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不同表面处理工艺压铸镁合金涂层耐蚀性研究 总被引:3,自引:0,他引:3
为了研究不同表面处理工艺下压铸镁合金涂层的抗腐蚀性能,通过浸泡腐蚀和电化学腐蚀的方法,比较了微弧氧化和无铬化学氧化等表面处理试样的耐蚀性.结果表明,无铬化学氧化和微弧氧化处理能显著提高镁合金表面耐蚀性,而以微弧氧化处理更优;且两种处理方法覆盖层对孔洞、裂纹不敏感.根据交流阻抗图谱,拟合得到了微弧氧化、无铬化学氧化和未处理三种试样电化学腐蚀时体系的等效电路,拟合结果与实测结果吻合.XRD分析表明这两种处理方法得到的覆盖层中主体相均为Mg3Al2Si3O12等含硅的尖晶石型氧化物和Mg0.36Al2.44O4、MgAl2O4等不含硅的镁、铝复合氧化物,有利于提高镁合金耐蚀性. 相似文献
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C-Si 梯度涂层对碳纤维性能的影响 总被引:1,自引:0,他引:1
本文提出并探索了在碳纤维表面化学气相沉积 C-Si 梯度涂层的新方法,研究了 C-Si 梯度涂层对碳纤维性能的影响。实验结果表明,碳纤维表面化学气相沉积 C-Si 梯度涂层结构中的 C,Si 元素均呈非晶态结构;梯度涂层能大幅度提高碳纤维的抗氧化性。梯度涂层减少了涂层与纤维基体的各种不匹配因素,缓和了涂层中热应力,限制了氧化反应的进行,使梯度涂层纤维氧化前后强度均明显高于 Si,SiC,SiO_2等单一涂层纤维。 相似文献
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黑色金属的碱性化学氧化膜,主要由磁性氧化铁组成。氧化膜的抗蚀性能虽小于磷化膜,但表面比磷化膜光泽美观,呈黑色或深兰色。而且由于它工艺稳定且可以采用浸肥皂填充处理,浸润滑油处理或涂漆,大大提高了其防护性能。因此仍被广泛采用。化学氧化处理工艺中,化学氧化膜的表面颜色与材料的合金成份和氧化规范有关,一般碳素钢和低合金钢呈黑色和黑兰色,合金钢则因含硅量的高低,氧化处理后其膜呈褐色到黑褐色,实际生产中则因工艺规范的变化出现红褐色而大大降低抗蚀 相似文献
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碳/碳复合材料氧化及其防护性能研究 总被引:13,自引:1,他引:12
采用快速化学气相沉积新技术,在沉积210h后制备出密度为1.77g/cm^3的碳/碳(简称C/C)复合材料,对其氧化动力学进行了研究,发现氧化起始点高达672℃,在氧化线性阶段Arrenius曲线由折点为700℃的两条直线组成,对应的氧化表观活化能分别为80.121kJ/mol。氧化表面动态观察表明,氧化从C/C复合材料表面原有孔隙处开始,而且碳纤维和基本碳同时氧化,最后剩下的是在碳纤维骨架周围分布着的极不均匀的,多孔状沉积碳,并为这种材料研制出了一种氧化防护涂层,该涂层成本低廉,涂刷工艺简单,通过静态空气恒温氧化及热震实验证明,涂层防氧化效果良好,并探讨了氧化防护机理。 相似文献
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利用冷喷涂技术制备了NiCoCrAlY涂层,并对涂层进行了真空预氧化处理。结合X射线衍射,扫描电镜和能谱分析等方法分析了NiCoCrAlY涂层真空预氧化前后的微观组织结构,并研究了真空预氧化处理对NiCoCrAlY涂层在1050℃下氧化行为的影响。结果表明:冷喷涂NiCoCrAlY涂层含氧量为0.25%(质量分数),孔隙率小于0.36%。真空预氧化处理使涂层由γ-Matrix Ni-Co-Cr单相结构转变为γ-Matrix Ni-Co-Cr固溶体和β-(Ni,Co)Al金属间化合物双相结构,并在涂层表面生成厚约0.47μm连续、致密的α-Al2O3氧化膜。喷涂态涂层和真空预氧化涂层在1050℃氧化200h后表面均生成致密、连续的以α-Al2O3为主的氧化膜。真空预氧化处理在100h内抑制了涂层表面尖晶石氧化物的形成,同时降低了氧化膜生长速率。 相似文献
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镁合金表面功能涂层制备与界面表征技术的研究进展 总被引:2,自引:0,他引:2
随着低碳经济的发展,汽车轻量化的呼声愈来愈高。镁合金作为最有前景的轻量化材料之一,其表面防腐功能涂层的研究已经越来越受到人们的重视。简要介绍了物理方法和化学方法制备镁基表面防腐功能涂层的工艺技术特点,重点讨论了衡量涂层质量的现行标准以及现有的各种测量界面结合强度的方法,特别是界面应变能释放率定量分析的方法,文中结合自己的实验结果进行了分析。 相似文献
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镁及镁合金作为硬组织植入替代材料具有显著的优越性,但如何对镁及镁合金进行表面改性以满足临床应用对生物材料耐蚀性能的苛刻要求,仍然是解决镁及镁合金在生物材料领域产业化应用的关键。本文综述了为提高镁基生物材料耐蚀性能研发的涂层材料种类、涂层表面改性技术的研究现状,提出了结合多种制备方法,通过对涂层的组成和结构设计来改善涂层的结合强度、稳定性及良好的生物适应性是今后努力的方向。 相似文献
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镁及其合金表面防护性涂层国外研究进展 总被引:21,自引:4,他引:21
综述了近年来国外镁及其合金表面防护性涂层的研究进展,其中包括化学转化涂层、阳极氧化膜层、镀层(电镀、化学镀)、扩散膜层、激光表面合金改性层、气相沉积层及有机涂层等在镁合金基体上的应用情况,分析了其各自的利弊,并对镁合金表面防护技术的发展方向进行了展望. 相似文献
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A. Scott 《Thin solid films》2009,517(24):6809-1608
Magnesium and its alloys have desirable physical and mechanical properties for a number of applications. Unfortunately, these materials are highly susceptible to corrosion, particularly in the presence of aqueous solutions. The purpose of this study is to develop a uniform, non-toxic surface treatment to enhance the corrosion resistance of magnesium alloys. This paper reports the influence of the coating bath parameters and alloy microstructure on the deposition of 3-mercaptopropyltrimethoxysilane (MPTS) coatings on magnesium alloy AZ91. The surface chemistry at the magnesium/MPTS interface has also been explored. The results indicate that the deposition of MPTS onto AZ91 was influenced by both the pH and MPTS concentration in the coating bath. Furthermore, scanning electron microscopy results showed that the MPTS film deposited uniformly on all phases of the magnesium alloy surface. X-ray photoelectron spectroscopy studies revealed that at the magnesium/MPTS interface, the molecules bond to the surface through the thiol group in an acid-base interaction with the Mg(OH)2 layer, whereas in the bulk of the film, the molecules are randomly oriented. 相似文献
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《材料科学技术学报》2016,(9)
Magnesium(Mg) and its alloys as a novel kind of biodegradable material have attracted much fundamental research and valuable exploration to develop its clinical application. Mg alloys degrade too fast at the early stage after implantation, thus commonly leading to some problems such as osteolysis, early fast mechanical loss, hydric bubble aggregation, gap formation between the implants and the tissue. Surface modification is one of the effective methods to control the degradation property of Mg alloys to adapt to the need of organism. Some coatings with bioactive elements have been developed, especially for the micro-arc oxidation coating, which has high adhesion strength and can be added with Ca, P, and Sr elements. Chemical deposition coating including bio-mimetic deposition coating, electro-deposition coating and chemical conversion coating can provide good anticorrosion property as well as better bioactivity with higher Ca and P content in the coating. From the biodegradation study, it can be seen that surface coating protected the Mg alloys at the early stage providing the Mg alloy substrate with lower degradation rate. The biocompatibility study showed that the surface modification could provide the cell and tissue stable and weak alkaline surface micro-environment adapting to the cell adhesion and tissue growth.The surface modification also decreased the mechanical loss at the early stage adapting to the loadbearing requirement at this stage. From the interface strength between Mg alloys implants and the surrounding tissue study, it can be seen that the surface modification improved the bio-adhesion of Mg alloys with the surrounding tissue, which is believed to be contributed to the tissue adaptability of the surface modification. Therefore, the surface modification adapts the biodegradable magnesium alloys to the need of biodegradation, biocompatibility and mechanical loss property. For the different clinical application, different surface modification methods can be provided to adapt to the clinical requirements for the Mg alloy implants. 相似文献