Abstract
Nanostructured multiphase zirconium aluminium oxide (MP-ZrAlO) composite films are deposited on zirconium substrate by plasma focus device. The XRD results reveal that the crystallinity of ZrO2 and Al2O3 phases is improved for 15 focus deposition shots (FDS), while it is decreased with increasing sample angular positions. A better crystallinity of m-ZrO2 and c-ZrO2 phases is achieved at 300 degrees C annealing temperature, while the re-crystallization of all phases except m-ZrO2 (111) phase is observed at 600 degrees C annealing temperature. The strains developed in ZrO2 (111) and Al2O3 (220) planes are found to be -3.8 x 10(-3) and +2.2 x 10(-3), respectively, for 15 FDS ion irradiations and remained constant for higher FDS ion irradiations. The weight fraction of m-ZrO2 phase decreased from 89 to 79%, while it increased from 11 to 21% for c-ZrO2 phase with increasing FDS. The weight fraction of m-ZrO2 phase increases from 89 to 92%, while it is decreased from 11 to 8% for c-ZrO2 phase with increasing sample angular (0 degrees-10 degrees) positions. At 300 degrees C annealing temperature, the weight fractions of m-ZrO2 phase decreases from 89 to 81%, while it increased from 11 to 19% for c-ZrO2 phase. The SEM microstructures reveal that the formation of nano-grains (range from 45 nm to 100 nm), nano-strips (width ranges from 333 nm to 750 nm and length ranges from 2.5 mu m to 9 mu m) and nano-rods (diameter ranges from 25 nm to 50 nm) observed in different micrographs of MP-ZrAlO composite films can be attributed to increasing FDS, sample angular positions and annealing temperature. The microhardness of MP-ZrAlO composite films deposited for 25 FDS ion irradiations is found to be 9.14 +/- 0.35 GPa which is approximately seven times than the microhardness of virgin zirconium. (C) 2013 Elsevier B.V. All rights reserved.