酸洗处理对氮化硅浆料流变行为的影响

EFFECT OF ACID LEACHING ON RHEOLOGICAL BEHAVIOR OF SILICON NITRIDE SUSPENSIONS

通过酸洗处理工艺对氮化硅粉体进行了表面改性 ,并研究了酸洗处理对粉体胶体特性及其浆料流动行为的影响 .结果表明 :酸洗处理之后悬浮粒子的等电点升高 ;XPS表面分析说明这是粉体表面氧化程度降低的缘故 .在酸洗处理之前 ,当固相体积分数 φ≤ 0 .3 0时 ,氮化硅浆料的流变行为符合Sisco模型 ;当 0 .3 5≤ φ≤ 0 .4 5时 ,流变行为符合Casson模型 .随着氮化硅浆料固相含量的提高 ,浆料由近似Newton流体逐渐转化为具有屈服应力特征的塑性体 .经酸洗处理的氮化硅浆料在固相体积分数 φ≤ 0 .4 0时 ,流变行为符合Sisco模型 ;当 0 .4 5≤φ≤ 0 .54时 ,流变行为符合Casson模型 .

Surface modification of Si 3N 4 particles by acid leaching and its effects on the colloidal behavior and the rheological behavior of Si 3N 4 suspensions were investigated. The experimental results indicate that the isoelectric point of Si 3N 4 particles is increased after acid leaching due to the decrease of the oxidation degree on the surface of the leached Si 3N 4. The rheological behaviors of the untreated Si 3N 4 suspensions follow the Sisco model in the range of φ ≤0.30 and Casson model in the range of 0.35 ≤ φ ≤0.45 very well. The suspensions change from near Newtonian fluid to plastic fluid having characteristics of yield stress with the increase of solid content of the suspension. And the rheological behavior of the suspensions follows the Sisco model in the range of φ ≤0.40 and Casson model in the range of 0.45≤ φ ≤0.54 perfectly after acid leaching.