CuCr₂O₄ particle growth and evolution across sol–gel routes and calcination profiles

ABSTRACT

CuCr₂O₄ spinel is a candidate coating material for central receivers in concentrating solar power to protect structural alloys against high temperature oxidation and related degradation. Coating performance and microstructure of dip-coated and sintered coatings is dictated by the initial particle size of the CuCr₂O₄ and sintering temperature, but can be compromised by particle agglomeration. In this study, sub-micron particles were synthesised through the Pechini and modified Pechini sol–gel methods. Phase composition was confirmed via X-ray diffraction. Particle growth during calcination of the nanoparticles at different temperatures (650°C, 750°C, 850°C) and times (between 1 and 24 h) was measured via laser diffraction and scanning electron microscopy. The modified Pechini method displayed evidence of smaller particle sizes and greater agglomeration. The kinetics of particle growth observed are consistent with a diffusion limited inhibited grain growth model.

KEYWORDS:

• Copper chromite
• sol–gel
• Pechini
• particle growth
• agglomeration

Acknowledgements

Dr. M. Sanders provided TGA/DTA operation and help with data interpretation. Sandia National Laboratories is a multi-mission laboratory manage and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U. S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Contamination from either scoop type was not found.

Additional information

Funding

This work was supported with a grant from the U.S. Department of Energy Solar Energy Technology Office underaward number DE-EE0008538 (Shane Powers, program manager). Primary particle size analysis was performed with a TESCAN Raman-SEM provided by National Science Foundation through grant #DMR-1828454.