Co-precipitated ZnAl2O4 spinel precursor as potential sintering aid for pure alumina system

Ultrafine ZnAl2O4 spinel hydrogel precursor synthesised from mixed salt solutions of Zn2+ and Al3+ ions using ammonium hydroxide-hexamethylenetetramine as basic media for co-precipitation was used as a bonding material and sintering aid for pure alumina systems. The hydrogel powder exhibited some we...

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Bibliographic Details
Published in:Ceramics international 2010-05, Vol.36 (4), p.1211-1215
Main Authors: Parya, T.K., Bhattacharyya, R.K., Banerjee, S., Adhikari, U.B.
Format: Article
Language:English
Subjects:
Aluminum oxide
Compressive strength
Firing
Hydrogels
Inhibitors
Precursors
Sintering (powder metallurgy)
Spinel
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Summary:Ultrafine ZnAl2O4 spinel hydrogel precursor synthesised from mixed salt solutions of Zn2+ and Al3+ ions using ammonium hydroxide-hexamethylenetetramine as basic media for co-precipitation was used as a bonding material and sintering aid for pure alumina systems. The hydrogel powder exhibited some well-defined ZnAl2O4 spinel phases at 800 C. Alumina compacts were fabricated by incorporating small amounts of the precursor in alumina powders and firing at different temperatures (1350-1500 C). The degree of densification was studied by measurement of fired shrinkage, apparent porosity, bulk density and cold crushing strength. Phase compositions and microstructural features of the sintered samples were evaluated by XRD and SEM respectively. The addition of 0.2% hydrogel powder to alumina had remarkable influence on the development of high mechanical strength. The in-situ formed ZnAl2O4 spinel dopant acted as a grain growth inhibitor in the alumina system.
ISSN:0272-8842
DOI:10.1016/j.ceramint.2010.01.013