Comparison of In-Flight Particle Properties, Splat Formation, and Coating Microstructure for Regular and Nano-YSZ Powders

Abstract

The relationship between atmospheric pressure plasma spray parameters and in-flight particle characteristics was determined. The morphologies of individual splats and the coating microstructure were studied for different stand-off distances and arc currents. Coating cross-sectional analysis showed that the total porosity of the coating increased with decreasing arc current, and increasing stand-off distance. Two different materials were used: the regular (r-YSZ) feed stock and the nano size (n-YSZ) agglomerated powder. The results illustrate that the r-YSZ coating has higher total porosity at higher arc currents than n-YSZ coating. The splat flattening degree and circularity was examined at different substrate temperatures for both powders. The results indicate that the flattening degree increased at high temperatures for the two materials, but the values for n-YSZ were higher than those for the r-YSZ. This study showed the operating regimes in which the use of n-YSZ yields improved coating properties.

In situ Particle Generation and Splat Formation During Solution Precursor Plasma Spraying of Yttria‐Stabilized Zirconia Coatings

“…The influence of substrate temperature on splat morphology has been investigated through various studies in case of conventional plasma spraying with spray‐grade powder feedstock for different coating‐substrate temperature combinations . The threshold substrate temperature for YSZ splats in conventional plasma spraying has been found to be around 100°C to yield the desired disk‐shaped splats .…”

Influencia de los parámetros de proyección por plasma atmosférico en recubrimientos de YSZ obtenidos a partir de polvos micro y nanoestructurados

“…Esto es debido a que los gránulos son más pequeños y por lo tanto, hay una mayor transferencia de energía entre el plasma y los gránulos (20,21). Sin embargo, no se puede extraer una conclusión tan evidente con las diferencias de temperatura, ya que su medición tiene mucho error y las diferencias de temperatura entre los dos materiales no son grandes.…”

Research Progresses of Atmospheric Plasma Sprayed Splat

“…无 机 材 料 学 报 第 32 卷 大气等离子体喷涂(atmospheric plasma spraying, APS)是热喷涂技术的一种, 诞生于上世纪五十年代 中期 [6] , 其特征是以高温高速的等离子体射流为热 源, 高温区温度可超过 8000 K, 可以熔化所有固态 物质 [7] , 因而在制备陶瓷涂层方面具有独特的优 势。在大气等离子体喷涂工艺中, 粉末颗粒被载气 送入高温高速的等离子体焰流, 经加热和加速 [6] 。 (2)影响粉体在等离子体焰流中温度和速率的提 升。一些研究者 [8][9][10][11] 以模拟方式分析了原料颗粒、载气 流量、功率等参数对熔滴温度和速率的影响。颗粒能 够进入到等离子体焰流的程度不同, 而等离子体焰流 自身的温度和流速也不均匀, 导致熔滴最终的温度和 速率结果较为复杂。 Elsebaei 等 [12] 以实验方式比较了偏 离喷枪中心不同距离的位置所观测到的熔滴在与基 体碰撞前的直径、速率和表面温度, 结果列于表 1。 从表 1 可以看出, 在给定的实验条件下, 等离子体焰 流中心区域对颗粒的加热和加速能力是比较好的; 粒 径较小的颗粒无法进入等离子体焰流中心, 最终获得 的温度和飞行速率较小; 而粒径较大的颗粒穿过了等 离子体焰流中心, 最终获得的温度和飞行速率更小。 [12] Table 1 Average values of the particle size, velocity and temperature at different radial positions from the plasma jet center line [12] Radial position /mm (SG-100 plasma torch: current-870A, stand-off distance-80 mm)…”