TC4钛合金微弧氧化膜层高温氧化性能研究

利用微弧氧化(MAO)技术在TC4钛合金表面原位制备陶瓷膜层,并通过硅酸钠水溶液对膜层进行了封孔处理。采用X射线衍射仪(XRD)分析了膜层相组成,通过扫描电子显微镜(SEM)观察了膜层表面形貌。通过粘结拉伸测试,比较了膜层在封孔前后与基体的结合强度。利用高温氧化实验,考察了TC4基体及膜层试样封孔前后的抗高温氧化性能。结果表明:微弧氧化膜层与基体间的结合强度较高,经封孔处理及高温氧化100 h后,膜基结合强度降低至4.29 MPa。与TC4基体相比,微弧氧化膜层的高温氧化增重量小,抗高温氧化性能得到了显著的提高。封孔处理提高了微弧氧化膜层的致密性,使其能更好地阻止氧透过膜层向基体内侵入,进一步提高了膜层的抗高温氧化性能。

Study on High Temperature Oxidation Property of TC4 Titanium Alloy by Micro-arc Oxidation

Ceramic coatings were prepared in situ on the surface of TC4 titanium alloy by means of micro-arc oxidation(MAO) technology, and the coatings were sealed with sodium silicate aqueous solution. The phase composition of the coatings was analyzed by X-ray diffractometer(XRD), and the surface morphology of the coatings were observed by scanning electron microscope(SEM). Through the bonding tensile test, the bonding strength between MAO coating and substrate before and after sealing was compared. Using high temperature oxidation experiments, the high temperature oxidation resistance of the TC4 substrate and coating samples before and after sealing was investigated. The results show that the bonding strength between MAO coating and substrate is high. After sealing and oxidation at high temperature for 100 h, the bonding strength of the coating decreases to 4.29 MPa. Compared with the TC4 substrate, the high temperature oxidation of the micro-arc oxidation coatings is lower, and the high temperature oxidation resistance is significantly improved. The sealing treatment improves the compactness of the micro-arc oxidation coating, so that it can better prevent oxygen from penetrating the coating into the substrate, and further improve the high temperature oxidation resistance of the coating.