A Canadian-Russian joint venture is developing the next generation of a compressor-blade coating that has dramatically extended the service life of military helicopter engines exposed to severe sand erosion while in Afghanistan and Iraq.

The next-generation coating, available next year, will provide "an order of magnitude better" erosion resistance, as well as add corrosion protection, says Philippe Rodger, president of Prince Edward Island-based MDS-PRAD Technologies. The enhanced coating is aimed at airlines wanting to extend the useful life of already-worn blades by halting further erosion.

The company is a joint venture between Canadian engine test-cell manufacturer MDS Aero Support and PRAD, a gas-turbine overhaul specialist in the Urals that developed the original coating to protect the engines of Russian helicopters operating in Afghanistan.

Rapid wear on General Electric T53s powering US Marine Corps Sikorsky CH-53Es operating in south-west Asia, with engines being removed every 100-110h, led to coating of the compressor blades. Since using the coating, no engines have had to be removed because of wear and the lead engine has exceeded 1,400h in the aircraft, MDS says.

GE is now treating blades in T58 engines powering USMC Boeing CH-46s, while the coating is being used in Rolls-Royce Gem and Gnome engines powering UK military helicopters operating in Afghanistan and Iraq.

A target market, says Rodger, is the inventory of worn compressor blades removed by airlines because they were close to the limits of wear. The coating's ability to stop any further erosion would allow those blades to be returned to service, he says, and avoiding the loss of performance from blade wear would also reduce airline fuel bills.

The coating is a titanium nitride metallic-ceramic matrix applied in multiple layers using automated physical vapour deposition.

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GE is using the new coating in T58s powering Boeing CH-46s

Source: Flight International