The cylinder head seals the combustion chamber together with the valves. The seat prevents the valve from hitting the cylinder head and scratching it. The physical and mechanical properties of materials must be considered in the selection of materials. Powder metallurgy materials are of high dimensional precision. The alloy selection and sintering process are flexible and it is material, time and energy saving. All these characters make it apparent competitiveness compared with other materials. So it is widely used in internal combustion engine.
