环境压力与气体成分对等离子喷涂纳米结构YSZ热障涂层微观结构的影响
发布时间：2018-09-17 10:05
【摘要】：近些年来,热喷涂技术得到了广泛的发展和应用。随着大气等离子喷涂技术的逐渐成熟,新型的低压等离子喷涂技术也受到了越来越广泛的关注。超低压等离子喷涂技术是在较低的压强(50-100Pa)下,利用大功率的等离子喷枪,可以使等离子射流的喷射速度达到超音速,继而沉积得到不同于传统的层状结构的涂层。本文主要运用三种不同的等离子喷涂方法,即大气等离子喷涂、低压等离子喷涂和超低压等离子喷涂,分别喷涂两种不同的YSZ纳米团聚粉末(烧结粉末和未烧结粉末),制备各种不同的涂层。实验中,还将分别使用两种不同的等离子工作气体(Ar-H2和Ar-He)来获得不同的等离子射流。然后,再将在不同条件下得到的涂层进行镶嵌、打磨、抛光、热腐蚀,继而在扫描电镜下观察涂层的横断面,来分析其组织结构的特点。实验结果表明：使用纳米团聚YSZ粉末,采用大气等离子喷涂可以制备出多孔的等轴晶热障涂层。在低压和超低压条件下,气体成分对涂层的微观组织有很大的影响,采用Ar-H2等离子气体制备的涂层中存在大块晶粒及较大的气孔。采用Ar-He等离子气体制备的涂层中晶粒更加均匀和细小,并可以制备出完全纳米等轴晶的涂层。在低压/超低压条件下,等离子体的射流特性与大气压下有很大区别,低压和超低压下可以制备出完全纳米等轴晶的涂层。超低压下制备的涂层晶粒更加细小。
[Abstract]:In recent years, thermal spraying technology has been widely developed and applied. With the maturation of atmospheric plasma spraying technology, new low pressure plasma spraying technology has been paid more and more attention. The ultra-low pressure plasma spraying technology can make the injection velocity of plasma jet reach supersonic speed under lower pressure (50-100Pa) and use the high power plasma spray gun, and then deposit the coating which is different from the traditional layered structure. This paper mainly uses three different plasma spraying methods, namely, atmospheric plasma spraying, low pressure plasma spraying and ultra low pressure plasma spraying. Two kinds of YSZ nano-agglomerated powder (sintered powder and unsintered powder) were sprayed to prepare different coatings. Two different plasma working gases (Ar-H2 and Ar-He) will be used to obtain different plasma jets. Then, the coatings obtained under different conditions were inlaid, polished, polished and hot corroded, and then the transverse sections of the coatings were observed under scanning electron microscope to analyze the structural characteristics of the coatings. The experimental results show that porous equiaxed thermal barrier coatings can be prepared by using nano-agglomerated YSZ powder and atmospheric plasma spraying. Under the condition of low pressure and ultra low pressure, the composition of gas has a great influence on the microstructure of the coating. There are large grains and large pores in the coating prepared by Ar-H2 plasma gas. The coating prepared by Ar-He plasma gas is more uniform and finer, and can be used to fabricate the complete nano-equiaxed coating. The characteristics of plasma jet at low / ultra-low pressure are different from those at atmospheric pressure, and a complete nano-equiaxed coating can be prepared under low pressure and ultra-low pressure. The grain size of the coating prepared at ultra low pressure is smaller.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB306
本文编号：2245528
[Abstract]:In recent years, thermal spraying technology has been widely developed and applied. With the maturation of atmospheric plasma spraying technology, new low pressure plasma spraying technology has been paid more and more attention. The ultra-low pressure plasma spraying technology can make the injection velocity of plasma jet reach supersonic speed under lower pressure (50-100Pa) and use the high power plasma spray gun, and then deposit the coating which is different from the traditional layered structure. This paper mainly uses three different plasma spraying methods, namely, atmospheric plasma spraying, low pressure plasma spraying and ultra low pressure plasma spraying. Two kinds of YSZ nano-agglomerated powder (sintered powder and unsintered powder) were sprayed to prepare different coatings. Two different plasma working gases (Ar-H2 and Ar-He) will be used to obtain different plasma jets. Then, the coatings obtained under different conditions were inlaid, polished, polished and hot corroded, and then the transverse sections of the coatings were observed under scanning electron microscope to analyze the structural characteristics of the coatings. The experimental results show that porous equiaxed thermal barrier coatings can be prepared by using nano-agglomerated YSZ powder and atmospheric plasma spraying. Under the condition of low pressure and ultra low pressure, the composition of gas has a great influence on the microstructure of the coating. There are large grains and large pores in the coating prepared by Ar-H2 plasma gas. The coating prepared by Ar-He plasma gas is more uniform and finer, and can be used to fabricate the complete nano-equiaxed coating. The characteristics of plasma jet at low / ultra-low pressure are different from those at atmospheric pressure, and a complete nano-equiaxed coating can be prepared under low pressure and ultra-low pressure. The grain size of the coating prepared at ultra low pressure is smaller.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB306
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