Nan Li1,Hyosim Kim1,Dongyue Xie1,Tim Graening2,Andrew Nelson2,Tyler Dabney3,Kumar Sridharan3,Stuart Maloy1
Los Alamos National Laboratory1,Oak Ridge National Laboratory2,University of Wisconsin–Madison3
Nan Li1,Hyosim Kim1,Dongyue Xie1,Tim Graening2,Andrew Nelson2,Tyler Dabney3,Kumar Sridharan3,Stuart Maloy1
Los Alamos National Laboratory1,Oak Ridge National Laboratory2,University of Wisconsin–Madison3
Due to the combined advantage of low thermal neutron absorption coefficient, good corrosion resistance in high temperature water, and satisfying mechanical properties, zirconium alloys have been widely used as a fuel cladding material in light water reactors (LWRs). Following the Fukushima-Daiichi accident in 2011, increasing concerns were triggered on the oxidation and hydrogen gas generation issues of Zr alloys under severe accident environments. Significant effort has been developed to apply Cr coatings to suppress water corrosion at elevated temperatures due to their extraordinary corrosion resistance, high melting point, good strength, high hardness, and good wear resistance. Here, two types of coating methods have been applied: (i) High Power Impulse Magnetron Sputtering (HiPIMS) to deposit a 6-micron Cr coating at Oak Ridge National Laboratory; (ii) cold spray to deposit a 50-micron Cr coating from the University of Wisconsin-Madison. Micro scale cantilever beams with a pentagonal cross section have been fabricated inside the Cr coating region. In situ bending tests were performed using a PI-85 Pico-indent system (Hysitron/Bruker Inc., USA) inside a scanning electron microscope (SEM). The beam failed brittlely at the interface of coatings and the Zry-4 plate. The adhesion strength correlated with the the fracture stresses of the Cr coatings on the Zry - 4 plates has been estimated.