Author :
Publisher :
ISBN 13 :
Total Pages : 196 pages
Book Rating : 4.:/5 (921 download)
Book Synopsis Incorporation of Silica Into RF Gel for the Synthesis of Porous Si3 N4/SiC Composite Via the Carbothermal Reduction and Nitridation by :
Download or read book Incorporation of Silica Into RF Gel for the Synthesis of Porous Si3 N4/SiC Composite Via the Carbothermal Reduction and Nitridation written by and published by . This book was released on 2008 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Incorporation of silica into RF solution, which was prepared via the sol-gel polycondensation of resorcinol and formaldehyde with sodium carbonate as catalyst was investigated. The reaction between silica precursor and RF solution is quite violent and strongly exothermic. The addition of acetic acid into RF solution damages methylene and methylene ether bridges of the RF clusters, which enables the incorporation of increased amount of silica into the RF clusters. According to the experimental results, silica precursor (APTMS, MPTMS) incorporates into RF clusters at positions of hydroxyl group. Then, the silica/RF gel was converted into silica/carbon composite by pyrolysis before subjected to the carbothermal reduction and nitridation to synthesize silicon nitride/silicon carbide. The results indicated that temperature and porosity of silica/carbon composite does not affect the formation of silicon nitride or silicon carbide. Phase of the product depends upon chemical structure of silica/RF gel formed by polycondensation.
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