کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1488197 1510724 2014 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The etching process of boron nitride by alkali and alkaline earth fluorides under high pressure and high temperature
ترجمه فارسی عنوان
فرایند اچینگ نیترید بور با فلوراید های قلیایی و قلیایی زمین تحت فشار بالا و درجه حرارت بالا
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
چکیده انگلیسی


• Appropriate etch processes of hBN and cBN under HPHT are proposed.
• The degree of the crystallization of hBN was decreased.
• A special cBN growth mechanism with a triangular unit is proposed.
• Plate-shape cBN crystals with large ratio of length to thickness were obtained.
• A strategy provides useful guidance for controlling the cBN morphology.

Some new etching processes of hexagonal boron nitride (hBN) and cubic boron nitride (cBN) under high pressure and high temperature in the presence of alkali and alkaline earth fluorides have been discussed. It is found that hBN is etched distinctly by alkali and alkaline earth fluorides and the morphology of hBN is significantly changed from plate-shape to spherical-shape. Based on the “graphitization index” values of hBN, the degree of the crystallization of hBN under high pressure and high temperature decreases in the sequence of LiF > CaF2 > MgF2. This facilitates the formation of high-quality cBN single crystals. Different etch steps, pits, and islands are observed on cBN surface, showing the strong etching by alkali and alkaline earth fluorides and the tendency of layer-by-layer growth. A special layer growth mechanism of cBN with a triangular unit has been found. Furthermore, the morphologies of cBN crystals are apparently affected by a preferential surface etching of LiF, CaF2 and MgF2. Respectively, the plate-shape and tetrahedral cBN crystals can be obtained in the presence of different alkali and alkaline earth fluorides.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Research Bulletin - Volume 51, March 2014, Pages 258–262
نویسندگان
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