| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a surface modification method for an internal combustion engine piston, capable of enhancing easily and inexpensively mechanical strength of the internal combustion engine piston or the like. <P>SOLUTION: A surface modified layer is formed by injecting injection powders containing a reinforcing element diffusion-permeated into the piston to enhance the strength, onto the Al-Si alloy-based piston obtained by casting and forging, under a prescribed condition. An element exhibiting a photocatalytic function by oxidation, such as Ti, Sn, Zn, Zr, and W, is selected as the reinforcing element, when a function such as fuel reforming is imparted onto the surface modified layer. Alloy elements get fine with recrystallization, by heating and cooling generated locally on the piston surface with collision with the injection powders, the reinforcing element in the injection powders is diffusion-permeated into the piston surface by activation adsorption, to form the modified layer having a metal texture containing the alloy elements and the reinforcing element micro-structured uniformly and finely, the strength of the piston is thereby enhanced, and the catalytic function such as the fuel reforming is also exhibited by selecting the element such as Ti. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
