The present disclosure provides a thermal spray alloy system that is more resistant to wear and/or corrosion than conventional alloy compositions. The disclosed alloys minimize or eliminate micro-cracks within the formed coating on the tool. The alloy comprises carbon, boron, and a fluxing agent selected from the group of aluminum, magnesium, or lithium. The alloy may also comprise titanium, silicon, manganese, molybdenum, nickel, and chromium, as well as other elements. The object to be coated may be any downhole component used in the oil and gas industry, or may be applied to any object or tool that needs an increased wear and/or corrosive protection layer including in diverse fields such as marine, chemical processing, and refining. A thermal spray coating with the disclosed alloy composition provides increased strength and resistance to spalling, breaking, cracking, deforming, and crack formation, as well as metallurgical bonding between the coating and the substrate.

A step is provided which performs a heat treatment at the sintering temperature of a sintered R-T-B based magnet or lower, while a powder of an RLM alloy (where RL is Nd and/or Pr; M is one or more selected from among Cu, Fe, Ga, Co and Ni) and a powder of an RH fluoride (where RH is Dy and/or Tb) are present on a surface of the sintered R-T-B based magnet. The RLM alloy contains RL in an amount of 50 at % or more, and a melting point of the RLM alloy is equal to or less than a temperature of the heat treatment. The heat treatment is performed while the RLM alloy powder and the RH fluoride powder are present on the surface of the sintered R-T-B based magnet at a mass ratio of RLM alloy:RH fluoride=96:4 to 5:5.

A step is provided which performs a heat treatment at the sintering temperature of a sintered R-T-B based magnet or lower, while a powder of an RLM alloy (where RL is Nd and/or Pr; M is one or more selected from among Cu, Fe, Ga, Co and Ni) and a powder of an RH fluoride (where RH is Dy and/or Tb) are present on a surface of the sintered R-T-B based magnet. The RLM alloy contains RL in an amount of 50 at % or more, and a melting point of the RLM alloy is equal to or less than a temperature of the heat treatment. The heat treatment is performed while the RLM alloy powder and the RH fluoride powder are present on the surface of the sintered R-T-B based magnet at a mass ratio of RLM alloy:RH fluoride=96:4 to 5:5.

A method for treating sheet metal is disclosed in which a material containing at least one alloying element is applied onto a first area of at least one surface of the metal sheet. A second area of the surface is kept free of the material. The metal sheet is subsequently heat treated in order to diffuse the alloying element into the first area of the metal sheet. The temperature of the first area is lower than the melting temperature of the metal sheet during the diffusion.

A method for treating sheet metal is disclosed in which a material containing at least one alloying element is applied onto a first area of at least one surface of the metal sheet. A second area of the surface is kept free of the material. The metal sheet is subsequently heat treated in order to diffuse the alloying element into the first area of the metal sheet. The temperature of the first area is lower than the melting temperature of the metal sheet during the diffusion.

A structure member includes a base formed of metal and a repair layer built in the base. The repair layer includes a plurality of capsules dispersed on the same plane, and a liquid repairing agent is enclosed in the capsules. The repair layer is disposed substantially parallel to a surface on which the structure member is exposed to the outside air. In addition, the repair layer can be disposed at a depth X set from a surface on which the structure member is initially exposed to the outside air. The capsule is formed of a material that breaks when exposed from the base.

A structure member includes a base formed of metal and a repair layer built in the base. The repair layer includes a plurality of capsules dispersed on the same plane, and a liquid repairing agent is enclosed in the capsules. The repair layer is disposed substantially parallel to a surface on which the structure member is exposed to the outside air. In addition, the repair layer can be disposed at a depth X set from a surface on which the structure member is initially exposed to the outside air. The capsule is formed of a material that breaks when exposed from the base.

A step is provided which performs a heat treatment at the sintering temperature of a sintered R-T-B based magnet or lower, while a powder of an RLM alloy (where RL is Nd and/or Pr; M is one or more selected from among Cu, Fe, Ga, Co and Ni) and a powder of an RH fluoride (where RH is Dy and/or Tb) are present on a surface of the sintered R-T-B based magnet. The RLM alloy contains RL in an amount of 50 at % or more, and a melting point of the RLM alloy is equal to or less than a temperature of the heat treatment. The heat treatment is performed while the RLM alloy powder and the RH fluoride powder are present on the surface of the sintered R-T-B based magnet at a mass ratio of RLM alloy:RH fluoride=96:4 to 5:5.

A step is provided which performs a heat treatment at the sintering temperature of a sintered R-T-B based magnet or lower, while a powder of an RLM alloy (where RL is Nd and/or Pr; M is one or more selected from among Cu, Fe, Ga, Co and Ni) and a powder of an RH fluoride (where RH is Dy and/or Tb) are present on a surface of the sintered R-T-B based magnet. The RLM alloy contains RL in an amount of 50 at % or more, and a melting point of the RLM alloy is equal to or less than a temperature of the heat treatment. The heat treatment is performed while the RLM alloy powder and the RH fluoride powder are present on the surface of the sintered R-T-B based magnet at a mass ratio of RLM alloy:RH fluoride=96:4 to 5:5.

Problem. To provide a chain pin which makes it possible to improve wear resistance even in an environment in which degraded oil is used. Solution. A large number of pins are mixed/agitated together with a particle mixture including a penetrant comprising chromium (Cr) powder and tungsten carbide (WC) powder, and an iron chloride (FeCl.sub.3) catalyst, and WC particles penetrate the surface of the pins together with chromium carbide (CrC). As a result, a chromium carbide layer in which WC particles are diffused in a CrC layer (CrCWC layer) is formed on the outermost surface part of the steel forming the parent material of the pins.