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MgAl 2 O 4 ‐Spinel Synthesized by High‐Energy Ball Milling and Reaction Sintering
Author(s) -
Henkel Lars,
Koch Dietmar,
Grathwohl Georg
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2009.02965.x
Subject(s) - sintering , ball mill , spinel , materials science , high energy , chemical engineering , metallurgy , mineralogy , chemistry , engineering physics , engineering
A new way to prepare magnesia‐alumina‐spinel was investigated making use of a mixed powder system of MgO and metallic Al‐3 wt% Mg. Intensive ball milling was applied which provides the formation of new powder particles as composite of both components in intimate contact. The new configuration of the particles had a significant impact on the reaction sintering behavior leading to single phase spinel microstructures at moderate temperatures below 1400°C. Optimized milling of the powder mixture was therefore required providing reduced crystallite sizes and strongly enlarged interfacial area shared by the reacting components. The optimal milling time was identified by the complete reaction of the starting powders to spinel during sintering. Shorter milling times led to incomplete reactions and longer milling times contaminated the milling product by debris from the milling tools. The amount of interfaces generated by the intimate mixing dominated the sintering reaction kinetics whereas the specific surfaces area was of secondary importance.