電解液中添加WS2無機奈米顆粒對AZ31鎂合金的微弧氧化陶瓷膜影響之研究

Effect of WS2 Inorganic Nanoparticles on AZ31 Mg Alloy with Micro-arc Oxidation Ceramic Film

鎂合金具有良好的物理特性為新一代之綠色材料，卻因為較差的物理、化學特性造成抗腐蝕與耐磨耗性較差，進而嚴重影響鎂合金之未來發展。微弧氧化技術為表面改質新興技術之一，其技術特色在於生成氧化膜於閥金屬（valve metal）如鎂、鋁、鈦之表面，並提升其抗腐蝕和耐磨耗特性。本次研究藉由AZ31鎂合金在電解液之中添加不同奈米顆粒和氧化時間以達到氧化膜性質變化，其電解液主軸以矽酸鹽為主。此外使用奈米顆粒以助於提升氧化膜耐磨耗、抗腐蝕等特性。透過SEM、XRD、EDS和電化學試驗等方式以分析不同微弧氧化之表面形貌、鍍膜厚度、抗腐蝕性之差異化。
由實驗得知，隨著微弧氧化時間增長，氧化膜之厚度與孔洞大小也隨之成長。透過添加奈米顆粒使其與氧化膜結合及填補表面之孔洞，進而提升氧化膜之硬度。添加WS2奈米顆粒之氧化膜具有較優異的機械性質，與添加氧化鋁奈米顆粒之氧化膜比較起來卻無較佳之抗腐蝕能力。氧化膜的厚度、表面形貌、緻密性和組成皆為影響抗腐蝕能力的因素。

Magnesium alloy has good mechanic properties and is considered the green material of the era. However, poor corrosion and wear properties limit its application. Micro-arc oxidation is one of the latest surface treatment technologies forming ceramic-like oxide coating on valve metal such as magnesium, aluminum, and titanium. This coating enhances anti-corrosion and wear abilities remarkably.
This study is focusing on the effects of various nanoparticles and the duration time in silicon electrolyte on MAO coatings and of AZ31 magnesium alloy. The SEM, XRD, EDS, and polarization curve to exam and analyze the MAO surface morphologies, coating layer, and corrosion properties. Thickness and pore size of oxidation film increased as the duration extended. The mechanical properties enhanced when adding nanoparticles into electrolyte bound with oxidation film and filling up pores on the surface. The results have shown that oxidation film with IF-WS2 has better mechanical properties (hardness), however, compared against oxidation film with Al2O3 nanoparticles it has poor anti-corrosion ability. Thickness, surface appearance, density, structure and composition of the oxidation layer may affect its anti-corrosion ability.