The effect of an iron powder catalyst clad with a Fe2O3 layer on the nucleation of diamonds

• Published in: Diamond and related materials Vol. 15; no. 9; pp. 1369 - 1373
• Main Authors: QIN, J. M, MA, H. A, CHEN, L. X, TIAN, Y, ZANG, C. Y, REN, G. Z, GUAN, Q. F, JIA, X
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 01.09.2006
• Subjects: Condensed matter: structure, mechanical and thermal properties; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General studies of phase transitions; High-pressure and shock-wave effects in solids and liquids; Mechanical and acoustical properties of condensed matter; Nucleation; Physics; Scanning electron microscopy; Moessbauer effect; Inorganic compounds; Nucleation; Catalysts; Metal powder; Transition element compounds; Diamonds; Binary compounds; Fe2O3 clad layer; Diamond; XRD; High temperature; Cladding product; Experimental study; High pressure; Time dependence; HPHT; Iron oxides
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2005.10.033

In this paper, we have researched the effect of a Fe2O3 clad layer covering iron catalyst particles on the nucleation of a diamond under high pressure and high temperature (HPHT). The Fe2O3 layer is deoxidized by graphite to form Fe3O4 and FeO at 5.7 GPa and 1600 deg C At the same time the iron melts and is exuded through the Fe2O3 layer, and then contacts with graphite, to cause the nucleation and growth of a diamond. Compared with a pure iron catalyst, the Fe2O3 clad layer distinctly restrains the nucleation of the diamond. Furthermore, the thicker the clad layer becomes, the more obvious this effect is. The Mossbauer spectrum, X-ray diffraction (XRD) and a scanning electronic microscope (SEM) were used to characterize and analyze the experimental samples.