溶液配比及电参数对钛阴极微弧电沉积氧化铝涂层的影响

EFFECTS OF ELECTROLYTE COMPOSITION AND ELECTRICAL PARAMETER ON ALUMINA COATINGS BY CATHODIC MICRO-ARC ELECTRODEPOSITION ON TITANIUM

用阴极微弧电沉积在钛表面生成Al2O3涂层,探讨溶液组成、放电电压及时间对涂层形貌、相组成及生长速率的影响。结果表明:涂层由αAl2O3和γAl2O3组成。随溶液中Al(NO3)3含量的增加,αAl2O3含量和涂层生长速率均先增后减。电导率决定了Al(NO3)3的摩尔浓度为0.2mol/l时是较佳值。乙醇与水的体积比对溶液的起弧影响很大,过高的含水量因溶剂效应大而不利于阴极微弧电沉积。随电压升高,涂层的生长速率增加,αAl2O3的含量增加。400V时,αAl2O3含量可达76%。延长放电时间,涂层的生长速率亦先快后慢。120min时,涂层厚度可达100μm。

Alumina coatings on titanium substrate were prepared by cathodic micro-arc electrodeposition. Effects of electrolyte composition, discharge voltage and time on morphologies, phase compositions and growth rates of the coatings were studied. Results show that the coatings are composed of α-Al2O3 and γ-Al2O3. With the increasing of Al(NO3)3 content in the electrolyte, both α-Al2O3 content and growth rates of the coatings first increase and then decrease. The Al(NO3)3 content of 0.2 mol/1 is the optimal one, which is decided by its conductivity. The arc-striking is greatly influenced by volume ratios of ethanol to water and the excessive water in the electrolyte is disadvantageous to cathodic micro-arc electrodeposition because of the high solvent effect. With the raising of voltage, the growth rate of the coatings increases and α-Al2O3 content increases as well. The α-Al2O3 content reaches 76% when the voltage is 400 V. The growth rates of the coatings are also fast firstly and then slow with prolonging the discharge time. The thickness of the coatings is up to 100 μm when treated for 120 min.