Atmospheric plasma sprayed thermal barrier coatings with high segmentation crack densities: Spraying process, microstructure and thermal cycling behavior
Atmospheric plasma sprayed thermal barrier coatings with high segmentation crack densities: Spraying process, microstructure and thermal cycling behavior
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DOI：
10.1016/j.surfcoat.2011.06.032
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发表时间：
2011-10-15
影响因子：
5.4
通讯作者：
Stoever, D.
中科院分区：
文献类型：
--
作者：
Karger, M.;Vassen, R.;Stoever, D.
热障涂层具有较高的应变容限，在航空涡轮的热气部分具有良好的应用前景。为提高常压等离子喷涂(APS)热障涂层的应变耐受性，用熔融和破碎的氧化钇稳定氧化锆(YSZ)制备了具有很高分段裂纹密度的400µm~500µm厚涂层。采用三重II型等离子喷枪和优化的喷涂工艺，获得了分段裂纹密度高达8.9 mm(-1)、孔隙率小于6%的涂层。分支裂纹密度很低，这对于良好的片间结合是不可避免的。热循环试验表明，所制备的涂层具有良好的应变耐受性。具有较高分段裂纹密度的样品在相当高的表面(1350摄氏度)和粘合涂层温度(高达1085摄氏度)下在燃烧器试验台测试中显示出良好的寿命，而裂纹密度较低的涂层的性能较差。断面和断口的微观结构研究表明，在不同裂纹密度的热震试验中，分段裂纹网络是稳定的。其主要失效机制是热生长氧化层(TGOS)和TBC附近TBC内部的分层和水平开裂。(C)2011爱思唯尔B.V.保留所有权利。
Thermal barrier coatings (TBCs) with high strain tolerance are favorable for application in hot gas sections of aircraft turbines. To improve the strain tolerance of atmospheric plasma sprayed (APS) TBCs, 400 mu m-500 mu m thick coatings with very high segmentation crack densities produced with fused and crushed yttria stabilized zirconia (YSZ) were developed. Using a Triplex II plasma gun and an optimized spraying process, coatings with segmentation crack densities up to 8.9 cracks mm(-1), and porosity values lower than 6% were obtained. The density of branching cracks was quite low which is inevitable for a good inter-lamellar bonding. Thermal cycling tests yielded promising strain tolerance behavior for the manufactured coatings. Samples with high segmentation crack densities revealed promising lifetime in burner rig tests at rather high surface (1350 degrees C) and bondcoat temperatures (up to 1085 degrees C), while coatings with lower crack densities had a reduced performance. Microstructural investigations on cross-sections and fracture surfaces showed that the segmentation crack network was stable during thermal shock testing for different crack densities. The main failure mechanism was delamination and horizontal cracking within the TBC near the thermal grown oxide layer (TGOs) and the TBC. (C) 2011 Elsevier B.V. All rights reserved.