کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5439069 | 1398191 | 2017 | 28 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Precursor synthesis and properties of nanodispersed tungsten carbide and nanocomposites WC:nC
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
سرامیک و کامپوزیت
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چکیده انگلیسی
Nanoscale tungsten carbide (WC) and WC:nC nanocomposites have been synthesized by the precursor method. The precursor, obtained in the form of a glassy mass by thermal treatment of a mixture of (NH4)10W12O41â7H2O and glycerol, was heated in inert gaseous atmosphere up to 1050-1100 °C. The concentration of chemically active carbon in the precursor and nanocomposites depends on the W/C ratio in the initial mixture. At W/C=1/3 pure tungsten carbide is formed; at W/C>1/3 composites of WC and free carbon (WC:nC) are formed. Heating of the precursor with W/C=1/6 up to 1100 °C in helium atmosphere results in the formation of carbon-encapsulated tungsten carbide nanoparticles. An increase in the precursor-heating rate leads to the formation of chain-like structures. Each chain consists of hexagonal WC grains with unit cell parameters a=2.93 Ã
and c=2.83Â Ã
. Free carbon in WC:nC composites forms agglomerates of carbon “nano-onions” of spherical or multi-layered tubular shapes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ceramics International - Volume 43, Issue 5, 1 April 2017, Pages 4131-4138
Journal: Ceramics International - Volume 43, Issue 5, 1 April 2017, Pages 4131-4138
نویسندگان
Vladimir N. Krasil'nikov, Ðvgenii V. Polyakov, Nikolai Ð. Khlebnikov, Nadezda V. Tarakina, Ðikhail V. Kuznetsov,