Sintering process and high temperature stability investigation for nano-scale CaB6 materials
Sintering process and high temperature stability investigation for nano-scale CaB6 materials
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DOI：
10.1016/j.ceramint.2010.06.005
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发表时间：
2010-09
影响因子：
5.2
通讯作者：
Lin Zhang;G. Min;Huashun Yu;Hui Yu
中科院分区：
文献类型：
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作者：
Lin Zhang;G. Min;Huashun Yu;Hui Yu
采用真空热压法制备了纳米级六硼化钙（CaB6）多晶，温度为1750℃，温度为32MPa，温度为5min。采用扫描电镜（SEM）、FESEM和原子力显微镜（AFM）对其形貌进行了观察，并与1550℃下烧结的块状材料进行了比较。观察结果表明，纳米级cab6块体结构中由于cab6纳米粉体的聚集作用，存在致密度高、致密度低的区域。其硬度、抗弯强度和断裂韧性分别为79.7HRA、198.7MPa和3.73 mpam /2，均优于相同烧结参数下烧结的cab6微米多晶。用DSC和TG测试了其高温稳定性。纳米多晶仅出现一个放热峰（1117.2°C），从1080°C开始，面积为- 167.7J/g，表明其稳定性远优于cab6纳米-微米复合多晶和微米多晶。
Calcium hexaboride (CaB6) polycrystalline was prepared from its nano-scale powders using vacuum hot-pressing method under 1750°C, 32MPa for 5min. SEM, FESEM and AFM were employed to observe morphology and compared with its bulk material sintered under 1550°C. Observations showed the structure of the nano-scale CaB6bulk has the regions with high and low compactness degree due to CaB6nanometer powder aggregations. The hardness, bending strength and fractural toughness were 79.7HRA, 198.7MPa and 3.73MPam1/2, respectively, better than those of CaB6micron-polycrystalline sintered under the same sintering parameters. DSC and TG were tested to investigate high temperature stability. Only one exothermic peak (1117.2°C) appeared in nano-polycrystalline which began at 1080°C and area was −167.7J/g, showing its stability is much better than CaB6nano-micron composite polycrystalline and micron-polycrystalline.