Influence of substrate temperature on morphology and behavior under cyclic thermal load of gas flow sputtered zirconia coatings
Influence of substrate temperature on morphology and behavior under cyclic thermal load of gas flow sputtered zirconia coatings
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DOI：
10.1016/j.surfcoat.2017.05.041
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发表时间：
2017-09
影响因子：
5.4
通讯作者：
N. Rösemann;K. Ortner;J. Petersen;M. Stöwer;M. Bäker;G. Bräuer;J. Rösler
中科院分区：
文献类型：
--
作者：
N. Rösemann;K. Ortner;J. Petersen;M. Stöwer;M. Bäker;G. Bräuer;J. Rösler
这项工作的目的是了解沉积过程中基材温度对气流溅射 (GFS) 部分氧化钇稳定氧化锆涂层 (PSZ) 的微观结构和晶体学特性的影响。PSZ 涂层沉积在 FeCrAl 合金基材上，基材温度在 500 °C 到 800 °C 之间变化。无论基材温度如何，所有涂层都是柱状的，但其形态各异。根据形态和 X 射线衍射 (XRD) 图案，确定了四组不同的亚微观结构，每组都由基材温度范围定义。这两个低温组表现出一种新颖的微观结构，其特征是三个密集的脊，间隔 120° 在柱中心汇聚。在这些脊的支撑下，小的堆叠板形成了羽毛状的孔隙。 XRD图谱揭示了除了四方和/或立方晶系之外的单斜晶系部分以及<111>生长方向。较高的温度会减少单斜晶系部分，直至其在 800 °C 时消失，同时生长方向变为 <100>。热循环实验在 1050 °C 至 100 °C 之间进行。在 1300 个周期的实验结束后，一组发生了宏观剥落，而其他样品则完好无损。在纯氧化铝鳞片和由嵌入氧化铝基体中的氧化锆颗粒组成的混合氧化物区域之间发现了微观分层。提出了一个假设来解释观察到的故障模式。
The aim of this work is to gain an understanding of the influence of substrate temperature during deposition on the resulting microstructure and crystallographic properties of gas flow sputtered (GFS) partially yttria stabilized zirconia coatings (PSZ).PSZ coatings were deposited on a FeCrAl-Alloy substrate, varying the substrate temperature between 500 °C and 800 °C. Regardless of the substrate temperature, all coatings were columnar, but varied in their morphology. Four different groups of sub-microstructures, each defined by a substrate temperature range, were identified based on morphology and X-ray diffraction (XRD) pattern.The two low-temperature groups exhibit a novel microstructure characterized by three dense ridges at intervals of 120° converging at the column center. Supported by these ridges small stacked plates lead to a featherlike porosity. The XRD pattern revealed a monoclinic fraction, besides the tetragonal and/or cubic one, and a <111> growth direction. Higher temperatures diminish the monoclinic fraction until it vanishes at 800 °C accompanied by a change in growth direction to <100>.Thermal cycling experiments were conducted between 1050 °C and 100 °C. Macroscopic spallation occurred for one group while the other samples were intact after the end of the experiment at 1300 cycles. Microscopic delaminations were found between a pure alumina scale and a mixed oxide zone, consisting of zirconia particles embedded into an alumina matrix. A hypothesis was proposed explaining the observed failure mode.