氮气压力对自蔓延燃烧法合成AlN的影响

Influence of Nitrogen Pressure on AlN Synthesized by SHS Method

以铝粉、NH4F为原料,Nb为添加剂,在N2压力小于0.5 MPa条件下,用高温SHS成功地合成了AlN粉体。研究了添加剂和N2压力对燃烧合成的影响,运用TG/DSC考察了粉末原料的氮化过程,采用XRD、SEM对粉体的物相、显微形貌进行观察表征。研究结果表明,当Al/NH4F=4,在添加剂Nb的作用下,合成的AlN粉体颗粒分布均匀、氧含量低且具有良好结晶形态;在反应前、中期,合适N2压力有助于提高粉体的转化率。

Aluminum nitride(AlN) powders were prepared by a self-propagating high-temperature synthesis(SHS) process.Aluminum and NH4F powders were used as start powders and Nb as additives,ignited in a nitrogen atmosphere under N2 pressure of 0.5 MPa.The influences of additives and nitrgen pressure on combustion synthesis were discussed.The nitriding process of powder mixtures,the phase composition and morphology of products were characterized by TG/DSC,X-ray diffraction(XRD) and scanning electron microscope(SEM),respectively.The results show that the as-prepared AlN particles were well-crystallized with uniform particle size distribution and low oxygen content under the action of Nb as additive and Al/NH4F=4;In the prophase and in the middle of the reaction the rate of Al conversion increased with nitrogen pressure increasing.