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Microwave‐Assisted Synthesis and Sintering of NZP Compounds
Author(s) -
Vaidhyanathan Balasubramaniam,
Agrawal Dinesh K.,
Roy Rustum
Publication year - 2004
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.1551-2916.2004.00834.x
Subject(s) - sintering , microwave , microstructure , materials science , oxide , phosphate , chemical engineering , activation energy , mineralogy , chemistry , composite material , metallurgy , organic chemistry , physics , quantum mechanics , engineering
We have identified the high microwave susceptibility of the sodium di‐hydrogen phosphate monohydrate (NHPM), NH 2 PO 4 ·H 2 O. This acid phosphate of sodium can be heated to >900°C when exposed to 2.45 GHz microwave radiation. Using NHPM and microwave energy, a novel single‐step synthesis of many important crystalline NZP compounds has been accomplished in a very short time. Interestingly, the combination of microwaves and nonstoichiometric oxide precursors for the preparation of NZP materials is found to reduce the reaction temperatures and enhance the reaction kinetics further. The microwave synthesis method is found to be simple and fast, minimizing the loss of volatile chemical species from the reaction. A microwave‐assisted procedure for the rapid sintering of NZP compounds has also been demonstrated. Densification (>97%) has been achieved in <30 min at sintering temperature much lower than normally required in conventional processes. Finer microstructure and better densification are the main advantages of the microwave sintering in this study.