ABSTRACT
Aeroengines make extensive use of coatings for a wide range of crucial applications, where they allow optimum bulk component properties, e.g. creep resistance, fatigue life, etc., to be combined with enhanced surface properties, e.g. wear and corrosion resistance. Coating applications include anti-fretting coatings on casing flanges, wear protection (WC/Co) on shafts, abrasive coatings (Al2O3, Cr3C2) on compressor blade tips, and anti-fretting/ wear coatings on the fan disk, fan blade root and fan snubbers (WC/Co, NiCrþ Cr3C2). Abradable coatings are used on compressor and other casing liningswhere they are combinedwith abrasive coatings on blade tips to produce conformal seals with minimal clearance when the blade is rotating. These seals are essential to minimize leakage of intake air between adjacent sections of the compressor which are operating at different pressures. Minimizing circumferential pressure leaks results in significant increases in efficiency.
