Effect of SiC content, additives and process parameters on densification and structure–property relations of pressureless sintered ZrB2–SiC composites
Effect of SiC content, additives and process parameters on densification and structure–property relations of pressureless sintered ZrB2–SiC composites
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DOI：
10.1016/j.ceramint.2012.09.066
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发表时间：
2013-04
影响因子：
5.2
通讯作者：
M. Mallik;Sabyasachi Roy;K. Ray;R. Mitra
中科院分区：
文献类型：
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作者：
M. Mallik;Sabyasachi Roy;K. Ray;R. Mitra
研究了SiC含量、添加剂和工艺参数对无压烧结ZrB 2-（10-40vol%）SiC颗粒复合材料致密化和结构-性能关系的影响。将1.2wt%C（以酚醛树脂的形式加入）和3wt%B_4C球磨混合的ZrB_2-SiC复合粉末在氩气气氛中于1950-2050 ℃烧结2 h或2000 ℃烧结1/2 ~ 3 h进行单轴冷压烧结。发现致密化的量随着烧结持续时间增加，并且通过在1250和1600°C下预先保持以通过上述添加剂减少粉末颗粒表面上的氧化物杂质（ZrO 2、B2 O3和SiO 2）而增加。平均尺寸小于ZrB 2的SiC的存在似乎有助于通过提高绿色密度、通过研磨介质的侵蚀增加WC含量和抑制基体晶粒生长来致密化。SiC和WC似乎都有助于减少氧化物杂质。此外，从研磨介质中获得的富含W，Fe和Co的杂质被发现在ZrB 2晶界处偏聚，并且似乎通过形成液相来帮助致密化，该液相完全润湿ZrB 2晶粒。硬度随SiC含量或烧结时间的增加而增加，但在烧结时间≥ 2 h时，由于晶粒长大，硬度降低。实验测得的弹性模量接近相应的理论预测值与SiC含量的增加，由于孔隙率的减少。
The effect of SiC content, additives, and process parameters on densification and structure–property relations of pressureless sintered ZrB2–(10–40vol%) SiC particulate composites have been studied. The ZrB2–SiC composite powders mixed by ball-milling with 1.2wt% C (added as phenolic resin) and 3wt% B4C have been uniaxially cold-compacted and sintered in argon environment at 1950–2050°C for 2h, or at 2000°C for durations between 1/2 and 3h. The amount of densification is found to increase with sintering duration, and by prior holding at 1250 and 1600°C for reduction of oxide impurities (ZrO2, B2O3and SiO2) on powder particle surfaces by the aforementioned additives. Presence of SiC with average size smaller than that of ZrB2appears to aid in densification by enhancing green density, increasing WC content by erosion of milling media, and inhibiting matrix grain growth. Both SiC and WC appear to aid in reduction of oxide impurities. Furthermore, the impurities enriched in W, Fe and Co obtained from milling media are found to be segregated at ZrB2grain boundaries, and appear to assist in densification by forming liquid phase, which completely wets the ZrB2grains. Hardness increases with SiC content or with sintering duration till 1h, but decreases for periods ≥2h due to grain growth. The experimentally measured elastic moduli approaches corresponding theoretically predicted values with increasing SiC content due to reduction in porosity.