Terminology for metallic coating， chemical treatment and related process
Some standard content:
National Standard of the People's Republic of China
Terminology for metallic coating, chemical treatment and related process GB/T 3138
Replacement of GB313882
This standard adopts the international standards ISO 2079-1981 Terminology for surface treatment and metallic coating - General classification and ISO 2080-1981 Electroplating and related technical vocabulary. 1 Subject content and scope of application
This standard specifies the definitions of terms for electroplating, chemical plating, chemical treatment, electrochemical treatment and related processes. This standard applies to the terms used in electroplating, chemical plating, chemical treatment, electrochemical treatment and related processes. 2 Basic concepts
2.1 Chemical corrosion Corrosion caused by chemical reaction of metals and non-metals in electrolyte solutions, dry gases and high temperatures. 2.2 Electric double layer Electric double layer The double layer formed when the charged particles are unevenly distributed between the two electrodes or the external power source charges the interface, resulting in the residual charge being concentrated on both sides of the interface.
2.3 Bipolar electrode Bipolar electrode is not connected to the external power source in reverse but is placed between the cathode and the anode. In the electrolytic wave, the side facing the anode acts as the cathode, and the side facing the cathode acts as the anode. 2.4 Thruwing capacity
Under certain conditions, the ability of the bonding liquid to make the distribution of the ammonium layer on the electrode (usually the cathode) more uniform than the initial current distribution. For the anodic deposition process, the definition is similar.
2.5 Decomposition potential The minimum potential (excluding the ohmic voltage drop of the falling liquid) that can make the electrochemical reaction continue at a significant rate. 2.6 Insoluble anode (inert anode) Anode that does not undergo anodic dissolution reaction when an insoluble current passes through it. 2.7 Electrochemical clecLrochcmistry
The science of studying the mutual transformation of chemical energy and electrical energy and the phenomena related to this process. 2.B Electrochemical polarization (activation polarization) activationpalarization Polarization caused by the slow charge transfer step on the electrode: 2.9 Electrochemical corrosion ekirur:herical corrosion The process of metal oxidation due to electrochemical reaction when the metal is in an electrolyte solution or the metal surface is covered with a liquid film. 2.10 Electrochemical erjuivalt State Administration of Technical Supervision 19950727 approved
1996-07-01 implementation
GB/T 3138—1995
When a unit amount of electricity (such as 1Ah. or 1C) passes through the electrode, the mass of the substance produced or consumed by the electrochemical reaction with 100% current efficiency is called the electrochemical equivalent of the relevant substance, usually expressed in g/C or g/Ah. Conductivity (specific conductivity) conductivity2. 11
The conductivity of a conductor per unit cross-sectional area and per unit length, usually expressed in S/m. 2.12 Electrophoresis
The migration of charged colloidal particles in a liquid medium relative to the liquid under the action of an external electric field. 3 Electromotive forceekcctrutnotiveforre
The potential between the two electrodes when the primary cell is open circuit: 2.14 Passivation potentialpassivationpotentialThe potential at which the metal anode electrolysis rate suddenly decreases when the metal electrode is anode polarized. Usually the corrosion current experiences a maximum value before reaching the passivation potential:
2. 15 Corrosion potentialcorrcasion potentialThe stable electric potential spontaneously established by metal materials in a specific corrosion environment. 2.16 Current density currentdensity
The current intensity passing through the electrode per unit area, usually expressed in A/dm\: 2.17 Current efficiency currcnt efficiency The ratio of the actual mass of the electrode reaction product to the electrochemical equivalent when a unit amount of electricity passes through the electrode, usually expressed in %. 2.18 Corrosion rate (v..), corrsian urrent (Corrosion reverse rate is the amount of material transformation per unit time on a specific surface of a material. Or according to Faraday's law, the corrosion rate is the current under the corrosion potential.
Corrosion current is
Io =nFVer
where; r—electrode reaction number;
\——Faraday constant;
w——corrosion rate.
2.19 Electrode
A conductor placed in a conductive medium (such as an electrolyte, a melt, a solid, or a gas). Current flows into or out of the conductive medium through it. 2.20 Electrode potential clcetrucdt putnitialUnder standard conditions, a certain electrode and a standard hydrogen electrode (as the negative electrode) form a primary cell. The measured electromotive force is called the standard hydrogen electrode potential of the electrode, or simply the electrode potential. The standard hydrogen electrode potential of an electrode can indicate the relative magnitude of the potential difference between the electrode and the solution interface.
2.21 Electrolyte
A substance that has ionic conductivity or can exhibit ionic conductivity under certain conditions (such as melting at high temperature or dissolving in a solvent to form a solution).
2.22 Electrolyte Solutiun County is a solution with ionic conductivity.
2.23 Degree of ionization The ratio of the number of Coulombs in the electrolyte in the form of ions to the total number of Coulombs. Usually expressed as %. 2.24 Depolarization
The phenomenon that the polarization of the electrode is reduced by adding a certain depolarizer to the electrolyte solution or electrode. 2.25 Equilibrium electrode potential The electrode potential at which the electrode reaction is in thermodynamic equilibrium. 2.26 Positive electrode
GB/T3138—1995
The electrode with the more positive potential in the two electrodes of the primary cell. 2. 27 Negative electrode The electrode with the more negative potential in the two electrodes of the primary cell. 2-28 Cathole
The electrode where the reduction reaction occurs, that is, the electrode where the reactant gains electrons. 2.29 Cathodic polarization polarizalion The phenomenon that the electrode potential of the cathode shifts to the negative direction when current passes through. 2.30 Cathodic coating A metal coating with a higher electrode potential than the base metal. 2.31 Cathodic
The electrode where oxidation reaction occurs, that is, the electrode that can accept electrons given by the reactants. 2.32 Anodeslime
The insoluble residue produced during the anodic dissolution process under the action of current. 2.33 AnodicPolarizatiorl The phenomenon that the electrode potential of the anode shifts to the positive direction when current passes through. 2.34 Anodic coating
A metal coating with a higher electrode potential than the base metal. 2.35 Transport number The ratio of the current carried by the base ion in the solution to the total current passing through when the electrolyte solution flows is called the transport number of the ion. 2.36 Overpotential uvcrpotential
The difference between the electrode potential and the thermodynamic half-equilibrium electrode potential when current flows through the electrode. 2.37 Diffusion layerwwW.bzxz.Net
A thin layer of solution with a concentration gradient near the electrode surface when current flows through. 2.38 Stray current straycurrcnt
The current flowing in other circuits (such as key slots or heaters, etc.) other than the circuit that needs to pass the current. 2. 39
Conductive salt
Salt substances added to the electrolyte to increase the conductivity of the solution. 2.40 Volutne current density The intensity of the current passing through a unit volume of electrolyte solution. Usually expressed in A/L. Deposition rate
The thickness of the metal deposited on the surface of the plated piece per unit time. Usually expressed in um/h. 2.42initial current distributionipritnarycurrentdistributionThe distribution of current on the electrode surface when there is no electrode polarization. 2.43iocalcarrosion
The phenomenon that the corrosion is mainly concentrated in the local area of the surface, while other parts are almost not corroded. 2.44polarizalion
The phenomenon that the electrode potential deviates from its equilibrium value when current passes through the electrode. 2.45polariznbiliy
The rate of change of electrode potential with current density, which is equivalent to the change of electrode potential caused by changing unit current density. 2.46polarizationcurvepolarizationcurveThe curve describing the relationship between electrode potential and current density passing through the electrode. 2.47interelectrodedistanceThe distance between two electrodes (positive and negative or cathode and anode) in a primary cell or electrolytic cell. 2.48 Emulsification
CB/T 3138—1995
The phenomenon that one liquid is dispersed in another liquid in very small droplets. 2.49 Stress corrosion stress corroston The cracking phenomenon of metal materials under the combined action of stress and corrosive environment. 2.50 Gassing
The phenomenon of obvious gas evolution during electrolysis. 2.51 Activation
The use of adjusting the effective ion concentration to achieve ideal behavior to eliminate the passivation state of the electrode surface. 2.52 Activity
The thermodynamic concentration of the components in the solution under standard conditions, that is, the effective concentration used to correct the deviation between the real solution and the ideal solution properties.
2.53 Standard electrode potential Ixrential Under standard conditions, the equilibrium potential at which the activities (or fugacity) of all reactants and products in an electrode reaction are equal. 2.54 Concentration polarization Polarization The polarization caused by the change in the concentration of reactants or products near the electrode surface when current passes through the electrode. 2.55 Passivation When the metal anode is polarized to a certain value in a certain solution, the metal dissolution rate does not increase, but decreases violently. This process of converting the metal from an "active state" to a "passive state" is called passivation. The passivation caused by anode polarization is called electrochemical passivation, while the passivation caused by the action of certain passivators in the solvent is called chemical passivation. 2.56 Pitting corrosion Pitting corrosion on the metal surface. Complex compound Metal ions or atoms form a compound with coordination bonds with a certain number of negatively charged energy groups or polar molecules in the electrolyte. 2. 58 Double salt
A compound formed by two salts in a certain proportion. It is essentially a coordination compound in the form of crystals: Hydrogen embrittlement
The metal or alloy absorbs hydrogen atoms and may be susceptible to stress. 2.60 Reepage hyrtrogen
Metal parts often absorb hydrogen atoms during corrosion, degreasing, and electroplating. 2.61
Interfacial tension
The force between two phases that causes the interface to shrink is called interfacial tension. If one of the phases is gas, it is called interfacial tension. 2.62 Critical current density currentdensity The maximum or minimum current density that can maintain the reaction within the potential range of the electrode reaction required for electroplating. When the maximum current density is greater than or equal to the maximum current density, the potential moves beyond the required range and new side reactions will occur. When the current density is less than or equal to the minimum current density, the electrode reaction rate decreases and cannot meet the production requirements.
2.63 Half-cell lalf cell1
A system formed by a single electrode and an electrolyte solution. 2.64 Galvanic cell
A device that can directly convert chemical energy into electrical energy. A galvanic cell can be regarded as a combination of two half cells. 2.65 Salt bridge salt bridge connects two halves of the cell and is used to reduce the potential of the liquid junction. It is usually a potting tube containing a high concentration of electrolyte solution (such as KCl and HCl).
2.66 pH value pI value
GB/T 3138-1995
The negative value of the common logarithm of the oxygen ion activity ni (or approximately the concentration). That is, pI = -lngai+. 2.67 Basis: material (substrate) on which metal can be deposited or a film can be formed. 2.68 Auxiliary annde Auxiliary annde used to improve the current distribution on the surface of the plated part. 2.69 Auxiliary cathode cathode
A cathode of a certain shape is added to a certain part of the workpiece where the current is concentrated to avoid defects such as burrs and burns. This additional cathode is sufficient as an auxiliary cathode.
cuntaet potential
2.70Contact potential
The potential difference generated at the interface when two different conductive materials come into contact. Intermerurystullinecorrosion2.71
Selective corrosion along the grain boundary. 2.72Solubility product product The product of the concentrations of the corresponding ions in a saturated solution of a sparingly soluble electrolyte at a certain temperature, the ratio of which is the same as its coefficient in the equation for the dissociation of the electrolyte. 2.73 Solubility The maximum number of grams of a substance that can be dissolved in 1 μg of solvent at a certain temperature and pressure. 2.74 Microcovering power The ability of metal ions in an electrolyte to be deposited in pores or scratches under certain conditions. 2.75 Tank potential The total potential between the two electrodes of a unit electrolytic cell during electrolysis. 2.76 Static electrode potential The electrode potential of a metal electrode in an electrolyte when no external current passes through it. 2.77 Chelate A coordination compound with a ring structure formed by the multi-position coordination of a central ion and a ligand. 2.78 Elevcling 2.79 Covering power
The ability of the plating solution to deposit metal to cover the entire surface of the plated part under specific electroplating conditions. 2.80 Sigrifleant surface The specified surface on the part before and after electroplating. The coating on this surface is extremely important for the appearance and (or) performance of the part. 2.81 Striking current The instantaneous high current passing through the electroplating process. 3 Plating methods
3.1 Chemical vapor deposition The process of producing a deposited layer by heat-induced chemical reaction or hot gas vapor reduction and condensation of the substrate. 3.2 Physical vapor deposition The process of depositing a micro-covering layer by evaporating and subsequently condensing a single substance or compound, usually in a high vacuum. 3.3 Chemical passivation ChemicalPpassivation The process of treating metal parts with a solution containing an oxidant to form a thin passive protective film on their surface. 3.4 Chemical oxidation Chemical oxidation The process of forming an oxide film on metal parts through chemical treatment. 3.5 Anodizing
CB/T 3138--1995
The process of electrolyzing metal parts as anodes in a certain electrolyte to form an oxide film with certain functions (such as protection, decoration or other functions) on their surfaces. 3.6 Chemical plating (white catalytic plating) Autocalytic plating The process of catalytic reduction of metal ions in the plating solution to form a metal coating on the surface of the activated substrate. 3.7 Laser electroplating Laser electroplating Electroplating under the action of laser.
3. Flash plating Flashplate Electroplating that produces a thin coating in a very short time. 3.9 Electroplating
The process of forming a uniform, dense, well-bonded metal or alloy deposit on the surface of a workpiece by electrolysis. 3.10 Mechanical plating In the presence of fine metal powder and suitable chemical reagents, a hard small ball is used to hit the metal surface so that the fine metal powder covers the surface.
3.11 Immersion plate
Metal deposits produced by the substitution reaction of one metal replacing another metal from the solution. For example: Fn-I tu*-+Cu+Fe2+
2 Electroforming
The process of making or replicating metal products (which can separate the mold and the metal deposit) by depositing metal on the mold by electrolysis. 3.13
Superimpoaed curtent electroplating Electroplating in which pulse current or alternating current is superimposed on direct current. 3.14 Bright plating
Electroplating with a glossy coating directly obtained from the plating bottle under appropriate conditions. 3.15 Alloy plating
The process of co-depositing two or more metals (including non-metallic elements) under the action of electric current. 3.16 Multilayer plating
Electroplating of several metal layers with different properties or materials on the same substrate. 3.17 Impact plating, strike plating
The method of depositing a thin metal layer in a short time at a high current density in a specific solution to improve the bonding force between the subsequently deposited coating and the substrate.
Metalelertrodeposilion
3.18 Metal electrodeposition
The process of reducing metal ions in the solution on the electrode to form a metal phase with the help of electrolysis. Including electroplating, electroforming, electrolytic refining, etc. 3.19 Brush plating
A method of selective electroplating using an electrode or brush connected to the anode and capable of providing the electrolyte required for electroplating, moving over the workpiece as the cathode.
3.20 Periodic reverx: planing
Electroplating in which the direction of the current changes periodically.
3.21 Conversion coating
A surface film containing a metal compound formed by chemical or electrochemical treatment of a metal, such as an acid salt film on zinc or radium or an oxide film on steel.
3.22 Rack plating
Electroplating using a mixing tool to hang a workpiece.
3.23 Composite plating (also called bulk plating) coniposite plating GB/T 3138—1995
The process of simultaneously depositing metal ions and insoluble non-metallic or other metal particles uniformly floating in the solution to form a composite coating by electrochemical or chemical methods.
3.24 Pulse plating
The process of electroplating using pulse power instead of direct current power. 3.25 Bluing (chemical oxidation of steel) blucing (chenical oxide) The process of heating steel parts in air or immersing them in an oxidizing solution to form a blue (black) oxide film on their surface. 3.26 High speed electroplating The process of electroplating under high cathode current density by adopting special measures to obtain a high deposition rate. 3.27 Barrel plating
The parts are electroplated in a rotating container, suitable for small parts. 3.28Plastics electroplating The process of electroplating a metal coating on a plastic part. 3.29Phosphaling
The process of forming a layer of insoluble phosphate protective film on the surface of steel. 4Pre-plating and post-plating treatment
4.1Pre-plating treatmentPrupluting
Various pre-plating technical treatments to expose the true surface of the material of the part and eliminate internal stress and other special purposes such as removing oil, oxides and internal stress.
4.2Positive plating
Post-plating technical treatment (such as passivation, hot melting, sealing and dehydrogenation, etc.) to enhance the protective performance, decorativeness and other special features of the plated parts.
4.3Chemical polishingThe process of treating metal parts in a certain solution to obtain a smooth and bright surface. 4.4 Chemical degreasing Alkaline degrcasing The process of removing surface dirt from a workpiece in an alkaline solution by chemical and emulsification. 4.5 Electropolishing Electropolishing The process of anodic polarization of metal parts in a suitable solution to make the surface smooth and bright. 4.6 Electrolytic degreasing Electrolytic degreasing The process of electrolyzing metal parts in an alkaline solution as anode or cathode to remove oil stains from the surface of the workpiece. 4.7 Electrolytic pickling Electrolytic pickling The process of electrolyzing metal parts in an electrolyte solution as anode or cathode to remove oxides and rust from the surface of the workpiece. 4.8 Bright dipping The process of immersing metal parts in a solution for a short time to form a bright surface. 4.9 Mechanical polishing The process of mechanical processing to improve the flatness and brightness of the surface of metal parts by using a high-speed rotating polishing wheel with a polishing kidney. 4.10 Solvent degreasing Solvent degreasing The process of removing oil stains from the surface of a workpiece using an organic quenching agent. 4.11 Bright pickling The process of removing oxides or other compounds on the surface of metal parts by chemical or electrochemical methods to make them bright. 4.12 Roughening The process of making the surface of the parts microscopically rough by mechanical or chemical methods, so that it changes from lyophilic to lyophilic, so as to improve the bonding force between the coating and the surface of the parts. 4.13 Sensitization The roughened conductive parts are immersed in the sensitizing solution to make them absorb reducing substances on the surface, so that when the activation treatment is carried out later, the precious metal ions can be reduced on the surface of the parts to form an "activation layer" or "catalytic film", thereby accelerating the chemical bond reaction process.
4.4Amalgamation (Hulue Dip) is the process of immersing metal parts such as copper or alloys in a salt solution to make the surface of the parts smooth. 4.15Brushing
is the process of using a rotating metal or non-metallic brush wheel (or brush) to remove the residual attachments on the surface of the parts and make the surface present a certain finish.
4.16Crewulsiwndegreasing is the process of removing oil stains on the surface of parts by using a liquid containing organic solvents, water and emulsifiers. 4.17Removal of Hydrogen (Decmbrittlement) is the process of heating metal parts at a certain temperature or using other treatment methods to remove the hydrogen absorbed in the metal. 4.18Annealing
is a heat treatment process in which the plated parts are heated to a certain temperature, kept for a certain period of time, and then slowly cooled. Annealing can eliminate the absorbed hydrogen in the coating, reduce the stress in the coating, and thus reduce its brittleness; it can also change the grain state or phase structure of the coating to improve the mechanical properties of the coating or give it certain electrical, thermal or other properties. 4.19 Countercurrent rinsing A multi-pass cleaning process in which the running direction of the workpiece and the flow direction of the cleaning water are mutually opposite. 4.20 Sealing After anodizing of aluminum parts, in order to reduce the porosity of the oxide film formed by anodizing, physical and chemical treatments are carried out in aqueous solution or steam medium, the purpose of which is to increase the anti-fouling ability and corrosion resistance of the anodized coating, improve the durability of the coating coloring or give it other required properties.
4.21 Dyeing power
The adhesion ability of dyes on anodized films or coatings 4.22 Stripping
The process of stripping the coating on the surface of the workpiece.
4.23 Thermal diffusion
The process of heating the plated part to diffuse the base metal and the deposited metal (one or more) to form an alloy layer. 4.24 Hot melting
The process of heating the plated part at a temperature slightly higher than the melting point of the plated metal to melt the bond layer surface and re-solidify it in order to improve the appearance and chemical stability of the coating such as tin or tin-lead alloy. 4.25 Colouring
The process of allowing organic or inorganic dyes to adsorb on the porous anodic oxide film to present various colors. 4.26 Decolorization
The process of removing the color from the colored oxide film with a decolorizer. 4.27 Shot peening
The process of spraying the metal surface with hard and small balls, such as metal shots. Its function is to pressurize and strengthen the surface, making it hard or have a decorative effect.
4.28 Sandblasting
The process of spraying sand stream to impact the surface of the workpiece to achieve decontamination, rust removal or roughening. Sprayrinsing
The process of using a spray of fine liquid stream to rinse the workpiece to improve the cleaning effect and save water. 4.30 Ultrasonic cleaning GB/T313B-1995
The method of using ultrasonic cleaning solution to more effectively remove oil and other impurities on the surface of the workpiece. 4.31 Weak etching
The process of immersing metal parts in a certain solution before electroplating to remove the extremely thin oxide film on the surface and activate the surface. 4.32 Pickling
The process of immersing metal parts in an etching solution of higher concentration and certain temperature to remove oxides, rust and other substances on them. 4.33 hi sr.tin finish
The process of treating the surface of a part to form a reflective layer. The treated surface has a satin-like non-mirror-like luster. 4.34 beurrrl burnishirg
The process of placing the part in a rotating container containing abrasive and tumbling liquid for tumbling. 4.35
grinding
The machining process of polishing a metal part with a wheel containing a wall material to improve the surface flatness of the part. 5 Materials and Equipment
5.1 Softening of water The process of removing (Mg-) plasma from water to reduce its hardness. 5.2 Busbars
Copper or lead bars connecting the rectifier (or DC generator) and the plating tank for conducting electricity. 5.3 Anode bag
Cotton or synthetic fabric bag placed on the anode to prevent anode sludge from entering the solution. 5.4 Brightening agent Agent (brightener) Additives added to the plating solution to form a bright coating. 5.5 Filteraid
To prevent the filter from over-filling and make the filtration go smoothly, insoluble additives with different degrees of fineness are used. 5.6 Inhibitor
Substances that can reduce the rate of chemical or electrochemical reactions, such as corrosion inhibitors used in strong etching. Surfactant surfaceactiveagent (surfactant) 5.7
Substances that significantly reduce the strength of the interface, commonly used as detergents, wetting agents, emulsifiers, softening agents, foaming agents, etc. 5.8 Emulsifying agent cmulsifying agent (emulsifier) A substance that can reduce the interfacial tension between different liquids and form an emulsion. 5.9 Complexant
A substance that can combine with metal ions or atoms to form a coordination compound. 5.10 Insulation inulaterlbayer (resin) A layer that is applied to an electrode or a part of it to make the surface of that part non-conductive. 5.11 Plating rack A tool used to hold and hang parts so that they can be placed in a tank for electroplating. Other treatments: Wetting agent
A substance that can reduce the interfacial tension between the workpiece and the solution, making the surface of the workpiece easily wetted by the solution. 5.13 Centrifuge
Equipment that uses centrifugal force to dehydrate and dry the workpiece. 5.14 Additive agtnt (additiv) A small amount of additive added to the plating solution to improve the electrochemical properties of the plating solution and improve the quality of the plated layer. 5.15 Buffering agent
GB/T 31381995
A substance that can keep the pH of the solution basically constant within a certain range. 5.16 Swept cathode
A cathode that is connected to the plated workpiece and the pole to make periodic reciprocating movements. 5.17 Diaphragm
A porous membrane or semipermeable membrane that separates the anode and cathode regions of the electrolysis. 5.18 Cheleiting agent A substance that can combine with metal ions to form chelates. 5.19 Keiling agent
An additive that can improve the microscopic flatness of the substrate surface during the electroplating process to obtain a flat and smooth coating. 5.20 Rectifier
A device that directly converts alternating current into alternating current. 6 Scratch test and inspection
6.1 Atmospheric corrosion test A test to test the atmospheric corrosion resistance of the coating in different climate zones according to the specified force method. 6.2 Neutral salt spray test (NSS test) Neutral altypray test (NSS-test) The corrosion resistance of the coating is tested by the specified neutral salt spray test. 6.3 Discontinuous water film
The phenomenon that the water film on the surface of the workpiece is discontinuous due to uneven wettability caused by pollution. This is a method to check the degree of cleaning.
6.4 pH meter pH meter
An instrument for measuring the pH value of a solution.
6.5 Porosity
The number of pinholes per unit area.
6. 6 Internal stress In the electroplating process, various reasons cause the change of the crystal structure of the coating, causing the coating to be stretched or compressed. However, because the coating has been fixed on the substrate, the coating is under stress. This internal force acting on the coating is called internal stress. 6.7 Conductivity gauge An instrument for measuring the conductivity of electrolyte solution. 6.8 Coulombmeter An instrument for measuring the amount of electricity passing through the electrode according to the mass product (towards gas) of the precipitate on the electrolytic process. 6.9 Rotating disk electrode An electrode for measuring the diffusion coefficient and electrochemical parameters of the liquid system. It is a metal rod embedded in a concentric plastic cylinder. The bottom surface of the metal rod is the working surface of the electrode. The electrode is connected to the rotating shaft of the rotating motor and is fixed on a stable frame as a whole. The working surface of the electrode is perpendicular to the rotating shaft, and its center is opposite to the center of the rotating shaft. In this way, when the electrode rotates, the phase close to the working surface of the electrode establishes a uniform and stable protective layer with a thickness related to the rotation speed.
6.10 Rotating ring disk electrode The ring disk electrode is an electrode with a concentric ring mounted on the working surface of the disk electrode. The ring and the two disks are separated by a thin layer of insulating material. The ring electrode is used to detect soluble reaction products on the disk electrode. The ring disk electrode is also a commonly used electrode for electrochemical testing. 6.11 Pinholes
Microscopic holes that penetrate from the surface of the coating to the bottom of the coating or the base metal. Copper arceleraled alt spray (CASS test) 6.12
An accelerated corrosion test conducted using a sodium chloride aqueous solution containing a specified caustic soda and acetic acid as a spray: 6.13 Reference electrode GB/T 3138 - 1995
Equilibrium electrode potential is very stable and highly reversible half-cell: it can form a primary cell with the other half-cell to determine the electrode potential of the latter.
6.14H mercury electrodecalomel electrode is a half-cell composed of mercury, mercurous chloride and potassium fluoride solution of a certain concentration (e.g. saturated solution). 6.15 solderability
The ability of the coating surface to be wetted by molten solder. 6.16 Hardness
The ability of a coating to resist scratching or pressing on its surface by other objects is an important mechanical property of the coating. Depending on the determination method, hardness can be expressed by non-return values, such as Brinell hardness, Luther hardness, Vickers hardness, Shore hardness and Knoop hardness. Hardness is usually measured by a microhardness tester.
6.17 Tarnish
The change in color of a metal or coating surface caused by corrosion, such as darkening, discoloration, etc. 6.18 Drapping corrosion testA test method that allows a specific corrosion solution to be controlled on the surface of a sample to test the corrosion resistance of the protective layer on the surface of the sample. 6.19 Glax electrode
An electrode that uses a thin glass film to isolate two solutions to generate a potential difference and is used to measure the pH value of the solution. 6.20 Adhesion
The degree of bonding strength between a coating and a substrate material, which can be expressed by the force required to separate the coating from the substrate. 6.21 Haring cell
A rectangular cell made of insulating material, with the cathodes in the cell corresponding to the two cathodes at the far and near ends, used to estimate the dispersibility of the plating solution and the degree of electrode polarization.
6.22 Potentiostatic method In order to obtain the relationship curve between electrode potential and current density, the electrode potential of the research electrode can be controlled to change according to a certain rule, and the corresponding current density can be measured at the same time. 6.23 Galvanostatic method In order to obtain the relationship curve between current density and electrode potential, the current density of the research electrode can be controlled to change according to a certain rule and the corresponding electrode potential can be measured at the same time. 6.24 Alternating current method.cmethoxl
A method of obtaining certain parameters of the electrode process from the response of the electrode potential by exciting the electrode with a small amplitude sinusoidal alternating current. 6.25
Dendritestre
A rough, loose, dendritic or irregularly protruding deposit formed on the cathode (especially at the edges and other high current density areas) during electroplating.
6. 26 Brittleness
The degree of deformation that the coating can withstand, which is mainly determined by the coating material and its internal stress. 6. 27
Peeling
The phenomenon of the coating detaching from the substrate in a flake-like manner.
Blistering
A concave defect in the electroplated layer caused by the loss of bonding between the coating and the base metal. 6.29
spalling
fragmentation or shedding of the plated surface layer due to some reason (e.g. uneven thermal expansion or contraction). 6.30 orange peel
surface treatment layer with a wavy appearance similar to that of chair leather, GB/T 3138
6.31 ion selective electrode an electrode whose potential varies with specific ions and concentrations. 6.32 sponge depusit a loose and porous deposit that is not firmly bonded to the substrate material. 6.33 burnt deposit
a dark, rough, loose, poor quality deposit formed under excessive current density, which often contains oxides or other substances. 6.34 pits
small pits formed on the plated surface due to various reasons during the electroplating process. whiskers
filamentous growths of metal coatings. Usually microscopic, sometimes formed during the electroplating process, sometimes generated during storage or use after treatment.
Corrosion test
A method of accelerated corrosion test in which the corrosive agent is made into a substitute and applied to the coating. 6.37 Hall cell
A trapezoidal groove with a certain size ratio. It is used to conduct a plating test to observe the quality of the coating under different current densities and study the influence of various factors on electroplating:
5.38 Spectro-electruxhemical method Spectro-electruxhemical method combines spectroscopic methods with conventional electrochemical methods. It is a new technology for in-situ characterization of molecular species related to electrochemical processes and studying the microstructure of electrode interfaces at the molecular level.38 Spectroscopic-electruxhemical method is a new technology that combines spectroscopic methods with conventional electrochemical methods. It is a new technology for in situ characterization of molecular species involved in electrochemical processes and studying the microstructure of electrode interfaces at the molecular level.38 Spectroscopic-electruxhemical method is a new technology that combines spectroscopic methods with conventional electrochemical methods. It is a new technology for in situ characterization of molecular species involved in electrochemical processes and studying the microstructure of electrode interfaces at the molecular level.
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