A sliding member includes a base substrate and a coating layer formed on the base substrate. The coating layer includes an inorganic part derived from at least one type of inorganic particles selected from the group consisting of iron base alloy particles, cobalt base alloy particles, chromium base alloy particles, nickel base alloy particles, molybdenum base alloy particles, and ceramic particles, and a metal part derived from at least one type of metal particles selected from the group consisting of iron base alloy particles other than listed in the above group, copper particles, and copper alloy particles. The inorganic part is bonded to another inorganic part and/or the metal part via interfaces therebetween, and the metal part is bonded to another metal part and/or the inorganic part via interfaces therebetween. The sliding member includes an interface layer including at least one of a diffusion layer and an intermetallic compound layer on at least one part of an interface between the base substrate and the coating layer or interfaces between the inorganic part and the metal part, the inorganic parts, and the metal parts. The interface layer has a thickness of equal to or less than 2 μm.

An iron-based alloy includes, in weight percent, carbon from about 1 to about 2 percent; manganese from about 0.1 to about 1 percent; silicon from about 0.1 to about 2.5 percent; chromium from about 11 to about 19 percent; nickel up to about 8 percent; vanadium from about 0.8 to about 5 percent; molybdenum from about 11 to about 19 percent; tungsten up to about 0.5 percent; niobium from about 1 to about 4 percent; cobalt up to about 5.5 percent; boron up to about 0.5 percent; nitrogen up to about 0.5 percent, copper up to about 1.5 percent, sulfur up to about 0.3 percent, phosphorus up to about 0.3 percent, up to about 5 percent total of tantalum, titanium, hafnium and zirconium; iron from about 50 to about 70 percent; and incidental impurities. The alloy is suitable for use in elevated temperature applications such as in valve seat inserts for combustion engines.

An iron-based alloy includes, in weight percent, carbon from about 1 to about 2 percent; manganese from about 0.1 to about 1 percent; silicon from about 0.1 to about 2.5 percent; chromium from about 11 to about 19 percent; nickel up to about 8 percent; vanadium from about 0.8 to about 5 percent; molybdenum from about 11 to about 19 percent; tungsten up to about 0.5 percent; niobium from about 1 to about 4 percent; cobalt up to about 5.5 percent; boron up to about 0.5 percent; nitrogen up to about 0.5 percent, copper up to about 1.5 percent, sulfur up to about 0.3 percent, phosphorus up to about 0.3 percent, up to about 5 percent total of tantalum, titanium, hafnium and zirconium; iron from about 50 to about 70 percent; and incidental impurities. The alloy is suitable for use in elevated temperature applications such as in valve seat inserts for combustion engines.

An engine head assembly includes a valve seat insert having a valve seating surface defining a center axis, and each of an inner peripheral surface and an outer peripheral surface extending circumferentially around the valve seat center axis. The outer peripheral surface includes an upper section interference-fitted with the engine head, and a lower section. A stiffness relief channel is formed by a relief cutout in the valve seat insert, and extends radially between the lower section of the outer peripheral surface and the engine head. The stiffness relief channel permits flexing of the valve seat insert to cushion valve seating to prolong engine valve and valve seat insert service life.

An engine head assembly includes a valve seat insert having a valve seating surface defining a center axis, and each of an inner peripheral surface and an outer peripheral surface extending circumferentially around the valve seat center axis. The outer peripheral surface includes an upper section interference-fitted with the engine head, and a lower section. A stiffness relief channel is formed by a relief cutout in the valve seat insert, and extends radially between the lower section of the outer peripheral surface and the engine head. The stiffness relief channel permits flexing of the valve seat insert to cushion valve seating to prolong engine valve and valve seat insert service life.

An engine valve includes a stem, a head comprising an outer lip surface, a seating surface extending from the outer lip surface toward the stem, and a combustion surface extending from the outer lip surface on the opposite side of the head as compared to the seating surface. The combustion surface includes a first convex arcuate surface spaced away from the outer lip surface, at least partially forming a raised ring, and a first concave arcuate surface spaced away from the outer lip surface, at least partially forming a dimple.

An engine valve includes a stem, a head comprising an outer lip surface, a seating surface extending from the outer lip surface toward the stem, and a combustion surface extending from the outer lip surface on the opposite side of the head as compared to the seating surface. The combustion surface includes a first convex arcuate surface spaced away from the outer lip surface, at least partially forming a raised ring, and a first concave arcuate surface spaced away from the outer lip surface, at least partially forming a dimple.

A hollow engine valve includes a shaft portion and an umbrella portion of which diameter is enlarged to form an umbrella shape to be provided on a base end of the shaft portion, a cooling material being enclosed in a hollow portion that is at least formed inside the shaft portion. The shaft portion comprises a first shaft portion in a tip end side, a second shaft portion that is provided in a base end side to have an outer diameter larger than that of the first shaft portion, and a stepped portion formed by a difference in the outer diameters between the first and second shaft portions. A wall thickness of the stepped portion is larger than that of the second shaft portion.

A hollow engine valve includes a shaft portion and an umbrella portion of which diameter is enlarged to form an umbrella shape to be provided on a base end of the shaft portion, a cooling material being enclosed in a hollow portion that is at least formed inside the shaft portion. The shaft portion comprises a first shaft portion in a tip end side, a second shaft portion that is provided in a base end side to have an outer diameter larger than that of the first shaft portion, and a stepped portion formed by a difference in the outer diameters between the first and second shaft portions. A wall thickness of the stepped portion is larger than that of the second shaft portion.

An internal combustion engine may include at least one cylinder and at least one hollow-heat valve. The at least one hollow-head valve may include a valve shaft and a valve head, and may be guided in a valve shaft guide. The engine may also include at least one valve seat ring on which the valve head sealingly lies when the at least one hollow-head valve is closed. The engine may additionally include a valve shaft seal with at least two seal lips and oil disposed between the valve shaft and the valve shaft guide. The at least one valve seat ring may be composed of a sintered metal including infiltrated copper. The valve shaft may include one of a chromium-containing coating and a boron carbide-containing coating.