悬浮液等离子喷涂热障涂层的沉积机制及热循环特性

悬浮液等离子喷涂(SPS)较大气等离子喷涂(APS)具有诸多优势,目前对SPS涂层沉积机理报道较少。采用6%~8%Y2O3-ZrO2(YSZ)悬浮液送料进行等离子喷涂制备热障涂层,利用激光粒度仪测试悬浮液中的YSZ粒度,采用扫描电镜(SEM)、光学显微镜观察雾化粒子形貌和涂层的显微组织,探讨涂层的热循环特性并分析其沉积机制。结果表明:悬浮液中93.38%的YSZ粒子尺寸在3.311μm以下;等离子火焰中雾化的YSZ粒子主要有熔融致密的小球状、未完全熔融的疏松球状和未熔融的原始无定形3种形态;喷涂时,小球状粒子撞击基体表面后主要形成直径3~7μm的致密扁平粒子,未完全熔融的疏松球状和无定形态粒子撞击基体时铺展不明显,粒子堆积时容易形成孔隙;粘结层与陶瓷层间横向裂纹的萌生扩展导致热障涂层最终脱落失效。     

液料等离子喷涂制备功能涂层的研究进展

液料等离子喷涂主要包括溶液前驱体等离子喷涂和悬浮液等离子喷涂两种,简要介绍了液料等离子喷涂的原理与特点,着重描述了液料等离子喷涂技术在制备热障涂层、生物陶瓷涂层、光催化涂层、固体氧化物燃料电池阳极涂层和气敏涂层方面的最新研究进展。液料等离子喷涂不仅解决了传统等离子喷涂的细粉输送难题,还具有工艺流程简单、沉积效率高和涂层结构精细等优点,特别适合于先进功能涂层的设计与制备。     

悬浮液等离子喷涂制备的热障涂层微观结构和性能

以纳米8wt.%Y2O3-ZrO2(YSZ)粉末为原料制备悬浮液,并将悬浮液喂料进行等离子喷涂制备热障涂层.采用XRD,SEM分析涂层的相组成与显微组织.结果表明:涂层中的晶粒保持在纳米尺度,涂层的相结构稳定.涂层表面覆盖着致密的扁平粒子组织,扁平粒子的平均等效直径为1.7 um,厚度均处在纳米尺寸.涂层内部为非层状结构,分布有大量的孔隙.这些组织和结构使得涂层具有优良的抗热震性能.     

低压等离子喷涂316L等轴晶涂层及其性能研究

为研究低压等离子喷涂等轴晶涂层组织性能和形成机理,采用大气等离子喷涂（APS）和低压等离子喷涂（LPPS）,分别制备了316L不锈钢涂层.利用金相显微镜,X射线衍射和显微硬度等方法,分析了2种涂层的金相组织、相结构、显微硬度和耐蚀性.结果表明：一定条件下制备的低压等离子喷涂SUS316L不锈钢涂层明显不同于传统大气等离...     

纳米结构热障涂层研究进展

本文主要综述了目前制备纳米结构热障涂层的三种方法,即大气等离子喷涂、溶液前驱体等离子喷涂和悬浮液等离子喷涂,并对这三种方法的工艺过程、制备原理、涂层的微观结构特征和研究现状进行了归纳。最后,总结了纳米结构热障涂层研究目前存在的问题,并对其发展趋势进行了展望。     

大气等离子喷涂Al2O3/ZnO/TiO2涂层微波介电性能的研究

采用高焓大气等离子喷涂技术,以纳米级ZnO、Al2O3和TiO2为原料,通过固相反应制得以ZnAl2O4为主相的陶瓷粉末,加入粘结剂聚乙烯醇(PVA),通过喷雾造粒的方法制备复合吸波陶瓷涂层(简称为AZT涂层).分析了AZT涂层的微观结构和相组成,探究了喷涂功率对AZT涂层微波介电性能的影响.结果表明,AZT涂层对比粉...     

微束等离子喷涂羟基磷灰石涂层

采用微束等离子喷涂(MPS) 在Ti6Al4V基体上制备了羟基磷灰石(HA)涂层, 并以大气等离子喷涂(APS)为对照. 利用光学显微镜、SEM和XRD分析技术对MPS涂层形貌、相组成和结晶度进行了研究. 结果表明: 在微束等离子喷涂过程中, HA 的分解程度比大气等离子喷涂有显著降低, 除了HA相, 仅形成β-TCP相和非晶相. MPS涂层的结晶度主要受喷涂距离的影响. 喷涂距离较短(<80mm)时, 涂层结晶度高于APS方法制备的涂层. 喷涂距离在130mm时, 涂层结晶度低. 大气等离子喷涂层含有β-TCP、α-TCP、TTCP、CaO和非晶. MPS涂层分解较APS少的主要原因是喷涂过程中HA粒子过热不严重.     

基于YSZ液料的液流/雾化等离子熔射射流形态及微观组织研究

采用8％(摩尔分数)YSZ粉末(d50=700 nm)配置熔射悬浮液料,比较了送料气压、熔射功率对液流和雾化等离子射流形态特征的影响.利用SEM对制备涂层的微观组织进行表征,结果表明:雾化较液流液料输送方式制备涂层组织结构更致密,两种液料输送方式下熔射距离的增加均导致部分熔融粒子增多,其有助于形成孔隙结构.基于雾化送料制备了厚度为30μm,孔隙率为1.5％的精细结构YSZ涂层,可用于固体氧化物燃料电池的电解质层.     

大气和低压等离子喷涂氧化铝涂层

根据大气(APS)和低压等离子喷涂(LPPS)的特点,采用两种不同的高纯氧化铝粉末制备了高纯氧化铝涂层.分别采用XRD和SEM对两种涂层的相和结构进行了研究,对涂层的显微硬度和断裂韧性进行了评价,并对涂层制备工艺和性能的关系进行了分析.结果表明:低压等离子喷涂制备的高纯氧化铝涂层韧性和致密性明显优于常压喷涂氧化铝涂层.     

涂层

20010601 等离子喷涂Ni-Cr-B-Si及激光重熔涂层的耐磨性 ──Liang G Y. Surface & Coatings Technology, 2000,12 7(2～3):233(英文)在Al合金上等离子喷涂Ni-Cr-B-Si和Ni-Cr-B-Si+WC,用CO_2激光器重熔合金涂层, 对比研究了激光重熔涂层和等离子喷涂涂层的耐磨性,用SEM分析了磨损形貌。结果表明, 激光重熔涂层和等离子喷涂涂层均具有良好的耐磨性,激光重熔Ni-Cr-B-Si涂层耐磨性 最好,优于等离子喷涂Ni-Cr-B-Si涂层;等离子喷涂Ni-Cr-B-Si+WC涂层的耐磨性优 于等离子喷涂Ni-Cr-B-Si涂层,但激光重熔并未改变二种涂…     

Nanostructured Sulfide Composite Coating Prepared by Atmospheric Plasma Spraying

Nanostructured FeS-SiC coating was deposited by atmospheric plasma spraying (APS). The microstructure and phase composition of the coating were characterized with SEM and XRD, respectively. In addition, the size distribution of the reconstituted powders and the porosity of the coating have been measured. It was found that the reconstitiuted powers with sizes in the range of 20 to 80 μm had excellent flowability and were suitable for plasma spraying process. The assprayed FeS-SiC composite coating exhibited a bimodal distribution with small grains (30～80nm) and large grains (100～200nm). The coating was mainly composed of FeS and SiC, a small quantity of Fe1-x S and oxide were also found. The porosity of the coating was approximately 19 %.     

等离子喷涂氧化锆纳米涂层显微结构研究

利用大气等离子喷涂（APS）技术,在不锈钢基体上制备了氧化锆纳米结构涂层.运用XRD、SEM与TEM等分析手段对喷涂用粉末原料和涂层的显微结构、物相组成进行了观察和确定.实验结果表明,纳米氧化锆粉末经喷雾造粒后的颗粒粒径主要分布在15～40μm之间,流动性好,适合于等离子喷涂用.等离子喷涂氧化锆纳米涂层颗粒分布在60～120nm之间,晶粒发育良好.涂层物相由四方和立方相氧化锆所组成.氧化锆纳米涂层的气孔率约为7％,结合强度为45MPa。     

Characterization of VPS-W coating layers on molybdenum after heat exposure

Tungsten (W) coating layers were successfully deposited using a vacuum plasma spraying (VPS) technique on a molybdenum (Mo) substrate. Tungsten powder with a median size of 10 μm was applied to prepare coatings via a plasma spray system. For the VPS process, argon and hydrogen were used as plasma-forming gases, and the coatings were deposited in 35 mbar vacuum pressure. A coating with a thickness of 300 μm was obtained, and some unmelted W powders were observed in the coating layer. This heat exposure experiment was performed in a sapphire crystal growing furnace at 2100 °C up to 110 h. After heat exposure, the VPS-W coating layers were soundly bonded with the Mo substrate due to the interdiffusion between W and Mo.     

等离子喷涂 AP40生物活性玻璃陶瓷涂层的结构和性能

采用大气等离子喷涂技术，在TiA16V4基体上制备了AP40玻璃陶瓷涂层．利用光学显微镜、SEM和XRD分析技术对涂层形貌、显微组织结构和相组成进行了研究．探讨了热处理工艺对涂层组织结构及其性能的影响，并按德国DIN 50160标准进行涂层的拉伸强度试验．结果表明：等离子喷涂AP40玻璃陶瓷涂层在喷涂态，只有较低的结晶度．喷涂工艺对涂层的孔隙率和粉末沉积率有较大的影响．合适的热处理工艺可提高涂层的结晶度，减少孔隙以及提高结合强度．     

微束等离子喷涂Al2O3陶瓷涂层特性

采用轴向中心送粉式微束等离子喷涂系统在2kW级的小功率条件下制备了Al2O3陶瓷涂层.研究了电弧功率、工作气体流量和喷涂距离对粒子速度与涂层组织结构和性能的影响.采用光学显微镜观察涂层的组织结构,采用X射线衍射分析涂层的相结构,采用磨粒磨损质量损失表征涂层的性能,用热辐射粒子速度温度测量系统测试工艺参数对喷涂粒子速度的影响.结果表明,电弧功率、工作气体流量和喷涂距离对粒子速度的影响都比较明显,粒子速度随着电弧功率和工作气体流量的增加而增加,随着喷涂距离的增加而下降.涂层的磨粒磨损质量损失随电弧功率的增加而减少,而随工作气体流量和喷涂距离的增加而增加.分析表明粒子的温度对涂层磨粒磨损质量损失有较大的影响.采用微束等离子喷涂可以制备磨粒磨损性能与传统等离子喷涂在38kW下制备的涂层相当的Al2O3涂层.     

Electrode coatings for high temperature hydrogen electrolysis

A discussion of fabrication techniques and performance testing of solid oxide components for use in hydrogen steam electrolysis is presented. Novel plasma spray techniques are utilized to deposit the thin ceramic oxide electrode, electrolyte, and interconnect layers on a planar intermetallic bipolar plate. Optimal porosity is achieved within the electrode microstructure through mixed feed techniques that are a combination of dry powder feed and liquid solution injection. The perovskite anode coatings formed from liquid precursor feedstock require post-deposition annealing in an oxygen-rich atmosphere to form the desired perovskite structures. Electrical conductivity measurements were measured for all electrodes and interconnect materials as a function of temperature to 1000 °C. Supported by the U.S. Department of Energy, Office of Nuclear Energy Science and Technology, under the DOE Idaho Operations Contract No. DE-AC07-05ID14517     

等离子喷涂碳化硼涂层相组成和电学性能研究

采用大气等离子喷涂,在不同喷涂距离下制备了碳化硼涂层,研究了喷涂距离对碳化硼涂层的显微结构、相组成和电导率的影响．用EDS和XPS分析了涂层的相组成;扫描电镜观察涂层的显微结构;标准四探针法测量涂层的电导率．结果表明,喷涂距离不仅会影响碳化硼涂层的显微结构,而且会改变碳化硼涂层的相组成;等离子喷涂碳化硼涂层的表面电导率随温度的增加而增加,表现出明显的半导体特性;涂层表面电导率同相组成和显微结构密切相关,涂层中B₂O₃相含量越高,气孔率越大,则涂层的电导率越低．     

Effects of spray parameters on the microstructure and property of Al2O3 coatings sprayed by a low power plasma torch with a novel hollow cathode

Al₂O₃ coating is deposited using a low power plasma torch with a novel hollow cathode through axial powder injection under a plasma power up to several kilowatts. The effects of the main processing parameters including plasma arc power, operating gas flow and spray distance on particle velocity during spraying, and the microstructure and property of the coating are investigated. The microstructure of the Al₂O₃ coating is examined using optical microscopy and X-ray diffraction analysis. The property of the coating is characterized by dry rubber wheel abrasive wear test. The velocity of in-flight particle is measured using a velocity/temperature measurement system for spray particle based on thermal radiation from the particle. The dependency of the microstructure and property of the coating on spray particle conditions are examined by comparing the particle velocity, and microstructure and abrasive wear weight loss of subsequent coating deposited by low power plasma spray with those of the coating by conventional plasma spray at a power one order higher. X-ray diffraction analysis of the coating revealed that Al₂O₃ particles during low power plasma spraying reach to sufficiently melting state prior to impact on the substrate with a velocity comparable to that in conventional plasma spraying. The experiment results have shown that processing parameters have significant influence on the particle conditions and performance of deposited Al₂O₃ coating. The coating of comparable microstructure and properties to that deposited by conventional plasma spray can be produced under a power one order lower. From the present study, it can be suggested that a comparable coating can be produced despite plasma power level if the comparable particle velocity and molten state are achieved.     

等离子喷涂制造固体氧化物燃料电池三合一电极

采用大气等离子喷涂法在阳极支撑上制备了电解质与阴极.利用X射线衍射分析了阴极与阳极喷涂前后的成分和相结构,用扫描电镜观察了SOFC( solid oxide fuel cell)三合一电极的截面形貌以及阳极、电解质与阴极的表面形貌.结果表明:喷涂前后阴极的化学成份未发生改变,阴极为单斜相、钙钛矿型的(La0.8Sr0.2MnO3)LSM;阳极在喷涂前为Ni/YSZ(Y2O3稳定ZrO2),在喷涂后Ni被氧化成NiO.由阳极、电解质与阴极构成的三合一电极界面不明显,其中电解质致密,阳极与阴极有一定孔隙.     

Effects of shroud gas injection on material properties of tungsten layers coated by plasma spraying

Coated tungsten layers on stainless steel substrates were are produced by atmosphere plasma spraying. A shroud gas injection method was employed to reduce the ambient air entrainment into the plasma jets. The effects of shroud gas on the material properties of the tungsten layers were investigated by finding the dependence of oxide content, coating thickness and porosity on the injection velocity, shielding width, and mass flux of the shroud gas. The high injection velocity was more effective than thick shroud shielding in protecting the plasma jets from ambient air engulfment, and the mass flux of the shroud gas showed negligibly small effects on the suppression of air entrainment. Therefore, in order to produce a thick tungsten coating with low porosity and oxide contents, high injection velocity with a limited flow rate is a desirable operating condition for shroud gas injection in atmospheric plasma spraying.