what is galvanisation?whai is its purpose?

Question

if zinc coating is done on tin then what r the cathode, annode and electrolyte used to give this coating?

Answer 1

Galvanization or galvanisation refers to any of several electrochemical processes named after the Italian scientist Luigi Galvani.





History
Originally, galvanization was the administration of electric shocks (in the 19th century also termed Faradism, after Michael Faraday). It stemmed from Galvani's induction of twitches in severed frogs' legs, by his accidental generation of electricity. This archaic sense is the origin of the meaning of galvanic when meaning 'affected/affecting, as

if by a shock of electricity; startled'. Its claims to health
benefits have largely been disproven, except for some

limited uses in psychiatry. See also: Galvanism, Violet wand
Later the word was used for
processes of electrodeposition. This remains a useful and broadly applied
technology, but the term "galvanization"
has largely come to be associated
with zinc coatings, to the exclusion
of other metals.
In current use, it typically means
hot-dip galvanizing, a chemical process that is used to coat steel or iron with zinc. This is done to reduce corrosion (specifically rusting) of the ferrous item; while it is accomplished by non-electrochemical means, it serves an electrochemical purpose.

Zinc Coatings
The remainder of the
article is about zinc anti-corrosion coatings.

Zinc coatings prevent
corrosion of the protected metal by forming a barrier, and by acting as a sacrificial anode if this barrier is damaged. When exposed

to the atmosphere, zinc reacts with oxygen to form zinc oxide,
which
further reacts with water molecules in the air to form zinc
hydroxide. Finally zinc hyroxide
reacts with carbon dioxide in the atmosphere to yield a thin, impermiable, tenacious and quite
insoluble dull gray layer of zinc carbonate which adheres extremely
well to the underlying zinc, so protecting
it from further corrosion, in a way
similar to the protection afforded to aluminium and stainless steels by their oxide layers.

Hot dip galvanizing deposits a thick,
robust layer that may be more than is necessary for the protection of the underlying metal in some applications. This is the case in automobile bodies, where additional rust proofing paint will be applied. Here, a thinner form of galvanizing is applied by electroplating, called "electro-galvanization". However, the protection this process provides is insufficient for products that will be constantly exposed to corrosive materials such as salt water. Nevertheless, most nails made today are electro-galvanized.

Galvanic protection (also known as sacrificial-anode or cathodic protection) can be achieved by connecting zinc both electronically (often by direct bonding to the protected metal) and ionically (by submerging both into the same body of electrolyte, such as a drop of rain). In such a configuration the zinc is absorbed into the electrolyte in preference to the metal that it protects, and maintains that metal's structure by inducing an electric current. In the usual example, ingots of zinc are used to protect a boat's hull and propellers, with the ocean as the common electrolyte.

As noted previously,

both mechanisms are often at work in practical applications.
For example, the traditional measure of a coating's effectiveness is resistance to a salt spray. Thin coatings cannot remain
intact indefinitely when subject to surface abrasion, and the
galvanic protection offered by zinc can be sharply contrasted to
more noble metals. As an example, a scratched or incomplete coating of chromium actually exacerbates corrosion
of the
underlying steel, since it is less electrochemically active than the substrate.


Galvanized surface with visible spangle
The size of crystallites in galvanized coatings is an aesthetic
feature, known as spangle. By varying the number of particles
added for heterogeneous nucleation and the rate of cooling
in a hot-dip process, the spangle can be adjusted from an apparently uniform surface (crystallites too small to see with the naked eye) to grains several centimeters wide.
Visible crystallites are rare in other engineering materials.
Protective coatings for steel constitute the largest use of zinc and rely upon the galvanic or sacrificial property of zinc relative to steel.

Answer 2

Galvanisation is a process by which metals dipped in molten zinc have a protective layer of zinc which prevents corrosion of the metals.This is done to metals that are less reactive than zinc such as iron and silver so that it prevents the corrosion of these metals .Galvanisation also finds it's application in a simple voltaic cell.

Answer 3

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RE:
what is galvanisation?whai is its purpose?

Answer 4

Galvanization is a kind of electroplating. But instead of gold or silver they cover something - usually iron - with a metal called zinc.

Iron will rust if it is left in contact with the air. That is also why they cover it with tin, like for tin cans.

Entire car bodies are sometimes galvanized. It gets its name, by the way, from the Italian scientist Luigi Galvani who studied electricity, His name is also used to name the Galvanic cell and the galvanometer.

;-D Way to go Luigi!

Answer 5

What Is Galvanising

Answer 6

Galvanisation is the covering of a metal with a layer of zinc metal. Its purpose is to prevent rusting.

Zinc metal is placed in a solution of its salt [Zn2+ (electrolyte)] and connected to the positive terminal (cathode). The metal is placed in the same solution and connected to the negative terminal(anode).

Answer 7

the process of dipping some metal in molten zinc to reduce its corrosive nature which leads to rusting is known as galvanisation

Answer 8

Galvanization is electrically coating metal with a mixture of tin, zinc and other alloys. Its purpose is to make the metal rust resistant.

Answer 9

galvanisation means coating of zinc with other metals.it prevents rusting

Answer 10

Galvanization is a chemical process to coat certain metals, like steel or iron with zinc. Why is this done? to retard rusting of the original metal.

Answer 11

coating of zinc on iorn sheets to prevent rusting .it protects as an invisible thin layer of zinc carbonate ZnCO3 ,Zn(OH)2, is formed .
uses - galvanized metal does not lose lusture , protectss from corrosion
used in - buckets,boxes,utensils