Some people protect the environment by recycling paper, plastic and glass. The Irish subsidiary of a US multinational specialising in the repair of jet engine components does its bit by recycling cobalt, tungsten, chromium and exotic alloys.

The SIFCO Turbine Group specialises in the repair of two types of jet engine components. It renews rather than replaces these parts which saves money but also makes environmental sense, according to Dr Aidan Kennedy who heads the company's research activity here.

"Gas turbine manufacture and its associated overhaul and repair activities, is increasingly characterised by recycling and re-use of materials and components. Financial considerations are at least as important as environmental concerns in driving the industry in this direction," he explained.

Many of the metals used in modern jet engines are rare and difficult to find, mine and alloy. Recycling "has an environmental dividend", he said.

Dr Kennedy is a senior materials technologist at Enterprise Ireland. He completed a three-year secondment to SIFCO last January and now divides his time between the two companies. "I remain by mutual agreement for 50 per cent of the time with SIFCO," he said. SIFCO is based in Cleveland, Ohio and established an Irish wing with a few dozen staff back in 1983. Employment has grown steadily since then to 450 in three Cork plants at Carrigtwohill, Blackrock/Mahon and Lough Mahon. Irish turnover is about £20 million (€38 million) and 5 to 10 per cent of this is reinvested in research, he said.

The company recently announced a five-year, £30 million research investment to be shared between Cork and US centres. This figure includes capital expenditure for the purchase of very expensive equipment which will be used to develop advanced technologies related to the company's turbine-repair business. The Irish research spend will be at least £1.5 million per year for the next five years, Dr Kennedy said. This does not include any funding for additional equipment which might be required.

The Cork company employs 10 to 15 engineers and scientists, most of them Irish graduates recruited from Cork Institute of Technology, the University of Limerick and other universities. It also has contacts with Materials Ireland, which provides a link between third-level materials research and the industrial sector.

The engine work is highly specialised and involves turbine blades - not the vanes you see as a jet's engines are started before take-off - but the blades from deep inside the engine's "hot section", Dr Kennedy explained. SIFCO also repairs "nozzle guide vanes" - stationary components also in the hot section which direct hot gases to the rotating turbine blades. Temperatures reach 1,000 degrees centigrade inside a modern engine and so "super alloys" have been developed that can withstand stress, temperature and the highly corrosive conditions caused when the fuel burns. They use complex alloys but also often have ceramic coatings to protect metal surfaces.

Companies that service jet engines can clean, repair and reassemble about 60 to 70 per cent of the parts, but not those from the hot section, Dr Kennedy said. SIFCO is one of only a handful of companies that does this work, and one of a few which remain independently owned.

The company has agreements to work on engines from all of the world's leading manufacturers including GE, Pratt and Whitney, Rolls Royce and CSMI. Repair costs only 10 to 20 per cent of the cost of replacement and can double or treble the lifespan of a component. The company has developed "special licensed technologies" to allow it to carry out repairs. Reconditioning typically might involve stripping the ceramic coatings from the part, brazing of cracks or fissures and then recoating. All of this requires special equipment to enable ceramics to be bonded to metal surfaces.

The research effort is directed on two levels, short-term production development and long-term technical development, Dr Kennedy said. The first involves bringing about improvements in today's procedures, the second enables the company to integrate emerging technologies into how it will carry out its repairs in the future.

The repair processes must be able to change as the manufacturing technology changes. For example, the company is developing a new brazing technique for the latest type of turbine blades.

Manufacturers have developed methods for producing components from a single alloy "crystal" as opposed to polycrystal components. This requires a new type of brazing to close cracks in the surface.

Coating metals is another particularly difficult process. The large research investment includes an electron beam, physical vapour, deposition unit which will be installed in Cork. Yet the company is already working on the next generation of coating technology, chemical vapour deposition.

The company has participated in two EU-funded Brite/Euram materials research and development projects. "Over the last few years SIFCO has initiated a number of research projects under national and EU and self funded programmes," Dr Kennedy said.