Abstract To reveal the generation mechanisms of the Ta-Si-O glass ceramics layer in dynamic oxidation environments, a 40 wt% TaB 2 -SiC coating was prepared by liquid phase sintering method. To obtain pure phase TaB 2 powders at lower temperature (1500 °C), excessive B 2 O 3 powders were added in raw materials to eliminate the TaC byproduct phase. The hexagonal pure phase TaB 2 powders own average particle size of about 386 nm. During the TGA dynamic oxidation tests, after the modification of 40 wt% TaB 2 , the initial weight loss temperature of the sample delayed by about 48%, while the weight loss percentage and rate in fastest weight loss zone decreased by about 61% and 53%, respectively. During oxidation, the generated Ta-oxides were peeled and carried away by the formed fluid SiO 2 glass layer to form “Ta-oxides halation” at first, which results the dissolution of Ta-oxides in the SiO 2 glass, thus forming the Ta-Si-O glass ceramics with dendritic structure. With the spread of the SiO 2 glass layer and growth of the Ta-Si-O dendrite, the Ta-Si-O glass ceramics gradually cover on the surface of the SiO 2 glass layer, forming the structure of Ta-Si-O/SiO 2 double glass layer that is capable of sealing and arresting of microcracks.

中文翻译：

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纯相TaB 2 粉末的低温合成及其动态氧化环境下Si基陶瓷涂层的抗氧化改性行为

摘要 为了揭示动态氧化环境下Ta-Si-O玻璃陶瓷层的生成机制，采用液相烧结法制备了40 wt% TaB 2 -SiC涂层。为了在较低温度（1500°C）下获得纯相 TaB 2 粉末，在原料中加入过量的 B 2 O 3 粉末以消除 TaC 副产物相。六方纯相TaB 2 粉末具有约386nm的平均粒径。在TGA动态氧化试验中，40 wt% TaB 2 改性后，样品的初始失重温度延迟了约48%，而最快失重区的失重百分比和失重率分别下降了约61%和53%。 ％， 分别。在氧化过程中，生成的Ta-氧化物被形成的流体SiO 2 玻璃层剥离并带走，首先形成“Ta-氧化物光晕”，这导致Ta-氧化物溶解在SiO 2 玻璃中，从而形成具有树枝状结构的Ta-Si-O玻璃陶瓷。随着SiO 2 玻璃层的扩展和Ta-Si-O枝晶的生长，Ta-Si-O玻璃陶瓷逐渐覆盖在SiO 2 玻璃层表面，形成Ta-Si-O/ SiO 2 双层玻璃层，能够密封和阻止微裂纹。