chromium cementation gears 14 which are made of carbon steel obtained with the same composition as that of example 1 are placed in case 12 of electric furnace 11 as shown in fig8 a mixed gas of 70 argon and 30 h 2 s is supplied from gas feed port 21 in lid 20 on which fan 19 is mounted the air in case 12 is vented from a port hole 22 thereafter the gears were taken out after heating at 600 u00b0 c for one hour in this example too a chromium sulfide zone is formed on the surface of the chromium zone on the gear and the same wear resistance and corrosion resistance as in the case of example 1 was obtained after a shaft made of brass is plated 5 u03bcin thickness with chromium this shaft is reacted with sulfur in mixed salt as shown in fig1 and thus chromium sulfide 1 u03bcin thickness was produced on the surface when this shaft was inserted in the hole of a bearing and was slided reciprocatingly wear loss was lowered to 1 5 as compared with a shaft made of brass which was not so treated since this invention is constituted as described hereinabove it has been found that the chromium sulfide has a lubricating property namely a wear resistance is produced on the surface of the chromium zone having corrosion resistance by merely performing a treatment such as the reaction of the chromium zone in sulfide after the chromium zone was formed on the surface of metal products merely by chromium cementation or chromium plating in this manner.