(1. 中南大学 粉末冶金国家重点实验室，长沙 410083；
2. 湖南省冶金材料研究所，长沙 410014)
摘 要: 采用等离子喷涂成形结合热等静压技术制备内径8 mm、长30 mm、壁厚16.5 mm的钨喉衬，测试喉衬在小型固体火箭发动机地面试车条件下的抗热震烧蚀性能。结果表明：等离子喷涂成形钨喉衬为典型的柱状晶层片结构，致密度仅为85.6%；经二步热等静压处理后，喉衬样件仍为层片结构，层片间微观缝隙及大部分孔隙消失，致密度提高至96.7%；地面试车实验后，钨喉衬整体结构完好，未出现炸裂和破碎现象，具有良好的抗冲刷和耐烧蚀性能，其线烧蚀率仅为4 μm/s。经SEM和XRD等检测发现，喉部以机械剥蚀为主，以熔化烧蚀及热化学烧蚀为辅，其烧蚀程度最为严重；收敛段为机械剥蚀和热化学烧蚀，其烧蚀程度次之；而扩散段则发生热化学烧蚀，其烧蚀程度最低。
关键字: 等离子喷涂成形；钨喉衬；热等静压；烧蚀
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
