Open    Access



High Temperature Oxidation of Zr-2.5%wt Nb Alloys Doped with Yttrium



Author(s)

Djoko Hadi Prajitno, Syoni Soepriyanto, Eddy Agus Basuki and Slameto Wiryolukito

Full-Text PDF XML     302 Views

DOI:10.17265/2161-6221/2013.12.010

Zirconium base alloys have been utilized in LWRs (light water reactors) as fuel element cladding tubes, fuel assembly spacer grids, guide tubes in PWRs (pressurized water reactors) due to their low neutron absorption and good corrosion resistance. The oxidation resistance of Zr alloys are strongly controlled by the phase presence and composition of the alloys. The beneficial effect of yttrium content on isothermal oxidation behavior of Zr-2.5%Nb-Y(Y = 0, 0.5, 1, 1.5 )in wt % alloy at high temperature has been studied. High temperature oxidation carried out in air furnace at 600,700 and 800 ^oC for 1, 4, and 9 h. Characterization by optical microscope showed that microstructure of Zr-2.5%Nb-Y alloys relatively unchanged. X-ray diffraction of the alloys depicted that the oxide scale formed during oxidation of zirconium alloys is monoclinic ZrO₂ and minor of tetragonal ZrO₂, while unoxidized alloy showed two phase a and b phase. SEM-EDS examination shows that depletion of Zr composition took place under the oxide layer. Kinetic rate of oxidation of zirconium alloy showed that increasing oxidation temperature will increase oxidation rate but increasing yttrium content in the alloys will decrease oxidation rate. The parabolic rate constant value decreasing with increasing yttrium in Zr-2.5%Nb alloys.

Oxidation, alloy, zirconium, yttrium.