微弧氧化处理对钛合金超声辐射杆抗腐蚀性能的影响  

Effect of micro-arc oxidation on corrosion resistance of titanium alloy ultrasonic radiation rod

作　　者：文康 张立华 李瑞卿[1,2] WEN Kang;ZHANG Li-hua;LI Rui-qing(Central South University, Changsha 410083, China;State Key Laboratory of High Performance and Complex Manufacturing, Changsha 410083, China;College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China)

机构地区：[1]中南大学轻合金研究院,湖南长沙410083 [2]高性能复杂制造国家重点实验室,湖南长沙410083 [3]中南大学机电工程学院,湖南长沙410083

出　　处：《材料热处理学报》2019年第3期141-147,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51575539;U1637601)

摘　　要：为了提高钛合金超声辐射杆在半连续铸造中的抗空化腐蚀性能,采用NaSiO_3-NaPO_3复合盐电解液在钛合金超声辐射杆表面制备了微弧氧化膜层,然后在700℃铝熔体环境下与未作处理的辐射杆对比开展空化腐蚀实验。采用硬度仪和附着力拉拔仪分别检测氧化层的硬度和结合强度,采用扫描电镜(SEM)观察了微弧氧化膜层、基体及空化腐蚀后的表面组织形貌,并利用能谱仪(EDS)及X射线衍射仪(XRD)分析了腐蚀产物。结果表明:所得微弧氧化膜层厚度为25～30μm,硬度达到866 HV0.05,膜层结合强度达到36 MPa;在高温铝熔体空化腐蚀15 h后,经微弧氧化处理的钛合金超声辐射杆的质量损失约为未作处理的钛合金辐射杆的1/3,平均腐蚀深度约为未作处理的辐射杆的1/2,其力学性能得到增强,化学稳定性有所提高,抗腐蚀性能显著增强。In order to improve the cavitation corrosion resistance of titanium alloy ultrasonic radiation rod in semi-continuous casting, a micro-arc oxidation film was prepared on its surface by using NaSiO3-NaPO3 compound salt electrolyte.Then the cavitation corrosion test was carried out under 700 ℃ aluminum melt environment compared with the untreated radiation rod. The hardness and bonding strength of the oxide layer were measured by hardness tester and adhesion drawing instrument respectively. The microstructure of the micro-arc oxidation film, the substrate and the cavitation corrosion surface was observed by scanning electron microscopy(SEM). The corrosion products were analyzed by energy dispersive spectrometer(EDS) analysis and X-ray diffractometer(XRD). The results show that the thickness of the micro-arc oxidation film is 25-30 μm, the hardness is 866 HV0.05, and the bonding strength is 36 MPa. After cavitation corrosion test for 15 h in 700 ℃ aluminum melt, the mass loss of the titanium alloy ultrasonic radiation rod treated by micro-arc oxidation is about 1/3 of that of untreated titanium alloy ultrasonic radiation rod, the average corrosion depth is about 1/2 of that of untreated rod, and its mechanical properties, chemical stability and corrosion resistance are significantly enhanced.

关 键 词：钛合金 微弧氧化 空化腐蚀 

分 类 号：TG174.44[金属学及工艺—金属表面处理]