Chemical vapour deposition diamond coating on tungsten carbide dental cutting tools

Abstract

Diamond coatings on Co cemented tungsten carbide (WC-Co) hard metal tools are widely used for cutting non-ferrous metals. It is difficult to deposit diamond onto cutting tools, which generally have a complex geometry, using a single step growth process. This paper focuses on the deposition of polycrystalline diamond films onto dental tools, which possess 3D complex or cylindrical shape, employing a novel single step chemical vapour deposition (CVD) growth process. The diamond deposition is carried out in a hot filament chemical vapour deposition (HFCVD) reactor with a modified filament arrangement. The filament is mounted vertically with the drill held concentrically in between the filament coils, as opposed to the commonly used horizontal arrangement. This is a simple and inexpensive filament arrangement. In addition, the problems associated with adhesion of diamond films on WC-Co substrates are amplified in dental tools due to the very sharp edges and unpredictable cutting forces. The presence of Co, used as a binder in hard metals, generally causes poor adhesion. The amount of metallic Co on the surface can be reduced using a two step pre-treatment employing Murakami etching followed by an acid treatment. Diamond films are examined in terms of their growth rate, morphology, adhesion and cutting efficiency. We found that in the diamond coated dental tool the wear rate was reduced by a factor of three as compared to the uncoated tool.

An overview of in vitro abrasive finishing & CAD/CAM of bioceramics in restorative dentistry

“…The conventional diamond burs used for handpiece machining operations have a number of problems associated with the heterogeneity of the crystallites, the decreased cutting efficiency, the need for repeated sterilization and the short tool life. More recently, diamond burs made of continuous films in the process of chemical vapor deposition (CVD) have been developed [95][96][97][98][99]. The major advantage of CVD over the other surface engineering techniques is its ability to coat uniformly on the complex components of dental burs [96,98].…”

A galvanic-chemical method for preparing diamond containing coatings

“…For these purposes, diamond-like coating (DLC), obtained by high-temperature decomposition of hydrocarbons, has found widespread use. These carbon-based materials are not pure diamond, but they have the structure and physicochemical properties similar to them [17,18]. Surfaces of prosthetic devices and implants having a diamond or diamond-like coatings are chemically inert, non-toxic for cells and do not cause inflammation or pathogenic processes [19].…”

Machining Cobalt-Based Dental Alloys with Tungsten Carbide Mills

“…A correct dental mill characterization is a difficult task, because of the complex conical multi-cutting surfaces of the milling tools. Some authors have studied dental milling applications, and diamond films have been considered a coating material for dental cutting tools [1][2][3][4][5]. Micro/nanocrystalline diamond films have also been coated on dental cutting tools [6].…”