摘要
本文选用镁元素含量为0.10, 0.34 ,1.0wt%的铜镁合金,用以研究铜镁合金初期氧化机理。通过测量氧化产物质量的增加来研究氧化动力学。对铜镁合金在氢气气氛中退火并用二次离子质谱(SIMS),EPMA检测了退火后铜镁合金表面附近元素Mg、Cu、O的分布素的分布。
用化学蚀刻方法对反应产物的性质进行分析,对不同浓度的铜镁合金即Cu-Mg0.10,Cu-Mg0.34,Cu-Mg1.0在400℃和800℃分别氧化60s,10min,240min并用SEM,TEM观察断面的氧化膜的组织形貌进而对其初期氧化机理进行研究。
研究结果表明,添加Mg有利于铜的抗氧化性的提高,但随着温度的升高这种抗氧化作用逐渐降低。三种不同Cu-Mg合金在氢气中退火后,在其表面均有MgO生成,且MgO均有不同程度的脱落,随着合金元素Mg的增加,MgO层的厚度不断增加,但当Mg的含量超过一定浓度,表面氧化层大范围脱落,并且其中探测到有元素Cu。铜在400℃至800℃时,铜的氧化反应动力学遵循抛物线定律,以Cu2O颗粒增长为主,而速率决定步骤推定为Cu2O中Cu铜原子向外扩散。晶格扩散在高温时对铜氧化有贡献,晶界扩散在400℃对铜氧化也同样有贡献。
Applications of copper have been thousands of years of human history and its many excellent features and amazing functionality made indelible contributions to the progress of human society. With the development of human civilization has produced a constant function and some new purposes. Its large variety of copper metal, are widely used in the form of alloys and compounds, have been deeply integrated into all fields of production and life. As human beings stepping into the 21st century, with rapid technological development, economic growth, the copper is an indispensable metal.
Copper’s electrical and thermal conductivity enlisted the first of metal materials; it plays an important role in the current electrified and electronic information society. Stepping into the 21st century, with the rapid development of electronic information industry, people put forward higher requirements overall performance conductive material. Copper, with its low-cost, high thermal conductivity and electrical conductivity, easy processing, easy assembly and a more superior mechanical properties make it the framework of electronic packaging in the lead, within the cable, flexible circuit boards and heat sinks in, chosen material, Although alloying seems to be a unique way to enhance corrosion resistance of Cu, selection of alloying elements is a careful work relating to different considerations due to the certain requirements in industry Study of the initial oxidation of copper is of great importance for an understanding of the corrosion mechanism. Therefore, it is important for improving the applications of copper to study high-temperature oxidation of copper.
The Initial oxidation of copper is useful for understanding of corrosion mechanism of copper, Zhu and others points of the group dynamics of impurities on initial oxidation of copper by adding small amounts of alloy elements can improve the ability of high temperature oxidation of copper. However, the copper alloy elements added to copper alloys to improve antioxidant capacity will also increase the resistance of copper alloy, thus affecting its conductivity. However, mostly copper alloy in the application form, so what kind of alloying elements used to improve the oxidation resistance of copper is essential. In more than 20 kinds of alloying elements in Al, Be, Mg is considered the most effective enhancement of antioxidant properties of copper metals, be as a threat to human health has a direct impact on their application. Now mainly Al and Mg tend to be chosen either, as compared to Mg and Al has a higher metal activity, and the more superior surface enrichment capability, as well as lower copper resistance after alloying. Cu-Mg alloy seems to be the best choice. Therefore, this paper will study and discuss the initial oxidation mechanism of Cu-Mg alloy
1 The oxidation kinetics of 6N Cu, Cu-0.12 wt% Mg, Cu-0.34 wt% Mg and Cu-1.0 wt% Mg alloys which were annealed at 600℃for 24 h in H2 atmosphere oxidized under 1 atm O2 from 600℃-900℃was studied. And the transition of surface morphology of three alloys during initial oxidation at 400℃and 800℃was analyzed respectively. The results of surface morphology and of the distribution of alloying elements in/near the surface, combined with the oxidation kinetics results, show that the MgO scale formed during annealing. When the content of Mg is too low, the MgO scale was too thin and discontinuous to cover the alloy surface leading to improved OR a little. On the contrary, if the Mg content is so high that the oxide scale formed during annealing was so thick that will be exfoliate during cooling , which lead to poor OR. The order of oxidation rate of four alloys as Cu-0.12 wt% Mg、Cu-1.0 wt% Mg and Cu-0.34 wt% Mg.
⒉The nucleation analysis of initial oxidation of Cu-(0.12, 0.34, 1.0 wt %) Mg alloys oxidized, respectively, for the 60s, 10min, 240min. The nucleation Cu2O occurs preferentially at grain boundaries, Mg elements in the form of the existence of nuclear Cu2O obstructive role. But this hinder are weaken as elevated temperature. Lattice diffusion of copper oxidation at high temperatures contributes to the grain boundary diffusion of copper oxide and the same as at 400℃.
⒊The analysis of the growth process on CuO and Cu2O grains, and the initial analysis of Cu-(0.12, 0.34, 1.0 wt %) Mg alloy oxidized for the 60s, 10min, 240min. the oxidation kinetics of copper followed parabolic election laws at 400℃to 800℃, Cu2O particle growth based, and rate-determining step is presumed to be the Cu atoms of Cu2O in the cuprous oxide diffuse out.
⒋The initial analysis of morphology of Cu-(0.12, 0.34, 1.0 wt %) Mg alloys oxidized for the 60s, 10min, 240min oxidation. The surface morphology of Cu-Mg alloy after annealing show quite different: CuMg0.12 of MgO thin oxide film is not continuous, CuMg0.34 dense oxide layer and the substrate the better, CuMg1.0 the MgO oxide film thicker .However, there have been shedding oxide film. The same Cu-Mg alloy components in the antioxidant capacity of different temperatures and after annealing is mainly the surface oxide film density, bond strength and high-temperature oxidation of the diffusion, segregation of alloying elements Mg and so on.
引文
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