Spark-plasma sintering of ZrB₂ ultra-high-temperature ceramics at lower temperature via nanoscale crystal refinement

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• 作者：Victor Zamora^a ; Angel L. Ortiz^a ; ^{alortiz@materiales.unex.es} ; ^{alortiz@unex.es} ; Fernando Guiberteau^a ; Mats Nygren^b
• 关键词：ZrB2 ; Ultra-high-temperature ceramics ; Sintering ; High-energy ball-milling
• 刊名：Journal of the European Ceramic Society
• 出版年：2012
• 期刊代码：53_09552219
• 类别：ms
• 出版时间：August, 2012
• 卷：32
• 期：10
• 页码：2529-2536
• 文件大小：1208 K

摘要

We have explored the feasibility of reducing the spark-plasma-sintering (SPS) temperature of additive-free ZrB₂ ultra-high-temperature ceramics (UHTCs) via crystal size refinement of the starting powder down to the low nanoscale. We found that under otherwise the same SPS conditions (75 MPa pressure, and 100 掳C/min heating ramp) nanoscale ZrB₂ can be densified at temperatures about 450 掳C lower than for the typical micrometre and submicrometre ZrB₂ powders, and at least 250 掳C below the ultra-fine powder temperature. Furthermore, the nanoscale crystal refinement also promotes the production of fine-grained ZrB₂ UHTCs. We also found that elimination of the B₂O₃ impurities plays an important role in the complete densification. The unequalled sinterability of the nanoscale ZrB₂ powders highlights the need to use high-energy ball-milling for the comminution of the typical commercially available ZrB₂ powders.