Accession Number : ADA264354


Title :   Structural Development in Ceramic Precursor Sols and Gels


Descriptive Note : Final rept. 15 Mar 89-14 Mar 92,


Corporate Author : MINNESOTA UNIV MINNEAPOLIS DEPT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE


Personal Author(s) : Mecartney, Martha L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a264354.pdf


Report Date : Mar 1993


Pagination or Media Count : 52


Abstract : The effect of water of hydrolysis on nucleation, crystallization , and microstructural development of sol-gel derived single phase LiNbO3 thin films has been studied using transmission electron microscopy (TEM), atomic force microscopy (AFM), x-ray diffraction (XRD), and differential lithium and niobium in ethanol was used for the preparation of sol. DSC results indicated that adding water to the solution for hydrolysis of the double ethoxides lowered the crystallization temperature from 500 deg C (no water) to 390 deg C (2 moles water per mole ethoxide). The amount of water has no effect on the short range order in amorphous LiNbO3 gels but rendered significant microstructural variations for the crystallized films. AFM studies indicated that surface roughness of dip coated films increased with increasing water of hydrolysis


Descriptors :   *CRYSTAL STRUCTURE , *PRECURSORS , *GELS , *CERAMIC MATERIALS , TEMPERATURE , SURFACE ROUGHNESS , NUCLEATION , COATINGS , NIOBIUM , ETHANOLS , LITHIUM NIOBATES , HYDROLYSIS , OXIDES , HEAT TREATMENT , GLASS , CRYSTALLIZATION , THIN FILMS , WATER


Subject Categories : Physical Chemistry
      Ceramics, Refractories and Glass
      Crystallography


Distribution Statement : APPROVED FOR PUBLIC RELEASE