In-situ synthesis and sintering of mullite glass composites by SPS
In-situ synthesis and sintering of mullite glass composites by SPS
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DOI：
10.1007/s40145-014-0108-y
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发表时间：
2014-06
影响因子：
16.9
通讯作者：
Jinyong Zhang;Haijiao Zhan;Z. Fu;R. Todd
中科院分区：
文献类型：
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作者：
Jinyong Zhang;Haijiao Zhan;Z. Fu;R. Todd
本文主要研究了加热速度和电流对放电等离子烧结(SPS)中非晶态前驱体晶化的影响。为此，合成了摩尔比为1：1的Al_2O_3-SiO_2干凝胶，并用SPS和热压(HP)进行了对比。物相分析表明，两种样品中唯一的结晶产物都是莫来石，而SPS样品中的Al_2O_3含量较低。显微组织显示，SPS样品中莫来石纤维体积分数较低，而HP样品中存在较高体积分数的细小等轴晶。Hp和SPS试件在微观结构上的主要差异可以用SPS试件的较高升温速率来解释。SPS模具的尺寸也影响所产生的莫来石纤维的尺寸和长径比，这可能是由于所需的电流不同或样品温度分布的不同所致。
The main subject of this work is an investigation of the effects of heating rate and current on the crystallisation of amorphous precursors in spark plasma sintering (SPS). For this, dry gel of Al2O3-SiO2with a molar ratio of 1:1, was synthesized and sintered in-situ by SPS, and also by hot pressing (HP) for comparison. Phase analysis showed that the only crystalline product in both cases was mullite, whose Al2O3content was lower in the SPS specimens. The microstructures showed a low volume fraction of large mullite fibers in the SPS specimens, whereas a high volume fraction of fine equiaxed grains was present in the HP specimen. The main difference in microstructure between HP and SPS specimens could be explained in terms of the higher heating rate of the SPS specimens. The size of the SPS die also affected the size and aspect ratio of the mullite fibers produced, which might have been due to either the different electrical current required or a difference in specimen temperature profile.