摘要
本文介绍了最新开发的超音速大气等离子喷涂(SAPS)技术制备细密柱晶结构热障涂层系统(SAPS-TBCs)的一些研究进展。由于SAPS喷涂15～45μm粒径的8YSZ氧化锆球形粉末在等离子射流中飞行速度约为400-450m/s,是普通大气等离子(APS:130～220m/s)2～3倍,可方便制备出体积分数达80%以上的薄片状细密柱晶结构TBC涂层,柱晶轴向长度可方便地控制在2～5μm,孔隙率可根据需要在1%～12%范围内调变。研究表明,这种结构的8YSZ-TBC涂层试样1100℃淬水热震循环可达400周次以上,比相应APS-TBC涂层热震性能(小于150周次)高2～3倍;涂层结合强度从APS-TBC的30MPa左右提高到SAPS-TBC的50MPa左右;一个有趣的现象是APS-TBC的隔热效果随着温度和热循环周次的增加而下降,而SAPS-TBC的隔热效果反而升高;对全包覆涂层试样进行的1100℃、1000小时高温氧化实验表明,除了SAPS陶瓷面层更为细密、更多晶界对O-2扩散起了较好的阻挡作用外,SAPS制备MCrAlY更为精细、纯净的底层合金组织也对TGO的氧化行为起了有益的作用,导致SAPS-TBC的TGO形态和动力学行为优于APS-TBC。此外,SAPS与APS一样,可在自然空间条件下采用相对简单、一气呵成的一步法工艺流程制备热障涂层,充分发挥其灵活方便、工艺稳定、低成本、高效率的生产优势,突显良好的产业化前景。
The recently investigation progress of the thermal barrier coating（TBC） with fine columnar grains was fabricated by a newly developed technology which was called supersonic atmospheric plasma spraying（SAPS）.The in-flight rate of molten particles of 8% Y2O3 stabilized ZrO2 powders（8YSZ） with diameter 15~45μm for the heat insulated top ceramic coat in the SAPS jet was on-line monitored by means of SprayWatch-2i.The results display that the in-flight rate of molten particles was about 400～450 m/s,2～3 times higher than that in conventional APS stream（130～220 m/s）,resulting in a remarkable finer microstructure for SAPS-TBCs.The volume fraction of finer lamella structure with columnar grains in SAPS-TBCs was above 80%,and their axial length of columnar grains were in the range of 2～5μm while the porosity of as-sprayed coating can be controlled from 1% to 12%.The unique microstructure of SAPS-TBCs was responsible for greatly improvement of their thermal cycling life.The thermal cycle number of SAPS-TBC specimens was above 400 cycles,2～3 times higher than that of conventional APS-TBCs（less than 150cyc.）.In addition,the bonding strength of SAPS-TBCs was about 50MPa,over 65% higher than that of APS-TBCs（approximately 30MPa）.Meanwhile,it was very interesting that the thermal insulation performance of SAPS-TBC rise with the increase of thermal cycles,while that of APS-TBCs descend with the increase of thermal cycles.And high temperature oxidation test on the fully coated samples at 1100℃ for 1000h demonstrated that SAPS-TBCs is beneficial to anti-oxidation as compared with APS-TBCs.Also,SAPS spraying process has the same advantages similar to the APS spraying process,such as easy operation process,lower cost and high efficiency etc.,so SAPS spraying technology will exhibit more important application in industry.
出处
《热喷涂技术》
2011年第2期1-14,40,共15页
Thermal Spray Technology
基金
国家"973计划"项目(2007CB707702)
国防"973计划"项目(613112-K3)
关键词
超音速等离子喷涂
热障涂层
测温测速
组织结构
热震
氧化
隔热
Supersonic atmospheric plasma spraying
Thermal barrier coating
Temperature and velosity on-line measuring
Coating tructure
Thermal shock
Oxidation
Thermal insulation
