A part includes a substrate made of a nickel-based superalloy, the substrate having a first average mass fraction of one or more first elements chosen from hafnium, silicon and chromium, the substrate having an open cavity in the part and a cooling channel, the substrate further including a surface layer partially forming the cavity, the surface layer having a second average mass fraction of the first element or first elements which is greater than the first average mass fraction.

A coated steel substrate coated with a first coating including above 40 wt. % of chromium and optionally one or several elements chosen from yttrium, silicon, calcium, titanium, zirconium, vanadium, niobium and nickel in an amount below 10 wt. % for each element, the balance being chromium and a second coating including from 2 to 30 wt. % of Aluminum, from 10 to 40 wt. % of chromium and optionally one or several elements chosen from yttrium, silicon, calcium, titanium, zirconium, vanadium, niobium and nickel in an amount below 10 wt. % for each element, the balance being iron, the steel substrate including Cr≤2.0% by weight; a method for the manufacture of this coated steel substrate; a method for the manufacture of a coated hot steel product; a coated hot steel product and the use of a hot steel product.

A metal porous material according to an aspect of the present disclosure is a metal porous material in sheet form that includes a frame having a three-dimensional network configuration, wherein the frame includes an alloy including at least nickel (Ni) and chromium (Cr), the frame 11 is a solid solution with iron (Fe), the frame includes a chromium oxide (Cr.sub.2O.sub.3) layer as an outermost layer and includes a chromium carbide layer located under the chromium oxide layer, the chromium oxide layer has a thickness not less than 0.1 μm and not more than 3 μm, and the chromium carbide layer has a thickness not less than 0.1 μm and not more than 1 μm.

A metal porous material according to an aspect of the present disclosure is a metal porous material in sheet form that includes a frame having a three-dimensional network configuration, wherein the frame includes an alloy including at least nickel (Ni) and chromium (Cr), the frame 11 is a solid solution with iron (Fe), the frame includes a chromium oxide (Cr.sub.2O.sub.3) layer as an outermost layer and includes a chromium carbide layer located under the chromium oxide layer, the chromium oxide layer has a thickness not less than 0.1 μm and not more than 3 μm, and the chromium carbide layer has a thickness not less than 0.1 μm and not more than 1 μm.

A metal porous material according to an aspect of the present disclosure is a metal porous material in sheet form that includes a frame having a three-dimensional network configuration, wherein the frame includes an alloy including at least nickel (Ni) and chromium (Cr), the frame 11 is a solid solution with iron (Fe), the frame includes a chromium oxide (Cr.sub.2O.sub.3) layer as an outermost layer and includes a chromium carbide layer located under the chromium oxide layer, the chromium oxide layer has a thickness not less than 0.1 m and not more than 3 m, and the chromium carbide layer has a thickness not less than 0.1 m and not more than 1 m.

A metal porous material according to an aspect of the present disclosure is a metal porous material in sheet form that includes a frame having a three-dimensional network configuration, wherein the frame includes an alloy including at least nickel (Ni) and chromium (Cr), the frame 11 is a solid solution with iron (Fe), the frame includes a chromium oxide (Cr.sub.2O.sub.3) layer as an outermost layer and includes a chromium carbide layer located under the chromium oxide layer, the chromium oxide layer has a thickness not less than 0.1 m and not more than 3 m, and the chromium carbide layer has a thickness not less than 0.1 m and not more than 1 m.

This present invention provides a method for preparing a stainless reinforcing steel bar resistant to corrosion of chloride ions, and belongs to the technical field of corrosion-resistant materials. This method particularly comprises the steps of: selecting a reinforcing steel bar blank, and performing oil removing, rust removing, water washing, and drying treatments on the surface of the reinforcing steel bar blank to be treated, or directly performing sand blasting or shot blasting on a reinforcing steel bar blank whose surface is only slightly rusted; placing the reinforcing steel bar blank in a chromium-containing environment, and keeping at a certain temperature for a certain time such that chromium in the environment is capable of diffusing into the surface of the reinforcing steel bar blank to form a chromium-containing diffusion layer, wherein an area in the diffusion layer where the weight content of Cr exceeds 12% meets the basic component requirements for a stainless steel, and this area is the effective diffusion layer described in this invention; and performing cooling treatment on the heat diffusion treated reinforcing steel bar. In this invention, a reinforcing steel bar blank is pre-formed, a heat diffusion technique is optimized, and the corrosion resistance to chloride ions of the stainless reinforcing steel bar of this invention is superior to that of the 316L stainless reinforcing steel bar.

This present invention provides a method for preparing a stainless reinforcing steel bar resistant to corrosion of chloride ions, and belongs to the technical field of corrosion-resistant materials. This method particularly comprises the steps of: selecting a reinforcing steel bar blank, and performing oil removing, rust removing, water washing, and drying treatments on the surface of the reinforcing steel bar blank to be treated, or directly performing sand blasting or shot blasting on a reinforcing steel bar blank whose surface is only slightly rusted; placing the reinforcing steel bar blank in a chromium-containing environment, and keeping at a certain temperature for a certain time such that chromium in the environment is capable of diffusing into the surface of the reinforcing steel bar blank to form a chromium-containing diffusion layer, wherein an area in the diffusion layer where the weight content of Cr exceeds 12% meets the basic component requirements for a stainless steel, and this area is the effective diffusion layer described in this invention; and performing cooling treatment on the heat diffusion treated reinforcing steel bar. In this invention, a reinforcing steel bar blank is pre-formed, a heat diffusion technique is optimized, and the corrosion resistance to chloride ions of the stainless reinforcing steel bar of this invention is superior to that of the 316L stainless reinforcing steel bar.

This present invention provides a method for preparing a stainless reinforcing steel bar resistant to corrosion of chloride ions, and belongs to the technical field of corrosion-resistant materials. This method particularly comprises the steps of: selecting a reinforcing steel bar blank, and performing oil removing, rust removing, water washing, and drying treatments on the surface of the reinforcing steel bar blank to be treated, or directly performing sand blasting or shot blasting on a reinforcing steel bar blank whose surface is only slightly rusted; placing the reinforcing steel bar blank in a chromium-containing environment, and keeping at a certain temperature for a certain time such that chromium in the environment is capable of diffusing into the surface of the reinforcing steel bar blank to form a chromium-containing diffusion layer, wherein an area in the diffusion layer where the weight content of Cr exceeds 12% meets the basic component requirements for a stainless steel, and this area is the effective diffusion layer described in this invention; and performing cooling treatment on the heat diffusion treated reinforcing steel bar. In this invention, a reinforcing steel bar blank is pre-formed, a heat diffusion technique is optimized, and the corrosion resistance to chloride ions of the stainless reinforcing steel bar of this invention is superior to that of the 316L stainless reinforcing steel bar.

This present invention provides a method for preparing a stainless reinforcing steel bar resistant to corrosion of chloride ions, and belongs to the technical field of corrosion-resistant materials. This method particularly comprises the steps of: selecting a reinforcing steel bar blank, and performing oil removing, rust removing, water washing, and drying treatments on the surface of the reinforcing steel bar blank to be treated, or directly performing sand blasting or shot blasting on a reinforcing steel bar blank whose surface is only slightly rusted; placing the reinforcing steel bar blank in a chromium-containing environment, and keeping at a certain temperature for a certain time such that chromium in the environment is capable of diffusing into the surface of the reinforcing steel bar blank to form a chromium-containing diffusion layer, wherein an area in the diffusion layer where the weight content of Cr exceeds 12% meets the basic component requirements for a stainless steel, and this area is the effective diffusion layer described in this invention; and performing cooling treatment on the heat diffusion treated reinforcing steel bar. In this invention, a reinforcing steel bar blank is pre-formed, a heat diffusion technique is optimized, and the corrosion resistance to chloride ions of the stainless reinforcing steel bar of this invention is superior to that of the 316L stainless reinforcing steel bar.