کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1476629 991158 2010 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermal expansion of EB-PVD yttria stabilized zirconia
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Thermal expansion of EB-PVD yttria stabilized zirconia
چکیده انگلیسی

Yttria stabilized zirconia (YSZ) layers, suited for thermal barrier coatings (TBCs) in turbine engines, were produced by electron-beam physical vapour deposition (EB-PVD) on metallic (Ni-based alloys) ceramic (Al2O3) substrates (typically at 1000 °C) using ingot compositions of about 4 mol% Y2O3–ZrO2. Employing powdered samples, removed from the surface of the as-deposited YSZ layers, precision X-ray diffraction data sets were recorded between 60 and 900 °C and the lattice parameters of the metastable, tetragonal (t′) and the cubic (c) phases were refined using Rietveld's method. It was unambiguously verified that phase (c) was present in all investigated samples as a minority phase already in the as-deposited state.The thermal expansion coefficients of the tetragonal phase (t′) (α11 = 9.3(2) × 10−6 K−1, α33 = 10.8(1) × 10−6 K−1) and the cubic phase (c) (α11 = 8.5(2) × 10−6 K−1) were evaluated from the refined temperature dependent lattice parameter values of this study, and turned out to be close to each other, but significantly different from the coefficient of the monoclinic phase (m) (α11 = 9.0 × 10−6 K−1, α22 = 1.2 × 10−6 K−1, α33 = 11.9 × 10−6 K−1, α13 = 0.0 × 10−6 K−1), which was derived from temperature dependent lattice parameter measurements published by Touloukian et al.5 The expansion coefficient of the monoclinic phase (m) exhibited a very pronounced anisotropy in contrast to the tetragonal phases (t′) and (t). Our values for (t′) and (c) were in excellent agreement with that of other tetragonal and cubic phases from the literature with quite different Y2O3 contents.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of the European Ceramic Society - Volume 30, Issue 12, September 2010, Pages 2491–2496
نویسندگان
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