Chapter 62. Investigation of the Reduction of NiAl2O4 - I: Neutron Diffraction Studies
- Don Bray
Published Online: 26 MAR 2008
Copyright © 1988 The American Ceramic Society
22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 19, Issue 3
How to Cite
Üstündag, E., Hanan, J. C., Clausen, B., Bourke, M. A. M., Sass, S. L. and Barbieri, T. J. (1988) Investigation of the Reduction of NiAl2O4 - I: Neutron Diffraction Studies, in 22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 19, Issue 3 (ed D. Bray), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294482.ch62
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1988
Print ISBN: 9780470375587
Online ISBN: 9780470294482
In situ metal-ceramic composites consisting of Ni particles embedded in alumina matrices were obtained by the partial reduction of NiAl2O4. The volume shrinkage that accompanies the reduction reaction generates residual stresses. Neutron diffraction studies were performed for the first time at various temperatures to study the evolution of phases in situ during reduction and to determine their stress state. It was determined that compressive stresses of several hundred MPa in magnitude can be generated inside the unreduced part of spinel. It was also found that the stress generation is strongly influenced by material and processing variables such as reduction temperature and the initial density of spinel. The diffraction results were then compared to finite element calculations and a reasonable agreement was obtained.
Neutron diffraction is a powerful method to investigate, in situ, the partial reduction of nickel spinel. Depending on processing conditions such as initial spinel density and reduction temperature compressive stresses on the order of −300 MPa can be generated in spinel demonstrating the effect of the volume shrinkage during reduction.