Tem Investigation of Phases Formed During Aluminium Wetting of MgO at [100], [110] and [111] Orientations

Archives of Metallurgy and Materials

N. Sobczak¹  R. Nowak¹  J. Morgiel²  J. Wojewoda-Budka²  M. Pomorska² 

[1] Foundry Research Institute, 73 Zakopianska st., Kraków Poland;Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta st., 30-059 Kraków, Poland

关键词: Keywords : Al/MgO reaction;    -Al2O3;    MgAl2O4;    microstructure;    TEM;    EDS;   

DOI  :  10.2478/amm-2013-0025

学科分类：金属与冶金

来源: Akademia Gorniczo-Hutnicza im. Stanislawa Staszica / University of Mining and Metallurgy

【 摘 要 】

The interaction of liquid aluminium (5N) with single crystal MgO substrates of [100], [110] and [111] orientations (surface roughness <1 nm) were studied using sessile drop wettability test performed at 1000ºC for 1 hour in vacuum (5 x 10-6 mbar). The observations performed using scanning electron microscopy (SEM) showed that the interaction of liquid metal with MgO crystals in all cases resulted in the formation of reaction products region (RPR) of thickness varying from ∽40 up to ∽80 microns in depth. In each case the RPR consisted mainly of coarse dendrite-like crystallites of few microns thick surrounded by net of much thinner channels. Occasionally away from the RPR centre the areas built of much finner but also dendrite- or filament-like crystallites were noted. The thin foils for transmission electron microscopy (TEM) investigations were cut using focused ion beam system (FIB) both from drop/RPR as well as RPR/MgO interfacial regions. The electron diffractions proved that the dominating coarse dendrite-like crystallites are of the same α-Al2O3 type throughout the whole RPR for all substrates orientations. Similarly, the colonies of finer crystallites always showed diffraction patterns characteristic for MgAl2O4 spinel. Therefore, the performed investigation indicated, that both the reaction layer depth and the reaction path represented by the sequence and type of phases present in Al/MgO RPR remain roughly similar for all examined orientations, i.e. that the substrate orientation control neither reaction kinetics, nor affects final phase composition of RPR.

【 授权许可】

Unknown