论文总字数：23900字

摘 要

铝是目前产量最大的有色金属结构材料，合金化处理得到的铝合金密度更低，比强度高于钢材料，比刚度与钢材料相当，机加工性能优良，导热导电性能良好，并且具有良好的低温性能。尽管铝合金具有诸多优良性能，但化学性质活泼、耐腐蚀性较差，限制了其在工程领域的广泛应用。而微弧氧化膜层大大提高了材料的耐蚀性。

本文首先采用微弧氧化法制备了选区激光融化陶瓷涂层，提高了基体的耐蚀性。扫描电镜结果表明，随着SLM功率的增加，涂层表面的堆积物增多，随着磷酸的加入，涂层表面变得光滑，微孔数量减少。XRD结果表明，该涂层是由γ - Al₂O₃，α - Al₂O₃组成的，随着SLM功率的提高，γ - Al₂O₃的峰值也随之增加。随着SLM功率和磷酸含量的增加，涂层厚度增加。随着激光制备参数的增加，涂层的腐蚀性能逐渐提高，腐蚀电流由5.674e^-006 A降低到4.175e^-006 A。涂层表面的微孔数减少，微孔数的减少提高了涂层的腐蚀性能，随着涂层中α-Al₂O₃含量的增加，涂层的耐蚀性得到提高。随着磷酸的加入，涂层的腐蚀电流由3.462e^-006 A降低到1.620e^-006 A。扫描电镜观察到镀层表面出现光滑区域，极大地提高了镀层的耐蚀性能。

接着进一步研究了耦合脉冲和TiC浓度对6063铝合金TiC/ Al₂O₃纳米复合涂层的影响。此外，还改善了基体的表面硬度、耐蚀性和摩擦性能。扫描电镜结果表明，随着纳米粒子浓度的增加和短脉冲的缩短，涂层的沉积量增加。此外，XRD结果表明，复合涂层主要由γ- Al₂O₃，α- Al₂O₃，TiC组成，并且随着TiC含量增加，复合涂层的表面粗糙度先增大后减小，而涂层的厚度则增大。结果表明，在TiC浓度为3 g/L、短脉冲为20%时，涂层表面硬度提高到610.4 Hv，腐蚀电流降低到8.979e⁻¹⁰ A。当TiC浓度为3 g/L，短脉冲为30%时，摩擦系数降至0.40。

关键词：微弧氧化，耦合脉冲，复合涂料，选区激光融化，腐蚀性能

Study on micro-arc oxidation film with strong corrosion resistance

and its technology

Abstract

Aluminum is the structure material of nonferrous metal with the largest output at present, the aluminum alloy obtained by alloying treatment has lower density, higher specific strength than steel material, and the specific stiffness is equivalent to steel material, with good machining performance, good thermal conductivity and good low temperature performance. Although aluminum alloy has many excellent properties, its chemical property is active and its corrosion resistance is poor, which limits its wide application in the engineering field. The corrosion resistance of the material is greatly improved by the micro-arc oxide film.

In this paper, the selective laser-melt ceramic coating was prepared by micro-arc oxidation method to improve the corrosion resistance of the substrate. SEM results showed that with the increase of SLM power, the accumulation of coating surface increased, and with the addition of phosphoric acid, the coating surface became smooth and the number of micropores decreased. XRD results showed that the coating was composed of γ - Al₂O₃ and α - Al₂O₃, and the peak value of γ - Al₂O₃ increased with the increase of SLM power. With the increase of SLM power and phosphoric acid content, the coating thickness increases. With the increase of laser preparation parameters, the corrosion performance of the coating gradually improved, and the corrosion current decreased from 5.674e^-006A to 4.175e^-006A. The number of micropores on the coating surface decreased, which improved the corrosion performance of the coating. With the increase of the content of leude-al2o3 in the coating, the corrosion resistance of the coating was improved. With the addition of phosphoric acid, the corrosion current of the coating decreased from 3.462e^-006A to 1.620e^-006A. The smooth surface of the coating was observed by SEM, which greatly improved the corrosion resistance of the coating.

And then we went further of the effects of short pulse and TiC concentration on TiC/ Al₂O₃ nanocomposite coating of 6063 aluminum alloy were further studied. In addition, the surface

hardness, corrosion resistance and friction performance of the matrix were improved. The SEM results showed that the deposition of the coating increased with the increase of the concentration of nanoparticles and the shortening of the coupling pulse. In addition, XRD results showed that the composite coating was mainly composed of γ - Al₂O₃,α - Al₂O_3,TiC, and with the increase of TiC content , the surface roughness of the composite coating first increased and then decreased.while the thickness of the coating increasedThe results showed that when the TiC concentration was 3 g/L and the short pulse was 20%, the surface hardness of the coating increased to 610.4 Hv and the corrosion current decreased to 8.979e⁻¹⁰ A. When the TiC concentration was 3 g/L and the short pulse was 30%, the friction coefficient dropped to 0.40.

Keywords: micro-arc oxidation, short pulse, composite coating, selected laser melting, corrosion performance

目录

第一章 绪论 1

1.1 课题研究的意义与背景 1

1.2微弧氧化的发展与应用 1

1.3微弧氧化的国内外研究现状 2

1.4本文研究内容 3

第二章 实验设备和实验方法 4

2.1引言 4

2.2试样制作 4

2.3实验方法 4

2.4结构和组成分析 5

第三章 选区激光熔化陶瓷膜层腐蚀性能的研究 6

3.1引言 6

3.2实验方法 6

3.3实验结果 6

3.3.1 MAO的过程 6

3.3.2 SEM 7

3.3.3 EDS 8

3.3.4 XRD 9

3.3.5粗糙度和厚度 16

3.3.6腐蚀性能 16

3.3.7对MAO涂层的SLM形貌进行分析 18

3.4 MAO涂层的生长过程分析 19

3.5本章小结 14

第四章 微弧氧化耦合脉冲制备膜层腐蚀性能的研究 15

4.1引言 15

4.2实验方法 15

4.3实验结果分析 15

4.3.1 SEM 15

4.3.2 EDS 17

4.3.3 XRD 17

4.3.4粗糙度和厚度 18

4.3.5微观硬度 19

4.3.6腐蚀性能 20

4.3.7摩擦系数与形貌 21

4.4短脉冲影响的机理 23

4.5 本章小结 24

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