Importance

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Abstract

Improved valves, such as exhaust valves for internal combustion engines and other valves subject to wear and corrosion and, in certain instances, impact forces which may cause degradation in structure and structural failure. In one form, a select portion of the surface of a valve component or components subject to degradation during use such as erosive and/or corrosive effects of fluid particles and liquid or vaporous fluid passing through the valve, is coated with a synthetic diamond material which is formed in situ thereon. In another form, the entire surface of the valve component is so coated. The component may be a movable poppet member for an exhaust valve for a combustion chamber of an internal combustion piston engine. The valve seat or insert may also be coated with synthetic diamond material, particularly the circular tapered inside surface thereof against which a portion of the underside of the head of the valve poppet which engages the seat when the valve is spring closed. By coating the entire head and stem of the valve poppet with synthetic diamond and overcoating or plating a solid lubricant, such as chromium on the outer surface of the diamond coating a number of advantages over conventional valve construction are derived including better heat and corrosion resistence, reduced wear resulting from seat and valve head impact contact and a reduction in the enlargement of surface cracks. Similar improvement are effected for the valve seat when so coated and protected. In a modified form, the entire interior or selected portions of the wall of the valve body or the combustion chamber containing the valve may be coated with synthetic diamond material with or without a protective overcoating.

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First Claim