改进的溶胶-凝胶工艺制备ZrB_2纳米粉体

采用改进的溶胶-凝胶工艺,以ZrOCl2、H3BO3和蔗糖为原料,以柠檬酸（CA）为络合剂,聚乙二醇（PEG）为分散剂,制备出均匀稳定的Zr-B-C体系溶胶,再以氨水为调节剂,实现溶胶向凝胶转化。在1 500℃温度下经碳热还原反应制备出粒径尺寸约为40 nm,类球状ZrB2粉体。采用XRD、SEM等微观分析手段,对制备的纳米粉体进行了相组成与微观形貌分析。实验中研究了改进的溶胶-凝胶中柠檬酸络合-聚合技术对溶胶性能的影响。结果表明：当n（柠檬酸）∶n（Zr离子）为1∶3时,可获得稳定的Zr-B-C体系溶胶;增大n（B）/n（Zr）值,有利于得到纯度较高、且相组成可控的ZrB2纳米粉体;加入质量分数为1.0%的PEG时,粉体的团聚性能得到很大改善。

Preparation of ZrB2 Nano-Powders by Novel Sol-Gel Technology

A stable and homogeneous Zr-B-C mixed sol system was obtained through sol-gel process using ZrOCl2,H3BO3 and sucrose as raw materials.Citric acid（CA） was adopted as complexing agent and polyethylene glycol（PEG600） was added in the system as dispersant.The transformation of sol to gel was achieved by adding ammonia water into the mixed sol drop by drop.Near-spherical ZrB2 particles with diameter of 40 nm were synthesized by carbonthermal reduction reaction at 1 500 ℃.XRD,SEM and other analysis methods were applied to study phase composition and microstructure of the nanoparticles as prepared.The effect of CA-complexation technology on the sol was also discussed in this paper.The results showed that stable Zr-B-C mixed sol system can be obtained when the molar ratio of Zr to CA is 3;pure and phase composition controllable ZrB2 powder can be prepared by increasing the molar ratio of B to Zr;dispersibility of the ZrB2 nanoparticles was better when 1.0%PEG was added.