摘要
为了有效提高钛合金阳极氧化膜抗电偶腐蚀的性能,在300～400g/LH2SO4,50～120g/LH3PO4溶液中,在电流密度2～3A/dm2和温度0～10℃下,采用脉冲阳极氧化技术制备了一种抗电偶腐蚀的钛合金阳极氧化膜,并采用电化学技术对该阳极氧化膜的抗电偶腐蚀机理进行了讨论。结果表明:该阳极氧化膜为厚度2～3μm的多孔膜;阳极氧化后,TC6钛合金的开路电位从-207mV(vsSCE)上升到132mV(vsSCE),腐蚀电流密度从2.3×10-2μA/cm2下降到1.4×10-3μA/cm2,表面膜的极化电阻从2.647×105Ω上升到6.109×107Ω,表面膜的膜电阻从543.8Ω上升到1790.0Ω;电偶腐蚀测量则表明,阳极氧化降低钛合金电偶腐蚀电流1/5以上,其电偶腐蚀的敏感性达到了B级。脉冲阳极氧化膜能有效提高钛合金抗电偶腐蚀性能。
Pulsed anodizing coating was prepared on titanium alloy substrate from an electrolyte con-taining 300～400 g/L H2SO4 and 50 ～ 120 g/L H3PO4 at a cur-rent density of 2 ～ 3 A/dm and temperature of 0-10℃ ,aiming at improving the resistance of the Ti alloy to galvanic corrosion. Electrochemical technique was used to study the mechanism for the anodizing coating to resist galvanic corrosion. Results show that the anodizing film was porous and had a thickness of 2 -3 μm. After anodizing the open circuit potential of TC6 titanium al-loy was increased from -207 mV ( vs SCE) to 132 mV (vs SCE) ,and its corrosion current was decreased from 2. 3 x 10-2 μA/cm to 1.4 x 10-3 μA/cm2. Moreover,the polarization re-sistance of the anodizing coating was increased from 2.647 x 103 Ω to 6. 109 x 107 Ω. In general,pulsed anodizing contributed to reduce the galvanic corrosion current density of Ti alloy by more than 20% and decrease its susceptibility to galvanizing corrosion. Therefore,it could be feasible to make use of pulsed anodizing to improve the resistance of Ti alloys to galvanic corrosion.
出处
《材料保护》
CAS
CSCD
北大核心
2009年第3期15-17,共3页
Materials Protection
关键词
脉冲阳极氧化
钛合金
电偶腐蚀
交流阻抗
极化曲线
titanium alloy
pulsed anodizing
mechanism
resist-ance to galvanic corrosion
