Preparation And Application Of Particle Size Controllable Silica Sol

Silica sol has a serics of advantageous properties,e.g. strong adsorbability, large specific surface, excellent insulation and good bonding, as well as good reactivity, harmless to the human and environment, and has been widely applied in casting, binder, metallurgy, investment casting, refractory, textile and pharmaceutical industries, the requirements of domestic and foreign products are more and more widely. But in terms of the overall level of the study of silica sol, the particle size controllability and colloidal dispersion also needs to be greatly improved. In addition, SiC as a new generation of nano-semiconductor materials, on the one hand can more easily compatible with the current mature IC process, on the other hand, on the other hand, it can play its unique performance in the nanometer-sized structure, have the excellent performance of the general material can not be achieved, in particular, have attracted much attention in the application of optical, electrical and magnetic.There are two parts in this study:The first part discussed and explored the preparation method of silica sol including ion exchange and metal silicon powder dissolution method; another part reported the synthesis of β-SiC by carbon thermal reduction with acidic silica so las silicon source and nanotubes and graphene oxide as a carbon source, respectively.In part1, the preparation process of silica sol by improving the traditional "ion exchange" and learnning the characteristics of the particles-growing process. The particle size of the growth process is divided into two processes:the nucleus preparation and colloidal particle grew up. The result shows that the silica sol is monodisperse, different particle size, high stability, including the acidic and alkaline. The preparation of raw materials cost, easy operation, simple process, with good reproducibility.Silicon fume dissolution for silicon sol has been widely studied, because of the finished product less impurity content, colloidal silica rounder uniform appearance, compact structure, good stability.The paper through a large number of experimental research, the ammonia and sodium silicate as alkaline catalyst, get the optimum process conditions of preparation, and also studied the method combined with ion exchange to get the large diameter, monodisperse, high stability acidic silica sol. In part2, reported the synthesis of β-SiC by carbon thermal reduction with acidic silica sol as silicon source and nanotubes and graphene oxide as a carbon source, respectively. Find carbon nanotubes for carbon source of similar to the morphology of the carbon nanotubes tubular structure; oxidation graphite as carbon source in the present different morphology of layer of line structure itself. XRD, SEM, TEM and IR characterization and analysis of the samples studied carbothermal reduction temperature, reaction time, the carbon and silicon ratio on the morphology.The optimum conditions of preparation has been gotten.In addition, the combination of the previous theoretical studies, experimental phenomena and results were analyzed, and make a reasonable interpretation of certain theoretical and provide some practical reference value of the production of silica sol.