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The present paper reports the new generation coating for piston rings which will be able to fills a demand of a market thus developed. The first step taken at the development is to clarify the sliding characteristics and the sliding mechanism between conventional plasma sprayed Mo coatings and chromium ceramic coatings. Plasma sprayed Mo coatings have high scuffing resistance with inferior coating life. Chromium ceramic coating films possess longer coating life than the plasma sprayed Mo coatings with lower scuffing resistance than the Mo coatings. Numerous basic studies and various measurement results obtained on operating ships in the present investigation have yielded a concept for new coatings that should have superior scuffing resistance as the Mo coatings possess, and longer coating life than that of chromium ceramic coatings possess as targets of the new coatings to be developed. The developed coatings are subjected to laboratory tests indicating the coatings to possess excellent properties. Namely, the developed coatings possess the scuffing resistance of about 1.8 times than that of conventional chromium ceramic coatings, and the coating life as longer as more than 4.3 times than that of the conventional chromium ceramic coatings. Furthermore, the developed coatings are confirmed to possess the same order of attacking property against the cylinder liners. Test conducted on operating ships have confirmed the same order of the coating life and superior sliding property as obtained at the laboratory tests. Thus, the actual applicability of the developed coating for main engines of operating vessels has been demonstrated.