Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8039068 | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms | 2018 | 7 Pages |
Abstract
Yttria-stabilized zirconia (YSZ) films with tetragonal (tâ²) phase was prepared on China Low Activation Martensitic steel (CLAMs) substrates by supersonic atmospheric plasma spraying (SAPS) with ZrO2-8â¯wt% Y2O3 nano-powders as feedstock. This study deals with the subject of the structural modifications and phase transformations in tâ² phase YSZ coatings induced by implantation of low-energy (60â¯keV) He ions. It is found that the phase transformation in tâ² phase YSZ coatings during helium ion-irradiation as a function of fluence can be divided into a two-stage process based on the microstructural evolution as follows: (i) In the case of He ions at 0.5â¯Ãâ¯1017â¯cm2 (â¼1.5â¯dpa), no obvious volume swelling can be detected, suggesting the irradiation-induced defects is primarily associated with a positive relaxation volume. Therefore, only tâ²â¯ââ¯t phase transformation was observed for the samples implanted at a fluence of 0.5â¯Ãâ¯1017â¯cmâ2. (ii) While increasing the fluence from 0.5â¯Ãâ¯1017â¯cmâ2 to 2â¯Ãâ¯1017â¯cmâ2, an increase in the defect concentrations can be observed, leading to an exponential growth in volume swelling from 3.2% to 9.7% observed. These high- density extended defects can induce a plastic deformation in the lattice structure, resulting significant lateral compressive stress. Correspondingly, the tâ²â¯ââ¯tâ¯+â¯c phase transformation was detected for the samples implanted at the fluence of 2â¯Ãâ¯1017â¯cmâ2. At a fluence of 10â¯Ãâ¯1017â¯cmâ2, the formation of the He bubbles, and ellipsoidal cavities can be observed by TEM, inducing the further volume swelling. Meanwhile, the intensity of (4 0 0)c peak increases while fluence increase from 2â¯Ãâ¯1017â¯cmâ2 to 10â¯Ãâ¯1017â¯cmâ2. Based on the experimental results, a reasonable mechanism for the phase transformation of tâ² phase YSZ samples during He ions irradiation is proposed.
Related Topics
Physical Sciences and Engineering
Materials Science
Surfaces, Coatings and Films
Authors
Bo Liu, Jianxiong Zou, Liwei Lin, Shanlin Wang, Yu Bai, Chunhai Liu, Qiran Li,