Investigation on plasma-sprayed ZrO2 thermal barrier coating on nickel alloy substrate

The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY-Y₂O₃ stabilized ZrO₂ transition layer and Y₂O₃ stabilized ZrO₂ ceramic layer are prepared on nickel alloy substrates using the plasma spray technique. The relationship among the composition, structure and property of the coatings are investigated by means of optical microscope, scanning electronic microscope and the experiments of thermal shock resistance cycling and high temperature oxidation resistance. The results show that the structure design of introducing a transition layer between Ni alloy substrate and ZrO₂ ceramic coating guarantees the high quality and properties of the coatings; ZrO₂ coatings doped with a little SiO₂ possesses better thermal shock resistance and more excellent hot corrosion resistance as compared with ZrO₂ coating materials without SiO₂; the improvement in performance of ZrO₂ coating doped with SiO₂ is due to forming more dense coating structure by self- closing effects of the flaws and pores in the ZrO₂ coatings. Biography of the first author: LU An-xian, Ph.D, professor, born in Jan. 1960, majoring in inorganic non-metal materials.     

Al_2O_3陶瓷涂层抗高温热冲击性能的研究

本文对Ａｌ２Ｏ３陶瓷涂层的高温热冲击性进行了研究，结果表明，在工作层与基体间增加过渡层能提高涂层的热冲击性，而具有更多孔隙的涂层将降低涂层的强度，降低涂层与基体的粘结强度，降低涂层对基体的保护作用，加速基底层的氧化，使涂层的抗高温热冲击性降低．     

铝合金上等离子喷涂NiCrAlCoY/ZrO2梯度热障层连接的研究

利用等离子喷涂法在发动机铝合金活塞上制得NiCrAlCoY与用质量分数为8％的Y2O3稳定的ZrO2梯度热障层。经热震实验、金相分析、SEM分析和TEM分析，结果表明该热障层具有良好的抗热冲击性和高温热稳定性，并且NiCrAlCoY与ZrO2间形成了化学键结合。这为今后解决TBCs可靠性的问题提出了新的思路。     

金属基陶瓷涂层的耐高温及抗热冲击性能

以自制无机胶粘剂、通过添加耐高温耐磨陶瓷骨料A12 O3,WC,SiC混合后涂覆于A3钢表面制得陶瓷涂层,研究了调胶比（氧化铜与磷酸盐的配比）、骨胶比（胶粘剂与陶瓷骨料的配比）不同对金属基陶瓷涂层耐高温及抗热冲击性能的影响;并分析了金属基体与陶瓷涂层间的结合机理．结果表明：调胶比为0．5g／ml此涂层能承受1300℃以上的高温．骨胶比比为0．30：1（质量比）时,制备的陶瓷涂层抗热冲击性能最佳,能承受600～700℃的16次以上的热震试验．     

Effects of ZrO_2 Nanoparticles on the Microstructure and Thermal-protective Properties of PEO Coating on Al-12.5%Si Alloy

PEO ceramic coatings including ZrO_2-Al_2O_3-SiO_2 in three phases were prepared on an Al-12.5%Si alloy in electrolyte solutions containing ZrO_2 nanoparticles. The microstructures and phases of the coatings were analyzed by SEM and XRD, and the heat insulation performance and the thermal shock resistance of the coatings were investigated. The compactness of the coating increased significantly and the hindrance of the Si element on plasma electrolytic oxidation process was effectively weakened. The growth rate of the coating was improved substantially with the addition of ZrO_2 nanoparticles. The PEO ceramic coatings are primarily composed of SiO_2 and high temperature steady phases such as a-Al_2O_3 and c-ZrO_2. Both the content of c-ZrO_2 and the heat-insulating property of the coating increased significantly. The ceramic coatings with special microstructure and composition formed in the solutions containing ZrO_2 nanoparticles possess excellent heat insulation performance and thermal shock resistance.     

Effect of ZrO2 （9mol % Y2O3） coating thickness on the electronic conductivity of Mg-PSZ oxygen sensors

The ZrO2 (9mol% Y2O3) coating was prepared evenly on the surface of MgO partially stabilized zirconia (Mg-PSZ) tube (oxygen sensor probe) by dipping the green Mg-PSZ tube in a ZrO2, (9mol% Y2O3) slurry and then co-firing at 1750℃ for 8 h. The double-cell method was employed to measure the electronic conductivity parameter and exam the reproducibility of the coated Mg-PSZ tube. The experimental results indicate that the good thermal shock resistance of the Mg-PSZ tube can be retained when the coating thickness is not more than 3.4μm. The ZrO2 (9mol% Y2O3) coating reduces the electronic conductivity parameter remarkably. probably due to the lower electronic conductivity of Y2O3-stabilized ZrO2 than that of MgO-stabilized ZrO2. Moreover, the ZrO2(9mol% Y2O3) coating can improve the reproducibility and accuracy of the Mg-PSZ tube significantly in the low oxygen measurement. The smooth surface feature and lower electronic conductivity of the coated Mg-PSZ tube should be responsible for this improvement.     

镁合金表面热喷涂Al-Al2O3/TiO2梯度涂层研究

采用氧乙炔火焰喷涂法，在AZ91D镁合金表面制备Al-Al2O3/TiO2梯度涂层。利用扫描电镜和电子探针对涂层的组织形貌、成分进行了分析。采用热震法测试了涂层结合强度，并对涂层耐磨性进行了测试。实验结果表明：Al梯度层与基体及陶瓷涂层结合良好。涂层具有较高的硬度、耐磨性及抗热震性。     

Microstructure and Thermal-protective Property of CPED Coating with ZrO_2 Nanoparticles Addition on Al-12Si Alloy

A novel thermal-protective coating has been successfully prepared by CPED process on a cast Al-12%Si alloy with the addition of ZrO_2 nano-particles in the electrolyte. The microstructures and phase composition of the coatings were analyzed by SEM and XRD, and the heat insulation performance and the thermal shock resistance of the coatings were investigated. With ZrO_2 nanoparticles addition, the cathode plasma discharge on the coating surface is more obvious than that without ZrO_2 nanoparticles addition, the coating is more uniform and compact, and the thickness of the coating increases. Furthermore, the content of Zr and Y elements increases and the degree of crystallization of the coating is more complete. The formation of the solid solution of yttrium stabilized zirconia is promoted by cathode plasma discharge. In addition, the thermal insulation temperature increases as ZrO_2 nano-particles are added to the electrolyte. After 1 000 cycles of thermal shock, there was no cracking in the coating surface layer, which indicated that the CPED coating with ZrO_2 nanoparticles addition possessed a good thermal shock resistance.     

相变对ZrO2／SiO2多层膜激光损伤阈值的影响

摘要：用电子束蒸发法制备出ZrO2／SiO2和YSZ／SiO2多层膜,分别测定了薄膜结构特性和激光损伤阈值. 实验结果表明：Y2O3稳定的ZrO2镀膜材料在电子束蒸发过程中不会发生相变,而未稳定的ZrO2则必然发生相变产生喷溅,使缺陷增加,从而使损伤阈值降低. 通过分析认为相变引起的缺陷是YSZ／SiO2和ZrO2／SiO2高反膜损伤阈值差别的主要原因.     

ZrO2陶瓷表面Cu-Ti复合渗镀研究

应用加弧辉光复合渗镀技术和自制Cu-Ti二元金属复合靶,对ZrO2陶瓷表面进行Cu-Ti复合渗镀。采用X射线能量色散谱分析（EDS）、扫描电子显微镜（SEM）面扫描、X射线衍射（XRD）、声发射划痕等试验方法对渗镀层的元素组成、成分分布、相组成、界面结合强度进行分析测试。结果表明渗镀层中存在Cu、Ti及Fe元素,各组分分布较为均匀,没有明显的成分偏聚现象;渗镀层由Cu2Ti、Cu2Ti4O、Ti8O15组成;渗镀层与陶瓷基体结合良好,在100 N最大载荷下未出现剥离和崩落现象。     

Al-Si合金Al2O3-ZrO2微弧氧化层生长及性能测试

针对单一Al2O3微弧氧化层不能满足基体Al-Si合金使用要求的问题,采用微弧氧化法在Al-Si合金表面制备了Al2O3-ZrO2复合陶瓷层,研究了涂层的组成、结构及生长过程;测试了涂层的隔热温度.研究结果表明：在Al-Si合金试样表面微弧氧化30 min后,涂层的表面形成＂火山喷射状＂组织形貌,截面由疏松层、致密层、过渡层组成;涂层由-αAl2O3,γ-Al2O3,m-ZrO2和t-ZrO2组成,t-ZrO2为涂层的主晶相,膜层的生长分为匀速生长阶段和缓慢生长阶段;膜层隔热温度可达30℃.     

热障涂层对活塞温度场影响的三维分析

为提高内燃机的工作效率和使用寿命,以表面涂覆热障涂层的发动机活塞为主要研究对象,综合分析热障涂层对活塞温度场的影响.建立了热障涂层活塞的三维模型,运用有限元软件对其进行了温度场分析计算,考察了不同涂层材料和涂层厚度对活塞温度场的影响情况.研究结果表明:0.4mm厚的ZrO2陶瓷涂层可使活塞的隔热效果提升约8.8%,并且隔热效果明显优于Al2O3、Si3N4和SiC;ZrO2涂层厚度每增加0.5mm,活塞金属基体顶面的最高温度下降约3.2℃,陶瓷涂层顶面的最高温度上升约8.3℃.     

Study on Squeeze Casting Metal-zirconium Composite Die Material by Hot Press Sintering

ZrO_2-5CrMnMo composite samples were prepared by hot press sintering.When NiCoCrAlY powders were used as the bonding layer and the different mixtures of NiCoCrAlY alloy and 3YSZ (3mol% yttria stabilized zirconia) ceramic powders were used as the transition layers,the connection between zirconia ceramic and 5CrMnMo steel were strengthened.Three composite samples with different structures were fabricated by heat spraying and hot press sintering.Shear and thermal shock cycle tests were conducted to characterize connection strength and thermal shock resistance of these samples.The shear strength reached 95.69 MPa,and the heating shock cycles achieved to the maximum value of 27.7 times.Microstructures and connection interfaces were analyzed by scanning electron microscopy.The hardness and wearing resistance of 3YSZ coat and 5CrMnMo substrate were compared,and the heat insulation property of composite samples were also discussed.It is shown that these composite materials fabricated in this research are benefited to be used as squeeze casting dies.     

平板式汽车ZrO2氧传感器多孔保护层研究

为开发平板式汽车ZrO2氧传感器的保护层,以MgAl2O4为主要原料,研制了适合于ZrO2氧传感器电极保护的多孔复合保护层,并对其气孔率和抗热冲击性能进行了研究。结果表明,保护层中造孔荆含量增多,其气孔率增大,附着强度降低,当造孔剂含量为4％～6％时,满足了多孔性保护层的要求,并且也能保持较好的抗热冲击性。     

稀土掺杂ZrO_2基热障涂层陶瓷材料研究进展

热障涂层用于燃气轮机的热端部件,不仅可以显著提高其使用温度,延长热端部件的使用寿命,而且提高了燃气轮机发动机的效率.介绍了稀土掺杂ZrO2基热障涂层的研究现状及发展趋势.结果表明LnO1.5-Ta2O5（或Nb2O5）-YSZ材料既可以提高传统YSZ热障涂层的使用温度,而且也降低了其热导率.LnO1.5-Ta2O5（或Nb2O5）-YSZ材料可以作为热障涂层系统中陶瓷顶层的下一代候选材料.     

基体表面状态对 Fe3Al/Al2O3复合涂层性能的影响

利用等离子喷涂方法在相同喷涂工艺条件下 ,分别在不同表面状态的Q2 35钢基体上制备了Fe3Al/Al2 O3陶瓷复合涂层 .通过对涂层的结合强度、抗热震性能等试验 ,分析研究了基体表面状态对涂层性能的影响 .结果表明 ,对基体进行有效的表面处理 ,使其获得高的表面粗糙度和表面活性 ,有利于涂层结合强度和抗热震性能的提高 ,基体表面预处理是保证涂层质量的重要环节 .Fe3Al是钢基体上制备陶瓷涂层较为理想的过渡材料     

锆英粉涂料涂层结构研究

通过研究锆英粉(其中有少量铝矾土)涂料层的断面结构,发现在高温条件下,锆英粉能分解出少量ZrO2微粉和SiO2;钢液表面的FeO能渗透到涂层中,与SiO2和水玻璃等形成铁橄榄石相;锆英粉能被水玻璃缓慢溶解,但其颗粒仍然能保持完整状态;SiO2、FeO、Al2O3、Na2O等生成了大量低熔点的玻璃相,填充其颗粒间空隙,形成致密层,能防止钢液渗透;涂层中的铝矾土在水玻璃的作用下,其颗粒状态消失,形成铝酸铁钠新相.     

工艺参数对LY12铝合金复合涂层的影响

以恒压模式在NaOH-Na2SiO3电解液中对LY12铝合金进行微弧氧化实验,然后用强流脉冲电子束轰击,采用扫描电镜、XRD、涂层测厚仪等检测手段,研究电参数对复合涂层的影响.结果表明：电压越高,氧化时间越长,微弧氧化膜越厚;电子柬复合处理后,涂层变得平整、致密,新相α-Al2O3峰值变高,耐摩擦磨损性能增加.     

铝合金微弧氧化陶瓷膜研究

在硅酸盐电解液中采用微弧氧化法在2024铝合金表面形成氧化物陶瓷膜．分别用扫描电镜、X射线衍射仪研究了陶瓷膜的组织形貌和相组成．相对致密均匀的膜层主要由α—Al2O3,γ-Al2O3和少量的非晶相物质组成．陶瓷层纳米硬度从内部到外部呈下降趋势．     

爆炸喷涂Al2O3陶瓷涂层的摩擦磨损性能

爆炸喷涂是提高材料表面性能的表面喷涂技术之一.本文旨在通过表面喷涂提高45钢基体表面的耐磨性、耐冲击性等性能.采用爆炸喷涂方法在45钢基体材料上喷涂Al2O3陶瓷和团聚陶瓷涂层,在摩擦磨损试验机上进行Al2O3陶瓷涂层的磨损试验,X衍射仪测试涂层表面结构,JB/T7509—94铁试剂方法测试涂层的孔隙率.通过分析和比较45钢基材与爆炸喷涂Al2O3陶瓷涂层的摩擦磨损性能,实验结果表明,喷涂Al2O3陶瓷涂层可以改善基材45钢的耐磨损性能,延长其使用寿命.此外,研究发现,团聚Al2O3陶瓷涂层比Al2O3陶瓷涂层要更耐磨;而爆炸喷涂Al2O3涂层的质量要好于等离子喷涂和火焰喷涂Al2O3陶瓷涂层.