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Tecvac specialise in overcoming the

surface engineering problems found in

demanding industries such as aerospace, offshore oil and gas engineering, medical devices and motorsport.

Pushing the Technical Frontier


The aerospace manufacturing industry faces a unique set of commercial,

technical and environmental challenges. To reduce fuel consumption and CO2 emissions, manu- facturers are innovating by introducing lighter materials such as carbon fibre in the airframe and titanium in weight bearing components. New materials bring new technical challenges.

Aerospace operators face similar issues. To remain competitive there is a need to reduce fuel consumption and maximise revenue from the aircraft by achieving greater time on-wing and less time in the service bay. Tecvac coatings contribute to these aims.

For all its advantages of extreme strength and weight reduction, carbon reinforced fibre composites bring a new set of problems. The drilling and cutting of carbon composite structures is much more difficult than with their metal counterparts. The heat generated by cutting metal components is dissipated by conduction through the metal, released through the swarf produced by machining and by drenching with cutting and cooling fluid. This is not possible with carbon fibre composites. The material conducts heat poorly and it is not usually desirable to drench

cool. Localised heating causes smearing of the bonding resins while the 4 SURFACE WORLD may 2013

extreme hardness of the carbon fibres blunts conventional cutting tools, requiring frequent stops for tool changes.

The application of diamond coatings to tooling overcomes these problems. Tecvac’s technical partner, Cemecon has developed diamond coatings that give the extreme hardness needed to resist erosion by the carbon fibres. Diamond coated tools retain their cutting edge up to eight times longer than conventionally hardened tools and generate less heat to mitigate smearing problems. Importantly they need fewer tool changes and so improve productivity.

Titanium is increasingly used in place of steel and other dense metals because of its strength, fatigue and corrosion resistance. Unfortunately, the material has very a poor coefficient of friction. Without surface treatment this can lead to a need for more frequent maintenance attention.

Tecvac’s answer to this problem is a duplex coating where the substrate is first stabilised by the production of a hardened nitride diffusion zone in the metal surface. This is followed by the application of a titanium or chromium nitride coating to aid lubricity. Both hardening and final coating are achieved in a single physical vapour deposition (PVD) cycle.

Aero Engines

PVD applied coatings have many applications within aero engines. One of the best examples of this is in the critical compressor stage of the engine where there can be a significant and sustained fuel saving, CO2 reduction and extended service intervals.

High temperature, pressure and the erosive forces of contaminated airflow all shorten the life of compressor aerofoils. Nitron Flight, a family of multi-layer coatings based on titanium, chromium, chromium/aluminium or carbon/ metal carbide, overcome these problems. Applied in six to eight layers, this low-stress surface coating is more resilient to delamination than a single layer coating of the same thickness. (continued on page 6)

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