CYLINDRICAL CVD DIAMOND AS A HIGH-PERFORMANCE SMALL ABRADING DEVICE

Columnar grain structure studies have been carried out on a small-curv ature radius cylinder substrate for the development of small abrading devices. An enhanced hot filament-assisted technique was used. The sub strate holder has a movable mechanism magnetically coupled to a d.c. m otor placed outside the reactor chamber. Free-standing diamond films a s thick as 1 mm were obtained on molybdenum wire substrates. The subst rates varied from 500 up to 1200 mu m diameter and were as long as 50 mm. A relationship of the curvature radius of the substrate surface wi th the growth rate and the spread of the column volume has been observ ed. A preferential diamond (111) surface morphology has been obtained, which is strongly dependent on diamond growth parameters, including t he substrate position and its angular velocity. Grain size up to aroun d 0.15 mm was obtained. In this work we also report an interesting app lication involving the characteristics of the (111) diamond surface as a small abrading device. Some results of cylindrical diamond burrs an d diamond drills for non-ferrous wear are shown. (C) 1998 Elsevier Sci ence S.A. All rights reserved.