کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1446584 988616 2012 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Phase stability of the two isomorphs monoclinic zirconia and hafnia under MeV ion irradiation
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Phase stability of the two isomorphs monoclinic zirconia and hafnia under MeV ion irradiation
چکیده انگلیسی

Zirconia and hafnia are known to exhibit similar phase transitions under temperature, pressure or swift heavy (i.e., GeV) ion irradiation. In the present study, both monoclinic zirconia and hafnia were irradiated with 5-MeV I ions in order to comprehend the underlying mechanism governing phase transition by low-energy ion irradiation. Surprisingly, it was found that, although monoclinic zirconia can easily transform to the tetragonal phase, monoclinic hafnia does not show any transition to the tetragonal structure even after irradiation with ∼19 displacements per atom. The absence of this phase transition in hafnia and its presence in zirconia clearly break the parallel between these two oxides in their response to intense excitation. Furthermore, this comparative study allowed severe constraints to be imposed on the possible mechanisms aimed at explaining phase transformation by low-energy ion irradiation. It is found that the monoclinic-to-tetragonal phase transition in these oxides is very likely driven by oxygen vacancies and occurs once their concentration reaches a certain value. The absence of phase transition in hafnia can thus be explained by the lower concentration level attained by these defects, owing to their higher diffusivity in this material. A similar mechanism can also be invoked to explain the remarkable phase stability of tetragonal zirconia under prolonged low-energy ion irradiation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 60, Issue 16, September 2012, Pages 5662–5669
نویسندگان
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