Nickel electroplating
Encyclopedia
Nickel electroplating is a technique of electroplating
a thin layer of nickel
onto a metal
object. The nickel layer can be decorative, provide corrosion
resistance, wear
resistance, or used to build-up worn or undersized parts for salvage purposes.
, cleaning, masking, pickling
, and etching may be used. Once the piece has been prepared it is immersed into an electrolyte
solution and is used as the cathode
. The nickel anode
is dissolved into the electrolyte in form of nickel ion
s. The ions travel through the solution and deposit on the cathode.
s and motorcycle
s. Other applications include hand tool
s and household items such as lighting
and plumbing fixture
s, wire racks, and appliances
.
Engineering nickel is used where brightness is not desired. Non decorative applications provide wear and corrosion protection as well as low stress build ups for dimensional recovery.
Electroplating
Electroplating is a plating process in which metal ions in a solution are moved by an electric field to coat an electrode. The process uses electrical current to reduce cations of a desired material from a solution and coat a conductive object with a thin layer of the material, such as a metal...
a thin layer of nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
onto a metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
object. The nickel layer can be decorative, provide corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
resistance, wear
Wear
In materials science, wear is erosion or sideways displacement of material from its "derivative" and original position on a solid surface performed by the action of another surface....
resistance, or used to build-up worn or undersized parts for salvage purposes.
Overview
Nickel electroplating is a process of depositing nickel on a metal part. Parts to be plated must be clean and free of dirt, corrosion, and defects before plating can begin. To clean and protect the part during the plating process a combination of heat treatingHeat treatment
Heat treating is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass...
, cleaning, masking, pickling
Pickling (metal)
Tarnision is a metal surface treatment used to remove impurities, such as stains, inorganic contaminants, rust or scale from ferrous metals, copper, and aluminum alloys. A solution called Tarnision liquor, which contains strong acids, is used to remove the surface impurities...
, and etching may be used. Once the piece has been prepared it is immersed into an electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
solution and is used as the cathode
Cathode
A cathode is an electrode through which electric current flows out of a polarized electrical device. Mnemonic: CCD .Cathode polarity is not always negative...
. The nickel anode
Anode
An anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID ....
is dissolved into the electrolyte in form of nickel ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
s. The ions travel through the solution and deposit on the cathode.
Watts
Watts nickel plating baths can deposite both bright and semi-bright nickel. Bright nickel is typically used for decorative purposes and corrosion protection. Semi-bright deposits are used for engineering nickel where a high luster is not desired.| Chemical Name | Formula | Bright | Semi-bright |
|---|---|---|---|
| Nickel sulfate | NiSO4·6H2O | 20–40 oz/gal | 30–40 oz/gal |
| Nickel chloride | NiCl2·6H2O | 8–20 oz/gal | 4–6 oz/gal |
| Boric acid Boric acid Boric acid, also called hydrogen borate or boracic acid or orthoboric acid or acidum boricum, is a weak acid of boron often used as an antiseptic, insecticide, flame retardant, as a neutron absorber, and as a precursor of other chemical compounds. It exists in the form of colorless crystals or a... |
B(OH)3 | 5–7 oz/gal | 5–7 oz/gal |
Nickel sulfamate
Sulfamate nickel plating is used for many engineering applications. It is deposited for dimensional corrections, abrasion and wear resistance, and corrosion protection. It is also used as an undercoat for chromium.| Chemical name | Formula | Bath concentration |
|---|---|---|
| Nickel sulfamate | Ni(SO3N2)2 | 40–60 oz/gal |
| Nickel chloride | NiCl2·6H2O | 0–4 oz/gal |
| Boric acid | B(OH)3 | 4–6 oz/gal |
All-chloride
All-Chloride solutions allow for the deposition of thick nickel coatings. They do this because they run at low voltages. However, the deposition has high internal stresses.| Chemical name | Formula | Bath concentration |
|---|---|---|
| Nickel chloride | NiCl2·6H2O | 30–40 oz/gal |
| Boric acid | B(OH)3 | 4–4.7 oz/gal |
Sulfate-chloride
A Sulfate-Chloride bath operates at lower voltages than a Watts bath and provide a higher rate of deposition. Although internal stresses are higher than the Watts bath they are lower than that of an all-chlorine bath.| Chemical name | Formula | Bath concentration |
|---|---|---|
| Nickel sulfate | NiSO4·6H2O | 20–30 oz/gal |
| Nickel chloride | NiCl2·6H2O | 20–30 oz/gal |
| Boric acid | B(OH)3 | 4–6 oz/gal |
All-sulfate
An all-sulfate solution is used for electro-depositing nickel where the anodes are insoluble. For example, plating the insides of steel pipes and fittings may require an anode.| Chemical name | Formula | Bath concentration |
|---|---|---|
| Nickel sulfate | NiSO4·6H2O | 30–53 oz/gal |
| Boric acid | B(OH)3 | 4–6 oz/gal |
Hard nickel
A hard nickel solution is used when a high tensile strength and hardness deposit is required.| Chemical name | Formula | Bath concentration |
|---|---|---|
| Nickel sulfate | NiSO4·6H2O | 24 oz/gal |
| Ammonium chloride Ammonium chloride Ammonium chloride NH4Cl is an inorganic compound with the formula NH4Cl. It is a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. Sal ammoniac is a name of natural, mineralogical form of ammonium chloride... |
NH4Cl3 | 3.3 oz/gal |
| Boric acid | B(OH)3 | 4 oz/gal |
Black nickel
Black nickel plating is a typically plated on brass, bronze, or steel in order to produce a non-reflective surface. This type of plating is used for decorative purposes and does not offer much protection.| Chemical name | Formula | Bath concentration |
|---|---|---|
| Nickel ammonium sulfate | NiSO4·(NH4)2SO4·6H2O | 8 oz/gal |
| Zinc sulfate Zinc sulfate Zinc sulfate is the inorganic compound with the formula ZnSO4 as well as any of three hydrates. It was historically known as "white vitriol". It is a colorless solid that is a common source of soluble zinc ions.-Production and reactivity:... |
ZnSO4 | 1.0 oz/gal |
| Sodium thiocyanate Sodium thiocyanate Sodium thiocyanate is the chemical compound with the formula NaSCN. This colorless deliquescent salt is one of the main sources of the thiocyanate anion. As such, it is used as a precursor for the synthesis of pharmaceuticals and other specialty chemicals... |
NaCNS | 2 oz/gal |
Applications
Decorative bright nickel is used in a wide range of applications. It offers a high luster finish, corrosion protection, and wear resistance. In the automotive industry bright nickel can be found on bumpers, rims, exhaust pipes and trim. It is also used for bright work on bicycleBicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....
s and motorcycle
Motorcycle
A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...
s. Other applications include hand tool
Hand tool
A hand tool is a device for performing work on a material or a physical system using only hands. The hand tools can be manually used employing force, or electrically powered, using electrical current...
s and household items such as lighting
Light fixture
A light fixture, light fitting, or luminaire is an electrical device used to create artificial light and/or illumination, by use of an electric lamp...
and plumbing fixture
Plumbing fixture
A plumbing fixture is an exchangeable device which can be connected to an existing plumbing system to deliver and drain away water but which is also configured to enable a particular use.-Common fixtures:The most common plumbing fixtures are:*Bathtubs...
s, wire racks, and appliances
Home appliance
Home appliances are electrical/mechanical machines which accomplish some household functions, such as cooking or cleaning. Home appliances can be classified into:*Major appliances, or White goods*Small appliances, or Brown goods...
.
Engineering nickel is used where brightness is not desired. Non decorative applications provide wear and corrosion protection as well as low stress build ups for dimensional recovery.
See also
- Electroless nickel immersion gold
- Electroless nickel platingElectroless nickel platingElectroless nickel plating is an auto-catalytic chemical technique used to deposit a layer of nickel-phosphorus or nickel-boron alloy on a solid workpiece, such as metal or plastic. The process relies on the presence of a reducing agent, for example hydrated sodium hypophosphite which reacts with...
- ElectroplatingElectroplatingElectroplating is a plating process in which metal ions in a solution are moved by an electric field to coat an electrode. The process uses electrical current to reduce cations of a desired material from a solution and coat a conductive object with a thin layer of the material, such as a metal...
- Chrome platingChrome platingChrome plating, often referred to simply as chrome, is a technique of electroplating a thin layer of chromium onto a metal object. The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness.-Process:A component to be chrome plated will...