铸造铝合金微弧氧化膜的生长动力学及耐蚀性能

GROWTH KINETICS OF MICROARC OXIDATION FILMS ON CAST ALUMINUM ALLOY AND THEIR CORROSION RESISTANCE

研究了ZL101铸造铝-硅合金微弧氧化陶瓷膜的生长动力学,探讨了膜生长厚度与电流密度(i)和生长速率(v)的关系。分析了膜的形貌和相组成,并用电化学法测量不同膜样品厚度的极化曲线。结果表明:膜生长分为3个阶段,氧化初期,i较高,但膜层生长较慢。在膜快速生长阶段,膜生长速率达到极大值。膜生长进入平稳期后,i基本保持恒定,样品的外部尺寸不再增加,膜逐渐转向基体内部生长。合金化元素硅的影响主要表现为氧化初期对膜生长的阻碍作用。铸造铝合金经过微弧氧化处理后,腐蚀电流大幅下降,极化电阻增加了几个数量级。较薄的微弧氧化膜同样大幅度提高了铝-硅合金的耐蚀性。

The growth kinetics of microarc oxidation films on ZL 101 cast aluminum-silicon alloy was investigated and the relation of ：he growth thinkness, current density （i） and growth rate （v） of ceramic films was discussed. The morphology and phase components 3f the films were analyzed, and the polarization curves of bare and coated alloys under different film thicknesses were measured. there are three stages for film growth process. At the initial oxidation stage, the film growth is slow, although the i is high. The growth rate reaches a maximum value during the quick growth of films. After the film growth becomes stable, the i decreases to a stable value; meanwhile, the dimensions of the alloy sample do not change, and the film mainly grows towards the interior of the alloy. the alloying element Si in aluminum-silicon alloy hinders film growth at the initial oxidation stage. By microarc discharge treatment, the corrosion current of alloy was greatly reduced and the polarization resistance increased by several orders of magnitude. Even for microarc oxidation film on aluminum-silicon alloy, the corrosion resistance was significantly improved.