Microstructure and mechanical properties of TaC ceramics with 1-7.5 mol% Si as sintering aid
Microstructure and mechanical properties of TaC ceramics with 1-7.5 mol% Si as sintering aid
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显微组织%20and%20机械%20性能%20of%20TaC%20陶瓷%20with%201-7.5%20mol%%20Si%20as%20烧结%20aid
DOI：
10.1111/jace.14806
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发表时间：
2017
影响因子：
3.9
通讯作者：
Wu Laner
中科院分区：
文献类型：
--
作者：
Geng Guihong;Liu Limeng;Wang Yujin;Hai Wanxiu;Sun Wenzhou;Chen Yuhong;Wu Laner
金属硅作为助烧剂对火花等离子烧结碳化钽陶瓷（TaC）有较好的致密化效果。当Si添加量为5.0 mol%（相当于Si重量的1.088%）及以上时达到满密度。含Si的TaC陶瓷致密化增强与TaC粉末中氧含量从~0.24 wt%降低到固结试样中的~0.03 wt%有关。其余的氧被收集在多晶连接处，在高温下形成SiO2基液体。冷却后，Ta、Si、O和C溶解于液体中，析出少量的低浓度TaSixand SiC相。Si的加入使TaC陶瓷的显微结构得到细化，平均晶粒尺寸由1.0 mol% Si时的11±8 μm减小到7.5 mol% Si时的3±2 μm。碳化硅中存在Ta溶质，TaC中存在Si溶质。含有7.5 mol% Si的TaC陶瓷具有较好的抗弯强度和断裂韧性，分别为646±51 MPa和5.0 MPa·m1/2。
Metallic Si as sintering aid was effective in densifying tantalum carbide ceramic (TaC) by spark plasma sintering (SPS) at 1700°C. Full density was reached at 5.0 mol% Si addition (equivalent to 1.088% Si in weight) and above. Enhanced densification of TaC ceramic with Si was associated with decrease in oxygen content from ~0.24 wt% in TaC powder to ~0.03 wt% in consolidated specimen. Rest of the oxygen species was collected at multigrain conjunctions to form SiO2‐based liquid at high temperatures. Upon cooling, Ta, Si, O, and C dissolving in the liquid precipitated minor phases of TaSixand SiC of low concentrations. Microstructure of TaC ceramics was refined by the Si addition, with average grain size decreasing from 11±8 μm at 1.0 mol% Si to 3±2 μm at 7.5 mol% Si addition. Ta solute in SiC and Si solute in TaC were evidenced. TaC ceramic containing 7.5 mol% Si had a relatively good flexural strength and fracture toughness of 646±51 MPa and 5.0 MPa·m1/2, respectively.