science

Nickel electroplating

Nickel electroplating is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Nickel electroplating rather than just read about it. In short: 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.

Key takeaways

Nickel electroplating belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Nickel electroplating to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Nickel electroplating from memory before moving on to harder problems.

Reference excerpt

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.

Overview Nickel electroplating is a process of depositing nickel onto 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 treating, 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 to form nickel ions (Ni2+). Just like in other electrodeposition processes, the ions travel through the solution and deposit on the cathode. The anode efficiency for nickel dissolution is close to 100%, unless the anode becomes passive due to problems with the process, in which case the efficiency drops to 0. The cathode efficiency depends on the process and varies between 90 and 97%. Due to this mismatch, during the plating the nickel concentration in the solution and the pH will slowly rise. The process takes minutes to hours depending on the current density and the intended thickness of the plating.

History Nickel electroplating was developed in the first half of the 19th century, with notable experiments made by Golding Bird (1837) and nickel nitrate patent by Joseph Shore (1840). The first practical recipe, an aqueous solution of nickel and ammonium sulfates, was invented by Böttger in 1843 and was in use for 70 years. The commercial success was achieved by Isaac Adams Jr., whose patent for a solution of nickel ammonium sulfate, while similar to Böttger's, had neutral pH that made the process easier to control. Adams enjoyed a near-monopoly in nickel plating from 1869 to 1886, when the consumption of nickel for plating reached 135 tons. In the US, Remington tried to use the nickel ammonium chloride solution (1868), in the process establishing the anode construction in the form of a platinum basket filled with nickel pieces, Edward Weston initiated the use of boric acid (patent issued in 1878), Bancroft figured out the role of chlorides in dissolving the anode (1906). Finally, Oliver P. Watts in 1916 established the Watts bath, variations of which are still widely used for decorative plating, with sulfamate solutions challenging it in the engineering applications. In the early 1930s, German electrochemist Max Schlötter developed the first practical bright nickel bath. After discovering that using organic aromatic polysulfonates produced a dramatically improved finish, he filed a patent in the USA for bright nickel deposition in 1932 (US Patent 1972693).

Types and chemistry

Watts baths A Watts bath, named for its inventor Oliver Patterson Watts, is an aqueous electrolyte solution for plating nickel from a nickel anode. It can deposit both bright and semi-bright nickel. Bright nickel is typically used for decorative purposes and corrosion protection. Semi-bright deposits are used for engineering applications where high corrosion resistance, ductility or electrical conductivity is important, and a high luster is not required.

Bath composition

Operating conditions Temperature: 40-65 °C Cathode current density: 2-10 A/dm2 pH: 4.5-5

Brighteners Carrier brighteners (e.g. paratoluene sulfonamide, benzene sulphonic acid) in concentration 0.75-23 g/L. Carrier brighteners contain sulfur providing uniform fine grain structure of the nickel plating. Levelers, second class brighteners (e.g. allyl sulfonic acid, formaldehyde chloral hydrate) in concentration 0.0045-0.15 g/L produce (in combination with carrier brighteners) brilliant deposit. Auxiliary brighteners (e.g. sodium allyl sulfonate, pyridinium propyl sulfonate) in concentration 0.075-3.8 g/L. Inorganic brighteners (e.g. cobalt, zinc) in concentration 0.075-3.8 g/L. Inorganic brighteners impart additional lustre to the coating. Type of the added brighteners and their concentrations determine the deposit appearance: brilliant, bright, semi-bright, satin.

Nickel sulfamate Sulfamate nickel plating is used for many engineering applications. It is deposited for dimensional corrections, abrasion and wear resistance, high efficiency coating and corrosion protection. It is also used as an undercoat for chromium.

Bath composition

Operating conditions Temperature: 40-60 °C Cathode current density: 2-25 A/dm2 pH: 3.5-4.5

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.

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-chloride bath.

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 insoluble anode.

Hard nickel A hard nickel solution is used when a high tensile strength and hardness deposit is required.

Black nickel "Black nickel" is a dark coating that consists primarily of nickel sulfide and metallic zinc and nickel. It is typically plated on brass, bronze, or steel in order to produce a non-reflective surface. This type of plating is used for decorative and military purposes and does not offer much protection.

Applications

Decorative coating 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 bicycles and motorcycles. Other applications include hand tools and household items such as lighting and plumbing fixtures, wire racks, firearms, and appliances. Modern coating technology makes deposited nickel to appear mirror-bright with no need of polishing, multi-layer applications are frequently used to improve the corrosion resistance of coated steel, zinc, copper, aluminum, and other metals. In order to prevent tarnishing, decorative electroplated nickel is typically coated with a thin layer of chromium.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Nickel electroplating

Start with the simplest possible case. Write down what Nickel electroplating claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nickel electroplating before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nickel electroplating ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nickel electroplating

In research: Nickel electroplating appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nickel electroplating in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nickel electroplating is common in secondary-school and first-year university syllabi. It links to neighbouring topics Corrosion prevention, Metal plating, Nickel, so understanding it makes those chapters shorter.
In everyday life: Look for Nickel electroplating outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Nickel electroplating in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nickel electroplating means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Nickel electroplating out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nickel electroplating in simple terms?

Why does Nickel electroplating matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nickel electroplating?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nickel electroplating.