工艺参数对钛合金微弧氧化涂层热控性能的影响

Influences of Process Parameters on Thermal Control Performance of Micro-Arc Oxidation Coating on Titanium Alloy

为了提高航空航天用钛合金的热防护性能,利用微弧氧化技术在TC4钛合金表面制备热控涂层,研究了工艺参数对涂层组成结构和性能的影响。利用扫描电镜(SEM)、X射线衍射仪(XRD)研究了涂层的结构与组成;分别采用紫外/可见/近红外分光光度计和便携式红外发射率仪评价了涂层的吸收率和发射率。结果表明:磷酸盐体系下制备的涂层表面宏观上呈黑色,微观上具备典型的多孔结构,主要由金红石相Ti O2和非晶态的P,Ti,Co等组成;增加电流密度和延长反应时间,均能提高涂层厚度和粗糙度,而添加剂浓度的改变对厚度和粗糙度影响不大;热控测试表明随着添加剂浓度增加、时间延长和电流密度增大,涂层的吸收率和发射率均呈升高趋势。

Thermal control coating was prepared by micro-arc oxidation on Ti alloy,and the influences of process parameters on the structure and property of coatings were studied.The scanning electron microscope and X-ray diffraction were used to analyze the structure and phase compositions of coatings.The absorptance and emissivity of coatings were studied by UV-Vis-NIR reflectance spectra and infrared TEMP 2000 A emissivity meter.Results showed that the MAO coatings prepared in phosphate system showed black at the macro level,and had typically porous structure.The coatings were composited of rutile TiO_2 and amorphous states including P,Ti and Co elements and so on.By increasing the current density and extending the processing time,the thickness and roughness of coatings were improved.However,the roughness and thickness of coating changed little when the concentration of additives changed.Besides,the thermal control tests indicated that the absorptance and emissivity of coating were improved by increasing the concentration of additives,extending the processing time and enhancing the current density.