Chemical vapour deposition of diamond films onto tungsten carbide dental burs

Considerable literature is now available on the deposition of CVD diamond onto flat substrates the most common being silicon. However, very little work has been reported on the deposition of diamond onto complex three-dimensional substrates such as dental burs, micro drills and biomedical implants. Diamond is hard, wear resistant, biocompatible and corrosion resistant and therefore is an attractive candidate for uses in dental tools and for medical devices. This study focuses on the deposition of diamond, using a hot filament CVD system, on cobalt-cemented tungsten carbide (WC-Co) rotary cutting dental burs. Conventional dental burs are generally made of sintered polycrystalline diamond (PCD). These have a number of problems associated with heterogeneity of the crystallite, decreased cutting efficiency and a short life. A preferential (1 1 1) faceted diamond has been obtained after 12 h deposition at a growth rate of 1.2 μm/h. Diamond coated WC-Co dental burs and conventional sintered burs are used in turning, milling and drilling operations for machining materials made from metal alloys and borosilicate glass. After machining with excessive cutting performance, calculations can be made on flank and crater wear areas. Diamond coated WC-Co dental bur offer significantly lower erosion and higher wear resistance compared to uncoated WC-Co tools and sintered burs.