Study of hydride precipitation on zircaloy-4 by electrolysis process

It had been conducted the hydration of zircaloy-4 by electrolysis in sulphuric acid electrolyte. In this experiment hydrogen in the from of atoms and ion is produced from electrolysis in a dilute sulphuric acid. The hydrogen is liberated in the vicinity of the cathode and the specimen itself was as the cathode. Electrolysis was performed at the current of 10 amperes and the potential of 30 volts. In this potential the affinity of zirconium increases and it is reactive enough to absorb hydrogen, which is close to the cathode. The absorbed hydrogen dissolves through the zircaloy-4. The hydrogenated specimens were heated at temperature 400 oC in inert atmosphere. Furthermore, the specimens were cooled in the furnace by the appropriate furnace cooling. The optical microscope was used for performing the metallographical analysis. The specimens were etched with solution of 25 ml 30% H2O2, 25 ml 70% HNO3 and 10 drops of 48% HF by swabbing technique for 10-20 seconds and washed by water. Based on ASTM 353 at 100x magnification the length of platelets is not less than 1.5 mm. From the microstructure image, hydride platelets have improperly been found, because part of them is in the particle from with diameter in the range of 1.4-7 micron meters which is uniformly distributed in the materials. The particle density is in the range of 13-36 particles per 3.5 mm2 of the material surface. The platelet orientation is not parallel to the rolling direction. This fact indicated that the basal plane of zircaloy-4 crystals is not paral let to the rolling direction