کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1475808 991130 2011 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of commercial anatase-TiO2 raw materials on the electrical characteristics of ceramics with positive temperature coefficient of resistivity
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Effect of commercial anatase-TiO2 raw materials on the electrical characteristics of ceramics with positive temperature coefficient of resistivity
چکیده انگلیسی

Cause and effect of commercially available anatase-TiO2 on the positive temperature coefficient of resistivity (PTCR) characteristics of donor- and acceptor-codoped (Ba,Ca)TiO3-ceramics have been investigated. Compositions containing several anatase raw materials have been studied by means of scanning electron microscopy, in particular EDXS/WDXS-techniques, as well as electron backscattering diffraction (EBSD) and impedance spectroscopy. It is clearly shown that the crystallographic modifications rutile and anatase are replaceable without any significant effect on the PTCR-characteristics, if these raw materials have similar physical and chemical properties such as grain size distribution, specific surface area and impurity content. Further it is demonstrated that the impurities of commercial anatase powders, which are a result of preparation conditions, strongly affect the electrical properties. By use of impedance analysis and electron backscattering diffraction we conclude that the differences in PTCR-characteristics can be attributed to the grain boundary region due to dopant distribution and segregative additive effects and not to microstructural modifications.


► Investigated the applicability of commercial anatase-TiO2 in (Ba,Ca)TiO3-based PTCR-ceramics.
► Verified the replaceability of the TiO2-modification rutile by anatase.
► Determined the effects of the main anatase-impurities phosphorus and potassium on the PTCR-characteristic in n-(Ba,Ca)TiO3.
► Demonstrated by using impedance analysis and EBSD that the increase in resistivity is only located at the grain boundaries.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of the European Ceramic Society - Volume 31, Issue 13, November 2011, Pages 2339–2349
نویسندگان
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