Accession Number : AD0628849

Title :   GRAIN BOUNDARY DIFFUSION IN MGO: ORIGIN OF THE EFFECT,

Corporate Author : RESEARCH AND ADVANCED DEVELOPMENT DIV AVCO CORP WILMINGTON MASS

Personal Author(s) : Wuensch,B. J. ; Vasilos,T.

Report Date : 1965

Pagination or Media Count : 16

Abstract : Preferential diffusion of Ni(2+) and Co(2+) along grain boundaries has been observed in certain bicrystals of MgO. This enhancement is due to impurity segregation at the boundary. The impurities responsible for the effect are the principal impurities contained within the single-crystal MgO: Ca, Si, and Fe. No enhancement has been observed in any bicrystal prepared above 1300C. This temperature corresponds to that at which studies of the mechanical properties of MgO have implied a reabsorption of impurity precipitates into solid solution. It is concluded that enhanced grain-boundary diffusion of cations in MgO is an extrinsic, rather than an intrinsic property of the boundary. (Author)

Descriptors :   (*GRAIN BOUNDARIES, DIFFUSION), (*MAGNESIUM COMPOUNDS, OXIDES), CRYSTALS, IMPURITIES, CALCIUM, SILICON, IRON, NICKEL, COBALT, SINGLE CRYSTALS

Subject Categories : Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE