热压烧结制备纳米Y-TZP材料

本文研究了热攻结制备纳米Ｙ－ＴＺＰ材料的过程，研究结果表明：热压结纳米前一些新的特点，主要是纳米Ｙ－ＴＺＰ材料在热压烧结时，由于软团聚未能有效地破碎。造成烧结过程中团聚体内部首先致密化，珉在体之间产生张力，导致裂纹状大气孔的出现，同时因石墨模具的限制，热压时的外压不足以克服塑性滑移产生所需的“阈值”，因此大气孔无法“压碎”，使产地密度比相同温度下无压结还低，针对热压烧结纳米Ｙ－ＴＺＰ材料的局限性。

Sintering of Nano Y-TZP Materials by Hot-pressing

The processing of synthesizing nano Y-TZP materials by hot-pressing was investigated. It was found that there were large crack-like pores in the sintered samples. The reason of this new phenomena was that the soft agglomerate in the powder was not efficiently destroyed. When sintered, the soft agglomerate sintered quickly and turned into hard agglomerate, as a result of the interaction between the hard agglomerate and the matrix, large pores formed. On the other hand, the applied pressure was limited because the low stress tolerance of the graphite die, so no plastic displacement could happen and those large pores could not be "squashed", As a result, the density of the samples sintered by hot-pressing was lower than that by pressureless sintering at the same sintering temperature. To overcome this shortage of hot-pressing, sinter-forging was applied and nano Y-TZP materials with grain size of about 85nm and relative density of 99% could be obtained