Recent Progress in the Study of the Kinetics of Sol-Gel SiO2 Synthesis Reactions

摘要

Sol-gel ceramic synthesis has drawn much interest in recent years. 1-5Organometallic molecules, usually metal alkoxides, are polymerized in an alcohol/water solution with dissolved acids or bases to form a ceramic or glass material with exquisite chemical and microstructural control. Since the chemistry and microstructure of the solid determine its properties, this technology can be used to design materials with specified mechanical, optical, electronic, and physicochemical properties. These materials may be monoliths, films, fibers, or powders. Sol-gel synthesis offers a degree of control of composition and structure at the molecular level unachievable with traditional sintering or precipitation methods. It also offers an economical alternative to layered vapor deposition manufacture of coatings and fibers. Owing to their controlled chemistry and microstructure, sol-gel ceramics can be densified at much lower temperatures than conventional sintering temperatures, thereby saving energy and protecting delicate structures in the material itself or in its substrates The microstructure can also be controlled to produce optical films, catalyst supports monolithic ceramic bodies, etc. Since the precursor molecules are pure and dissolved, atomic placement and bonding can be controlled to tune mechanical optical. (jg).