科研之友
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摘要
In this article, an unusual agglomerated powder of Y2O3-stabilized ZrO2 (YSZ) that did not undergo calcination was introduced as a feedstock for thermal spray deposition using internal injection atmospheric plasma spray (APS) and the very-low-pressure plasma spray (VLPPS) methods at an ambient pressure of 100-150 Pa. The results show that the microstructure of the coating is influenced not only by the spray parameters (such as arc gas composition, ambient pressure, and arc current) but also by the manufacture process of the agglomerates particularly the sintering process. The microstructure of the coating exhibited a bimodal structure if the APS method was used; in this case, the microstructure resembles that of other nanostructured coatings using regular agglomerated-sintered feedstock. A coating having a novel fully nano-equiaxed structure with a microporosity of 10-15% was first successfully deposited using VLPPS with 20Ar-30He SLPM plasma gas flows at a current of 500 A. The experimental results suggest that the nano-scale equiaxed structure in the coating is directly formed from original nanoparticles that had undergone melting, while inside the nozzle they were subsequently solidified on the substrate. The VLPPS method, which offers some unique advantages over the conventional plasma spray process, is generic in nature and can potentially be used to deposit a wide variety of ceramic coatings for diverse applications. The thermal conductivity values of the fully nanostructured and bimodal structured coatings were measured, and the microstructures of the coating both in the as-sprayed state and after heat treatment for 10 h at 1300 degrees C were investigated.
- 出版日期2016-1
- 单位大连海事大学
