The chemical stability of the surface of stainless steel (SUS) 304 in acid immersion tests is greatly improved by the laser implant-deposition (LID) process, i.e., the simultaneous deposition and incorporation of silicon by KrF excimer laser irradiation. The etching depths of the treated samples in 1.32 N HCl solution are substantially zero at the laser irradiation conditions of more than 40 pulses and of more than 400 mJ/cm2 at the surface. By the quantitative verification of cathodic polarization in 1 N H2SO4, the highest polarization resistance is estimated to be 26.7 times that of the nontreated sample.

Surface hardening of SUS304 resulting from the process of doping and deposition of Si by irradiation of a KrF excimer laser beam in a SiH4 gas ambient is investigated, and variations of the surface hardness are examined for different numbers of laser pulses and the laser fluences. The hardening is due to Si incorporation in high concentration. The continuous distribution of Si atoms across the surface layer suggests that a very high adhesion strength of the deposited Si films can be formed. The specific process for surface modification is referred to as laser implant-deposition (LID).