly consists of Ce O2, Si C, Al and Al 2 O 3 phases with a thickness of about 20 μm. There is no clear boundary between MAO coating and silicon conversion coating, and the interface is well bonded . The oxidation weight gain of TA15 alloy is 0.5875 mg / cm 2 at 0.25 ℃ for 20 h and the weight gain of micro-arc oxidation coating is 0.2513 mg / cm 2, while the composite coating significantly improves the oxidation resistance and the weight gain only 0.0506 mg / cm2.700 ℃ to room temperature after thermal shock 50 cycles, the composite coating was not found flaking, showing good thermal shock resistance.