1. The card-house structure constructed by h-BN flakes was regarded as the main factor to prevent the densification of the composite.
认为卡片房式结构是妨碍BN基复合陶瓷致密化的主要原因。
2. It is difficult to obtain high densified composite by pressureless sintering even if liquid phase can produce during sintering, because the card-house structure can not be destroyed.
无压烧结时因不能消除原有的卡片房式结构,故虽有液相出现,也难以获得高致密度的BN基复合陶瓷。
3. The high enough pressure exerted on the sintering body during hot pressing can destroy the card-house structure and high densified composite can be available.
热压过程中施加的压力足够大时,可以破坏这种卡片房式结构,使片状BN定向排列,因而能获得高致密度的BN基复合陶瓷。
4. However, for the low specific surface area AlN powders synthesized from the precipitated precursor, its sintering temperature increased. AlN and BN were sintered at the same time in this composite ceramics. AlN matrix was not densified when h-BN flakes formed the card-house structure, which could prevent the densification process of AlN-BN composite ceramics. Therefore, it is difficult to produced high density and high thermal conductivity composites.
在以沉淀前驱物合成的低比表面积的AlN粉末为原料时,AlN粉末开始烧结的温度升高,AlN和BN的烧结几乎同时进行,在片状的BN晶体交叉堆积形成卡片房式结构时,AlN基体材料仍未致密,BN形成的卡片房式结构会阻碍AlN-BN材料的收缩,难以制备出高致密度和高热导率的复合陶瓷材料。
5. The XRD and SEM analyses show when 10% or more hBN lubricatives are added they can scatter uniformly in the matrix, in addition, hot pressing technique can make the microstructure perfectly dense because the card-house structure of hBN is destroyed and the orientation arrangement of hBN is imKey words: Al2O3/hBN, Ceramic composites, Self-lubrication, Microstructure
结果表明,hBN引入量为10%时已有足够的量均匀分散在基体中;相同烧成温度下,热压过程中施加的压力可以破坏hBN的卡片房式结构,伴随液相的出现有利于hBN的定向排列,获得了结构致密的自润滑复合陶瓷材料。