A composition of a copper alloy for a laser cladding valve sheet is disclosed. The copper alloy includes a matrix structure and a hard phase, which includes 12 to 24 wt % of Ni, 2 to 4 wt % of Si, 8 to 30 wt % of Fe, more than 5 wt % and less than 10 wt % of Mo, 2 to 10 wt % of Al, and the balance Cu. The interfacial delamination may be suppressed in a fatigue environment by micronizing the hard phase and the distribution thereof, thereby improving fatigue resistance and wear resistance.

The present invention for coating a valve head (6) of an inlet and/or outlet valve (4) comprises a preparation of a surface, which is to be coated, of the valve (4) for a coating, and a coating of the prepared surface with a ceramic high-temperature coating (22).

The present invention for coating a valve head (6) of an inlet and/or outlet valve (4) comprises a preparation of a surface, which is to be coated, of the valve (4) for a coating, and a coating of the prepared surface with a ceramic high-temperature coating (22).

A nickel-niobium intermetallic alloy contains, in weight percent, silicon from about 1.5 to about 3.5 percent; chromium from 5 to about 15 percent; nickel from about 45 to about 75 percent; niobium from about 14 to about 30 percent; cobalt up to about 7 percent; and iron up to about 10 percent; wherein the nickel plus niobium content is about 70 to about 90 percent and the total silicon, chromium, cobalt and iron content is about 10 to about 30 percent. The alloy can have a cast microstructure of at least 95 volume percent intermetallic phases and no more than about 5 volume percent solid solution phases. The intermetallic phases can include rod-like intermetallic phases of Ni.sub.3Nb and Ni.sub.8Nb.sub.7. The microstructure can be a lamellar microstructure and/or the microstructure can have less than 5 volume percent Ni—Fe and Ni—Co rich intermetallic phases.

An internal combustion engine includes an engine block, a piston, a cylinder head, and a valve train. The engine block includes a cylinder block including a cylinder bore and a crankcase defining a crankcase chamber with a crankshaft positioned within the crankcase chamber. The piston is coupled to the crankshaft and configured to reciprocate within the cylinder bore. The cylinder head is coupled to the cylinder block. The valve train includes a camshaft, a first and second pushrod, a first and second rocker arm, an exhaust valve housed, and an intake valve. The first rocker arm, the second rocker arm, the exhaust valve, and the intake valve each include at least a layer of a low friction material. The first and second pushrod each pass through a pushrod seal to prevent fluid from reaching the rocker chamber to fluidly isolate the rocker chamber from the crankcase chamber.

The present invention addresses the problem of providing a sintered alloy valve guide capable of inhibiting valve adhesion even in a high-temperature environment. The problem can be solved by a sintered alloy valve guide impregnated with a lubricating oil including pores that are sealed on the valve guide outer circumferential surface. More particularly, the problem is solved by the sealing step of performing a sealing treatment of pores on the outer circumferential surface of a sintered body impregnated with a lubricating oil.

The disclosure includes manufacturing a semimanufactured cylinder head (3) having a shielding curtain portion (16g) and spraying metal powder (P) onto an annular valve seat portion (16f) using a cold spray method to form a valve seat film (16b). The shielding curtain portion (16g) projects in an annular shape from an annular edge portion of an opening portion (16a) of an intake port (16) or an opening portion (17a) of an exhaust port (17) toward the center (C) of the port. The annular valve seat portion (16f) is located on an outer side of the port than the shielding curtain portion (16g).

The disclosure includes manufacturing a semimanufactured cylinder head (3) having a shielding curtain portion (16g) and spraying metal powder (P) onto an annular valve seat portion (16f) using a cold spray method to form a valve seat film (16b). The shielding curtain portion (16g) projects in an annular shape from an annular edge portion of an opening portion (16a) of an intake port (16) or an opening portion (17a) of an exhaust port (17) toward the center (C) of the port. The annular valve seat portion (16f) is located on an outer side of the port than the shielding curtain portion (16g).

Provided is a hard particle in which Cr and W, that are quickly diffused in Mo, are present at the same time as Ni and Mn. Specifically, the hard particle contains Cr: 5% by mass to 20% by mass, W: 2% by mass to 19% by mass, Mo: 25% by mass to 40% by mass, Ni: 10% by mass to 22% by mass, Mn: 10% by mass or less, C: 2.0% by mass or less, Si: 2.0% by mass or less, and a remainder: Fe and unavoidable impurities.

An iron-based alloy includes, in weight percent, carbon from about 0.75 to about 2 percent; manganese from about 0.1 to about 1 percent; silicon from about 0.1 to about 1 percent; chromium from about 3 to about 6 percent; nickel up to about 4 percent; vanadium from about 1 to about 3 percent; molybdenum from about 4 to about 7 percent; tungsten from about 4 to about 7 percent; cobalt from about 4 to about 7 percent; boron up to about 0.1 percent; nitrogen from about 0.001 to about 0.15 percent, aluminum from about 0.001 to about 0.6 percent, copper from about 0.1 to about 1 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 65 to about 80 percent; and incidental impurities. The alloy is suitable for use in elevated temperature applications such as in valve seat inserts for combustion engines.