کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
701362 | 1460820 | 2006 | 5 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Investigation of relaxation of nanodiamond surface in real and reciprocal spaces Investigation of relaxation of nanodiamond surface in real and reciprocal spaces](/preview/png/701362.png)
The structure of a nanodiamond powder with an average grain size of 5 nm was investigated using large-Q neutron diffraction. Both Bragg scattering and PDF analysis were employed. The effect of annealing under vacuum at temperatures up to 1200 °C was studied. The studies lead to a tentative model of nanocrystalline diamond, where the core with a perfect diamond lattice is surrounded by a shell of compressed diamond lattice, and this core–shell structure is enveloped in a non-diamond carbon. The non-diamond envelope of nanograins, a “gas-like” carbon, is stable up to 1000 °C and transforms into a graphite phase (an onion-type structure) at about 1200 °C. The amount of non-crystalline carbon in the powder annealed below 1000 °C is about 10%. In the sample annealed at 1200 °C a graphite-type carbon, with a total of about 15% of sp2 bonds is formed.
Journal: Diamond and Related Materials - Volume 15, Issues 11–12, November–December 2006, Pages 1813–1817