Preparation of TaB2-SiC oxidation protective coating for carbon materials by liquid phase sintering
Preparation of TaB2-SiC oxidation protective coating for carbon materials by liquid phase sintering
复制标题
液相烧结法制备碳材料TaB2-SiC氧化防护涂层
DOI：
10.1016/j.ceramint.2018.03.105
复制
发表时间：
2018
影响因子：
5.2
通讯作者：
Ziyu Li
中科院分区：
文献类型：
--
作者：
Xuanru Ren;Lifeng Wang;Peizhong Feng;Ping Zhang;LiTong Guo;Ziyu Li
为了控制TaB 2-SiC涂层中TaB 2相的微观结构和数量，在原位反应法的基础上发展了一种液相烧结法制备TaB 2-SiC涂层，包括TaB 2粉末的合成和TaB 2-SiC涂层的进一步制备。以Ta 2 O 5、B2 O3和C为原料，采用碳热还原法在1500 °C下制备了平均粒径为491 nm的六方相TaB 2粉体。以TaB 2、SiC、C粉末为原料，采用液相烧结法在2373 K下制备了TaB 2-SiC涂层。涂层的厚度约为350 µm。与SiC涂层相比，经TaB 2改性的试样失重率从17.7%降低到11.8%，最快失重区的平均失重速率从−6 × 10− 3 mg cm−2s− 1降低到−5 × 10− 3 mg cm−2s−1。氧化过程中，Ta氧化物逐渐溶解在硅酸盐玻璃中，形成具有树枝状结构的Ta-Si-O微晶玻璃，显著提高了玻璃层的韧性和稳定性。Ta-Si-O微晶玻璃具有封闭和阻止微裂纹的能力，可提高涂层的抗氧化能力。
To control the microstructure and amounts of TaB2phase in the TaB2-SiC coating, a novel liquid phase sintering method was developed on the basis of in-situ reaction method to prepare the TaB2-SiC coating, which includes synthesis of TaB2powders and further preparation of TaB2-SiC coating. With Ta2O5, B2O3and C employed as raw materials, hexagonal TaB2powders were prepared by carbothermal reduction method at 1500 °C, whose mean particle size is 491 nm. The TaB2, SiC, C powders, and the low melting point phases Si and silica sol were used to prepare the TaB2-SiC coating by liquid phase sintering at 2373 K. The thickness of the coating is about 350 µm. Compared with the SiC coating, the weight loss of the samples modified by TaB2decreased from 17.7% to 11.8%, and the average weight loss rate of the fastest weightloss zone reduced from −6 × 10−3mg cm−2s−1to −5 × 10−3mg cm−2s−1. During oxidation, the Ta-oxides would gradually dissolve in the silicate glass to form Ta-Si-O glass ceramics with dendritic structure, which significantly improved the toughness and stability of the glass layer. The Ta-Si-O glass ceramics possesses the ability of sealing and arresting the microcracks, which can enhance the oxidation protective ability of the coating.