Effect of Soaking Time and Molding Pressure on in-situ Synthesis of β-SiC Whiskers in Reaction-bonded SiC Ceramics
Effect of Soaking Time and Molding Pressure on in-situ Synthesis of β-SiC Whiskers in Reaction-bonded SiC Ceramics
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DOI：
10.1007/s41779-022-00722-5
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发表时间：
2022-02
影响因子：
1.9
通讯作者：
Xinbin Lao;Yage Li;Zhi-Fan Tu;Xiaoyang Xu;Weihui Jiang;Jianye Liang;Tao Wang
中科院分区：
文献类型：
--
作者：
Xinbin Lao;Yage Li;Zhi-Fan Tu;Xiaoyang Xu;Weihui Jiang;Jianye Liang;Tao Wang
为了提高SiC陶瓷的高温强度，采用反应键合烧结的方法成功地原位合成了β-SiC纳米晶须，并与α-SiC团聚体结合，研究了保温时间和成型压力对β-SiC纳米晶须原位合成的影响。从晶须形貌和性能方面得到了优化的工艺参数。结果表明：< 2 h的短浸泡时间导致sio2的碳热还原不够充分，SiO气体分压较低，抑制了β-SiC晶须的生长；浸泡时间过长导致碳化硅团聚体活性氧化，结构严重疏松。由于成型压力导致的密度对β-SiC晶须的特征有显著影响，随着成型压力的增加，SiC晶须的成品率降低。当保温时间和成型压力分别为2 h和20 MPa时，得到的SiC晶须长径比在130 ~ 200之间最高，制备的样品具有最佳的性能：孔隙率为17.5%，容重为2.46 g/cm3，冷断裂模量（CMOR）为45.8 MPa，热断裂模量（HMOR）为57 MPa。
To enhance the high-temperature strength of SiC ceramics, β-SiC nanowhiskers were successfullyin-situsynthesized to bond with α-SiC aggregates by using a reaction-bonded sintering method, and the effects of soaking time and molding pressure on thein-situsynthesis of β-SiC nanowhiskers were studied. The optimized processing parameters were obtained from the aspects of whisker morphology and properties. The results showed that short soaking time of < 2 h resulted in the insufficient carbothermal reduction of SiO2and the low partial pressure of SiO gas, which suppressed the growth of β-SiC whiskers. Excess soaking time of > 2 h led to the active oxidation of the SiC aggregates and the seriously loosened structure. The density as the result of molding pressure had significant influences on the features of β-SiC whiskers, and the yield of SiC whiskers decreased with the increasing molding pressure. When the soaking time and molding pressure were set as 2 h and 20 MPa, respectively, the obtained SiC whiskers exhibited the highest aspect ratio of 130 ~ 200 and the as-prepared sample possessed the optimal properties: 17.5% for porosity, 2.46 g/cm3for bulk density, 45.8 MPa for cold modulus of rupture (CMOR), 57 MPa for hot modulus of rupture (HMOR).