Consolidation of SiC/BN composite through MA-SPS method
Consolidation of SiC/BN composite through MA-SPS method
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DOI：
10.1007/s10853-008-2782-z
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发表时间：
2008-07
影响因子：
4.5
通讯作者：
Y. Kodera;N. Toyofuku;Hiroyasu Yamasaki;M. Ohyanagi;Z. Munir
中科院分区：
文献类型：
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作者：
Y. Kodera;N. Toyofuku;Hiroyasu Yamasaki;M. Ohyanagi;Z. Munir
为了改善SiC的可加工性和抗热震性，选择了Hisonal-BN作为SiC/BN复合材料的第二相。本研究以Si + C + BN粉末为原料，采用机械合金化法制备了纳米SiC/BN复合材料，并在不添加任何烧结助剂的情况下进行了SPS烧结。MA后的XRD结果显示不存在对应于SiC和BN的尖峰。在SPS过程中，XRD上SiC和BN峰的密度和强度随着温度的升高而增加。当SiC/BN为50/50至100/0时，复合材料的最终密度达到约90 - 99%。在固结过程中，同时观察到结晶，相分离和有序化。这一现象可以加速传质过程，从而在不添加任何烧结助剂的情况下实现SiC/BN复合材料的烧结。在50/50的SiC/BN比率下，由于高孔隙率，通过具有烧结助剂的常规方法制备的纳米结构的参考样品的维氏硬度不能测量。然而，在我们的研究中制备的固结良好的样品显示出约3 GPa的硬度。
Hexagonal-BN has been selected as a second phase for SiC/BN composite to improve SiC’s machinability and thermal shock resistance. In this research, nano-metric SiC/BN was prepared through mechanical alloying (MA) from Si + C + BN powder and then consolidated by SPS without any sintering aids. XRD results after MA revealed the absence of sharp peaks corresponding to SiC and BN. The density and the intensity of the SiC and BN peaks on XRD increased with temperature during SPS. The final density of the composite reached approximately 90–99% with 50/50 of SiC/BN to 100/0. During the consolidation process, crystallization, phase separation, and ordering were observed simultaneously. This phenomenon could accelerate the mass transfer for the consolidation and the preparation of bulk SiC/BN composite without any sintering aids. In a 50/50 SiC/BN ratio, the Vickers hardness of the nano-structured reference sample prepared by the conventional method with sintering aids could not be measured due to high porosity. However, the well-consolidated sample prepared in our research showed a hardness of approximately 3 GPa.