Forming Reason and Resolving Measures of Island Defects on the Surface of Zirconium Alloy Plate

The reason of island defects on the the surface of zirconium alloy plate after pickling was analyzed by morphology observation of island defects, chemical composition analysis and surface treatment tests. The resolving measures was risen to avoid the island defects. The results show that the island defects were formed because the inclusion and oxide layer on the surface of plate resulted in the different pickling rates. The island defects could be avoided by adding the polishing before pickling to uniform the plate surface and using zirc-alloy with niobium to form NbF film during picking that could reduce the amount of island defects.