Removal of carbon compounds adsorbed on a surface of iron and steel

Research Project

Project/Area Number	07455332
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	工業分析化学
Research Institution	Tohoku University
Principal Investigator	TAKADA Kunio Institute for Materials Research・Tohoku University Lecturer, 金属材料研究所, 講師 (50005930)
Co-Investigator(Kenkyū-buntansha)	ISHIKURO Mikio Institute for Materials Research・Tohoku University Research Associate, 金属材料研究所, 助手 (80005991) OKU Masaoki Institute for Materials Research・Tohoku University Associate Professor, 金属材料研究所, 助教授 (90005968)
Project Period (FY)	1995 – 1996
Project Status	Completed (Fiscal Year 1996)
Budget Amount *help	¥6,500,000 (Direct Cost: ¥6,500,000) Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000) Fiscal Year 1995: ¥5,800,000 (Direct Cost: ¥5,800,000)
Keywords	iron and steel / micro amounts of carbon / carbon adsorbed on a surface ofiron and steel / combustion in resistance furnace / infrared absorption / Nitrogen atmosphere chamber / 試料表面吸着炭素の吸脱着 / 試料表面吸着炭素成分 / 吸着炭素成分の除去 / 空気巻き込み防止装置の開発 / 燃焼-赤外線吸収法
Research Abstract	When micro amounts of carbon in iron and steel were determined with combustion-infrared absorption method, the analytical value became larger than a true value. Because carbon in carbon compounds adsorbed on surface of them was determined together with carbon in them. Therefore, the less the carbon in them, relatively the larger the error of analytical value of carbon. Maybe carbon compounds in the air are adsorbed on the surface of them. Removal of carbon compounds on the surface was investigated. In the first place, in order to determine micro amounts of carbon on surface of them, a nitrogen atmosphere chamber was attached to an analyzer with combustion-infrared absorption method. The chamber was designed and made by us. It was made of stainless steel and was a box of size 240mm (1) X250mm (W) X220mm (H). Nitrogen could flow into the chamber through 4 inlets at flow rate arbitrarily from zero to 20 1/min. The chamber could protect oxygen in the combustion furnace of the analyzer from mixture of air. Therefore, by using it, micro amounts of carbon on surface of iron and steel could be determined separately from carbon in them. Hence, results as follows were obtained ; (1) micro amounts of carbon on surface of iron and steel were determined precisely and accurately. (2) micro amounts of carbon on surface of iron and steel became greater with increasing of time for standing them in the air or carbon dioxide atmosphere. (3) when iron and steel were heated at 450ﾟC for 10 min in the air or cleaned in acid as hydrofluoric or hydrochloric acid, carbon compounds on surface of them were removed. But carbon in them was not lost.