STP1028

    Influence of Solution Chemistry on the Microstructure of Sol-Gel Derived Films

    Published: Jan 1988


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    Abstract

    Recent work in this laboratory has demonstrated that the crystalline phase of titania deposited onto silica fibers by sol-gel techniques can be altered through changes in solution chemical equilibria brought about by variations in pH or chloride ion concentration. Molecular characterization of the solution microstructure and identification of the crystalline phase for deposited films is accomplished by Raman spectroscopic methods. The rutile phase of TiO2 has been identified in films deposited from solutions prepared with TiCl4 and HCl after a low-temperature densification (ca. 250°C) step. The more commonly observed anatase phase was formed without the addition of acid. Increased concentration of HCl in an alcoholic ethyl titanate solution results in increased stress in the anatase phase. A mixture of rutile and stressed anatase phases is found upon addition of LiCl to the acidic titaniumn alkoxide solution. These results suggest that the gel microstructure, which is a function of the solution chemistry, directly affects the crystal structure of the dehydrated, densified gel.

    Keywords:

    phase identification, Raman spectroscopy, sol-gel coatings, thin films


    Author Information:

    Ferris, KF
    Pacific Northwest Laboratory, Richland, Washington,

    Exarhos, GJ
    Pacific Northwest Laboratory, Richland, Washington,

    Nguyen, C
    Pacific Northwest Laboratory, Richland, Washington,


    Paper ID: STP18563S

    Committee/Subcommittee: E13.08

    DOI: 10.1520/STP18563S


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