热处理工艺对氧化锆纳米粉末及其涂层结构与性能的影响
文献类型：学位论文
| 作者 | 姚星合 |
| 学位类别 | 硕士 |
| 答辩日期 | 2011-06-02 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 朱永平 |
| 关键词 | 氧化钇稳定氧化锆 粉末热处理方法 等离子喷涂 热障涂层 涂层性能 |
| 其他题名 | Study on the Influence of Heat Treatment on Microstructure and Properties of Nanosized Zirconia Powder and Coating |
| 学位专业 | 材料学 |
| 中文摘要 | 本文研究了高温烧结、等离子炬和等离子流场三种热处理工艺对ZrO2-8%molY2O3（8YSZ）球形颗粒的结构、形貌及其等离子喷涂涂层微观组织结构与性能的影响。水热合成的8YSZ纳米粉末，经过离心干燥后分别进行上述三种不同的热处理工艺，经过热处理的团聚体粉末在相同的等离子体喷涂条件下喷涂制备成纳米结构热障涂层。利用光学显微镜和扫描电镜分析粉末粒径大小、颗粒形貌、涂层显微组织，用X-ray衍射分析原始粉末、离心造粒粉末、热处理粉末和涂层的相组成，测量粉末的松装密度和流动性，对热处理工艺对涂层结合强度和热震性能的影响进行研究，为材料制备及性能提高提供参考依据。三种热处理工艺处理后的粉末晶粒度均在100nm以下，是保持有纳米结构的8YSZ团聚体。经高温烧结的粉末随烧结温度的升高和时间的延长，晶粒长大，烧结程度加剧，松装密度增大，流动性提高，单斜相含量从7.54%降低至2.04%；经等离子炬和等离子流场球化的粉末，表面非常致密且光滑，粉体的松装密度和流动速度大大提高，分别达到了2.12g/cm3、40s/50g，和2.41g/cm3、30s/50g，单斜相的含量甚微，从XRD谱图中已观测不到单斜相的特征峰。 等离子喷涂涂层结构为纳米-微米复合结构，微米结构主要来源于完全熔化的纳米团聚体颗粒；纳米结构由粉末原料中保留下来的纳米晶粒和涂层沉积过程中急冷形成的纳米晶粒两部分组成。涂层的物相组成为单一的非平衡四方相（t'-ZrO2），等离子体喷涂过程中粉末原料中存在的单斜相m相全部转变为非平衡四方相t'相。等离子炬球化法制备的8YSZ粉体所获得的等离子喷涂涂层的结合强度最好，平均为25MPa，抗热震性能最好，1200℃恒温5min，水冷，热循环达41次；而采用等离子流场球化法制备的8YSZ粉体所获得的等离子喷涂涂层的结合强度最差，平均为11MPa，抗热震性能最差，热循环次数为17次；经1200℃、2h烧结的8YSZ粉体所获得的等离子喷涂涂层的结合强度和抗热震性能居中，平均分别为21MPa和38次热循环。 |
| 英文摘要 | The effects of high-temperature sintering, plasma torch and plasma flow heat treatment on the properties of 8YSZ spherical powders and plasma sprayed coatings were investigated. The 8YSZ nanopowders were synthesized by hydrothermal method. After spray granulation and heat treatment with high-temperature sintering, plasma torch and plasma flow process, respectively, the nanostructured thermal barrier coatings are prepared under the same plasma spraying conditions. Optical microscopy and scanning electron microscopy were used to observe the morphology and particle size of the starting nanocrystalline powders and the agglomerated powders as well as to examine the microstructure of the thermal barrier coatings. X-ray diffraction was used to analyze the crystal structure of the powders and the coatings. Inaddition，apparent density and flowability of the powders were measured. The bonding strength and thermal shock performance of the coatings were studied to provide references for material preparation and its performance enhancement. The 8YSZ powders after heat treatment remain original nanostrueture.The grain and the bulk density increased with the temperature and the time increasing, as well as the monoclinic phase content decreased from 7.54% to 2.04%. The surfaces of the powders treated by plasma torch and plasma flow were very dense and smooth. Powder bulk density increased greatly to 2.12 g/cm3 and 2.41 g/cm3, and the flowability increased to 40 s/50g and 30 s/50g, respectively. The characteristic peaks of monoclinic phase can not be observed in the XRD pattern. The results show that the properties of the coating are closely related to the heat treatment. The plasma sprayed coating derived from plasma torch treated powder of 8YSZ has the highest bonding strength of 25 MPa and the best thermal shock resistance of 41 thermal cycles which is under water cooling after treated at 1200℃ for 5 min. The coating fabricated by plasma flow treated 8YSZ has very low bonding strength of 11 MPa and poor thermal shock resistance of 17 thermal cycles. The performance of coatings prepared by sintered 8YSZ rely on the temperature and the time of treatment and the best mechanical properties were obtained when 8YSZ powder treated at 1200℃ for 2 h, the average bonding strength was 21 MPa and the thermal shock was 38 cycles. |
| 语种 | 中文 |
| 公开日期 | 2013-09-23 |
| 页码 | 77 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1680]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 姚星合. 热处理工艺对氧化锆纳米粉末及其涂层结构与性能的影响[D]. 中国科学院研究生院. 2011. |
入库方式： OAI收割
来源：过程工程研究所
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