粉体复合镁合金微弧氧化膜层的制备和性能的研究

发布时间：2018-01-13 20:31

本文关键词：粉体复合镁合金微弧氧化膜层的制备和性能的研究　出处：《沈阳理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：镁合金以其优良的性能被广泛的应用。然而镁较负的电位使其需进行表面处理提高抗腐蚀能力。镁合金经微弧氧化处理后能显著提高基体的耐蚀性和强度。本文通过向电解液中加入功能粉体,利用微弧氧化技术,在基体合金表面形成粉体复合微弧氧化膜。研究添加的不同功能粉体对微弧氧化膜性能的影响,并采用SEM、XRD、电化学测试、点滴试验等检测手段进行膜层性能的检测。电解液中加入溶胶-凝胶法制得的铁氧体粉体,利用微弧氧化技术,在基体合金表面制出粉体复合膜。研究了电解液配方、粉体添加量、外加磁场等对复合膜层的影响,优化出了最佳的基础电解液配方及粉体的添加量。结果表明,加入纳米铁氧体粉体后膜层表面的孔洞和裂纹减少,膜层相成分增加了铁氧体相,膜层中Fe、Ba、Zn三种元素含量显著提高,复合膜层的腐蚀电位由微弧氧化膜的-1.089V增加到-0.869V,腐蚀电流由2.26×10-6A减小到2.95×10-7A,耐蚀性明显提高。外加磁铁条件可以促进复合膜层中铁氧体的含量,提高膜层的耐蚀性能,膜层的腐蚀电位由-0.869V提高到-0.813V,腐蚀电流由2.95×10-7A下降到1.86×10-7A。电解液中加入液相还原法制备的纳米镍粉,在镁合金表面制备出镍粉复合微弧氧化膜层。研究了粉体的添加对复合膜层耐蚀性及微观组织结构的影响,优化出了最佳的粉体添加量,并分析了甘油的加入及封闭实验对膜层性能的影响。结果表明,加入粉体后,复合膜层的表面光滑致密,孔洞量及尺寸减小,耐蚀性能明显提高,复合膜腐蚀电位为-0.843V,腐蚀电流为4.682×10-7A。甘油的加入可以使微弧氧化反应变得稳定,膜层放电孔径变小,提高了膜层的致密性和抗腐蚀能力,腐蚀电位为-0.832V,腐蚀电流为1.436×10-7A。封闭实验可以减少复合膜层的微孔数量,使膜层几乎无微孔和裂纹,提高膜层的抗腐蚀能力。通过化学镀的方法制备镍包覆Si C粉体,将制得的粉体加入到电解液中制备粉体复合微弧氧化膜。实验研究了镍包覆Si C粉体的添加对复合膜层耐蚀性及微观组织结构的影响,确定了实验的粉体添加量,并分析了超声波分散条件及封闭实验对膜层的影响。结果表明,粉体复合后的微弧氧化膜层表面致密,孔洞减少,几乎无裂纹,膜层的耐蚀性能有所提高,腐蚀电位为-0.913V,腐蚀电流为1.548×10-6A。超声波条件促进膜层中镍包覆Si C粉体的含量,增加膜层的耐蚀性能,腐蚀电位为-0.902V,腐蚀电流为4.164×10-7A。封闭实验可以减少复合膜层的微孔数量,使膜层几乎无微孔和裂纹,提高膜层的抗腐蚀能力。
[Abstract]:Magnesium alloy for its excellent performance has been widely used. However, the negative potential of magnesium is needed to improve corrosion resistance and surface treatment. Magnesium alloy after micro arc oxidation treatment can significantly improve the matrix corrosion resistance and strength. Through adding powder to the electrolyte, using micro arc oxidation technology, the formation of powder composite micro arc oxidation in the matrix alloy surface. The influence of different function of powder added on microarc oxidation performance, and the use of SEM, XRD, electrochemical detection, detection means for drop test of film performance. Adding ferrite powder prepared by sol gel electrolyte, using microarc oxidation technology in the matrix alloy surface prepared by powder composite membrane. The effects of electrolyte formula, adding amount of powder, the effects of magnetic field on the composite film, optimized the best formula and add basic electrolyte powder Volume. The results show that the addition of nano ferrite powder after surface pores and cracks reduced film phase composition increased the ferrite phase, the film of Fe, Ba, Zn significantly increased the content of three elements, the corrosion potential of composite coatings increased by microarc oxidation of -1.089V to -0.869V, the corrosion current by 2.26 * 10-6A reduced to 2.95 * 10-7A, improved corrosion resistance. External magnet conditions can promote the content of ferrite composite coatings, improving the corrosion resistance of the coatings, the corrosion potential of the film increased from -0.869V to -0.813V, the corrosion current by 2.95 * 10-7A 1.86 * 10-7A. down to add liquid electrolyte prepared by reduction of nano nickel powder and on the surface of magnesium alloy were prepared by microarc oxidation coating nickel powder composite was studied. The effect of adding powder to composite coating corrosion resistance and microstructure, optimized the adding amount of powder is the best, and analyzes the glycerol Join and closure of the influence on film performance. The results show that adding powder, composite film surface is smooth and compact, and the amount of pore size decreases and the corrosion resistance increased, the corrosion potential of -0.843V composite film, the corrosion current is 4.682 * 10-7A. the addition of glycerol can make the microarc oxidation reaction becomes stable, the discharge aperture change small, improves the coating compactness and corrosion resistance, the corrosion potential of -0.832V, the corrosion current is 1.436 * 10-7A. blocking experiment can reduce the number of microporous composite film, the film almost no pores and cracks, improve the corrosion resistance of the film. Was prepared by chemical plating nickel coated Si C powder. The prepared powder was added to the preparation of powder composite micro arc oxidation electrolyte system. Experimental study of the effect of adding nickel coated Si C powder to composite coating corrosion resistance and microstructure, determined by experiment The powder adding amount, and analyzed the ultrasonic dispersion conditions and closure of the influence on film. The results show that the powder of the composite ceramic coating surface is dense, almost no cracks, holes will reduce and the corrosion resistance of coatings increased, the corrosion potential of -0.913V, the corrosion current is 1.548 * 10-6A. ultrasonic condition to promote the content of nickel Si coated C powder coating, increase the corrosion resistance of coatings, the corrosion potential of -0.902V, the corrosion current is 4.164 * 10-7A. blocking experiment can reduce the number of microporous composite film, the film almost no pores and cracks, improve the corrosion resistance of the film.

【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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