| 摘要 |
PURPOSE:To form a boride layer on the surface of a steel material without deteriorating the nature of said material by coating a pasty boriding agent on the surface of the steel material consisting of carbon steel, etc., and heating the steel material to the temp. of the A1 transformation point thereof or below with a glow discharge. CONSTITUTION:A pasty boriding agent 12 consisting essentially of B4C and SiC which is a thickener, etc. is coated to about 2mm. thickness on the surface to be treated of a steel material 11 consisting of carbon steel or low alloy steel and having about 20mm. diameter. Said material is placed on a negative electrode base 14 in a vacuum vessel 13, and while the inside of the vessel 13 is evacuated by a vacuum pump 15, a gaseous mixture 16 of N2 and H2 is supplied into the vessel 13 and a negative voltage is applied to the material 11 from a DC power source 17 through the base 14 and a positive electrode to the vessel 13 to generate a glow discharge 19, thereby heating the material 11. If the material 11 is heated for about 6hr at about 650 deg.C of lower temp. than about 732 deg.C which is the A1 transformation point of said material, the boride layer of about 50mum thickness is formed. The boride layer of about 40mum is obtd. even if the inside of the vessel 13 is not maintained in the N2 atmosphere. |
