Porous 3-D Titanium Substrates Obtained by Powder Metallurgy for Nanodiamond Film Growth

Abstract

Power metallurgy has been used to produce compacts by two different routes. In this work, porous three-dimensional (3-D) substrates were prepared by the conventional pre-forms sintering method. Titanium powders were uniaxial pressed at 110 Mpa and vacuum (1 x 10-5 Pa) sintered at 1500 K. Another group of substrates were obtained by the space holder technique. Irregular shaped carbamide particles (210 – 250 m diameters) were mixed to Ti powders, pressed and sintered. Before the sintering the compacts were heated at 470 K for 3 h to eliminate the spacing holder agent. Nanodiamond films were grown by hot-filament chemical vapor deposition technique on such substrates at 870 K from a mixture of Ar/H2 (80%-18,5%) respectively and a solid carbon source. SEM images show the substrates totally covered by a nanodiamond film including deeper planes. Raman Spectra confirm the good quality of the nanodiamond film.