Abstract
The future production of low enriched uranium nuclear fuel for test reactors requires a well-adhered diffusion barrier coating of zirconium (Zr) on the uranium/molybdenum (U-Mo) alloy fuel. In this study, the interfacial bond between plasma sprayed Zr coatings and U-Mo fuel has been characterized for localized bond strength by microcantilever beam testing. Test results have revealed the effect of specific flaws such as cracks and pores on the bond strength of interfaces with a sampling area of approximately 20 µm2. TEM examination has shown the Zr/U-Mo interface to contain rows of very fine grains (5-30 nm) with the Zr in contact with UO2. Bond strengths of plasma sprayed samples have been measured that are similar to those of diffusion-bonded samples showing the potential for plasma sprayed Zr coatings to have high bond strength.
