FORMATION OF BORIDE LAYER CONTAINING SINGLE PHASE Fe2 B ON MATERIAL CHIP OBTAINED FROM BORON-TREATING AGENT AND IRON MATERIAL

摘要

PROBLEM TO BE SOLVED: To form the boride layer, especially the boride layer containing single phase Fe2B on an iron material by using, as activating substances, a combination of potassium tetrafluoroborate and calcium fluoride, having a specified composition. SOLUTION: Potassium tetrafluoroborate and calcium fluoride are contained, as activating substances, in a boron treating agent in amounts of 1-5 wt.% and 5-40 wt.%, respectively, based on the total weight of the boron treating agent. Boron carbide is advantageously contained in an amount of 2-10 wt.% as a boron-releasing agent in the treating agent and further, silicon carbide is also contained as an inert filler in the treating agent. The especially suitable composition of the treating agent is, by weight, 3-5% boron carbide, 2-4% potassium tetrafluoroborate, 10-30% calcium fluoride and 61-85% silicon carbide. The boride layer containing single phase Fe2B on an iron material chip can be formed by coating the surface of the material chip with the treating agent and then heating the coated material chip at 800-1,100 deg.C until a boride layer having a desired thickness is formed.