SiC纤维/YSZ复合热障厚涂层韧性及热震性能研究

doi:10.15541/jim20150349

摘要/Abstract

摘要：

采用大气等离子喷涂(APS)技术, 以ZrO₂-8wt%Y₂O₃(8YSZ)和团聚的P7216(8YSZ和珍珠岩粉)粉末为原料, 在基体上制备了厚度大于4 mm的SiC纤维/YSZ(SFY)复合厚热障涂层, 通过扫描电子显微镜(SEM)分析了涂层的显微结构, 发现SFY涂层具有钢筋混凝土结构, 这种结构能够防止因为涂层厚度增加而引起的失效。此外, 基于计算机的断层成像技术分析热障涂层孔隙率的变化, 考察了SFY涂层和YSZ 热障涂层的抗热震性能、断裂韧性以及热导率性能, 并探讨了纤维的增韧机制。研究结果表明, SFY涂层具有更高的断裂韧性值和更好的抗热震性能, 25℃时SFY涂层的热导率为0.632 W/(m·K), 大约是传统YSZ热障涂层热导率的一半。SiC纤维对涂层内部裂纹的偏转和截止作用, 防止了裂纹扩散长大, 形成网状微裂纹结构, 有效提高了涂层的抗热震性能和断裂韧性。

关键词: SFY复合热障涂层, 热导率, 断裂韧性, 热震

Abstract:

Using ZrO₂-8wt%Y₂O₃ (8YSZ) and agglomerated P7216 (8YSZ and Perlite powder ) powders as raw materials, SiC fiber/YSZ (SFY) composite thick thermal barrier coatings (TBCs, >4 mm in thick) were prepared by Atmospheric Plasma Spray (APS) on substrate. The microstructures of columnar coating were analyzed by scanning electron microscope (SEM). It showed that SFY coatings had a reinforced concrete frame structure, which protected the coatings from failure caused by thickened coatings. Based on the technique of computed tomography, the porosity of TBCs were investigated. And the thermal shock, fracture toughness and thermal conductivity (TC) of both SFY and YSZ coatings were examined and discussed for the SiC fiber toughening mechanism. Test results showed that the SFY coatings had higher fracture toughness and better thermal shock resistance than the YSZ TBCs. At 25℃, the TC of SFY coatings was 0.632 W/(m·K), about 50% reduction of typical APS YSZ TBCs. Data from this study showed that the SiC fiber effectively hindered crack growth and diffusion by crack deflection and crack termination of SFY coating, which was beneficial for growing of the reticular microcrack and improving thermal shock resistance and fracture toughness.

Key words: SFY composite thermal barrier coatings, thermal conductivity, fracture toughness, thermal shock

中图分类号:

TQ174

马榕彬, 程旭东, 邹隽, 李秦煜, 黄霞. SiC纤维/YSZ复合热障厚涂层韧性及热震性能研究[J]. 无机材料学报, 2016, 31(2): 190-194.

MA Rong-Bin, CHENG Xu-Dong, ZOU Jun, LI Qing-Yu, HUANG Xia. Toughness and Thermal Shock of SiC Fiber/Yttria-stabilized-zirconia Composite Thick Thermal Barrier Coatings[J]. Journal of Inorganic Materials, 2016, 31(2): 190-194.

图/表 7

表1 等离子喷涂参数

Table 1 Spraying conditions of atmospheric plasma spray

Spraying condition	Parameter
Are current/A	450
Primary plasma gas flow/(L·min^-1)	Ar (0.55)
Secondary plasma gas flow/(L·min^-1)	N₂ (0.3)
Powder carrier gas	N₂
Powder feed rate/(g·min^-1)	20
Spray distance/mm	85

图1 SFY复合热障涂层的截面宏观形貌(a)和扫描电镜照片(b)

Fig. 1 (a) Macro morphology and (b) SEM image of cross-section of SFY composite TBCs systems

图2 SFY复合热障涂层截面的SEM照片(垂直于轴向)

Fig. 2 SEM images of the cross-section of the SFY composite TBCs (perpendicular to the axial)

图3 SiC纤维/YSZ复合热障涂层中的纤维增韧机制

Fig. 3 Toughening mechanism of fiber in the SiC fiber/YSZ composite TBCs (a) Crack deflection; (b) Crack termination

表2 两种涂层试样的断裂韧性值

Table 2 Fracture toughness of two types of coating

Coating ID	YSZ-K_IC /(MPa·m^1/2)	SiC fiber/YSZ-K_IC /(MPa·m^1/2)
1	1.11	1.53
2	1.17	1.74
3	1.11	1.89
4	1.13	1.82
5	1.12	1.37
Average value	1.13	1.67

表3 SFY复合热障涂层和YSZ涂层的热震寿命及其涂层厚度

Table 3 Number of sustained cycles for SFY composite TBCs and YSZ coatings, and the corresponding coating thickness

Coating ID	SiC fiber/YSZ		YSZ
Coating ID	Thickness /mm	Cycles	Thickness /mm	Cycles
6	4.33	53	1.53	20
7	4.24	52	1.47	23
8	4.15	55	1.42	29
Average	4.24	53.3	1.47	24

图4 SiC纤维/YSZ复合热障涂层热震后的表面裂纹形貌

Fig. 4 Surface crack growth pattern of SiC fiber/YSZ composite TBCs after thermal shock

参考文献 16

[1]	CAO X Q, VASSEN R, STOEVER D.Ceramic materials for thermal barrier coatings.Journal of European Ceramic Society, 2004, 24(1): 1-10.
[2]	LI DE-LING, CHEN XU-DONG, YE WEI-PING, et al.Carbon fibet reinforced zirconia themal barrier and ablative thick composite coating.Journal of Wuhan University of Technology, 2010, 32(8): 18-21.
[3]	LU HAORAN, WANG CHANG-AN, ZHANG CHENGUANG.Influence of Ln3+ and B3+ ions co-substitution on thermophysical properties of LnMB11O19-type magnetoplumbite LaMgAl11O19 for advanced thermal barrier coatings.J. Am. Ceram. Soc., 2013, 96(4): 1063-1066.
[4]	CHEN XIAOLANG, ZOU BINGLIN, WANG YING, et al.Microstructure and thermal cycling behavior of air plasma-sprayed YSZ/LaMgAl11O19 composite coatings.Journal of Thermal Spray Technology, 2011, 20(6): 1328-1338.
[5]	LEE P H, LEE S Y, KWON J Y, et al.Thermal cycling behavior and interfacial stability in thick thermal barrier coatings. Surf. Coat. Technol., 2010, 205(5): 1250-1255.
[6]	GUO H B, VABEN R, STOVER D.Atmospheric plasma sprayed thick thermal barrier coatings with high segmentation crack density.Surf. Coat. Technol., 2004, 186(3): 353-363.
[7]	BESHISH G K, FLOREY C W, WORZALA F J, et al.Fracture toughness of thermal spray ceramic coatings determined by the indentation technique.J. Therm. Spray Technol., 1993, 2(1): 35-38.
[8]	WANG XIN, WANG CHANGJIANG, ALAN ATKINSON.Interface fracture toughness in thermal barrier coatings by cross- sectional indentation.Acta Materialia, 2012, 60(17): 6152-6163.
[9]	GOPAL DWIVEDI, VAISHAK VISWANATHAN, SANJAY SAMPATH, et al.Fracture toughness of plasma-sprayed thermal barrier ceramics: influence of processing, microstructure, and thermal aging.J. Am. Ceram. Soc., 2014, 97(9): 2736-2744.
[10]	SCHWINGEL D, TAYLOR R, HAUBOLD T, et al. Mechanical and thermaophysical properties of thick PYSZ thermal barrier coatings: correlation with microstructure and spraying parameters. Surf. Coat. Technol., 1998, 108-109: 99-106.
[11]	XU ZHENHUA, DAI JIANWEI, NIU JING, et al.Thermal shock behavior of platinum aluminide bond coat/electron beam-physical vapor deposited thermal barrier coatings.Journal of Alloys and Compounds, 2014, 617: 185-191.
[12]	ZHONG XINGHUA, ZAO HUAYU, ZHOU XIAMING, et al.Thermal shock behavior of toughened gadolinium zirconate/YSZ double-ceramic-layered thermal barrier coating.Journal of Alloys and Compounds, 2014, 593: 50-55.
[13]	]ZHAO YUEXING, LI DACHUAN, ZHONG XINGHUA, et al. Thermal shock behaviors of YSZ thick thermal barrier coatings fabricated by suspension and atmospheric plasma spraying.Surf. Coat. Technol., 2014, 249: 48-55.
[14]	VASSEN R, STUKE A, STOVER D.Recent developments in the field of thermal barrier coatings.J. Therm. Spray Technol., 2009, 18(2): 181-186.
[15]	LEVI C G, HUTCHINSON J W, VIDAL-SEFIFM H, et al.Environmental degradation of thermal barrier coatings by molten deposits.MRS Bull., 2012, 37(10): 932-941.
[16]	SIEBERT B, FUNKE C, VABEN R, et al. Changes in porosity and Young's modulus due to sintering of plasma sprayed thermal barrier coatings. J. Mater. Process. Technol., 1999, 92/93: 217-223.