微弧等离子喷涂制备莫来石/金属复合热障涂层

运用微弧等离子喷涂制备了莫来石/金属复合热障涂层.研究了涂层的微观结构、结合强度、隔热性能和抗热震性能.复合涂层结构为莫来石颗粒被"包裹"在金属层片状结构中;涂层的结合强度大于30 MPa.随着涂层中莫来石含量的增加,涂层的隔热性能有所提高,随涂层表面温度的升高,涂层的隔热温度也不断提高,涂层的最高隔热温度为125℃.1 150℃的水淬热震试验表明,基体变形是导致涂层失效的重要原因之一,随着涂层中莫来石含量的增加,涂层的抗热震次数先增加后减小,粉末中莫来石含量为40%的涂层的抗热震性能最好,抗热震次数最多为72次.     

热障涂层的CMAS腐蚀失效及对策研究综述

研制具有长寿命、高性能的热障涂层（TBCs）,是制造我国大功率航空发动机、发展新一代超音速战机的一项十分紧迫的任务。由于外来沉积物CaO-MgO-Al2O3-SiO2（CMAS）渗入涂层而导致TBCs失效的现象越来越受到人们的重视,在过去的一段时间里,很多学者对CMAS渗入后涂层的失效机理进行了大量的研究并尝试了一些缓解CMAS渗入涂层的方法。本文针对当前应用最为广泛的“层状多孔结构”的等离子喷涂涂层及“细长柱晶结构”的电子束辅助物理气相沉积涂层,系统地梳理了近年来国内外学者对TBCs在CMAS渗入条件下的失效机制及涂层缓解CMAS渗入方面的最新研究成果,为制备高性能的TBCs提供帮助。     

Improving the methodology for coating defects detection

A vacuum impregnation procedure for examining the microstructure of thermal spray coatings has been evaluated using a low-viscosity fluorescent resin. The use of confocal laser scanning microscopy for examining the microstructure allows three-dimensional image reconstruction of the sample. Relationships between defects (i.e., porosity or micro/macrocracking) and coating properties can be established more accurately with the proposed methodology because it enables quantitative analysis.     

微弧等离子喷涂制备空心莫来石隔热涂层研究

采用微弧等离子喷涂方法制备了空心微珠莫来石隔热涂层。研究了涂层的结合强度、隔热性能和抗热震性能。实验结果表明：拉伸断裂发生在莫来石涂层内,涂层的平均结合强度约为5.63 MPa;稳态测量涂层隔热温度,当涂层表面温度为400℃～800℃时,涂层的隔热温度变化范围为11.5℃～40℃;热震温度为400℃～800℃间隔100℃时,涂层的抗热震次数分别为165、135、117、81和34次;涂层先从试样边沿开始剥落,并呈加速剥落的趋势。涂层失效主要原因是由于热震过程中残余应力积聚造成的。     

热氧化温度对非平衡磁控溅射TiN镀层的影响

通过SEM和XRD法,研究不同热氧化温度下闭合场非平衡磁控溅射离子镀技术制备的TiN镀层形貌、相结构及性能的变化。结果表明:非平衡磁控溅射离子镀TiN镀层在700℃以下性能基本稳定,具有良好的热氧化性能,尽管600℃时生成少量TiO2相,但600℃之前断口形貌及组织结构保持稳定;700℃时镀层的单位质量氧化增重率迅速增加,氧化曲线出现拐点,镀层失效。     

U表面Al及Ti/Al双重镀层的电化学腐蚀行为

采用动电位极化技术和扫描电镜(SEM)对U表面Al及Ti/Al双重镀层在含50μg/gCl^－的KCl溶液中的电化学腐蚀行为进行研究。研究结果表明：U表面Al镀层和Ti/Al双重镀层的腐蚀为局部腐蚀，其腐蚀速度明显低于裸体U，能够对U表面提供较好的保护。Al镀层相对U基体为阳极性镀层，能对U基体提供牺牲性保护；Ti镀层相对U基体为阴极性镀层，对U基体的保护是基于镀层对腐蚀介质的物理屏障作用。     

Thin film getter coatings for the GSI heavy-ion synchrotron upgrade

For the future project the Facility for Antiproton and Ion Research (FAIR) at GSI, an accelerator system with a base pressure of 10⁻¹⁰ Pa is required. The low pressure is needed to reduce the charge exchange rate between the accelerated ions and the residual gas molecules and therefore to increase the ion beam lifetime. Among the different measures undertaken to upgrade the existing UHV system, the installation of non-evaporable getter (NEG)-coated dipole and quadrupole chambers is foreseen. For this purpose a licence agreement for the non-evaporable thin film getters was signed between GSI and CERN in the end of June 2005.A new dedicated magnetron sputtering facility was designed and commissioned at GSI to perform the Ti-Zr-V coating on the dipole chambers of the heavy-ion synchrotron (SIS 18).Those pipes, made from stainless steel, have an elliptical cross section, are 3 m long, and are characterised by a wall thickness of 0.3 mm and a 15° bending angle.The characterisation of the thin films produced has been carried out by Rutherford backscattering spectroscopy (RBS), energy dispersive X-ray spectroscopy (EDX) and elastic recoil detection analysis (ERDA) for the chemical composition, scanning electron microscopy (SEM) for the morphology, and X-ray photoelectron spectroscopy (XPS) for the activation behaviour.The coating facility, its operating mode, and the first results obtained on the NEG characterisation by means of the different techniques will be described.     

激光熔覆WC/Ni60B复合涂层在水润滑滑动摩擦环境下的磨损特性

采用激光熔覆技术制备了Ni60B镍基合金涂层以及微米WC、纳米WC和微-纳米WC颗粒增强的Ni60B基复合涂层（分别称为WCm、WCn和WCmn复合涂层）.对制备涂层在Amsler200磨损试验机上进行了不同载荷和滑动距离的水润滑滑动磨损试验.结果表明：WC颗粒的加入显著提高了Ni60B涂层的耐磨性.WCm复合涂层和纳米WCn复合涂层的耐磨性差别不大,但磨损形貌不同.涂层在水润滑环境下的磨损量均远远低于干滑动摩擦,其原因是水膜的支撑或隔离作用降低了涂层与磨轮之间的接触应力,水的冷却作用减少了摩擦热引起的温度升高,降低了涂层摩擦表面的温升和热软化.水润滑摩损条件下,WCm和WCn复合涂层中过饱和W元素发生扩散和聚集.