Microstructure and phase stability of suspension high velocity oxy-fuel sprayed yttria stabilised zirconia coatings from aqueous and ethanol based suspensions
Microstructure and phase stability of suspension high velocity oxy-fuel sprayed yttria stabilised zirconia coatings from aqueous and ethanol based suspensions
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DOI：
10.1016/j.jeurceramsoc.2017.10.026
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发表时间：
2018-04-01
影响因子：
5.7
通讯作者：
Hussain, T.
中科院分区：
文献类型：
--
作者：
Bai, M.;Maher, H.;Hussain, T.
用悬浮高速氧燃料(SHVOF)热喷涂两种7-8wt%Yttria稳定氧化锆(YSZ)悬浮液，以获得先进的高温涂层。在800℃和1000℃下对自支撑涂层进行了72h的热处理，水和乙醇两种液体载体的SHVOF涂层在微观结构和相稳定性方面表现出不同的表现。乙醇涂层在热处理后仍保持完全的四方相组成，而水性涂层在1000℃时发生了不希望的四方相向单斜相转变，低于先前报道的热喷涂YSZ涂层的温度(>；1200℃)。热处理不仅导致了两种涂层的致密化，而且还导致了水性涂层中晶体的过度长大，促进了不希望发生的相变。相反，乙醇悬浮液有利于Y在喷雾过程中的均化，从而提高了相稳定性。
Two commercial 7-8 wt.% Yttria Stabilised Zirconia (YSZ) suspensions were sprayed by Suspension High Velocity Oxy Fuel (SHVOF) thermal spraying for advanced high temperature coatings. Heat treatments of the free-standing coatings were conducted at 800 degrees C and 1000 degrees C for 72 h. The SHVOF coatings using two liquid carriers: water and ethanol, behaved differently in terms of micro-structure and phase stability. The ethanol coatings retained a fully tetragonal composition after heat treatments; while the aqueous coatings, however, underwent the undesirable tetragonal to monoclinic phase transformation at 1000 degrees C, which is lower than previously reported temperatures (> 1200 degrees C) in thermal sprayed YSZ coatings. The heat treatments not only resulted in densification of both coatings, but also caused excessive crystallite growth in aqueous coatings promoting the undesirable phase transformation. On the contrary, the ethanol suspension improved the phase stability by favouring the homogenization of yttrium during spraying.