Accession Number : AD0282373

Title :   KINETICS OF SINTERING OF RUTILE SINGLE CRYSTAL SPHERES

Corporate Author : MICHIGAN UNIV ANN ARBOR COLL OF ENGINEERING

Personal Author(s) : O'BRYAN,H.M. JR. ; PARRAVANO,G.

Report Date : FEB 1962

Pagination or Media Count : 1

Abstract : The sintering of single crystal rutile has been studied in air and in reducing atmosphere in the temperature range 900 to 1350 C using a sphereto-sphere model. Rate data show that there are two sintering periods: a slow initial growth characterized by a rate exponent n = 7 and a more rapid subsequent period n = 2. The development of flat surfaces or facets on the particles is used to explain the two periods. A scaling exponent of 3 and an activation energy of 70 kcal/mole indicate that volume diffusion is the sintering mechanism. The initial rate exponent cannot be explained. Increase sinterability of reduced rutile is explained by the defect structure. Facet formation on rutile spheres is discussed. (Author)

Descriptors :   *TITANIUM COMPOUNDS, AIR, CONTROLLED ATMOSPHERES, HEAT TREATMENT, KINETIC THEORY, REDUCTION, SINGLE CRYSTALS, SINTERING, SURFACE PROPERTIES, TEMPERATURE

Distribution Statement : APPROVED FOR PUBLIC RELEASE