Epitaxial Growth of Spinel by Reaction in the Solid State

Abstract

The condensed-state reaction between single crystals of A1203 and MgO was conducted in air at 156OOC. Spinel formed as two product layers which were shown to agree with the proposed mechanism. The crystallographic orientation of the parent crystals had no effect on the rate of spinel growth. The orientation of the spinel grown from sapphire was the same as that found by other investigators for isomorphic crystals. The orientation of spinel grown from periclase was largely dependent on the transport mechanism across the periclase-spinel interface.

Morphology of Spinels and Al<SUB>2</SUB>O<SUB>3</SUB> Particles in an Al<SUB>2</SUB>O<SUB>3</SUB>/Al-Mg-Si Composite Material Revealed by Scanning Low Energy Electron Microscopy

“…All values are lower than 10%, which also supports the given orientation relationship as that enabling easy nucleation of a spinel on the Al 2 O 3 surface. According to Rossi and Fulrath,16) the growth of a spinel on sapphire occurs by only a slight shift in the oxygen position and results in the same orientation relationship between the spinel and the sapphire as that mentioned above. Figure 9(a) shows a SLEEM image of particles on the surface of a composite material.…”

Microstructural development of interface layers between co-sintered alumina and spinel compacts

“…It was proposed that the reaction rate (thickness of interlayer) was independent of crystallographic orientation of parent oxides. 1 However, columnar grains are observed to slightly decrease in number as they move away from spinel, indicating some coalescence of grains.…”

“…[1][2][3] Other relevant studies involved magnesia and spinel interfaces, 15 7 But no study was found in the literature regarding the reaction at the interface between polycrystalline alumina and polycrystalline spinel. Hence this study fills this gap in the literature.…”

“…The extent of the formation of the spinel phase or the interface between magnesia (MgO) and alumina (Al 2 O 3 ) has been studied from different perspectives in order to understand if a good bond can be achieved between the two or to investigate the diffusion behaviors of the components. [1][2][3] Most of these studies involved heating of diffusion couples, some others involved heating of single/poly crystals of a component in contact with a powder of the second component. In the literature, sintering behavior of co-pressed and co-sintered powders of oxide/oxide, metal/oxide and metal/metal pairs are reported.…”

The Wear of Tundish Stopper Refractories by Inclusion Slags

“…The reaction caused cracking, probably due to a volume expansion. 10,11) The removal of the periclase grains exposed fresh carbon matrix for oxidation, and then further slag attack on newly exposed periclase grains. The two reactions worked in concert to cause progressive severe wear, as observed.…”