EP3098334A1 - Electrolytic process for coating metal surfaces to provide high wear resistance - Google Patents

Electrolytic process for coating metal surfaces to provide high wear resistance Download PDF

Info

Publication number
EP3098334A1
EP3098334A1 EP16171777.2A EP16171777A EP3098334A1 EP 3098334 A1 EP3098334 A1 EP 3098334A1 EP 16171777 A EP16171777 A EP 16171777A EP 3098334 A1 EP3098334 A1 EP 3098334A1
Authority
EP
European Patent Office
Prior art keywords
process according
surfactant
electrolytic bath
boron carbide
tank
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP16171777.2A
Other languages
German (de)
English (en)
French (fr)
Inventor
Marco BURATTI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Metalcoating Srl
Original Assignee
Metalcoating Srl
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metalcoating Srl filed Critical Metalcoating Srl
Publication of EP3098334A1 publication Critical patent/EP3098334A1/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D15/00—Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/02—Maintaining the aggregation state of the mixed materials
    • B01F23/023—Preventing sedimentation, conglomeration or agglomeration of solid ingredients during or after mixing by maintaining mixed ingredients in movement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/10—Mixing by creating a vortex flow, e.g. by tangential introduction of flow components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/50—Circulation mixers, e.g. wherein at least part of the mixture is discharged from and reintroduced into a receptacle
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D21/00—Processes for servicing or operating cells for electrolytic coating
    • C25D21/10—Agitating of electrolytes; Moving of racks
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/08—Electroplating with moving electrolyte e.g. jet electroplating
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/10—Electroplating with more than one layer of the same or of different metals
    • C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
    • C25D5/14—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium two or more layers being of nickel or chromium, e.g. duplex or triplex layers
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/48—After-treatment of electroplated surfaces
    • C25D5/50—After-treatment of electroplated surfaces by heat-treatment
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/60—Electroplating characterised by the structure or texture of the layers
    • C25D5/615—Microstructure of the layers, e.g. mixed structure
    • C25D5/617—Crystalline layers
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/60—Electroplating characterised by the structure or texture of the layers
    • C25D5/615—Microstructure of the layers, e.g. mixed structure
    • C25D5/619—Amorphous layers

Definitions

  • the present invention relates to an electrolytic process for coating metal surfaces. More particularly, the present invention relates to an electrolytic process for coating metal surfaces with a layer comprising a nickel/phosphorus alloy matrix and boron carbide particles, in order to provide high wear resistance.
  • the coatings of metal articles are conventionally made by chromium plating, namely electrolytic deposition of a chromium layer having a thickness of the order of 100 ⁇ m.
  • the chromium plating has low costs, it does not always allow to obtain high-uniformity coatings, especially in the case of surfaces with complex geometry (for example, groovings or other deep embossings) wherein, due to the tip effect, excessive thicknesses are obtained on the tips and pour thickness are obtained in the grooves of the embossings.
  • the use of hexavalent chromium gives serious problems as for the environmental sustainability, due to the high toxicity of this metal, as well as causing high costs in terms of energy and the disposal thereof.
  • Another type of coating suitable for conferring wear resistance is that one which uses tungsten carbide, which allows to obtain surfaces with high hardness (Vickers hardness of about 1300 HV), but very high costs, such that to limit the use to specific industrial applications.
  • the patent application EP 1 067 220 A2 discloses a process for manufacturing a coating with boron carbide into a nickel-phosphorus matrix, wherein the article to be coated is subjected to electrodeposition into an electrolytic bath comprising two or more nickel salts, in particular a mixture of nickel sulfate and nickel chloride, at least one complexing agent, at least one phosphorus salt, a detensioning agent and boron carbide in the powder form having a particle dimension from 3 to 6 ⁇ m.
  • the cathode consists of the material to be coated, while the anode consists of electrolytic nickel.
  • the electrolytic process is carried out at a temperature from 40°C to 70°C with a current density from 1 to 10 A/dm 2 , under stirring.
  • the article thus coated is then subjected to a heat treatment, in particular at a temperature from 250°C to 400°C.
  • the Applicant considered the technical problem to manufacture a coating of metal surfaces which allows to obtain high wear resistance, and at the same time high performances in terms of corrosion resistance against oxygen or other chemical agents, with controlled and uniform thicknesses, also in the presence of surfaces having a complex geometry. Furthermore, the Applicant considered the problem to develop a process of electrolytic coating which allows the use of insoluble anodes, namely anodes that remain unchanged during the process, without significant consumption of the material constituting such anodes, thus allowing the use of insoluble anodes commonly used in the conventional chromium plating processes.
  • the present invention relates to a process for coating a metal article, which comprises:
  • Such process allows to obtain the metal article coated with a layer comprising a nickel/phosphorus (Ni/P) alloy matrix and boron carbide particles having an average size from 0.01 ⁇ m to 2 ⁇ m, which are present in an very high amount, generally from 10% to 50% by volume, preferably from 5% to 45% by volume, with respect to the total volume of the coating.
  • the coating layer thus obtained has a very high wear resistance, also at high temperatures, and high hardness (up to 1500 HV), and at the same time high thickness uniformity.
  • the metal article to be coated can be formed at least partially by one metal, for example, selected from: steel, aluminum, copper, brass, cast iron, and others.
  • the process in accordance with the present invention can be advantageously used for coating metal articles in various technical fields, in particular for coating cylinders for the production of corrugated cardboard, or for coating the internal surface barrel of firearms, that has groovings with an extremely precise geometry and where the abrasive action of bullets is very height, with the develop of high amounts of heat.
  • the boron carbide particles have an average size from 0.01 ⁇ m to 2 ⁇ m, preferably from 0.05 ⁇ m to 1 ⁇ m.
  • the boron carbide particles in suspension are present in an amount preferably from 1 g/l to 20 g/l, more preferably from 5 to 15 g/l.
  • the aqueous solution comprises at least one Ni(II) salt with an anion containing sulfur, for example nickel (II) sulfate. More preferably, this is nickel (II) sulfamate (Ni(SO 3 NH 2 ) 2 ).
  • nickel (II) sulfamate Ni(SO 3 NH 2 ) 2 .
  • the use of nickel (II) sulfamate is particularly preferred as it allows to increase the electrodeposition rate, with a substantial improvement in terms of productivity and cost of the process.
  • the aqueous solution can comprise at least another Ni(II) salt, preferably selected from: nickel (II) carbonate, nickel (II) acetate. It is also possible to use nickel (II) chloride, although this is not particularly preferred if the cathode is a nickel cathode, as the presence of chloride ions causes the consumption of the nickel electrode due to anodic attack.
  • the aqueous solution comprises Ni (II) ions in a total concentration of from 0.3 moles/l to 3.0 moles/l, more preferably from 0.5 moles/l to 1.5 moles/l.
  • the aqueous solution comprises a Ni(II) salt with an anion containing sulfur, and a second salt selected from nickel (II) carbonate and nickel (II) acetate, the concentration of the first salt being comprised between 0.3 moles/l and 1.8 moles/l, more preferably between 0.5 moles/l and 1.4 moles/l; the concentration of the second salt being comprised between 0.02 moles/l and 1.0 moles/l, more preferably between 0.05 moles/l and 0.6 moles/l.
  • phosphorus compound As far as the phosphorus compound is concerned, this is selected from: phosphoric acid, phosphorous acid, hypophosphorous acid or salts thereof.
  • salts for example, alkaly metal salts (for example potassium, sodium) or alkaline-earth metal salts (for example magnesium, calcium) can be used.
  • the phosphorus compound is a phosphorous acid/hypophosphorous acid mixture, or salts thereof, preferably in a weight ratio comprised between 0.8:1 and 1.2:1. It is believed that such mixture allows to further enhance the characteristics of the final coating, thus achieving an optimal compromise between crystalline phase and amorphous phase in the coating material and therefore between hardness and corrosion resistance thereof.
  • the amount of phosphorous compound to be added to the electrolytic bath is mainly selected depending on the type of nickel/phosphorus alloy to be obtained, namely a so-called "low-phosphorus” alloy, namely in general with an amount of phosphorus from 1 to 8% by weight, extremes included (with respect to the weight of the Ni/P alloy), or a so-called “high-phosphorus” alloy, namely in general with an amount of phosphorus higher than 8% and lower than or equal to 16% by weight (with respect to the weight of the Ni/P alloy).
  • the obtaining of a high-phosphorus phosphorus/nickel alloy allows to significantly increase the corrosion resistance of the coating, in particular resistance to the corrosion due to the contact with water with a high content of salt, for example sea water.
  • a low-phosphorus phosphorus/nickel alloy has a lower corrosion resistance, but is characterized by a higher hardness with respect to a high-phosphorus alloy.
  • the aqueous solution comprises at least one iodide of an alkaly metal, preferably potassium iodide. It is believed that the presence of iodide in the electrolytic bath allows to further enhance the corrosion resistance of the coating, in particular the corrosion resistance in salt fog, a particularly severe test for any material.
  • the iodide of an alkali metal is present in the solution in an amount comprised between 0.1 and 10 g/L, more preferably between 0.5 and 3g/L.
  • the aqueous solution comprises at least one surfactant, which has mainly the function to facilitate the deposition of the boron carbide particles, particularly when these particles have reduced tank sizes so tending to form agglomerates that remain in suspension or deposit to the bottom of the electrolytic tank instead of depositing on the metal surface together with the Ni/P alloy.
  • the surfactant is a cationic, non-ionic or amphoteric surfactant, as these, being positively charged or being neutral, do not undergo the electrostatic repulsive action from the cathode where the deposition of boron carbide occurs.
  • the cationic surfactant is preferably selected from tetraalkylammonium salts R 1 R 2 R 3 R 4 N + X - wherein R 1 is an C 8 -C 24 alkyl, while R 2 , R 3 , R 4 , equal to or different from each other, are C 1 -C 6 alkyls; X - is an anion, preferably chloride ion or bromide ion. Particularly preferred are the alkyltrimethylammonium salts, such as, for example: cetyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, cetyltrimethylammonium chloride.
  • the non-ionic surfactant is preferably selected from: polyoxyethilene C 8 -C 24 -alkyl ethers, polyoxypropilene C 8 -C 24 -alkyl ethers, oxyethylene/oxypropilene copolymers C 8 -C 24 -alkyl ethers, polyoxyethylene C 6 -C 24 -alkylphenyl ethers, glucosides C 8 -C 24 -alkyl ethers.
  • the non-ionic surfactant is capable of increasing in a particularly effective way the wettability of the particles of boron carbide, slowing the sedimentation and promoting particles to be kept in suspension.
  • non-ionic surfactant is particularly effective to prevent the packing of the boron carbide on the bottom of the tank. Therefore, the use of such surfactant is advantageous both during the deposition step and in those steps wherein the plant does not work and so the solution is maintained at rest.
  • the amphoteric surfactant having zwitterionic hydrophilic groups, is preferably selected from: C 8 -C 24 -alkyl betaines, C 8 -C 24 -alkylamidopropyl betaines, C 8 -C 24 -alkylamphodiacetates, C 8 -C 24 -alkilamphodipropionates.
  • an amphoteric surfactant is preferably used because it provides the boron carbide particles with a charge, thus increasing the amount of said particles in the coating layer obtained by electrolytic deposition.
  • the surfactants at least partially fluorinated, preferably cationic, non-ionic or amphoteric surfactants, are particularly preferred. These generally have formula: Rf-Q-T where:
  • T can be selected from:
  • amphoteric surfactant has general formula wherein:
  • the non-ionic surfactant has general formula: Rf-Q-Y wherein:
  • the concentration of said at least one surfactant is preferably comprised between 0.01 g/l and 2 g/l, more preferably between 0.05 g/l and 1 g/l.
  • the aqueous solution has a pH from 0.5 to 4, more preferably from 1.5 to 3.
  • a strong acid is preferably added to the aqueous solution, in particular an aqueous solution of sulfuric acid.
  • a buffering agent may be advantageous, for example a boric/borate acid or acetic acid/acetate system.
  • the aqueous solution further comprises at least one detensioning agent, which has the function to reduce tensions which are generated within the coating mainly due to the presence of phosphorous, tensions which can cause a deterioration of the coating layer, with the formation of cracks and possible detachments thereof.
  • at least one detensioning agent which has the function to reduce tensions which are generated within the coating mainly due to the presence of phosphorous, tensions which can cause a deterioration of the coating layer, with the formation of cracks and possible detachments thereof.
  • the detensioning agents is preferably selected from: saccharin; thiocarbamic acid, possibly N or N,N' substituted by C 1 -C 4 alkyls, or derivatives thereof, such as salts or C 1 -C 4 esters, preferably N,N'-diethyl-carbamic acid or salts or esters thereof; thiocompounds (for example thiourea, ammonium sulphocyanide, potassium sulphocyanide).
  • the concentration of the detensioning agent is preferably comprised between 0.2 g/l and 10 g/l, more preferably between 4 g/l and 8 g/l.
  • the aqueous solution further comprises at least one complexing agent, which is preferably selected from the carboxilic acids or derivatives thereof, such as, for example: citric acid, lactic acid, malic acid, malonic acid, succinic acid, glycolic acid, or mixtures thereof.
  • the lactic acid is particularly preferred.
  • the concentration of the complexing agent is preferably comprised between 0.05 moles/l and 2 moles/l, more preferably between 0.5 moles/l and 1 moles/l.
  • the final coating has a high amount of phosphorous. Therefore, in such cases, it is preferable to work with a bath at high concentrations of phosphorous in the absence of the detensioning agent and/or of the complexing agent, as said agents generally tend to reduce the content of phosphorus in the bath, as well as reducing the deposition ratio.
  • the Applicant noted that the presence of boron carbide particles in the electrolytic bath affects the deposition ratio of the coating layer, thus causing a slowing of the rate at which said deposition occurs. Therefore, according to a preferred aspect, before carrying out the electrodeposition in the presence of boron carbide particles, the article is preventively coated with a first coating layer by electrodeposition in a first electrolytic bath consisting of an aqueous solution, free of boron carbide particles, comprising:
  • such deposition sequence enables a first fast deposition of the first layer free of boron carbide, while the second deposition, which is slower, enables to give the desired wear and corrosion resistance properties to the surface of the article.
  • an overall saving of time with respect to that one necessary for an single deposition in the presence of boron carbide, with evident advantages for the overall productivity of the process, is obtained.
  • said process can be carried out according to conventional modes, provided that a constant and homogeneous movement of the electrolytic bath is ensured, mainly in order to maintain in suspension the boron carbide particles without causing perturbations in the process of electrolytic deposition. Particularly, it is appropriate to avoid the formation of preferential routes for the flow of the suspension into the electrolytic bath, which could cause a lack of homogeneity in the coating layer.
  • the recycling system comprises at least one intake line of the bath provided with an intake head inserted into the tank, at least one supply line of the bath into the tank which leads into a distribution chamber delimited by an external wall of the tank and by an internal wall provided with passing holes through which the bath flows into the tank.
  • the passing holes are homogeneously distributed along the perimeter of the inner wall, thus making an intake of the bath into the tank as much as possible uniform, without generating preferential flows which would cause nonhomogeneity in the electrolytic deposition of the coating layer.
  • the intake head is preferably placed at a certain distance from the bottom of the tank, so as to avoid obstructions of the intake line, especially when the boron carbide particles are deposited on the bottom after a prolonged shutdown of the apparatus.
  • the recycling system comprises at least two supply lines of the bath into the tank, which lead into the tank in diametrically opposite positions, preferably at the same level in the tank and tangential with respect to the external wall, so as to make a rotary flow of the suspension into the tank.
  • the two supply lines lead into the lower part of the tank, in correspondence of the bottom, so that the inlet flows contribute to the mixing of boron carbide particles possibly settled on the bottom.
  • the recycling system comprises a third supply line placed in correspondence of a different level of the tank with respect to the two above-mentioned supply lines, preferably in the top of the tank, in order to make a better mixing of the suspension into the tank because of convective motions derived from liquid flows placed at several heights.
  • the process according to the present invention can be carried out within a wide range of temperatures, generally from 30°C to 90°C, preferably from 40°C to 70°C. Lower temperatures to the above-mentioned ranges would cause a reduction of the electrodeposition efficiency, while higher temperatures would have as a disadvantage an excessive evaporation of the electrolytic bath, with consequent inefficiency from the energetic point of view.
  • the electrolytic bath preferably has a pH value from 1 to 5, more preferably from 1.5 to 3.
  • the metal article to be coated is immersed in the the electrolytic bath, which acts as cathode, and an anode, preferably an insoluble anode, for example an anode selected from: anodes made of titanium platinized or coated with mix oxides; anodes made of stainless steel (for example AISI 316), possibly coated with a noble metal, for example gold or platinum; nickel anodes.
  • anode preferably an insoluble anode, for example an anode selected from: anodes made of titanium platinized or coated with mix oxides; anodes made of stainless steel (for example AISI 316), possibly coated with a noble metal, for example gold or platinum; nickel anodes.
  • the passage necessary to carry out the process of electrodeposition is obtained tank to the connection of the electrodes with a generator of continuous electric energy, so as to obtain a current density in the electrolytic bath generally comprised between 1 and 40 mA/cm 2 , preferably between 5 and 30 mA/cm 2 .
  • the process of electrodeposition is carried out for a time so as to obtain the desired thickness of the coating, which is generally comprised between 5 ⁇ m and 100 ⁇ m, more preferably between 10 ⁇ m and 40 ⁇ m.
  • the article thus coated is subjected to a heat treatment, at a temperature generally comprised between 250°C and 400°C, preferably between 300°C and 375°C, for a time variable within wide limits, for example between 1 and 24 hours, preferably between 6 and 18 hours.
  • the heat treatment mainly has the aim to form the Ni/P alloy, thus removing the hydrogen formed during the electrolytic process, so as to obtain a coating layer stable and homogeneous, thus minimizing defects and internal tensions.
  • the apparatus comprise an electrolytic tank (1), preferably cylindrical-shaped, and a system for recycling the electrolytic bath comprising at least one intake line (2) of the bath provided with one intake head (3) inserted into the tank (1), at least one supply line (4', 4" and 4"') of the bath into the tank (1) which leads into a distribution chamber (5), preferably present on the top of the tank (1), delimited by an external wall (6) of the tank (1) and by an internal wall (7) provided with passing holes (8) through which the bath flows into the tank (1).
  • the arrows in Figure 1 have the aim to show the direction of the flows of the electrolytic bath.
  • the apparatus comprises three supply lines of the electrolytic bath into the tank (1), a first one (4') placed in correspondence of the lower portion of the tank (1), a second one (4") placed at the same height and in the position diametrically opposite with respect to the first one (4'), and a third one (4"') placed in correspondence of the higher portion of the tank (1).
  • the combination of the three inlet flows has the function to create a movement of the electrolytic bath both in circular direction, along the internal wall (7), and in vertical direction, so as to increase the mixing and therefore the homogeneity of the suspension during the electrolytic process and minimizing the risk of flows with preferential directions.
  • the recycling system of the electrolytic bath is obviously provided with a pump (9) and a plurality of valves (10', 10") in order to put into pressure the supply and intake lines and suitably managing the flows of the electrolytic bath into the tank (1).
  • a water-based electrolytic bath (total volume: 200 ml) consisting of: NiSO 4 1.16 moles/l; H 3 PO 3 0.3 moles/l; lactic acid 0.5 moles/l; saccharin 1 g/l; non ionic surfactant 0.35 g/l; was prepared.
  • Boron carbide particles was added to the bath in an amount equal to 10 g/l, having average sizes equal to 0.4 ⁇ m.
  • the electrolytic bath had a pH value equal to 2.0.
  • the electrodeposition process was carried out into an apparatus as illustrated in Figure 1 , maintaining the electrolytic bath at a temperature of about 65°C.
  • the current density was maintained at a pH value of about 20 mA/cm 2 for three hours.
  • the coating was made on a steel plate, used as a cathode, while a titanium anode coated with mix oxides was used as an anode.
  • a coating layer of the plate having a thickness of about 120 ⁇ m, containing about 4% by weight of phosphorous, having Vickers hardness equal to 750 HV, is obtained.
  • a water-based electrolytic bath (total volume: 200 ml) consisting of: NiSO 4 1.16 moli/l; H 3 PO 3 1.0 moli/l; Lactic acid 0.5 moli/l; saccharin 1 g/l; non-ionic surfactant 0.35 g/l; was prepared.
  • Boron carbide particles were added to the bath in an amount equal to 10 g/l, having average sizes equal to 0.4 ⁇ m.
  • the electrolytic bath had a pH value equal to 2.0.
  • the electrodeposition process was carried out into an apparatus as illustrated in Figure 1 , maintaining the electrolytic bath at a temperature of about 65°C.
  • the current density was maintained to a value of about 20 mA/cm 2 for three hours.
  • the coating was made on a steel plate, used as a cathode, while a titanium anode coated with mix oxides was used as an anode.
  • a coating layer of the plate having a thickness of about 120 ⁇ m, containing about 12% by weight of phosphorous, having Vickers hardness equal to 450 HV, is obtained.
  • a water-based electrolytic bath (total volume: 200 ml) consisting of: Ni sulfamate 1.1 moles/l; H 3 PO 3 0.22 moles/l; Lactic acid 0.5 moles/l; saccharin 1 g/l; fluorinated non ionic surfactant 0.35 g/l; was prepared.
  • Boron carbide particles were added to the bath in an amount equal to 10 g/l, having average sizes equal to 0.4 ⁇ m.
  • the electrolytic bath had a pH value equal to 2.0.
  • the electrodeposition process was carried out into an apparatus as illustrated in Figure 1 , maintaining the electrolytic bath at a temperature of about 65°C.
  • the current density was maintained at a value of about 20 mA/cm 2 for three hours.
  • the coating was made on a steel plate, used as a cathode, while a titanium anode coated with mix oxides was used as an anode.
  • a coating layer of the plate having a thickness of about 60 ⁇ m is obtained, containing about 4% by weight of phosphorous, having Vickers hardness equal to 590 HV, is obtained.
  • ESEMPIO 4 high-P Ni/P alloy.
  • a water-based electrolytic bath (total volume: 200 ml) consisting of: Ni sulfamate 1.1 moles/l; H 3 PO 3 0.8 moles/l; Lactic acid 0.5 moles/l; saccharin 1 g/l; fluorinated non ionic surfactant 0.35 g/l; was prepared.
  • Boron carbide particles were added to the bath in an amount equal to 10 g/l, having average sizes equal to 0.4 ⁇ m.
  • the electrolytic bath had a pH value equal to 2.0.
  • the electrodeposition process was carried out into an apparatus as illustrated in Figure 1 , maintaining the electrolytic bath at a temperature of about 65°C.
  • the current density was maintained at a value of about 20 mA/cm 2 for one hour.
  • the coating was made on a steel plate, used as a cathode, while a 316 L stainless steel anode was used as an anode.
  • a double layer coating was made ( Figure 3 ), where the first layer was free of boron carbide particles, while the second layer contained boron carbide particles.
  • a first water-based electrolytic bath (total volume: 200 ml) consisting of a solution so called "high-ratio" and high-phosphorous, free of boron carbide particles, comprising: • phosphorous acid 100 g/L • nickel sulfate (NiSO 4 * 6H 2 O) 55 g/L • sulforic acid (H 2 SO 4 ) 30 g/L • sodium acetate (CH 3 COONa) 120 g/L • KI 10 g/L, was prepared.
  • the electrolytic bath was brought at a pH value equal to 3.0 with NaOH.
  • the electrodeposition process was carried out into an apparatus as illustrated in Figure 1 , maintaining the electrolytic bath at a temperature of about 60°C.
  • the current density was maintained at a value comprised in the range of 7-10 mA/cm 2 for one hour.
  • the coating was made on a steel plate, used as a cathode, while a pure nickel anode was used as an anode.
  • the first coating layer As far as the first coating layer is concerned, a deposition efficiency of 120 ⁇ m/h and a hardness of 750 HV were observed. However, after a heat treatment at 400°C for 1h, it was possible to obtain an enhanced hardness of said first layer equal to about 1100 HV. Furthermore, the coating layer obtained had a weight content of phosphorous equal to about 14%.
  • a second electrolytic bath (total volume: 200 ml) was prepared.
  • the electrolytic bath was brought at a pH value equal to 2.0 with an aqueous solution of H 2 SO 4 .
  • a suspension of boron carbide thus prepared was added to the aqueous solution.
  • 1 g/L of a fluorinated non-ionic surfactant was added to 10 g/L of boron carbide and the whole was subjected to stirring for 10 minutes and ultrasonic for 5 minutes.
  • 2 g/L of an amphoteric surfactant having functional groups containing fluorine were added to the mixture thus obtained and the whole was subjected under stirring for 10 minutes.
  • the electrodeposition process was carried out into an apparatus as illustrated in Figure 1 , maintaining the electrolytic bath at a temperature of about 80°C.
  • the current density was maintained at a value of 2 mA/cm 2 for one hour.
  • the coating was made in the same electrolytic cell of the first layer by using as a cathode that one coated with the first layer.
  • a deposition efficiency of the second layer between 10 and 30 ⁇ m/h and an hardness of said second layer of 900 HV were observed. However, after a heat treatment at 400°C for 1 hour, it was possible to obtain an enhanced hardness equal to about 1350 HV. Furthermore, the coating layer obtained has a weight content of phosphorous equal to about 7%.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Electroplating Methods And Accessories (AREA)
EP16171777.2A 2015-05-29 2016-05-27 Electrolytic process for coating metal surfaces to provide high wear resistance Withdrawn EP3098334A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ITUB2015A001322A ITUB20151322A1 (it) 2015-05-29 2015-05-29 Processo elettrolitico per il rivestimento di superfici metalliche allo scopo di conferire alta resistenza all’usura.

Publications (1)

Publication Number Publication Date
EP3098334A1 true EP3098334A1 (en) 2016-11-30

Family

ID=53901046

Family Applications (1)

Application Number Title Priority Date Filing Date
EP16171777.2A Withdrawn EP3098334A1 (en) 2015-05-29 2016-05-27 Electrolytic process for coating metal surfaces to provide high wear resistance

Country Status (2)

Country Link
EP (1) EP3098334A1 (it)
IT (1) ITUB20151322A1 (it)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017110276A (ja) * 2015-12-18 2017-06-22 石原ケミカル株式会社 不導態形成性の軽金属上への導電性皮膜形成方法
IT201700079843A1 (it) * 2017-07-14 2019-01-14 Metalcoating S R L Processo elettrolitico per il rivestimento di superfici metalliche allo scopo di conferire alta resistenza alla corrosione e all'abrasione.
WO2020083808A1 (de) * 2018-10-24 2020-04-30 Mahle International Gmbh Gaswechselventil

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0005890A2 (en) * 1978-06-06 1979-12-12 Akzo N.V. Process for depositing composite coatings containing inorganic particles from an electroplating bath
JPS6411998A (en) * 1987-07-01 1989-01-17 Riken Kk Wear resistant sliding member
US6109778A (en) * 1997-09-22 2000-08-29 United States Filter Corporation Apparatus for homogeneous mixing of a solution with tangential jet outlets
EP1067220A2 (en) 1999-07-06 2001-01-10 SBR S.r.l. Article plated with boron carbide in a nickel-phosphorus matrix, and process and bath for its preparation
US20110308958A1 (en) * 2009-03-13 2011-12-22 Ipt International Plating Technologies Gmbh Nickel-containing layer arrangement for intaglio printing

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0005890A2 (en) * 1978-06-06 1979-12-12 Akzo N.V. Process for depositing composite coatings containing inorganic particles from an electroplating bath
JPS6411998A (en) * 1987-07-01 1989-01-17 Riken Kk Wear resistant sliding member
US6109778A (en) * 1997-09-22 2000-08-29 United States Filter Corporation Apparatus for homogeneous mixing of a solution with tangential jet outlets
EP1067220A2 (en) 1999-07-06 2001-01-10 SBR S.r.l. Article plated with boron carbide in a nickel-phosphorus matrix, and process and bath for its preparation
US20110308958A1 (en) * 2009-03-13 2011-12-22 Ipt International Plating Technologies Gmbh Nickel-containing layer arrangement for intaglio printing

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
JI BO JIANG ET AL: "Electrodeposition and Hardness and Corrosion Resistance Propertie of Ni/Nano-B<sub>4</sub>C Composite Coatings", ADVANCED MATERIALS RESEARCH, vol. 399-401, 22 November 2011 (2011-11-22), pages 2055 - 2060, XP055245791, DOI: 10.4028/www.scientific.net/AMR.399-401.2055 *
Z. GUO ET AL: "Microstructure and wear resistance of electrodeposited RE-Ni-Mo-P-B 4 C-PTFE composite coating", MATERIALS SCIENCE AND TECHNOLOGY, vol. 20, no. 2, 1 February 2004 (2004-02-01), GB, pages 257 - 260, XP055245785, ISSN: 0267-0836, DOI: 10.1179/026708304225011270 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017110276A (ja) * 2015-12-18 2017-06-22 石原ケミカル株式会社 不導態形成性の軽金属上への導電性皮膜形成方法
IT201700079843A1 (it) * 2017-07-14 2019-01-14 Metalcoating S R L Processo elettrolitico per il rivestimento di superfici metalliche allo scopo di conferire alta resistenza alla corrosione e all'abrasione.
WO2019012496A1 (en) * 2017-07-14 2019-01-17 Metalcoating S.R.L. ELECTROLYTIC METHOD FOR COATING METALLIC SURFACES SO AS TO PROVIDE HIGH CORROSION AND ABRASION RESISTANCE
US11242608B2 (en) 2017-07-14 2022-02-08 Metalcoating S.R.L. Electrolytic processes for coating metal surfaces to provide high resistance to corrosion and abrasion
WO2020083808A1 (de) * 2018-10-24 2020-04-30 Mahle International Gmbh Gaswechselventil

Also Published As

Publication number Publication date
ITUB20151322A1 (it) 2016-11-29

Similar Documents

Publication Publication Date Title
US10662540B2 (en) Electrolyte for electroplating
KR20110106303A (ko) 수소-방출 캐소드로서 적합한 전극
US9644279B2 (en) Zinc-nickel alloy plating solution and plating method
EP3178968B1 (en) Copper-nickel alloy electroplating bath
EP3098334A1 (en) Electrolytic process for coating metal surfaces to provide high wear resistance
TWI452179B (zh) 金鍍覆液
JP6250663B2 (ja) 樹枝状構造を有するニッケル−コバルト被覆の電着プロセス
US2693444A (en) Electrodeposition of chromium and alloys thereof
JPH0246676B2 (it)
JP2009062577A (ja) ニッケルめっき浴
WO2018185154A1 (en) Method for electrolytically depositing a chromium or chromium alloy layer on at least one substrate
JP2007308801A (ja) ニッケル・コバルト・リン電気メッキの組成物及びその用途
US20040031694A1 (en) Commercial process for electroplating nickel-phosphorus coatings
Abdel Hamid et al. Electrodeposition and characterization of chromium–tungsten carbide composite coatings from a trivalent chromium bath
CN114622238B (zh) 一种过渡金属基析氢析氧双功能电极的制备及应用
Feng et al. Effect of ultrasonication on Ni–Mo coatings produced by DC electroformation
CN109023461A (zh) 组成调制的锌-铁多层涂层
RU2437967C1 (ru) Способ осаждения композиционных покрытий никель-ванадий-фосфор-нитрид бора
Lopes et al. Evaluation of formic acid and cyclohexylamine as additives in electrodeposition of Zn coating
Abd El Rehim et al. Electrodeposition of amorphous cobalt-manganese alloys on to steel from gluconate baths
EP3498888A1 (en) Electrode manufacturing method
JP5874107B2 (ja) 亜鉛−ニッケル合金めっき液並びにニッケル供給方法
JP4740528B2 (ja) ニッケル−モリブデン合金めっき液とそのめっき皮膜及びめっき物品
KR101173879B1 (ko) 니켈플래시 도금용 다기능성 과포화 슬러리 도금용액
Wehner et al. Electrochemical investigations on the influence of electrolyte composition of Watts baths with special regard to throwing power

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20170522

RBV Designated contracting states (corrected)

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

17Q First examination report despatched

Effective date: 20181016

17Q First examination report despatched

Effective date: 20181025

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20201201