原位包覆制备氮化硅复合粉体的研究

摘要

通过尿素均匀沉淀方法制备氮化硅复合粉体,利用尿素的分解来生成Y-Al 前驱体包覆层.此方法既解决反向共沉淀法pH值难以控制的难题,又避免球磨法分散不均匀的现象.结果表明:Si3N4粉体通过尿素均匀沉淀的方法可实现Y-Al前驱体包覆,利用SEM图可观察到氮化硅粉体表面形成核壳结构.对Y-Al前驱体包覆的Si3N4粉体采用1750℃热压烧结,研究发现样品具备优良的烧结性能和力学性能,其抗弯强度达到817 MPa.%A simple precipitation method has been developed for the preparation of yttrium aluminum precursor coated Si3N4powders without resorting to uncontrollable pH value, and further avoid the inhomogeneous phenomenon of sintering additives via mechanical ball-milling method. The experimental results indicated that the microstructure of the precursor exhibited a core - shell structure using scanning electron microscopy (SEM). After sintering, the composition reveals excellent sintering and mechanical properties.And then flexural strengthen of the Si3N4powders coated by urea co-precipitation method was improved to 817 MPa at 1 750℃.