Abstract:To better understand the effect of tin on the corrosion behavior of Zr-Sn-Nb-Fe alloy, Zr-XSn-1Nb-0.3Fe (X=0 wt%~1.5 wt%) sheets were prepared and corroded by a static autoclave in 360 oC/18.6 MPa pure water, 360 oC/18.6 MPa/0.01 mol·L-1 LiOH aqueous solution and 400 oC/10.3 MPa superheated steam. The characteristics of the precipitates were analyzed by TEM, the crystal structure transformation of the oxide film during corrosion and its effect on the corrosion resistance of alloys were characterized by laser-Raman spectrometry. Results show that the corrosion mass gain decreases when tin content decreases from 1.5 wt% to 0.6 wt%. As tin content decreases from 0.6 wt% to 0, the corrosion mass gain hardly changes in pure water and steam. However, it is found that the corrosion mass gain increases in LiOH aqueous solution. The microstructural characteristic indicates that the crystal structure and mean size of the precipitates in all tested alloys are almost the same even though the tin considerably changes, but the area fraction of precipitates in the alloy decreases with the tin content increasing when all of the samples are heat-treated in the same condition. It is observed that the oxide film of alloys consists mostly of m-ZrO2 and t-ZrO2 when alloys are corroded in a short time. With the prolongation of corrosion time, the t-ZrO2 transforms to m-ZrO2. The higher the transformation rate, the lower the t-ZrO2 content in the oxide film and the higher the corrosion rate of alloy specimens.