Abstract: The present invention is to provide a chrome-plated part having a corrosion resistance in normal and specific circumstances and not requiring additional treatments after chrome plating, and to provide a manufacturing method of such a chrome plated part. The chrome-plated part 1 includes: a substrate 2; a bright nickel plating layer 5b formed over the substrate 2; a noble potential nickel plating layer 5a formed on the bright nickel plating layer 5b. An electric potential difference between the bright nickel plating layer 5b and the noble potential nickel plating layer 5a is within a range from 40 mV to 150 mV. The chrome-plated part 1 further includes: a trivalent chrome plating layer 6 formed on the noble potential nickel plating layer 5a and having at least any one of a microporous structure and a microcrack structure.

Abstract: An aqueous acidic trivalent chromium electrolyte comprising trivalent chromium ions and a complexing agent for maintaining the trivalent chromium ions in solution is provided in which the aqueous electrolyte comprises additives capable of producing a coating on a substrate having a desired dark hue. The additives typically comprise a dispersion of colloidal silica and an additional additive selected from thiocyanate ions and/or iron ions. The electrolyte is used in a method of producing the desired dark-hued decorative chromium coating on a substrate by electrodeposition.

Abstract: A coating for protecting a base material from wear and corrosion includes a first layer deposited directly onto an outer surface of the base material. In addition, the coating includes a second layer deposited directly onto the first layer. The first layer is positioned between the base material and the second layer. The first layer includes chromium having a first micro-crack density and the second layer comprises chromium having a second micro-crack density that is less than the first micro-crack density.

Abstract: An nickel plating layer (5a) intended for corrosion current distribution is formed over a body (2), and a 0.05 to 2.5 micrometers thick surface chrome plating layer (6) made of trivalent chromium is formed on the surface thereof using basic chromium sulfate as a source of metal. Further on the same, a not less than 7 nm thick chromium compound film (7) is formed by cathode acidic electrolytic chromatin. The corrosion distribution nickel plating layer (5a) has a function of forming a microporous structure, a microcrack structure, or the both of the same in the surface chrome plating layer (6).

Abstract: A method of forming a tool marking structure includes: a coloring step of coloring a predetermined position of the first protective layer so as to form a marking area with a color layer and forming the first protective layer on a bottom surface of the marking area, and a second-time surface processing step of forming a second protective layer on a non-marking area of the tool.

Abstract: A method for producing a structured hard chromium layer, during which chromium from an electrolyte is deposited onto a workpiece, which contains: a) a Cr(VI) compound in a quantity corresponding to between 50 and 300 g/l of chromic anhydride; b) 0.5 g/l to 10 g/l sulfuric acid, and; c) 5 g/l to 15 g/l aliphatic sulfonic acid having 1 to 6 carbon atoms. The electrolyte comprises substantially no compounds from the group consisting of ammonium molybdate, alkaline molybdate, alkaline earth molybdate, ammonium vanadate, alkaline vanadate and alkaline earth vanadate, ammonium zirconate, alkaline zirconate and alkaline earth zirconate, and is processed with a cathodic efficiency of 12% or less. A method for producing a coating, to a structured hard chromium layer, a coating and an electrolyte.

Abstract: An nickel plating layer (5a) intended for corrosion current distribution is formed over a body (2), and a 0.05 to 2.5 micrometers thick surface chrome plating layer (6) made of trivalent chromium is formed on the surface thereof using basic chromium sulfate as a source of metal. Further on the same, a not less than 7 nm thick chromium compound film (7) is formed by cathode acidic electrolytic chromatin. The corrosion distribution nickel plating layer (5a) has a function of forming a microporous structure, a microcrack structure, or the both of the same in the surface chrome plating layer (6).

Abstract: It is disclosed a method of depositing a seal coating and a seal system comprising at least two layers on the surface of an article. The upper or surface layer has a higher chromium activity than a bottom layer, to reduce a diffusion of cobalt and the formation of cobalt oxide is reduced. The coating of invention may be heat-treated to reduce or optimize the formation of cobalt oxide to sustain the wear property.

Abstract: A chromium plating bath containing trivalent chromium ions and hexavalent chromium ions is prepared by a method including the steps of: (A) mixing chromic acid and an organic acid in an aqueous solution containing these acids and reducing chromic acid by the organic acid so as to prepare an aqueous solution not containing hexavalent chromium ions; (B) adding a pH adjustor to the aqueous solution not containing hexavalent chromium ions so as to adjust pH to a value of 1 to 4; and (C) further adding chromic acid to the aqueous solution not containing hexavalent chromium ions and having undergone the pH adjustment so as to prepare an aqueous solution containing trivalent chromium ions and hexavalent chromium ions. The chromium plating bath containing both trivalent chromium ions and hexavalent chromium ions can be prepared while easily and assuredly adjusting the contents (content ratio) of trivalent chromium ions and hexavalent chromium ions to predetermined values (a predetermined value).

Abstract: It is disclosed a method of depositing a seal coating and a seal system comprising at least two layers on the surface of an article. The upper or surface layer has a higher chromium activity than a bottom layer, to reduce a diffusion of cobalt and the formation of cobalt oxide is reduced. The coating of invention may be heat-treated to reduce or optimize the formation of cobalt oxide to sustain the wear property.

Abstract: A method for electroplating a plastic substrate includes the following steps, a plastic substrate is firstly provided. The plastic substrate is then pretreated to form a noble metal coating. The noble metal coating is coated with a copper coating. A first chrome coating is electroplated onto the copper coating using a first electrolyte including a chromic component. A second chrome coating is electroplated onto the first chrome coating using a second electrolyte including a chromyl component.

Abstract: An improved direct current chrome plating process which results in increased corrosion resistance as compared to conventional processes. Particularly, in comparison with conventional processes, an improved process as broadly contemplated herein can preferably include an additional processing step involving the application of a distinct chemical solution. This additional step, consequently, will lead to a chrome plated product having variant layers of chrome plating rather than the single layer as produced conventionally.

Abstract: A method of forming a surface finish of trivalent chromium on metal or plastics substrates by electrodeposition from an aqueous plating solution of trivalent chromium ions in which the trivalent chromium is deposited on a layer of silver or silver alloy whereby the color and/or corrosion resistance of the trivalent chromium is comparable to surface finishes of hexavalent chromium. The invention avoids the health and safety risks associated with the electrodeposition of hexavalent chromium surface finishes.

Abstract: The present invention provides a chrome-plated sliding member free from periodical decreases in wear resistance or seizure resistance without the necessity to intentionally bend a multi-layer hard chrome plating film. This is a sliding member having a multi-layer hard chrome plating film on the sliding surface of the substrate 1. Microcracks 6 opening to the outer surface side of the individual hard chrome plating layers are distributed in hard chrome plating layers 2, 3, 4 and 5. The microcracks of the individual hard chrome plating layers comprise relatively shallow portions 6a where bottoms stop within a single layer, and relatively deep portions 6b and 6c where cracks run through two or more layers. The quantities of the microcracks expressed by the area ratios of microcracks on a cross-section of the hard chrome plating film include a quantity of the portions where cracks stop within a single layer within a range of from 1.5 to 35.

Abstract: A method of coating a metal surface, particularly an inner surface of a gun barrel, with a chromium layer, includes the following steps: electrolytically precipitating on the metal surface a plurality of partial chromium layers in a superposed relationship by electric current pulses equaling the number of the partial chromium layers; and selecting the duration of each pulse such that a crystallite growth of individual partial chromium layers is stopped prior to a natural termination thereof for obtaining a globular polytropic structure of the entire chromium layer.

Abstract: The present invention relates to a galvanic bath, to a process for the precipitation of chromium onto objects, and to the use of the process for the generation of textured hard-chrome layers on machine components. The galvanic bath contains in aqueous solution at least one compound delivering chromium(VI)-ions, and it comprises a) chromium(VI)-ions in an amount that corresponds to 100 to 600 g/ltr of chromic acid anhydride, b) sulfate ions in the form of sulfuric acid and/or of a soluble salt thereof in a molar concentration ratio of chromium(VI)-ions to sulfate ions (SO4−2) ranging from 90:1 to 120:1, and c) 2-hydroxyethane sulfonate ions in an amount that corresponds to 0.01 to 3.0 g/ltr of the sodium salt.

Abstract: The present invention provides a chrome-plated sliding member free from periodical decreases in wear resistance or seizure resistance without the necessity to intentionally bend a multi-layer hard chrome plating film. This is a sliding member having a multi-layer hard chrome plating film on the sliding surface of the substrate 1. Microcracks 6 opening to the outer surface side of the individual hard chrome plating layers are distributed in hard chrome plating layers 2, 3, 4 and 5. The microcracks of the individual hard chrome plating layers comprise relatively shallow portions 6a where bottoms stop within a single layer, and relatively deep portions 6b and 6c where cracks run through two or more layers. The quantities of the microcracks expressed by the area ratios of microcracks on a cross-section of the hard chrome plating film include a quantity of the portions where cracks stop within a single layer within a range of from 1.5 to 35.

Abstract: Using a chrome plating bath containing organic sulfonic acid, plating is conducted by application of a pulse current to thereby form a crack-free lower chrome layer on a steel substrate. The lower chrome layer has a compressive residual stress of 100 MPa or more and a crystal grain size of from 9 nm to less than 16 nm. Subsequently, by application of a direct current, a cracked upper chrome layer is formed on the lower chrome layer, to thereby obtain a chrome plated part. The lower chrome layer imparts the chrome plated part with heat resistance and corrosion resistance, and the upper chrome layer imparts the chrome plated part with wear resistance and good sliding properties.

Abstract: A structured surface coating is electrochemically deposited on an (electrically conductive) surface of a component. The component to be coated forms the cathode in a galvanic bath. The process current is raised in discrete steps in a nucleation phase during which island formations are deposited on the surface, with brief pauses between each increase of between 0.1 and 30 sec. The process current is then maintained at a constant level, during which the islands grow. The process sequence may be repeated several times.

Abstract: A structured surface coating is electrochemically deposited on an electrically conductive surface of a component. The component to be coated forms the cathode in a galvanic bath. The process current is raised in discrete steps in a nucleation phase during which island formations are deposited on the surface, with brief pauses between each increase of between 0.1 and 30 sec. The process current is then maintained at a constant level, during which the islands grow. The process sequence may be repeated several times.

Abstract: A process for electrochemically depositing a structured surface layer on a component, such as a machine component, particularly a steel water cylinder of a printing press, is disclosed. The process comprises the steps of defining an electrical parameter, such as a potential and/or an electrical current, effecting an electro-chemical layer deposition; and depositing a surface layer on the component with a structured outer surface topography. The depositing step is performed by providing an initial pulse of the electrical parameter and forming a plurality of island formations of deposition material on a surface of the component to be electro-chemically coated, and subsequently providing a follow-up pulse of the electrical parameter and causing a growth of the deposition material on the plurality of islands for causing the structured outer surface topography.

Abstract: A method for producing a tin free steel having double layers consisting of a lower layer of flatly deposited metallic chromium and an upper layer of insoluble hydrated chromium oxide which is characterized by a dissolution of soluble hydrated chromium oxide after the formation of three layers consisting of a bottom layer of metallic chromium, a middle layer of insoluble hydrated chromium oxide and an upper layer of soluble hydrated chromium oxide on a steel base by using a chromic acid electrolyte with a small amount of fluoride compound.By using this tin free steel, a welded can body can be produced at high speed without the removal of the plated layer in the welded part because this tin free steel has an excellent weldability.

Abstract: A method of forming sliding surfaces, wherein a first plating layer with a relatively high level of hardness is formed by using a first plating liquid which is at a relatively low temperature; and a second plating layer with a hardness lower than that of the first plating layer is formed on the surface of the first plating layer by using a second plating liquid which is at a temperature higher than that of the first plating liquid; the second plating layer being honed to a predetermined thickness.

Abstract: Using a chrome plating bath containing organic sulfonic acid, plating is conducted by application of a pulse current to thereby form a crack-free lower chrome layer on a steel substrate. The lower chrome layer has a compressive residual stress of 100 MPa or more and a crystal grain size of from 9 nm to less than 16 nm. Subsequently, by application of a direct current, a cracked upper chrome layer is formed on the lower chrome layer, to thereby obtain a chrome plated part. The lower chrome layer imparts the chrome plated part with heat resistance and corrosion resistance, and the upper chrome layer imparts the chrome plated part with wear resistance and good sliding properties.