镁合金表面合金化及电泳涂装工艺

介绍了镁合金表面合金化及电泳涂装工艺流程。讨论了镁合金表面合金化的工艺配方及其操作步骤。研究了镁合金的前处理、防腐涂装以及装饰性涂装工艺条件及其涂膜性能。为镁合金产品的防腐装饰提供了新的途径。     

镁合金件有机防护涂层的耐腐蚀性能研究

为提高镁合金的耐腐蚀性能,利用复合有机涂层技术在ZM5铸镁合金表面制得防腐涂层。研究了镁合金的前处理、有机防腐涂装以及装饰性涂装工艺条件及其涂膜性能。利用化学转化膜对镁合金进行表面处理,再用复合有机涂层提高镁合金的防腐性能。结果表明:该有机涂层体系对镁合金有较好的腐蚀防护作用,化学转化膜可以提高镁合金与有机涂层的结合力并提高其耐腐蚀性。     

镁合金高耐蚀表面处理技术的研究进展

[目的]随着加工技术水平的不断提高,镁合金应用范围迅速扩展,市场需求不断增长。然而镁合金化学活性高,在环境中极易发生腐蚀而造成金属部件失效。因此镁合金的防腐处理至关重要。[方法]综述了改善镁合金耐蚀性的几种常用表面处理技术的研究进展,包括化学转化、微弧氧化、电镀、电泳沉积、溶胶-凝胶处理、水热处理和喷涂。[结果]对镁合金进行适当的表面处理能够显著提高其耐蚀性。[结论]目前镁合金表面防腐处理已取得一定的进展,但还有许多待改进之处。     

镁合金表面防护处理技术的研究现状与前景展望

镁合金因其具有优良的性能而日益受到重视,但是镁合金耐腐蚀性较差限制了它的应用。综述了镁合金环保型防护处理技术,包括化学氧化处理、阳极氧化、微弧氧化、金属镀层等技术,分析了镁合金表面防腐处理技术的发展趋势。     

镁合金的腐蚀及其表面转化膜技术

镁合金有诸多优点,因其极易受到腐蚀而限制了它的发展和应用。综述了镁合金表面的腐蚀形式及转化膜技术,重点介绍了全面腐蚀和局部腐蚀及化学转化膜、阳极氧化膜和有机物转化膜的现状、工艺、耐蚀机理及发展趋势等,展望了镁合金及其防腐技术未来的发展方向。     

镁合金表面处理工艺及有机防护涂层耐腐蚀性能

为提高镁合金的耐腐蚀性能,研究了镁合金的化学转化膜技术原理、有机防腐涂装层次结构及其涂膜防腐性能。结果表明该化学转化膜可以提高镁合金与有机涂层的结合力,同时配套复合有机涂层体系对镁合金有较好防护及耐腐蚀性能。     

航天器用镁合金防腐-热控一体化涂层制备工艺研究

针对航天器在地面装配、测试期间镁合金材料防腐蚀和在轨期间镁合金材料高发射率辐射换热需求,通过涂层组分配比、涂层厚度对涂层性能影响研究,制备了一种半球发射率(εH)≥0.88、真空总质量损失(TML)≤1%、可凝挥发物(CVCM)≤0.1%的防腐-热控一体化涂层。制备的涂层可耐受1 008 h中性盐雾试验、504 h湿热试验和-196~100℃的100次冷热交变试验,具备良好的防腐蚀和热控性能,可用于航天器镁合金材料表面防腐和热控处理。     

镁合金防护底漆的研制

镁合金作为新型材料,具有其他金属材料无法比拟的优点。镁合金主要由镁元素构成,由于镁元素相对比较活泼和镁合金表面有大量缝隙导致其易被环境腐蚀,因此在化学氧化成膜的基础上研制了一套封闭清漆、防护底漆。其中封闭清漆和防护底漆树脂都选用了改性环氧树脂和复合聚酰胺固化剂,防护底漆颜填料选用了钝化颜料锌铬黄和屏蔽填料云母粉、石墨烯等,使得镁合金基材喷涂涂层之后的耐中性盐雾和耐湿热性达到了1 500 h,完全能够满足我们使用镁合金基材所需的防腐要求。     

AZ31镁合金表面防腐胶粘涂层的研制

胶粘涂层法是有效提高镁合金耐腐蚀性能的表面处理技术之一.以E-44环氧树脂、低分子量650#聚酰胺、云母氧化铁等为主要原料,制备了适用于AZ3l镁合金基体的防腐胶粘涂层.研究了填料含量对涂层外观、施工性和耐蚀性能的影响.结果发现,当填料质量分数为60%、涂层厚度为180～220μm时,防腐胶粘涂层具有良好的外观及施工性,附着力为1级,耐盐雾时间168 h.     

[V10O28]6-柱撑纳米水滑石在AZ31镁合金有机防腐涂层中的应用

研制了一种以钒酸盐阴离子([V10O28]6-)柱撑纳米水滑石防腐颜料替代铬酸盐,用于AZ31镁合金腐蚀防护的有机涂层.研究了水滑石在不同浓度的NaCl溶液里的吸附和离子交换性能,以及钒酸盐缓蚀剂的极化曲线:考察了该水滑石防腐颜料的添加比例对镁合金环氧防腐涂层性能的影响,并通过电化学交流阻抗(EIS)测试技术对各试样进行了性能检测.结果表明,添加了20%(质量分数)水滑石的环氧涂层对镁合金具有较好的防腐作用.     

医用镁合金仿生钝化技术研究进展

在医用镁合金功能化表面改性技术中,仿生钝化具有其他方法无可比拟的优越性。利用仿生钝化技术,可在镁合金表面原位制备兼具优异生物相容性、生物活性和降解控制功能的生物磷灰石膜层,全面满足镁合金生物医用对表面质量的苛刻要求。本文分别从前处理、钝化工艺、钝化后处理等方面,综述了医用镁合金仿生钝化技术的研究进展,并展望了医用镁合金仿生钝化技术的发展趋势。     

Corrosion resistance and chemical stability of super-hydrophobic film deposited on magnesium alloy AZ31 by microwave plasma-enhanced chemical vapor deposition

A super-hydrophobic film was successfully deposited on magnesium alloy AZ31 by the microwave plasma-enhanced chemical vapor deposition (MPECVD) process. The film surface showed a static water contact angle of more than 150°. The hydrophobicity and root mean square roughness of the film surface increased with an increase in deposition time. The anticorrosion resistance of the deposited film was estimated by electrochemical impedance spectroscopy (EIS) measurements. The EIS measurements and appropriate equivalent circuit models revealed that the super-hydrophobic film considerably improved the anticorrosion resistant performance of magnesium alloy AZ31. The anticorrosion mechanism of the super-hydrophobic film was also considered. Moreover, the chemical stability of the super-hydrophobic film in acidic, neutral, and alkaline aqueous solutions was investigated. The super-hydrophobic film showed high chemical stability in acidic and neutral aqueous solutions.     

镁合金微弧氧化陶瓷膜层性能研究进展

镁合金微弧氧化陶瓷膜具有较好的耐蚀性和机械性能.综述了镁合金微弧氧化膜耐蚀性、硬度、摩擦磨损和拉伸性能等的最新研究进展,归纳了电解液成分和工艺参数对陶瓷膜耐蚀性和机械性能的影响.概括了镁合金微弧氧化处理技术的不足之处.     

镁合金化学氧化膜的耐蚀性研究

研究了镁合金氧化膜在酸、碱及盐溶液中的腐蚀行为,用光学显微镜观察了氧化膜及腐蚀后表面形貌,从腐蚀形貌、腐蚀类型及氧化膜状态等几方面对镁合金的腐蚀行为进行了分析。结果表明:在0.5 mol/L H2SO4、3.5%NaCl、0.5 mol/L NaOH溶液中,镁合金氧化膜的耐蚀性比镁合金基体好。     

镁的表面处理

综述了镁及其合金的表面清洗，化学处理，阳极氧化，涂敷有机物等表面处理方法。     

苯甲酸钠对AM60镁合金在氯化钠溶液中的缓蚀作用

为了改善AM60镁合金的抗腐蚀性能,通过电化学阻抗、极化曲线和浸泡等方法研究了苯甲酸钠(SB)对AM60镁合金在3.5%氯化钠溶液中的缓蚀作用,并考察了温度对缓蚀率的作用规律,借助扫描电镜观察了不同温度和不同SB浓度下镁合金腐蚀后的表面形貌,分析了SB的缓蚀机制。结果表明:SB明显减缓了AM60镁合金的腐蚀速率,当其浓度为0.5 mol·L^-1时,缓蚀率达到75%以上,这主要是因为SB在AM60镁合金表面发生了物理吸附,这种吸附为放热、熵增的自发过程,形成的多分子吸附层隔离了镁合金和腐蚀介质的直接接触。随着SB浓度增加,镁合金腐蚀反应活化能增大,缓蚀率随之而增大。当SB浓度增大到0.7 mol·L^-1以后,由于分子间排斥作用占主导作用,导致缓蚀率没有明显增加,且随着温度从25℃升高到70℃,SB的缓蚀率略有下降。     

Novel composite films prepared by sol–gel technology for the corrosion protection of AZ91D magnesium alloy

A novel composite films technology was developed to improve the anticorrosion performance of AZ91D magnesium alloy. The composite films were prepared via sol–gel method which is a simple application procedure within industry. The structure of xerogels and films, morphology of films were analyzed using thermo-gravimetric (TG) and differential thermal analysis (DTA), Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scan electron microscopy (SEM). The anticorrosion performance of the sol–gel coated and uncoated samples in 3.5 wt.% NaCl neutral solution had been evaluated by electrochemical tests. The results demonstrated that the composite films “Ce inner film/Mg outer film” exhibited better corrosion resistance.     

Improved corrosion resistance of Al2O3 ceramic coatings on AZ31 magnesium alloy fabricated through cathode plasma electrolytic deposition combined with surface pore-sealing treatment

In this study, we explored the phase compositions and morphologies of the ceramic coatings from different aluminum sources (aluminum isopropoxide, aluminum nitrate, or a mixture of the two) prepared using cathode plasma electrolytic deposition (CPED) onto AZ31 magnesium alloys. Scanning electron microscopy and X-ray diffraction analyses of these coatings indicate that the deposited ceramic made from aluminum isopropoxide was composed of γ-Al₂O₃ whereas the one made from aluminum nitrate was composed of MgA1₂O₄, and that the former was more compact and uniform than the latter. A composite coating was prepared using epoxy resin as a protective layer that sealed the micropores on the CPED coating, thereby further improving its anticorrosion property. The elemental distribution of the cross-section of the composite coating was examined via energy dispersive spectroscopy. Corrosion resistance was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy in a 3.5?wt% NaCl medium, and a salt spray test. The results indicate that the corrosion protection property of the Al₂O₃/epoxy resin coating of the magnesium alloy was better than that of the single Al₂O₃ coating. A cross-cut test revealed that the adhesion of the Al₂O₃/epoxy resin composite coating to the magnesium alloy surface was better than that of the single epoxy resin coating. The approach presented herein provides an attractive way to modify the surface of magnesium alloys to improve anticorrosion.     

Novel hybrid sol-gel coatings for corrosion protection of AZ31B magnesium alloy

This work aims to develop and study new anticorrosion films for AZ31B magnesium alloy based on the sol-gel coating approach.Hybrid organic-inorganic sols were synthesized by copolymerization of epoxy-siloxane and titanium or zirconium alkoxides. Tris(trimethylsilyl) phosphate was also used as additive to confer additional corrosion protection to magnesium-based alloy. A sol-gel coating, about 5-μm thick, shows good adhesion to the metal substrate and prevents corrosion attack in 0.005 M NaCl solution for 2 weeks. The sol-gel coating system doped with tris(trimethylsilyl)-phosphate revealed improved corrosion protection of the magnesium alloy due to formation of hydrolytically stable Mg-O-P chemical bonds.The structure and the thickness of the sol-gel film were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The corrosion behaviour of AZ31B substrates pre-treated with the sol-gel derived hybrid coatings was tested by electrochemical impedance spectroscopy (EIS). The chemical composition of the silylphosphate-containing sol-gel film at different depths was investigated by X-ray photoelectron spectroscopy (XPS) with depth profiling.