钛基体上氧化铝膜层的耐高温和耐腐蚀性能研究

Study of High Temperature Oxidation and Corrosion Resistance of Sol-Gel Alumina Coating on Titanium Alloy

钛材高温氧化严重,为了提高其使用性能,采用溶胶凝胶法在钛合金材料表面制备了耐腐蚀性能优良的三氧化二铝膜层。通过700℃下氧化增重的测量、扫描电镜对涂层高温氧化前后表面形貌的观察以及其在3.5%NaCl溶液中的阳极极化曲线测量表明,带涂层的试样在700℃、20h的增重仅有0.0280mg/cm2,无涂层的试样增重为1.0052mg/cm2;带涂层的试样ΔE=1203.5mV,裸露钛合金试样的ΔE=154.6mV。在钛合金材料表面制备的氧化铝溶胶凝胶膜层具有提高钛合金材料表面抗高温氧化和耐腐蚀性能的特点。

Alumina coating was prepared on the surface of titanium alloy using sol-gel method so as to improve the high-temperature oxidation resistance and service performance of the titanium alloy. The oxidation-induced weight-gain of the alumina coating at 700 ℃ was measured, while the surface morphologies of the coating before and after the high-temperature oxidation were observed using a scanning electron microscope. Moreover, the polarization curves of the coating and the Ti alloy substrate in aqueous solution of 3.5%NaCl were plotted.It was found that the weight-gain for the coating subject to heating at 700 ℃ for 20 h was 0.028 0 mg/cm^2,much smaller than 1.005 2 (mg/cm^2),that of the Ti alloy substrate.At the same time,the Δ E value for the coating was as much as 1 203 5 mV,much larger than 154.6 mV,that of the Ti alloy substrate. This indicated that the sol-gel Al_2O_3 coating on the Ti alloy surface had excellent corrosion resistance and could effectively increase the high temperature oxidation resistance and corrosion resistance of Ti alloy.