Chapter 62. Investigation of the Reduction of NiAl2O4 - I: Neutron Diffraction Studies

  1. Don Bray
  1. Ersan Üstündag1,
  2. Jay C. Hanan1,
  3. B. Clausen2,
  4. M. A. M. Bourke2,
  5. S. L. Sass3 and
  6. T. J. Barbieri3

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294482.ch62

22nd Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 19, Issue 3

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

Author Information

  1. 1

    Department of Materials Science, Keck Laboratory, California Institute of Technology, Pasadena, CA 91125

  2. 2

    Manuel Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, NM 87545

  3. 3

    Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780470375587

Online ISBN: 9780470294482

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Keywords:

  • alumina;
  • magnitude;
  • ceramic;
  • microstructure;
  • atmosphere

Summary

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.