High-enthalpy hybrid water/argon-stabilized plasma (WSP-H) torch may be used for efficient deposition of coatings from dry powders, suspensions, and solutions. WSP-H torch was used to deposit two complete thermal barrier coatings (TBCs) with multilayered top-coat. NiCrAlY was used as bond-coat and deposited on nickel-based superalloy substrates. Top-coat consisted of up to three sublayers: (i) yttria-stabilized zirconia (ZrO2-8 wt.%Y2O3-YSZ) deposited from solution, (ii) gadolinium zirconate (Gd2Zr2O7-GZO) deposited from suspension, and (iii) optional yttrium aluminum garnet (Y3Al5O12-YAG) overlayer deposited from suspension. Each of the sublayers was intended to provide different functionalities, namely improved fracture toughness, low thermal conductivity, and high erosion resistance, respectively. High-temperature performance and thermal shock resistance of the deposited coatings were tested by thermal cycling fatigue “TCF” test (maximum temperature 1100 °C, 1 h dwell per cycle) and “laser-rig” test (maximum temperature ~ 1530 °C, 5 min dwell per cycle) exposing samples to isothermal and gradient thermal conditions, respectively. In both tests, coatings endured around 800 test cycles which shows great potential for further development of these layers and their application in demanding thermal conditions. Analysis of the samples after the test showed microstructural changes and identified reason of ultimate coating failure.

中文翻译：

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液体原料制备的等离子喷涂多层 NiCrAlY/YSZ/GZO/YAG 热障涂层的高温循环


高焓混合水/氩稳定等离子体 (WSP-H) 炬可用于从干粉末、悬浮液和溶液中有效沉积涂层。 WSP-H 炬用于沉积两层完整的热障涂层 (TBC) 和多层面漆。 NiCrAlY 用作粘结层并沉积在镍基高温合金基材上。面涂层由最多三个子层组成：(i) 从溶液中沉积的氧化钇稳定氧化锆 (ZrO2-8 wt.%Y2O3-YSZ)，(ii) 从悬浮液中沉积的锆酸钆 (Gd2Zr2O7-GZO)，以及 (iii)可选的钇铝石榴石 (Y3Al5O12-YAG) 覆盖层由悬浮液沉积而成。每个子层旨在提供不同的功能，即分别提高断裂韧性、低导热率和高耐腐蚀性。通过热循环疲劳“TCF”测试（最高温度 1100 °C，每个循环停留 1 小时）和“激光钻机”测试（最高温度 ~ 1530 °C，每个循环停留 5 分钟）将样品分别暴露于等温和梯度热条件下。在这两项测试中，涂层都经历了大约 800 个测试周期，这表明这些层的进一步开发及其在苛刻的热条件下的应用具有巨大的潜力。测试后对样品的分析显示了微观结构的变化，并确定了最终涂层失效的原因。