Micro-segregations in liquid phase sintered silicon carbide ceramics
Micro-segregations in liquid phase sintered silicon carbide ceramics
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DOI：
10.1016/j.jeurceramsoc.2009.12.019
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发表时间：
2010-04
影响因子：
5.7
通讯作者：
M. Herrmann;R. Neher;K. Brandt;S. Hoehn
中科院分区：
文献类型：
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作者：
M. Herrmann;R. Neher;K. Brandt;S. Hoehn
研究了具有不同第二相量的 LPSSiC 陶瓷在现场辅助烧结 (FAST) 过程中的致密化行为。在致密材料中发现了尺寸为数百微米的微观偏析。有时在气压烧结材料中会发现这种偏析。通过 EBSD 和 XRD 对结晶状态的研究表明，这些微观偏析与大 YAG（钇铝石榴石）晶体的形成有关。通过测量扩散偶中的浓度分布来研究钇在晶界中的迁移率。在 1850°C (10−6cm/s) 下测定的高扩散系数表明观察到的偏析是由冷却过程中第二相的结晶动力学引起的。
The densification behaviour of LPSSiC ceramics with different amount of secondary phases was investigated during Field Assisted Sintering (FAST). In the densified materials micro-segregations were found with dimensions of several 100μm. Sometimes such segregations were found in gas pressure sintered materials. The investigation of the state of crystallisation by EBSD and XRD revealed that these micro-segregations are connected with the formation of large YAG (Yttrium aluminium garnet) crystals. The mobility of yttrium in the grain boundaries was investigated by measuring concentration profiles in diffusion couples. The high diffusion coefficient determined at 1850°C (10−6cm/s) indicates that the observed segregations are caused by the crystallisation kinetics of the secondary phases during cooling.