高压烧结AlN陶瓷的残余应力研究

Residual stress of aluminum nitride ceramics sintered at high pressure

利用六面顶技术,在5.0GPa/1 700℃/75~125min条件下高压烧结制备了无烧结助剂的AlN陶瓷块体材料。利用微区拉曼光谱对其残余应力进行了测量,研究了烧结时间对其残余应力的影响,并探讨了残余应力产生的原因及消除的方法。研究表明,微区拉曼光谱是一种测量AlN高压烧结体残余应力的有效方法;在5.0GPa/1 700℃/75min条件下高压制备的AlN陶瓷存在着1.4GPa的残余压应力,且残余应力会随着烧结时间的延长而增大;高压烧结AlN陶瓷产生残余应力的主要原因是AlN晶格产生畸变,这种畸变是长时间施加高压产生的,退火是消除AlN高压烧结体的有效手段。

AlN ceramics were prepared by high-pressure sintering at 5.0 GPa and 1 700℃for 75-125 min in a cubic anvil high-pressure and high-temperature apparatus（China type）without sintering additives.The residual stresses have been evaluated by micro-Raman spectroscopy in AlN ceramics sintered at high pressure.The influence of sintering time on the residual stress was studied,and the causes and elimination method of residual stress were investigated.The results show that the Raman spectra can effectively measure the residual stresses in AlN body materials.The residual compression stress of the AlN ceramics sintered at 5.0 GPa and 1 700℃for125 min is 2.0 GPa,which increases with the extension of the sintering time.Residual compression stress of the AlN ceramics sintered at 5.0 GPa and 1 700℃for 75 min is 1.4 GPa.It is important to point out that the stress arises from lattice mismatch and distortion.And high pressure sintering is considered to be the main factor that would cause the lattice distortion of the ceramics.Annealing is an effective method which removes residual stresses in AlN ceramics.