SURFACE AND CORROSION STUDY OF LASER-PROCESSED ZIRCONIUM ALLOYS

Reactor Grade Zirconium (Zircaloy-2) was laser-glazed and laser-alloyed with nickel (Ni) or chromium (Cr) powders. Laser alloying produced a surface that was macroscopically, chemically homogeneous. However, at the microscopic level the melt zone was a mixture of microcrystalline pure zirconium (Zr) and extremely fine grain, or possibly amorphous, solid solution regions of Zr and alloying elements. Corrosion tests (potentiodynamic and long-term immersion) were conducted in 10% FeCl3 solution. The potentiodynamic tests showed i(corr) and E(corr), were a strong function of surface conditioning, altered by grit-blasting, laser processing, acid cleaning, and heat treating. Significant improvement was achieved in corrosion resistance by laser-glazing and laser-alloying.