AZ31镁合金的氧化膜研究

太原理工大学毕业论文(设计)

I AZ31镁合金氧化膜的研究

摘 要

在镁合金表面生成保护膜对镁合金起到保护作用，是一种最简单经济的方式。本文对AZ31镁合金进行化学氧化成膜和电化学氧化成膜。所用的镁合金试样表面积约为10-40cm2。其中，化学氧化采用低浓度铬酸常温，化学氧化液的成分及含量为：CrO3（5g/L）、CaSO4（5g/L）。对其氧化时间进行优化，得到2min左右时，氧化效果较好。另外，本文采用了几种不同的电化学氧化方法成膜，发现电化学氧化液成分为NaOH/Na2SiO3/C6H5OH的电化学氧化方法所得的膜效果不错。之后，改变这种电化学氧化液中各成分的含量，以进一步证明各成分的作用。在化学氧化和电化学氧化成膜后，对试样进行静电粉末喷涂，测试涂膜性能。发现涂膜性能良好。

另外，研究结果还表明：铬酸化学氧化所得的膜层均匀致密，孔隙率低。电化学氧化所得的膜表面粗糙、多孔，孔隙率高。对六价铬废液可以采用沉淀法回收处理。

关键词：AZ31镁合金，化学氧化，电化学氧化，静电喷涂 太原理工大学毕业论文(设计)

II A Study on the Oxide Film of AZ31 Magnesium Alloy

Abstract

A protective film on the surface of magnesium alloy can be used to protect the

magnesium alloy, which is one of the most economical and simplest methods. In this

paper, the chemical oxidation films and electrochemical oxidation films were prepared for

AZ31 magnesium alloy. The surface area of magnesium alloy samples used in this paper was

about 10-40cm2. Among them, the chemical oxidation films with low concentration

of chromic acid were obtained at room temperature. The composition and content of

chemical oxidation solution was CrO3 (5g/L), CaSO4 (5g/ L). Optimize its oxidation time, we

found that the effect was better when the oxidation time is about 2min. In addition, several

different methods of electrochemical oxidation films were used. When the electrochemical

oxidation which solution components were NaOH、Na2SiO3 and C6H5OH were adopted , the

effect was better . After then, to provide further evidence of the role of each component, we

changed the contents of each component in the electrochemical oxidation of solution . The

electrostatic powder coating was conducted after forming chemical oxidation films or

electrochemical oxidation films. Coating performance was good when testing the properties.

In addition, the results also showed that: chromate films obtained from chemical oxidation

were even and tight, which porosity was lower. The surface of membranes from

electrochemical oxidation were rough and porous, which porosity was higher. Waste solution

including hexavalent chromium compounds could be recycled by precipitation method.

Key words: AZ31 magnesium alloy, chemical oxidation; electrochemical oxidation;

electrostatic spray 太原理工大学毕业论文(设计)

I 目录

摘要 ............................................................................................................................................ I

Abstract .................................................................................................................................... II

第1章 绪论 ............................................................................................................................. 1

1.1.镁及镁合金特性.............................................................................................................. 1

1.1.1.镁合金特点 ............................................................................................................... 1

1.1.2.镁合金牌号 ............................................................................................................... 1

1.2.镁合金的应用.................................................................................................................. 2

1.2.1.镁合金在汽车领域的应用 ....................................................................................... 3

1.2.2.镁合金在3C行业的应用 ........................................................................................ 4

1.2.3.镁合金在航天领域的应用 ....................................................................................... 4

1.2.4.镁合金在军事领域的应用 ....................................................................................... 5

1.2.5.镁合金在医疗器械上的应用前景 ........................................................................... 5

1.3.镁合金腐蚀...................................................................................................................... 6

1.3.1.镁单质的不稳定性 ................................................................................................... 6

1.3.2.镁合金的第二相和杂质 ........................................................................................... 7

1.3.3.镁合金的环境因素 ................................................................................................... 7

1.3.4.镁合金的自然氧化膜 ............................................................................................... 7

1.4.镁合金表面防护.............................................................................................................. 8

1.4.1.化学氧化处理 ........................................................................................................... 8

1.4.2.阳极氧化处理 ......................................................................................................... 10

1.4.3.微弧氧化处理 ......................................................................................................... 12

1.4.4.有机涂层处理 ......................................................................................................... 12