Interdiffusion and Structural Changes in the Cr sub(2)O sub(2)-Al sub(2)O sub(3)(ZrO sub(2)) Diffusion Couple under Microwave Heating

• Published in: Powder metallurgy and metal ceramics 2013-03, Vol.51 (11-12), p.666-676
• Main Authors: Get'man, OI, Panichkina, V V, Paritskaya, L N, Radchenko, PYa, Samelyuk, A V, Skorokhod, V V, Bykov, YuV, Eremeev, A G
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Chromium; Diffusion; Heating; Interdiffusion; Mathematical analysis; Microwaves; Recrystallization
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-013-9482-1

The interdiffusion and microstructural evolution of the Cr sub(2)O sub(3)-Al sub(2)O sub(3) (5 vol.% ZrO sub(2)) diffusion couple are studied in the temperature range 1600-1800 degree C under microwave heating (24 Hz) and, for comparison, under traditional heating using electron microprobe analysis and microscopic analysis. It is found that the concentration of chromium is distributed differently in Al sub(2)O sub(3) in diffusion zones under microwave and traditional heating. This is due to greater contribution of grain-boundary diffusion to the effective diffusion flux under microwave heating. Bulk diffusion and average grain-boundary diffusion coefficients are calculated. The grain size in the diffusion zone toward Al sub(2)O sub(3) is smaller after microwave heating. Traditional heating induces grain growth by recrystallization, whereas two processes, recrystallization and polygonization, are superimposed during microwave heating. The polygonization is due to the generation of dislocations under thermal stresses originating from nonuniform temperature distribution in the diffusion zone with variable concentrations of the components. The calculated bulk and grain-boundary diffusion coefficients can be used to predict the kinetics of various diffusion mass-transfer processes in Al sub(2)O sub(3) and Cr sub(2)O sub(3) oxides and their mixtures.