A spring steel wire includes a main body made of a steel and having a line shape, and an oxidized layer covering an outer peripheral surface of the main body. The steel constituting the main body contains not less than 0.5 mass % and not more than 0.7 mass % C, not less than 1 mass % and not more than 2.5 mass % Si, not less than 0.2 mass % and not more than 1 mass % Mn, and not less than 0.5 mass % and not more than 2 mass % Cr, with the balance being Fe and unavoidable impurities. The steel constituting the main body has a pearlite structure. The oxidized layer has a thickness of not less than 2 μm and not more than 5 μm. The oxidized layer contains not less than 60 mass % Fe.sub.3O.sub.4.

The present invention is a method to treat an external layer on a steel or stainless steel substrate. More particularly the disclosure provides a method to increase the amount of manganochromite spinel (Cr.sub.2MnO.sub.4) in the outer most surface of a steel or a stainless steel. The present disclosure seeks to provide a process to prepare a treatment of an external surface on a steel or stainless steel substrate by subjecting the surface to an atmosphere of steam and air or synthetic air (a combination of oxygen and other inert gases such as nitrogen or argon) while subjecting the substrate to a static electrical charge from +7.0 to +14.0 kV. The present disclosure also seeks to provide the coated substrate.

The present invention is a method to treat an external layer on a steel or stainless steel substrate. More particularly the disclosure provides a method to increase the amount of manganochromite spinel (Cr.sub.2MnO.sub.4) in the outer most surface of a steel or a stainless steel. The present disclosure seeks to provide a process to prepare a treatment of an external surface on a steel or stainless steel substrate by subjecting the surface to an atmosphere of steam and air or synthetic air (a combination of oxygen and other inert gases such as nitrogen or argon) while subjecting the substrate to a static electrical charge from +7.0 to +14.0 kV. The present disclosure also seeks to provide the coated substrate.

There is provided a method for manufacturing a soft magnetic member where a coating formed of an α-Fe.sub.2O.sub.3 single phase having a high electrical resistivity is formed on a soft magnetic alloy substrate. A soft magnetic alloy substrate is heated in an atmosphere containing water vapor and inert gas to form a coating on the soft magnetic alloy substrate. The atmosphere has an oxygen partial pressure in a range of 0 to 1.5 kPa. A soft magnetic member including the soft magnetic alloy substrate and the coating formed on its surface can be obtained.

There is provided a method for manufacturing a soft magnetic member where a coating formed of an α-Fe.sub.2O.sub.3 single phase having a high electrical resistivity is formed on a soft magnetic alloy substrate. A soft magnetic alloy substrate is heated in an atmosphere containing water vapor and inert gas to form a coating on the soft magnetic alloy substrate. The atmosphere has an oxygen partial pressure in a range of 0 to 1.5 kPa. A soft magnetic member including the soft magnetic alloy substrate and the coating formed on its surface can be obtained.

An anti-coking surface having a thickness up to 15 microns comprising from 15 to 50 wt. % of MnCr.sub.2O.sub.4 (for example manganochromite); from 15 to 25 wt. % of Cr.sub.0.23Mn.sub.0.08Ni.sub.0.69 (for example chromium manganese nickel); from 10 to 30 wt. % of Cr.sub.1.3Fe.sub.0.7O.sub.3 (for example chromium iron oxide); from 12 to 20 wt. % of Cr.sub.2O.sub.3 (for example eskolaite); from 4 to 20 wt. % of CuFe.sub.5O.sub.8 (for example copper iron oxide); and less than 5 wt. % of one or more compounds chosen from FeO(OH), CrO(OH), CrMn, Si and SiO.sub.2 (either as silicon oxide or quartz) and less than 0.5 wt. % of aluminum in any form provided that the sum of the components is 100 wt. % is provided on steel.

An anti-coking surface having a thickness up to 15 microns comprising from 15 to 50 wt. % of MnCr.sub.2O.sub.4 (for example manganochromite); from 15 to 25 wt. % of Cr.sub.0.23Mn.sub.0.08Ni.sub.0.69 (for example chromium manganese nickel); from 10 to 30 wt. % of Cr.sub.1.3Fe.sub.0.7O.sub.3 (for example chromium iron oxide); from 12 to 20 wt. % of Cr.sub.2O.sub.3 (for example eskolaite); from 4 to 20 wt. % of CuFe.sub.5O.sub.8 (for example copper iron oxide); and less than 5 wt. % of one or more compounds chosen from FeO(OH), CrO(OH), CrMn, Si and SiO.sub.2 (either as silicon oxide or quartz) and less than 0.5 wt. % of aluminum in any form provided that the sum of the components is 100 wt. % is provided on steel.

Provided is an alloy material including a metal oxide thin layer that can be formed using a simple method at low cost and can further suppress volatilization of Cr, which causes deterioration of a fuel cell, compared with a case where conventional expensive materials are used. Disclosed is a manufacturing method for an alloy material including a coating treatment step for coating a substrate made of a Fe—Cr based alloy with Co, and an oxidation treatment step for performing oxidation treatment on the substrate in a moisture-containing atmosphere after the coating treatment step.

Provided is an alloy material including a metal oxide thin layer that can be formed using a simple method at low cost and can further suppress volatilization of Cr, which causes deterioration of a fuel cell, compared with a case where conventional expensive materials are used. Disclosed is a manufacturing method for an alloy material including a coating treatment step for coating a substrate made of a Fe—Cr based alloy with Co, and an oxidation treatment step for performing oxidation treatment on the substrate in a moisture-containing atmosphere after the coating treatment step.

An anti-coking surface having a thickness up to 15 microns comprising from 15 to 50 wt. % of MnCr.sub.2O.sub.4 (for example manganochromite); from 15 to 25 wt. % of Cr.sub.0.23Mn.sub.0.08Ni.sub.0.69 (for example chromium manganese nickel); from 10 to 30 wt. % of Cr.sub.1.3Fe.sub.0.7O.sub.3 (for example chromium iron oxide); from 12 to 20 wt. % of Cr.sub.2O.sub.3 (for example eskolaite); from 4 to 20 wt. % of CuFe.sub.5O.sub.8 (for example copper iron oxide); and less than 5 wt. % of one or more compounds chosen from FeO(OH), CrO(OH), CrMn, Si and SiO.sub.2 (either as silicon oxide or quartz) and less than 0.5 wt. % of aluminum in any form provided that the sum of the components is 100 wt. % is provided on steel.