Abstract: An object comprising a chromium-based coating on a substrate is disclosed, wherein the chromium is electroplated from an aqueous electroplating bath comprising trivalent chromium cations, wherein the chromium-based coating comprises 87-98 weight-% of chromium, 0.3-5 weight-% of carbon, and 0.1-11 weight-% of nickel and/or iron, and wherein the chromium-based coating has a Vickers microhardness value of 1000-2000 HV, and wherein the chromium-based coating does not contain chromium carbide. Further is disclosed a method for its production, and an aqueous electroplating bath.

Abstract: An object comprising a chromium-based coating on a substrate is disclosed. The chromium is electroplated from an aqueous electroplating bath comprising trivalent chromium cations, wherein the chromium-based coating comprises: a first chromium-containing layer, on the substrate, having a thickness of at least 100 nm, and a Vickers microhardness value of 700-1000 HV; a second chromium-containing layer, on the first chromium-containing layer, having a Vickers microhardness value that is at least 1.3 times higher than the Vickers microhardness value of the first chromium-containing layer, and a crystal size of 8-35 nm; and wherein the chromium-based coating exhibits a critical scratch load value (LC2) of at least 60 N in the adhesion test according to ASTM C1624-05 (2015; point 11.11.4.4), and wherein the chromium-based coating does not contain chromium carbide. Further is disclosed a method for its production.

Abstract: An aqueous electroplating bath is disclosed. The aqueous trivalent chromium bath comprises:—trivalent chromium cations in an amount of 0.12-0.276 mol/l,—ammonium ions in an amount of 4.0-6.0 mol/l, and—carboxylate ions in an amount of 2.0-7.4 mol/l, and the molar ratio of trivalent chromium cations to the carboxylate ions is 0.016-0.099, and the pH of the aqueous trivalent chromium bath is 2-6.

Abstract: An object comprising a chromium-based coating on a substrate is disclosed. The chromium is electroplated from an aqueous electroplating bath comprising trivalent chromium cations, wherein the chromium-based coating comprises at least one chromium-containing layer, the chromium-based coating does not contain macrocracks, wherein a macrocrack is a crack that extends from the outer surface of the chromium-based coating, through the chromium-based coating, to the substrate, the chromium-based coating has a Vickers microhardness value of 800-1100 HV, and the chromium-based coating exhibits a critical scratch load value (LC2) of at least 80 N in the adhesion test according to ASTM C1624-05 (2015; point 11.11.4.4). Further is disclosed a method for its production.

Abstract: An object comprising a chromium-based coating on a substrate is disclosed. The chromium is electroplated from an aqueous electroplating bath comprising trivalent chromium cations, wherein the chromium-based coating comprises: a first chromium-containing layer, on the substrate, having a thickness of at least 100 nm, and a Vickers microhardness value of 700-1000 HV; a second chromium-containing layer, on the first chromium-containing layer, having a Vickers microhardness value that is at least 1.3 times higher than the Vickers microhardness value of the first chromium-containing layer, and a crystal size of 8-35 nm; and wherein the chromium-based coating exhibits a critical scratch load value (Lc2) of at least 60 N in the adhesion test according to ASTM C1624-05 (2015; point 11.11.4.4), and wherein the chromium-based coating does not contain chromium carbide. Further is disclosed a method for its production.

Abstract: An aqueous electroplating bath is disclosed. The aqueous trivalent chromium bath comprises:—trivalent chromium cations in an amount of 0.12-0.276 mol/l,—ammonium ions in an amount of 4.0-6.0 mol/l, and—carboxylate ions in an amount of 2.0-7.4 mol/l, and the molar ratio of trivalent chromium cations to the carboxylate ions is 0.016-0.099, and the pH of the aqueous trivalent chromium bath is 2-6.

Abstract: An object comprising a chromium-based coating on a substrate is disclosed, wherein the chromium is electroplated from an aqueous electroplating bath comprising trivalent chromium cations, wherein the chromium-based coating comprises 87-98 weight-% of chromium, 0.3-5 weight-% of carbon, and 0.1-11 weight-% of nickel and/or iron, and wherein the chromium-based coating has a Vickers microhardness value of 1000-2000 HV, and wherein the chromium-based coating does not contain chromium carbide. Further is disclosed a method for its production, and an aqueous electroplating bath.

Abstract: An object including a chromium-based coating on a substrate and a method for its production are disclosed. The chromium-based coating having a first layer on the substrate, wherein the first layer has a top surface on the opposite side to the substrate and includes fissures within the first layer, and wherein the material of the first layer is predominantly formed of chromium and chromium carbide; the chromium-based coating further having a second layer on the first layer, the second layer at least partially filling the fissures in the first layer and at least partially covers the top surface of the first layer, wherein the material of the second layer is selected from a group consisting of: chromium oxide, carbon, and a combination of chromium oxide and carbon.

Abstract: A chromium-based coating including chromium (Cr), carbon (C) and iron (Fe), Cr being electroplated from a trivalent Cr bath. The coating is further includes nickel (Ni) electroplated from the Cr bath having at least 20 mg l?1 Ni cations, in that C is at least partially in the form of at least one chromium carbide compound, in that the coating has been heat-treated at a temperature of 400-1,200° C., and in that the hardness of the coating is at least 1,500 HV on a Vickers microhardness scale as measured according to standard SFS-EN ISO 4516. A method for producing a coating and to a coated object is also disclosed.

Abstract: An object including a chromium-based coating on a substrate and a method for its production are disclosed. The chromium-based coating having a first layer on the substrate, wherein the first layer has a top surface on the opposite side to the substrate and includes fissures within the first layer, and wherein the material of the first layer is predominantly formed of chromium and chromium carbide; the chromium-based coating further having a second layer on the first layer, the second layer at least partially filling the fissures in the first layer and at least partially covers the top surface of the first layer, wherein the material of the second layer is selected from a group consisting of: chromium oxide, carbon, and a combination of chromium oxide and carbon.

Abstract: The invention relates to a chromium-based coating comprising at least one layer rich in crystalline phase or phases of nickel (Ni) and/or Ni compounds, and at least one layer rich in crystal-line phase or phases of chromium (Cr) and/or Cr compounds, Cr being electroplated from a trivalent chromium bath. The coating is characterized in that the it further comprises one or more crystalline phases of chromium-nickel-phosphorus (CrNiP), which CrNiP phase has been produced by heat treating a coating comprising at least one layer of nickel-phosphorus (NiP) and at least one layer of Cr. The invention also relates to a method for producing a chromiumbased coating and to a coated object.

Abstract: To produce a chromium-containing multilayer coating on an object, alternate layers of nickel phosphorus alloy and trivalent chromium are deposited on the object until a desired thickness of coating has been reached. The coated object is then subjected to one or more heat treatments to improve the mechanical and physical properties of the coating and to produce multiphase layers comprising layers containing crystalline Ni and crystalline Ni3P and layers containing crystalline Cr.

Abstract: To produce a trivalent chromium based coating on an object, a layer of nickel phosphorus alloy is deposited on the object, an intermediate layer of another metal or metal alloy or ceramic is deposited on the NiP layer, and a chromium layer is deposited from a trivalent chromium bath on the intermediate layer. The coated object is subjected to one or more heat treatments to harden the coating and to produce multiphase layers including at least one layer containing crystalline Ni and crystalline Ni3P and at least one layer containing crystalline Cr. The intermediate layer can consist of copper, molybdenum, a metal alloy or a non-metallic solid, such as an oxide, nitride or carbide of a metal.

Abstract: A chromium-based coating including chromium (Cr), carbon (C) and iron (Fe), Cr being electroplated from a trivalent Cr bath. The coating is further includes nickel (Ni) electroplated from the Cr bath having at least 20 mg l?1 Ni cations, in that C is at least partially in the form of at least one chromium carbide compound, in that the coating has been heat-treated at a temperature of 400-1,200° C., and in that the hardness of the coating is at least 1,500 HV on a Vickers microhardness scale as measured according to standard SFS-EN ISO 4516. A method for producing a coating and to a coated object is also disclosed.

Abstract: The invention relates to a chromium-based coating comprising at least one layer rich in crystalline phase or phases of nickel (Ni) and/or Ni compounds, and at least one layer rich in crystal-line phase or phases of chromium (Cr) and/or Cr compounds, Cr being electroplated from a trivalent chromium bath. The coating is characterized in that the it further comprises one or more crystalline phases of chromium-nickel-phosphorus (CrNiP), which CrNiP phase has been produced by heat treating a coating comprising at least one layer of nickel-phosphorus (NiP) and at least one layer of Cr. The invention also relates to a method for producing a chromiumbased coating and to a coated object.

Abstract: To produce a chromium-containing multilayer coating on an object, alternate layers of nickel phosphorus alloy and trivalent chromium are deposited on the object until a desired thickness of coating has been reached. The coated object is then subjected to one or more heat treatments to improve the mechanical and physical properties of the coating and to produce multiphase layers comprising layers containing crystalline Ni and crystalline Ni3P and layers containing crystalline Cr.

Abstract: To produce a trivalent chromium based coating on an object, a layer of nickel phosphorus alloy is deposited on the object, an intermediate layer of another metal or metal alloy or ceramic is deposited on the NiP layer, and a chromium layer is deposited from a trivalent chromium bath on the intermediate layer. The coated object is subjected to one or more heat treatments to harden the coating and to produce multiphase layers including at least one layer containing crystalline Ni and crystalline Ni3P and at least one layer containing crystalline Cr. The intermediate layer can consist of copper, molybdenum, a metal alloy or a non-metallic solid, such as an oxide, nitride or carbide of a metal.

Abstract: A method for producing a trivalent chromium based coating on a metal substrate, a layer of nickel phosphorus alloy is deposited on a metal substrate and a trivalent chromium layer is electroplated on the Ni—P layer. The coated metal substrate is subjected to one or more heat treatments to harden the coating and to produce multiphase layers including at least one layer containing crystalline Ni and crystalline Ni3P, and at least one layer containing crystalline Cr and crystalline CrNi. By using this method it is possible to produce coatings having a Vickers microhardness value higher than 2000 HV.