| 摘要 |
PURPOSE:To improve abrasion resistant and heat conduction properties or the like by a constitution wherein double layered structure of first layer, including a valve abutting surface, and second layer, as a base material supporting the first layer, is formed and respective layers are constituted of specified constituents such as Pb or the like consisting of specified weight ratio respectively. CONSTITUTION:The iron based sintered alloy of double layered structure, consisting of the first layer 1 including the abutting surface of the valve and the second layer 2 supporting the first layer, is formed. The first layer 1 is constituted in weight ratio of the constituents of Mo; 2.5-15%, Co; 1-15%, C; 0.5- 1.5%, Pb; 5-20% and balance of Fe and impurities of up to 2% while hard particles, principally constituted of Mo having average particle diameter of 10-30mu are dispersed uniformly in the constitution. The second layer is constituted in weight ratio of the constituents of C; 0.5-1.5%, Pb; 3-20% and balance of Fe and impurities of up to 2%. Further, Pb in said respective layers 1, 2 are infiltrated into the air holes of the sintered bodies and the difference in the amount of C of respective layers 1, 2 is specified to up to 0.3%. |
