NaOH-Na_2SiO_3-Na_2WO_4体系下负向电压对ZAlSi12Cu2Mg1微弧氧化膜特性及组织的影响  

Effects of Cathodic Voltages on the Characteristics and Microstructure of Ceramic Coatings Fabricated on ZAISi12Cu2Mg1 Alloy by Microarc Oxidation in NaOH-Na_2SiO_3-Na_2WO_4 Electrolyte

作　　者：刘永珍[1] 刘向东[1] 王晓军[1] 韩春霞[1] 刘彩文[1] 

机构地区：[1]内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051

出　　处：《稀有金属材料与工程》2007年第A03期134-137,共4页Rare Metal Materials and Engineering

基　　金：内蒙古科技攻关项目(20040202)

摘　　要：交流电源中负向电压对铝合金微弧氧化陶瓷膜形成过程及其组织性能有重要影响。本文研究了在NaOH-Na_2SiO_3-Na_2WO_4电解液体系下负向电压对ZAlSi12Cu2Mg1铸造铝合金微弧氧化陶瓷膜厚度、硬度及截面形貌的影响。试验中,负向电压从85 V到110 V变化。利用电涡流测厚仪测量陶瓷膜的厚度,用显微硬度计测量陶瓷膜截面的显微硬度,并进行截面形貌观察。试验结果表明:负向电压的提高,有利于陶瓷膜厚度和显微硬度的增加,但负向电压达到一个极限值后,陶瓷膜表面变粗糙,甚至烧蚀,膜层与基体结合变差,陶瓷膜中开始出现裂纹,显微硬度下降;在负向电压为适合值95V时,得到的陶瓷膜厚度为110μm,显微硬度为8810 MPa(HV);同时,沿陶瓷膜厚度方向,从陶瓷膜与基体结合界面到陶瓷膜表层,显微硬度呈现先增加后降低的趋势,在致密层中显微硬度存在一个最大值。Cathodic voltage of alternate-current pulse power supply has great effects on the formation and characteristics of ceramic coatings formed on aluminum alloys in microarc oxidation process. In this work, ceramic coatings were prepared by microarc oxidation on ZAISil2Cu2Mgl alloy through varying cathodic voltages from 85 V to 110 V in a NaOH-Na2SiO3-Na2WO4 electrolyte. The influences of cathodic voltages on the thickness, microhardness and microstructure of ceramic coatings were investigated. The electric vortex thickness indicator was employed to measure the thickness of the ceramic coatings, The microhardness tester was used to measure the microhardnesses of the ceramic coatings and to analyze the cross-sectional microstructures of ceramic coatings. It is found that the thickness and microhardness of the ceramic coating grow swiftly with increasing cathodic voltage. But the surface of ceramic coating becomes coarse or ablative, and microhardness decreases gradually for excessive cathodic voltage. In addition, the ceramic coating is incapable of adhering to the substrate tightly, and cracks appear in the ceramic coating as cathodic voltage exceeds the limit. The thickness and microhardness of ceramic coating fabricated by keeping the cathodic voltage at 95 V were 110 μm and 8810 MPa （HV）, respectively. From the interface of substrate and ceramic coating to the dense layer, the microhardness rises gradually, reaches the highest value in dense layer, and then decreases lower in coarse layer.

关 键 词：微弧氧化 负向电压 ZALSI12CU2MG1 陶瓷膜 

分 类 号：TG174.451[金属学及工艺—金属表面处理]