对比无压烧结和热压烧结制备的Al2O3／B4C芯块，研究了烧结温度、粉体球磨时间对其开孔率和密度的影响；通过扫描电镜和X射线衍射仪分析了Al2O3／B4C芯块结构、形貌和相态。结果表明：球磨4h有利于芯块的烧结，并且热压烧结的芯块性能明显优于无压烧结的，适宜的烧结温度为1550-1650℃，过低或过高都会降低芯块的致密性，在1600℃热压烧结芯块的性能最好，其相对密度和开孔率达到96．41％和0．08％；热压烧结能促进芯块的致密化，可获得细小、均匀的显微组织，其致密化温度比无压烧结降低100℃以上。
Al2O3/B4C pellets sintered by hot-press were compared with those by pressureless, and the effects of sintering temperature and milling time on open porosity and density of the pellets were investigated. The microstructure, surface morphology and phase state were investigated by SEM and XRD. The results show that the powders milled for 4 h were beneficial to sintering. The pellets sintered by hot pressing were much better than those by pressureless sintering. The suitable temperature for sintering was in the range of 1550-- 1 650℃, and the pellets＇ density decreased if the temperature was higher or lower. The best relative density and open porosity of Al2O3/B4C pellets hot pressed at 1 600 ℃ were 96.41% and 0. 08%, respectively. Hot pressed Al2O3/B4C pellets got densified quickly, that the densification temperature was lower above 100 ℃ than the pressureless sintered one, and the microstructure was fine and uniform.
参考文献
| [1] | Liu Yonghe;Yin Sheng;Zhang Weijing;Lai Hoyi .Thermodynamic analysis of the self-propagation high-temperature synthesis Al_2O_3/B_4C composite[J].Scripta materialia,1998(9):1237-1242. |
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