47results about How to "Wide current density range" patented technology

The invention relates to multi-coordination-agent cyanide-free electrogilding liquid and an electrogilding process, which belong to the technical field of electrogilding. The electrogilding liquid is prepared from a main coordination agent, an auxiliary coordination agent, potassium hydroxide, potassium carbonate, goldpotassium chloride, combined additives and ultrapure water. The electrogilding process comprises the following steps: 1, preprocessing a substrate; 2, electroplating an intermediate nickel plating layer; 3, electrogilding, namely washing the substrate after electroplating the intermediate nickel plating layer with ultrapure water, directly feeding the substrate into a plating cell containing the multi-coordination-agent cyanide-free electrogilding liquid to be electrogilded, taking out a sample from the electrogilding liquid after the electrogilding, washing the surface of the sample by utilizing distilled water, and drying the sample through cold air. Double coordination agents are used as the coordination agents of gold ions in the electrogilding liquid, so that a cyanide-free electrogilding system which has high current efficiency, smoothness and compactness in plating layer crystallization, wide current density range, wide temperature requirement and capability of guaranteeing the golden bright appearance of the plating layer compared with those of a single coordination agent system is obtained.

Provided are a process for producing a membrane/electrode assembly for a polymer electrolyte fuel cell and a process for producing a polymer electrolyte fuel cell, capable of achieving a high output voltage in a wide current density range.

At least one of an anode and a cathode in a membrane/electrode assembly for a polymer electrolyte fuel cell is formed through a catalyst layer forming step of applying a first coating fluid containing a catalyst and an ion exchange resin, onto a substrate to form a catalyst layer; a gas diffusion layer forming step of applying a second coating fluid containing carbon fibers and an ion exchange resin, onto the catalyst layer to form a gas diffusion layer to serve as an outermost layer of the membrane/electrode assembly for the polymer electrolyte fuel cell; and a peeling step of peeling the substrate off from the catalyst layer. The membrane/electrode assembly for the polymer electrolyte fuel cell is disposed between two separators each having a gas channel formed on a surface thereof so that surfaces of the outermost layers are adjacent to the respective separators, whereby the gas diffusion layer is adjacent to the separator.

Provision of a process for producing a membrane/electrode assembly for a polymer electrolyte fuel cell which can produce a high output voltage in a wide current density range.

A process for producing a membrane/electrode assembly for a polymer electrolyte fuel cell, comprising an anode and a cathode each having a catalyst layer, and an electrolyte membrane interposed between the catalyst layer of the anode and the catalyst layer of the cathode;

• • said process comprising:
  • a gas diffusion layer-forming step of applying a gas diffusion layer-coating fluid containing carbon fibers having a fiber diameter of from 1 μm to 50 μm and a proton conductive polymer, on a substrate to form a gas diffusion layer;
  • a removal step of removing the substrate from the gas diffusion layer formed in the gas diffusion layer-forming step; and
  • a step of disposing at least one such a gas diffusion layer thus prepared, on a surface of the catalyst layer of at least one of the anode and the cathode, on which the electrolyte membrane is not disposed.

The invention discloses a process for plating cadmium on a shaped steel part with a deep/blind hole, which comprises the following steps of: chemical oil removal, electrolytic oil removal, hot water washing, cold water washing, acid washing, cold water washing, neutralizing, cold water washing, cyanogen-less cadmium plating, cold water washing, hot water washing, compressed air drying, tempering dehydrogenizing, bright dipping, cold water washing, surface conditioning, middle-temperature phosphating, cold water washing, drying and detection, wherein the formula of each liter of electroplating liquid comprises: 40 to 50g of cadmium sulfate, 180 to 220g of ammonium chloride, 50 to 70g of nitrilotriacetic acid, 25 to 30g of ethylene diamine tetraacetic acid, a main additive, a brightener and a refiner, and the pH value is 6.2 to 6.7. The process effectively improves the quality and stability of special products, guarantees the use performance of the products and prolongs the service life of the products; and the production process is clean and environmentally-friendly, can effectively protect the environment and the physical and metal health of operators and meets the requirements of pollution-free production.

The present invention provides a new non-cyanide electro cooper plating bath of EDTA system and use method thereof. In the electro copper plating bath, using disodium EDTA or dipotassium EDTA as main complexant, using copper sulfate or basic copper carbonate as main salt, using trisodium citrate, potassium citrate or potassium sodium tartrate as auxiliary complexant, using sodium nitrate or potassium nitrate as conductive salt, using sodium hydroxide or potassium hydrate as pH value regulator. The invention also provides a use method of the non-cyanide electro cooper plating bath. The invention has advantages: simple plating bath formula, easy control and operation, wide temperature range of plating bath using, high current efficiency, fine crystallization coating, good appearance color, stable plating bath, strong uniform plating and covering ability, low cost, easy wastewater treatment. The invention can be used for pre copper plating or direct electro-coppering instead of virulent cyaniding electro-coppering process.

The invention relates to a processing technique of an oil delivery pipe, belonging to the technical field of alloy processing. The technique comprises the following steps: machining alloy steel to obtain an oil delivery pipe blank; carrying out electroplating treatment on the oil delivery pipe blank in a 20-30-DEG C nickel-electroplating solution by an auxiliary anode electroplating technique, wherein the electroplating solution is composed of 5-7 g/L zinc oxide, 110-130 g/L sodium hydroxide, 0.6-1 g/L nickel and 150-300ml of additive; sequentially carrying out polishing treatment, passivating treatment and rust prevention treatment on the electroplated oil delivery pipe blank to obtain an oil delivery pipe semifinished product; and carrying out seal treatment on the oil delivery pipe semifinished product to obtain the oil delivery pipe finished product. The oil delivery pipe has reasonable component combination; and under the synergistic actions of the component elements, the zinc-nickel alloy is electroplated on the surface by the auxiliary anode electroplating technique, the passivating treatment and rust prevention treatment are then carried out, and finally, the seal treatment for silanization treatment is carried out to further enhance the corrosion resistance and mechanical properties of the oil delivery pipe.

The invention provides an alkaline copper plating solution with a main coordination agent of methylenediphosphonate, and relates to non-cyanide electroplating field. The plating solution comprises the following components: methylenediphosphonate (MDP) with concentration of 30-100 g/L, cupric ion with concentration of 3-25 g/L, and carbonate ion with concentration of 10-80 g/L. By using sodium hydroxide or potassium hydroxide, pH value of the solution is adjusted to 7.5-13.5. The plating solution in the invention has the characteristics of simple formula, no cyanide pollution, small concentration polarization generated in an electroplating process, good stability of the plating solution, and wide allowable current density range. By using the plating solution to plate copper on iron matrix, zinc matrix, zinc alloy matrix or aluminium zinc galvanizing directly, a copper plating layer with good bonding force with the matrix is obtained.

The invention provides a combination type zincate zinc-plating brightener, wherein 13.6g of the imidazole, 10.3g of the triethylene-tetramine, 30ml of the formalin of which the concentration is 37 percent and 15ml of the water are added in a reactor, the reactor is heated up to reach the temperature of 40 DEG C, the chloroepoxy propane is dripped down at a temperature below 80 DEG C, the temperature is risen to 140 DEG C and the heat is preserved. The invention has the advantages of good physical properties of the plating coat, wide range of the current density, bright and even colors and low cost.

The invention relates to a method for electroplating zinc in neodymium iron boron magnet ionic liquid. According to the method, a neodymium iron boron magnet treated before plating is used as a cathode, a zinc sheet is used as an anode, the ionic liquid is adopted as electroplating liquid, under the magnetic stirring condition, a power supply is conducted, the temperature, the current intensity and the electroplating time are controlled for electroplating, and then, bright dipping, passivation and aging treatment are carried out. The method is applied to the neodymium iron boron magnet electroplating, the process is simple, the price of medicine is low, the operation temperature is low, more importantly, the hydrogen evolution reaction is avoided, the obtained plating layer is bright and compact, the combination of the plating layer and a base body is firm, and the corrosion resistance performance is good.

The invention relates to the technical field of electroplating additives and discloses environment-friendly brightener for non-cyanide alkaline zinc plating and a preparation method thereof. The brightener is prepared through polymine, IMZE, nitrogen heterocyclic derivatives, modified aromatic aldehyde compounds, epoxy chloropropane and water. According to the environment-friendly brightener for non-cyanide alkaline zinc plating and the preparation method thereof, the brightness of a galvanization layer is improved, the thickness of the galvanization layer can reach 30 micrometers, the galvanization layer is free of frangibility, and the dispersing power and the covering power of plating solution exceed those of traditional alkaline zinc plating brightener.

The invention relates to rapid low-temperature black nickel water for nickel plating and copper plating post-processing. The black nickel water contains components such as zinc salt, nickel salt, thiocyanate, conductive salt, water and the like. The black nickel water is characterized in that the operating temperature is 25-50 DEG C; the operating time is 1-5 min; and pH value is 4.5-5.5. The black nickel water is prepared according to the following steps of: adding 50-70% of water in the raw materials into a stirring device; successively pouring other components; finally adding the rest of the water; and stirring for at least 5 minutes to obtain the finished product. The black nickel water produced in the invention is clear, has stable performance and wide range of temperature and current density, is convenient to operate, and has long service life. As the product can be used at the temperature of 30-40 DEG C, electric energy consumed during heating process is greatly saved; in addition, the heating time is short, thus saving time.

The present invention relates to a cyanide-free copper electroplating method for reducing porosity of a copper plating layer. According to the cyanide-free copper electroplating method, a substrate is alternately subjected to a direct current electroplating unit and a pulse electroplating unit, the pH value of the electroplating solution is controlled to 12-13, the temperature is 50-70 DEG C, the cathode current density for copper electroplating in each direct current electroplating unit is 0.5-3.0 A/dm<2>, the electroplating time is 2-3 min, the pulse average current density for copper electroplating in each alternating current electroplating unit is 0.5-3.0 A/dm<2>, the duty ratio is 15%, and the electroplating time is 2-3 min. The plating layer obtained through the method has minimal porosity when the plating layer thickness is 10-20 mum.

The invention discloses a cyanide-free silver-electroplating solution mainly prepared from silver nitrate, sodium thiosulfate, anhydrous sodium sulfite, ammonium acetate, potassium acetate, boric acid, nicotinic acid and deionized water. The electroplating solution disclosed by the invention contains no extremely toxic substances in components and is prepared according to a cyanide-free formula so as to reduce environment hazards. The electroplating solution contains the simply and easily obtained components so as to be relatively low in cost. The electroplating solution is relatively good in stability and free of phenomena such as sedimentation, discoloration and the like after being placed for a long term; in addition, the electroplating effect of the electroplating solution placed for a long term is same as that of a new prepared electroplating solution. The electroplating solution is also relatively good in dispersing power and throwing power, relatively wide in allowed current density range and capable of obtaining a silver electroplating layer with favorable performance within the allowed current density range. The obtained silver electroplating layer is consistent in smoothness, fine and dense in crystal, relatively strong in binding force with a matrix, smooth and bright in appearance, free of discoloration after being placed in the air for a long term, and excellent in discoloration resistance.

The invention provides a combination type zincate zinc-plating brightener, wherein the urotropin, the dimcthylamine of which the concentration is 33 percent and the water are added in a reactor, the formaldehyde of which the concentration is 37 percent is dripped in the reactor and stirred for 30 minutes, the chloroepoxy propane is dripped down, the mixed liquid is heated up to the reflux temperature and the heat is preserved for 2 hours. The invention has the advantages of good physical properties of the plating coat, wide range of the current density, bright and even colors and low cost.

Provided is an aluminum plating solution that has a wide current density range in which aluminum plating can be performed and that has a low solution resistance. The aluminum plating solution contains an aluminum halide, at least one selected from the group consisting of an alkylimidazolium halide, an alkylpyridinium halide, and a urea compound, and an ammonium salt represented by the general formula (1) below. A concentration of the ammonium salt is 1 g/L or more and 45 g/L or less.

NR₄⁺.X⁻  General formula (1)

In the general formula, R each represent a hydrogen atom or an alkyl group which may have a side chain and which has 15 or less carbon atoms, X represents a halogen atom, and R may be the same or different from each other.

The invention provides an environmentally-friendly non-cyanide alkaline silver plating electroplating liquid having a dispersive capacity reaching up to 84.12 percent, which is considerably higher than a dispersive capacity being 59.4 percent to 72.7 percent in the same domestic industry, and is approximate to a dispersive capacity being 86.04 percent in the foreign advanced technology; a platingliquid performance is greatly improved compared with a domestic company, and the surface gloss and the stability of a plating layer are remarkably improved; compared with the foreign advanced technology, the invention still has a margin but undoubtedly has a great pioneering significance and enthusiasm on improving a domestic non-cyanide alkaline silver plating technology and breaking a foreign high-technology monopoly, and has a wide market prospect; a full silver plating layer with a bright mirror surface can be obtained, a current density range is wide, a surface is smooth, an anti-tarnishproperty is good, the corrosion resistance and the wear resistance are high, a binding force of the plating layer is good, a dispersive capacity and a covering capacity are excellent, electroplating wastewater is treated easily, the maintenance is simple, and the economy and the practicability are realized.

The invention relates to a zincate zinc-plating brightener. The zincate zinc-plating brightener is prepared from the components by parts: 20-30 parts of amino dimethane, 28-35 parts of zinc chloride,25-30 parts of boric acid, 14-17 parts of 2.4-dichlorobenzaldehyde, 5-8 parts of polyethylene glycol single dodecane ether and 1-3 parts of sodium citrate. According to the zincate zinc-plating brightener, the sodium citrate and the polyethylene glycol single dodecane ether are added to the brightener to enhance stability of a system, the amino dimethane and the 2.4-dichlorobenzaldehyde are added,thus the brightener has the wide current density range, the zinc chloride and the boric acid are added to improve the polarization action of the brightener, the brightener does not contain addition agents of aromatic hydrocarbon and amine, environmental protection is achieved, safety and non-toxicity are achieved, performance is stable, a plating layer is uniform and compact, brightness of metalsis improved, the preparation technology is simple, the cost of raw materials is low, and the brightener has good economic benefit.

A trivalent black chromium electroplating agent easy to prepare comprises potassium chloride, ammonium chloride, boric acid, chromium trichloride, potassium thiocyanate and methionine. The potassium chloride, the ammonium chloride and the boric acid are used as main materials, the chromium trichloride is added, so that the color can be changed from white to green, other additives do not need to beadded to adjust the color, and meanwhile, the mixed use of the potassium chloride, the ammonium chloride, the boric acid and the chromium trichloride can maintain the chromium concentration of a bathsolution without separately adding chromium salt in the process of preparing an electroplating solution; therefore, the preparation process can be simplified, the preparation time can be shortened, the purchase cost of raw materials can be saved, and the preparation process can be simpler and more convenient; and by adding the potassium thiocyanate and the methionine, the plating layer depositionspeed of the plating solution of the trivalent black chromium electroplating agent can be improved, the covering capacity of the trivalent black chromium electroplating agent can be improved, a chromium layer can be deposited on the surface of a workpiece plated by the trivalent black chromium electroplating agent, and the corrosion resistance of the surface of the workpiece can be greatly improved by the chromium layer.

The invention relates to a method for preparing a super-hydrophobic Zn-Fe alloy coating through electro-deposition in eutectic ionic liquid, and belongs to the field of electro-deposition. According to the method, a zinc source, an iron source, a solubilizer, a viscosity reducer, a pH regulator and the like are dissolved in the eutectic ionic liquid with choline chloride and ethylene glycol being a hydrogen bond acceptor and donor to prepare electrolyte; and in the electro-deposition process, electro-deposition is carried out for 10-60min at the constant current of 10-500mA/cm<2> under the temperature of 40-90 DEG C to obtain the super-hydrophobic Zn-Fe alloy coating with good corrosion resistance. According to the super-hydrophobic Zn-Fe alloy coating, the iron content ranges from 1wt% to 20wt%, the water contact angle is greater than or equal to 160 degrees, the rolling angle is smaller than or equal to 4 degrees, and good hydrophobic performance and corrosion resistance are shown. The method is easy to operate, safe and reliable, the electro-deposition process is free of hydrogen evolution and other side reactions, the current efficiency is high, the coating does not need passivation treatment, the plating solution is easy to recycle, and the method is an environment-friendly method for preparing the super-hydrophobic Zn-Fe alloy coating.

The invention discloses an electroplating liquid for electroplating treatment. The electroplating liquid comprises the following compositions according to mass ratio: 9-10g/L of nickel sulfate, 0.6-0.8g/L of a hydrogen removal agent, 4-5g/L of citric acid, 4-6g/L of fluoroboric acid, 0.6-0.8g/L of lead acetate, 2-3g/L of glycol, 20-24g/L of stannous fluoborate, 6-8g/L of sulfuric acid, 5-6g/L of sodium hypophosphite and 4-6g/L of a brightening agent. After being electroplated by the electroplating liquid, the surface of a copper wire is good in corrosion resistance, excellent in conductivity, and antiwear; the nickel, lead and phosphorus elements are added, so that the diffusion of copper atoms towards the electroplating liquid can be effectively prevented; and the precipitation speed is fast, the current density range is wide, the electricity consumption is low, the electroplating quality is good, and the service life of the metal copper wire is prolonged.