金属陶瓷涂层耐蚀性能研究

在不锈钢、纯铜及铝合金上,采用溶胶－凝胶浸清提拉法可制作连续的对钨起保护的ＳｉＯ２、ＴｉＯ２、Ａｌ２Ｏ３及ＳｉＯ２－ＴｉＯ２陶瓷涂层。通过阳极极化曲线、循环动电位极化曲线、点蚀电位、三氯化铁腐蚀试验、５％硫酯腐蚀试验及氧化试验研究了陶瓷涂层对金属的保护性能。结果表明,这些陶瓷涂层大大提高了基本金属的耐蚀性及抗氧化能力。     

耐热防腐蚀复相陶瓷涂层的研究

在经表面预处理的普通碳素钢上，采用热化学反应法制备均匀的陶瓷涂层。微观结构分析和性能检测表明，涂层为含有ＭｇＡｌ２Ｏ４、Ａｌ６ＳｉｏＯ１３、ＺｒＯ２等的复相陶瓷结构。涂层与基体的结合强度较高，耐热防腐蚀性能优异，抗热震性较好。     

工业纯铜煤矸石陶瓷涂层制备及耐蚀性能研究

以煤矸石为主要原料,添加一定量的铝粉、氧化硼和氧化铈,采用热化学反应技术在工业纯铜基体上制备了煤矸石陶瓷涂层和稀土改性陶瓷涂层,并对涂层结构、抗热震性及耐蚀性进行了测试.实验结果表明:陶瓷涂层对纯铜的耐蚀性有一定改善;煤矸石陶瓷涂层和稀土改性陶瓷涂层的耐酸性分别为基体的1.52倍、2.39倍,耐盐性分别为基体的1.29倍、2.01倍,耐石油介质性分别为基体的1.50倍、2.00倍.     

复合陶瓷涂层对碳钢防腐蚀性能的电化学研究

利用电化学阻抗谱法就Al2O3、SiC、ZrO2复合陶瓷涂层对碳钢的防腐蚀性能进行了研究.结果表明:ZrO2复合陶瓷涂层的防腐蚀性能明显高于Al2O3、SiC复合陶瓷涂层.讨论了阻抗谱图特征变化与涂层结构与性能变化的关系.     

Fe3Al-Al2O3陶瓷梯度涂层性能研究

利用等离子喷涂制备了不同成分设计的多种Fe3Al-Al2O3陶瓷复合涂层，采用金相显微镜、SEM、XRD及电子探针等手段，研究了涂层的微观组织及成分分布，并对涂层的结合强度、显微硬度及抗热震性能进行了试验研究。结果表明，Fe3Al过渡层的引入可有效地改善涂层的质量，Fe3Al金属间化合物是钢基体上制备陶瓷涂层较为理想的过渡材料。涂层成分的梯度化有利于涂层结合强度和抗热震性能的提高。     

金属基体激光熔覆陶瓷基复合涂层的裂纹成因及控制方法

参考了较多国内外有关文献,较为系统地分析了金属基体激光熔覆陶瓷基复合涂层裂纹的形成机理,总结出降低裂纹倾向的方法:选择合适的激光熔覆参数;激光熔覆时对金属基体进行预热或后热处理;采用添加中间过渡层或梯度涂层的方法;在金属基体激光熔覆陶瓷基复合材料中添加增韧、增塑元素。这些方法为控制金属基体激光熔覆陶瓷基复合涂层的裂纹形成提供了有益参考。     

等离子喷涂工艺稳定性对陶瓷涂层组织和性能的影响

采用正交试验设计方法研究了等离子喷涂主要工艺参数对Cr2O3涂层组织、抗拉结合强度和耐蚀性的影响,并用方差分析方法对试验结果进行分析。结果表明,影响涂层性能和性能稳定的最重要的工艺参数为电弧电流,其次为涂层厚度;涂层内孔隙率是影响涂层结合性和耐蚀性的主要原因;陶瓷涂层的腐蚀为陶瓷层内部的化学腐蚀。     

反应等离子喷涂Fe-A12O3-FeAl2O4复合涂层的反应机理研究

金属／陶瓷复合涂层具有金属的韧性和陶瓷的高强度、高硬度等优点，利用反应等离子喷涂技术将Fe2O3／Al复合粉制备成金属／陶瓷复合涂层，以X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)等分析技术研究了该复合涂层的反应机理和涂层性能。结果表明：涂层具有以层状的FeAl2O4、Al2O3为骨架，球形的Fe及部分FeAl为弥散相的复合组织；复合粉体反应形成涂层的过程是分步进行的，而且在熔滴到达基体后部分反应仍继续进行；一定程度上，由于反应过程受到Al元素的扩散限制，同时等离子喷涂的冷却速度较高，使得涂层中主要含有FeAl2O4及少量的FeO。     

重力分离SHS法制备钢管Al2O3内衬耐热耐磨涂层的研究

采用重力分离SHS制备了钢管内衬Al2O3涂层,进行了力学、抗热震、耐蚀等性能测试,研究了管径、装料密度及不同含量SiO2、CrO3添加剂对涂层组织与性能的影响。研究结果表明,涂层主要物相结构为α-Al2O3+FeAl2O4相,添加剂SiO2和CrO3不改变涂层的主要相组成。反应过程中熔融金属Fe在钢管基体和内衬陶瓷层之间形成了一层金属过渡层。当添加2%SiO2+6%CrO3时,涂层孔隙率最小,硬度最大,抗热震性能最好,耐蚀性也较好,具有良好的综合性能。实验条件下,管径25cm、装料密度1.5g/cm3的内衬涂层硬度为1917HV,孔隙率为9.0%。     

新型陶瓷涂层的制备、结构调控及应用研究进展

陶瓷材料在特定应用场合下常需针对性地改善其某项性能,如抗氧化、耐烧蚀、吸波/透波特性等,一种有效的解决方案是在陶瓷材料表面制备具有特殊性能的陶瓷涂层,如热障涂层、环境障涂层等。陶瓷涂层的常用制备方法包括气相沉积法、热喷涂法、溶胶-凝胶法等。目前,针对单一涂层的制备工艺已具备较为成熟的基础,研究者通过辅助增强改进或不同工艺结合等方法,加强对涂层结构的调控,从而实现性能的进一步优化。近年来,探索具有优异性能的新涂层体系以及对涂层成分、结构的精确调控成为了陶瓷涂层研究的热点。稀土化合物本身具备优异的性能,且具有独特的掺杂改性效果,广泛应用于热/环境障涂层;MAX相陶瓷兼具金属及陶瓷的优点,制备的抗氧化涂层具备优异的自愈合特性;此外,在复相陶瓷涂层体系中,实现不同相之间的互补效应,能够发挥其各自的优点。为解决单层涂层功能单一、与基体匹配性差等问题,研究者设计了不同的新型陶瓷涂层结构。多层涂层中,过渡层的引入显著提高了涂层与基体的结合强度;梯度涂层中,涂层与基体之间的成分浓度、热膨胀系数等呈梯度分布,可有效防止涂层失效;纳米相增强涂层中,纳米增强相的引入可抑制裂纹的产生和扩展,从而显著提高涂层的...     

Resistance of thermal barrier ceramic coatings to hot salt corrosion

Stabilized zirconia ceramics appear to have considerable potential as thermal barriers or corrosion-resistant coatings for application to gas turbine components. Salt corrosion tests have indicated however that under some conditions vanadium impurities in the fuel may cause accelerated failure of these coatings as a result of destabilization of the zirconia phase. The corrosion resistance, thermal stability and structure of the coatings depend to a large extent on the chemical composition of the ceramic phase. The results of a study of the behavior of plasma-sprayed Y₂O₃ZrO₂ coatings towards combustion gases and the typical salt deposits likely to be encountered in gas turbines which burn fuels containing sodium, sulfur, lead and vanadium impurities are described.     

APPLICATION OF HIPING-THICK CERAMIC COATINGS ONTO METALS

The demand for high performance in the combustion equipment used in the automobile and aerospace industries is creating renewed interest in the use of ceramic protective coatings on metal surfaces. Sometimes, thick coating layers are required as thermal barriers or for wear resistance and hardness. Although plasma spraying is one of the promising processes available for depositing thick ceramic coatings onto metal surfaces, the presence of porosity in the coating coupled with lack of corrosion resistance of the coated materials, and the generally low strengths of both the coating layer and the coating-matrix interface may limit the use of the process. HIP treatment of ceramic coatings allows one to obtain dense coatings and also to increase the interfacial bond strength. The present paper reviews the recent advances in the post-HIPing of ceramic coatings as well as the use of HIP for sinter-coating by which a ceramic powder compact is sintered and bonded simultaneously to a metal surface.     

SiCP/AZ31镁基复合材料微弧氧化膜结构与性能分析

采用微弧氧化表面处理技术在SiC颗粒增强AZ31镁基复合材料表面制备保护性陶瓷膜.分析了陶瓷膜的表面形貌、截面组织和相组成,并测量了膜层的硬度、热震和电化学腐蚀特性.结果表明,陶瓷膜由MgO、Mg₂SiO₄和少量同电解液组成元素相关的相所组成,膜内还残留少量SiC_P增强体.膜层的最高硬度可达到HV800,比复合材料基体提高五倍以上.经过100次热循环(500℃→水淬)后膜层与复合材料结合良好,显示该膜层有较好的抗热震性能.微弧氧化处理后,SiC_P/AZ31镁基复合材料的抗腐蚀能力得到较大提高.     

镁合金微弧氧化工艺条件对陶瓷膜耐蚀性的影响EI

利用交流阻抗研究了微弧氧化电解液组分及浓度、电流密度、处理时间等对镁合金氧化陶瓷膜于3.5%(质量分数,下同)NaCl溶液中的耐蚀性的影响规律,同时对经不同浸泡时间时氧化陶瓷膜的耐蚀性进行了测试,以探讨氧化膜的耐蚀机理。研究得出:随着硅酸钠、氟化钠、甘油含量的增加以及微弧氧化电流密度的增大和处理时间的延长,微弧氧化陶瓷膜的耐蚀性均呈现出先增强后降低的趋势;经一定的腐蚀时间后,微弧氧化陶瓷膜的多孔层最终遭到破坏,而紧密层对防腐蚀起着至关重要的作用。     

冷喷涂Al基复合涂层的制备及耐蚀性能研究

铝合金以其轻量化特性及优异的耐腐蚀性能得到广泛应用.冷喷涂技术具有低温高速沉积的特点,是制备铝防腐涂层的有效方法.采用机械混合的方式制备了铝基-陶瓷相混合粉末,并通过冷喷涂在Al1060表面制备了Al5056,Al5056-Al2O3,Al5056-SiC,Al5056-WC 4种涂层.通过 Image-Pro Plu...     

Vapor deposition of technetium coatings by thermolysis of volatile carbonyl complexes: I. Conditions and efficiency of coating deposition from various starting compounds

The microstructure, chemical and phase composition, and corrosion resistance of coatings deposited by thermolysis of vapors of volatile technetium carbonyl compounds on a titanium support are studied. The relationship between the nature of the starting compound, conditions of the heat treatment of the coatings, and their chemical and phase composition and corrosion resistance is analyzed. Vacuum annealing at a high temperature (no less than 900°C) is the necessary condition for preparing corrosion-resistant coatings. The highest corrosion resistance is attained at low (<2%) and high (>15%) carbon content of the coating. Some samples are not inferior to dense technetium foil in the corrosion resistance. Ways of further improvement of the deposition process are outlined.     

Vapor deposition of technetium coatings by thermolysis of volatile carbonyl complexes: II. Chemical and phase composition,microstructure, and corrosion resistance of coatings

The microstructure, chemical and phase composition, and corrosion resistance of coatings deposited by thermolysis of vapors of volatile technetium carbonyl compounds on a titanium support are studied. The relationship between the nature of the starting compound, conditions of the heat treatment of the coatings, and their chemical and phase composition and corrosion resistance is analyzed. Vacuum annealing at a high temperature (no less than 900°C) is the necessary condition for preparing corrosion-resistant coatings. The highest corrosion resistance is attained at low (<2%) and high (>15%) carbon content of the coating. Some samples are not inferior to dense technetium foil in the corrosion resistance. Ways of further improvement of the deposition process are outlined.     

金属锆微弧氧化电解液体系和氧化时问对陶瓷膜层的影响

分别用钨酸钠、偏铝酸钠、硅酸钠电解液体系在金属锆表面上制备了氧化锆陶瓷膜。探讨了电解液种类、氧化时间对膜层相结构、微观形貌和耐蚀性的影响。结果表明：氧化膜成分、组织结构、形貌和耐蚀性受电解液种类影响较大;钨酸钠、偏铝酸钠体系陶瓷膜由单斜相组成,而硅酸钠体系则形成了异常的正交相及单斜相,其膜层的耐蚀性不同程度地优于钨酸钠...     

Hardness recovery of ceramic coated aluminium matrix composites using thermal-shock resistant sol-gel silica coatings

Sol-gel silica coatings increase wear and corrosion resistance of aluminium matrix composites, but a heat treatment stage at temperatures as high as 500 °C is usually required to consolidate the ceramic coating. Under these thermal conditions, sol-gel ceramic coatings tend to crack and the aluminium matrix hardness strongly reduces. Present paper describes how the combination of a certain sol-gel procedure accompanied with quenching treatment in silicone oil allows recovering most of the hardness of the substrate, while keeping undamaged the sol-gel silica coating deposited.     

镁合金/环氧聚氨酯涂层体系的耐腐蚀性能

环氧聚氨酯(ER/PU)涂层具有良好的电绝缘性、耐腐蚀性以及与金属基体的附着力,能够有效地阻挡或缓解Cl-,NO3-,SO2-4,H2O和O2等对镁合金基材的侵蚀,提高镁合金的耐腐蚀性能.为此,采用附着力、铅笔硬度测试,浸泡、失重法、盐雾及电化学试验等方法研究了聚氨酯(PU)涂层及环氧聚氨酯(ER/PU)涂层对镁合金的腐蚀保护效果及机理.结果表明,2种涂层体系都显著提高了镬合金的耐腐蚀性能,与基材附着良好、且硬度高,但后者效果更好.