Gel Sintering

Sol—Gel Sintered Aluminum Oxide. A new and much more versatile sintered alumina abrasive is now produced from aluminum monohydrate, with or without small additions of modifiers such as magnesia, by the sol—gel process (see Sol-gel technology). The first modified sol—gel abrasive on the market, Cubitron, was patented (27) and produced by the 3M Corporation for products such as coated belts and disks. The success of this material promoted intensive research into sol—gel abrasives. 

Silica gel sintered TLC plates pretreated with K2Cr2C>7 and activated at 100°C for 2 hours. 4-dimethylamino- benzaldehyde 48... 

Manufactured abrasives include silicon carbide, fused aluminum oxide, sintered aluminum oxide, sol-gel sintered aluminum oxide, fused zirco-nia-alumina, synthetic diamond, cubic boron nitride, boron carbide, slags, steel shot, and grit. 

FIGURE 13.2 Scaiming electron micrographs of fractnre snrfaces of cordierite composition gels sintered at 1300°C for 2 h (a) nanocomposite and (b) homogeneons (single phase). (Reprinted with permission from Kazakos, A.M., Komameni, S., and Roy, R., J. Mater. Res., 5, 1095, 1990.)... 

When silica gel is heated to higher temperatures (100 to 1000° C) the cavity system undergoes change. The porous material thickens. Silica gel sinters and the causes of this sintering are ... 

Another area of research where XPS has been applied is in the properties and structure of glasses in relation to processing method. Glasses have traditionally been prepared by the melt-quench route, however interest in sol-gel (sintered gel) based glasses has led to claims that sol-gel processing may have a number of distinct advantages over melt-quench... 

Hirayama, H., Hiraki, K., Nishikawa, Y., and Fukazawa, S. (1984). Thin-layer chromatography of carbohydrates on silica gel sintered plates. Kinki Daigaku Rikogakubu Kenkyu Hokoku 20 121-126 Chem. Abstr. 1984, 101,126298a. 

Ikawa, S. (1976). Purification of methylated bile acids recovered from thin-layer chromatograms on silica gel-sintered plates. J. Chromatogr. 117 227-231. 

Satoh S., Susa K. Experimental study of porous gel sintering. J. Amer. Ceram. Soc. 1985 68 399-402... 

One of the compounds that have drawn attraction of the investigators in the area of sol-gel powderless ceramics is barium titanate, BaTiOs. An initial report came from Frey and Payne (1995) who prepared and used barium and titanium methoxyethoxides under controlled atmosphere for synthesis. The modified alkoxides were hydrolyzed by addition of a solution of water in 2-methoxyethanol. The sol was cast, sealed and aged. Drying at above 50°C yielded monolithic gels sintering of the gels at 800-1300°C produced... 

Nogami and Moriya [58] showed that the chemical and microstructural differences between acid- and base-catalyzed gels were reflected in their densification behavior. The initial shrinkage of the base-catalyzed gel could be described using Frenkel s equation, Eq. 14. The acid-catalyzed gels sintered at lower temperatures, and the kinetics of densification did not... 

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