(1. 中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083；
2. 湖南省冶金材料研究所，長沙 410014)
摘 要: 采用等離子噴涂成形結(jié)合熱等靜壓技術(shù)制備內(nèi)徑8 mm、長30 mm、壁厚16.5 mm的鎢喉襯，測試喉襯在小型固體火箭發(fā)動機(jī)地面試車條件下的抗熱震燒蝕性能。結(jié)果表明：等離子噴涂成形鎢喉襯為典型的柱狀晶層片結(jié)構(gòu)，致密度僅為85.6%；經(jīng)二步熱等靜壓處理后，喉襯樣件仍為層片結(jié)構(gòu)，層片間微觀縫隙及大部分孔隙消失，致密度提高至96.7%；地面試車實(shí)驗(yàn)后，鎢喉襯整體結(jié)構(gòu)完好，未出現(xiàn)炸裂和破碎現(xiàn)象，具有良好的抗沖刷和耐燒蝕性能，其線燒蝕率僅為4 μm/s。經(jīng)SEM和XRD等檢測發(fā)現(xiàn)，喉部以機(jī)械剝蝕為主，以熔化燒蝕及熱化學(xué)燒蝕為輔，其燒蝕程度最為嚴(yán)重；收斂段為機(jī)械剝蝕和熱化學(xué)燒蝕，其燒蝕程度次之；而擴(kuò)散段則發(fā)生熱化學(xué)燒蝕，其燒蝕程度最低。
關(guān)鍵字: 等離子噴涂成形；鎢喉襯；熱等靜壓；燒蝕
plasma spray forming
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Hunan Metallurgy Material Research Institute, Changsha 410014, China）
Abstract:The tungsten nozzle with inner diameter of 8 mm, length of 30 mm and wall thickness of 16.5 mm was produced by plasma spray forming (PSF) and hot isostatic pressing (HIPing). The resistance of thermal shock and ablation property of tungsten throat was investigated by firing test on a small solid rocket motor (SRM). The results show that a lamellar structure consisting of vertical columnar grains is found in PSF deposits with relative density of 85.6%. After two-step HIPing, the relative density of deposits remaining lamellar structure increases to 96.7%. After firing testing, the specimen has entire form and no breaks, which indicates that tungsten nozzle has good resistance to thermal shock and ablation. The line ablation rate of throat is only 4 μm/s. From results of scanning electron microscopy (SEM) and X-ray diffractometer (XRD), the ablation of throat is the most serious for combinative results of mechanical denudation, melt ablation and thermochemistry ablation. The second serious ablation is convergence part, the ablation behaviors of which are mechanical denudation and melt ablation. While the ablation content of dilation part is the slightest for only thermochemistry ablation taking place.
Key words: plasma spray forming; tungsten nozzle; hot isostatic pressing; ablation
