Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

The application of diamond films to enhance the erosive wear resistance of cemented tungsten carbide components

Research was aimed at the application of diamond film technology to cemented carbide materials. In particular two important applications are being developed to improve the wear resistance of cemented carbide choke trim components and cutting tools. The choke trim components are used to control the flow of oil and gas in oil rigs. Depending on their operational environment they can have a service life of as little as one week because of erosive wear from sand-bearing oil or gas. The replacement costs for remote subsea valves can be as much as 0.7 million ECU. The second area of application of the diamond coatings is to enhance the wear resistance of cemented carbide cutting tools used in the machining of carbon fibre based composites in aircraft manufacture. It is intended that the diamond coatings due to their outstanding hardness and erosive wear resistance give a 5 to 20 fold increase in component lifetime.

The main technical difficulties to overcome are:
the poor adhesion of diamond to cemented carbide, due in particular to the cobalt binder holding the tungsten carbide grains together;
the development of a microwave diamond deposition system to coat complex geometries particularly at the choke trim orifice edges where the majority of erosive wear is experienced;
on achieving enhanced adhesion and erosive wear resistance in a laboratory deposition system, to upscale this technology to simultaneously coat four choke trim components in a prototype composed of two separate systems (one of them has been working since 1996).

Reported by

Asociacion de la Industria Navarra (AIN)
Calle San Cosme y San Damian s/n
31191 Cordovilla-Pamplona
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