高温钛合金表面YSZ热障涂层性能研究-材料加工工程专业毕业论文.docx

Classified Index:
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Dissertation for the Master Degree in Engineering
RESEARCH ON PROPERTIES OF YSZ THERMAL BARRIER COATINGS ON HIGH TEMPERATURE TITANIUM ALLOY
Candidate:
Zhang Kezhao
Supervisor:
Associate Prof. Tianjing
Academic Degree Applied for:
Master of Engineering
Speciality:
Materials Processing
Engineering
Affiliation:
School of Materials Science and
Engineering
Date of Defence:
July, 4th, 20012
Degree-Conferring-Institution:
Harbin Institute of Technology
摘要
高温钛合金由于抗氧化性能较差,限制了其适用范围,通过在表面采用等离子喷涂的方式,以 NiCrAlY 合金作为粘结层,制备了 YSZ 热障涂层,提高了其
使用温度和应用范围。
等离子喷涂制备的热障涂层内部存在缺陷,通过 Image J 软件计算其孔隙率约为 15%,线扫描结果显示 NiCrAlY 粘结层和 TNW700 钛合金基体之间的结合
方式以机械结合为主,呈现出一定的冶金结合趋势,粘结层和 YSZ 陶瓷涂层之间的结合方式为机械结合;等离子喷涂使 TNW700 钛合金的硬度显著增大,通过表面粗糙度计算原理计算出涂层的表面粗糙度在 Ra3~Ra6 之间;
对 TNW700 合金和热障涂层进行高温抗氧化实验的结果表明,热障涂层的存在使抗氧化性能有了显著的提升,通过线扫描和面扫描分析,在 N iCrAlY 粘结层中存在的热生长氧化层(TGO)阻碍了外界的氧向基体扩散,热障涂层的抗氧化性
随着涂层厚度的增加而增加;
对热障涂层进行高温热腐蚀实验,XRD 分析结果表明在热腐蚀实验过程中没有物相转变,能谱分析结果显示在 YSZ 涂层表面生成了 Na2ZrO3,截面线扫描结果显示涂层内部残留了熔盐,总体说来,热障涂层表现出了良好的抗腐蚀性能, 涂层的抗腐蚀性能随着涂层厚度的增加而增加;
对热障涂层进行热震实验,XRD 物相分析表明在此过程中没有发生相转变, 涂层发生了翘曲现象,翘曲程度随着涂层厚度的增加而减小,扫描电镜下观察发现 YSZ 表面有裂纹产生,而且生成了白色的点状物,进一步的能谱分析表明可能
是粘结层中的 Cr、Al 元素在热震过程扩散至 YSZ 涂层表面,进而和 ZrO2 反应生
成的锆酸盐。
关键词热障涂层 TNW700 钛合金高温氧化高温腐蚀热震
Abstract
High temperature titanium alloys are limited in its application range because of its poor oxidation resistance. Thermal Barrier Coatings, which are prepared on the surface of titanium alloys using plasma spraying technology, can improve its service temperature and application range.
As known to all, there are defects in the YSZ coatings prepared by plasma spraying, and the porosity is about 15% calculated by Image J. The results of line scanning under SEM show that the binding mode of NiCrAlY bonding layer and TNW 700 titanium alloy belongs to mechanical bonding, while the transformation from mechanical bonding to metallurgical bonding was found at the same time. On the other hand, the way bination between bonding lay