放电等离子烧结制备透明AlN陶瓷

Fabrication of transparent AlN ceramics by spark plasma sintering

采用放电等离子烧结(sparkplasmasintering,SPS)技术,添加不同含量CaF2为烧结助剂,成功制备了透明氮化铝(AlN)陶瓷.SPS技术具有烧结快速,烧结体致密度高的特点,是制备透明AlN的有效方法.CaF2的加入量的提高,有利于烧结体的致密度和透过率的提高.当CaF2加入量为3%(质量分数)时,烧结体致密度不再继续提高,但仍有利于透过率的提高,此时烧结体透过率最高为54.7%.SEM、XRD、TEM和EDX结果表明烧结体具有很高的致密度、纯度,均匀的晶粒形状和尺寸,晶界及三角晶界处观察不到第二相的存在,从而保证了烧结体良好的光学性能.

AIN powders containing deliberating amounts of calcium fluoride （CaF2） were consolidated by spark plasma sintering （SPS） technique and transparent AIN ceramics were fabricated. Samples obtained by SPS achieved high densities in short time, which indicated SPS was an efficient method for the fabrication of transparent AIN ceramics. Heterogeneity in the color of the sintered pure AIN ceramics was observed. With the increase of CaF2, density and transmittance of the sintered AIN were improved. An increase in the amount of CaF2 to 3% in mass did not further increase the density, but did improve the transmittance. The sample doped with 3% CaF2 yielded the highest maximum transmittance of 54.7%. The high transmittance was attributed to high purity, the homogenous microstructures and the less-grain boundary phases, which was confirmed by the results from XRD, SEM, TEM and EDX.