Accession Number : ADA337472

Title :   Advanced Ceramics from Liquid Solution

Descriptive Note : Final rept. 1 Dec 93-30 Nov 97

Corporate Author : CALIFORNIA UNIV LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s) : Mackenzie, John D.

PDF Url : ADA337472

Report Date : JAN 1998

Pagination or Media Count : 50

Abstract : This Final Technical Report for the period from 1 December 1993 to 30 November 1997 presents a summary of research performed on two classes of materials prepared by the sol-gel method. The first class of materials is the Ormosils. Work has been carried out on the structure and mechanical properties of Ormosils and a model was presented to account for the dependence of properties on structures, especially for the rubbery Ormosils. The high temperature stability of rubbery Ormosils was found to be enhanced by the presence of small amounts of iron ions. A method was developed for the introduction of carbon black into Ormosils. Aerogels of 95% porosity were known to be extremely fragile. By the incorporation of poly dimethyl siloxane, the resultant Ormosils were rendered rubbery. The second family of materials investigated consisted of ferroelectric thin films. Single crystals of KNbO3 films were grown by the sol-gel method, etched to form waveguides and shown to emit green light when impinged upon by infrared lasers due to second harmonic effects. A theory was postulated which enabled the understanding of ferroelectric behavior shown by amorphous oxide films. A technique was developed for the successful growth of multilayed stack of alternating oxide films. A new family of organic-inorganic hybrids which showed ferroelectric behavior was discovered by the invoirporation of an organic dye, TDP, into the SiO2 network of a gel containing minute crystallite of LiNbO3 or BaTiO3.

Descriptors :   *CERAMIC MATERIALS, *LITHIUM NIOBATES, *SOL GEL PROCESSES, MECHANICAL PROPERTIES, LIQUIDS, STRUCTURAL PROPERTIES, THIN FILMS, HYBRID SYSTEMS, FERROELECTRIC MATERIALS, THERMAL INSULATION.

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE