Preet Kumar

M. Tech 1st Year

Enrollment No.- 14551009

Centre of Nanotechnology

Dip coating refers to the immersing of a substrate

into a tank containing coating material, removing

the piece from the tank, and allowing it to drain. The

coated piece can then be dried by force-drying or

baking. It is a popular way of creating thin film

coated materials along with the spin coating

procedure.

The dip coating process can be, generally, separated into 3 stages:

Immersion: the substrate is immersed in the solution of the coating material at a constant speed preferably judder free

Dwell time: the substrate remains fully immersed and motionless to allow for the coating material to apply itself to the substrate

Withdrawal: the substrate is withdrawn, again at a constant speed to avoid any judders. The faster the substrate is withdrawn from the tank the thicker the coating material that will be applied to the board.

Fig. 2: Gelation process during dip coating process,

obtained by evaporation of the solvent and subsequent

destabilization of the sol

Owing to its simplicity, this method lends itself to

automation. Film thickness is controlled by coating

viscosity and rate of withdrawal from the tank. Dip

tanks come in all shapes and are sized to accommodate

the largest object to be coated.

Dip coating has its drawbacks, including: light parts

tend to float and fall from the conveyor; film thickness

can vary from top to bottom ("wedge effect"); fatty

edges develop on the bottom of parts as excess coating

drains; and refluxing by the solvent vapors above the

tank removes some of the coating

Dip coating processes are used for plate glass for

solar energy control systems (Calorex®) and anti-

reflective coatings (Amiran®) on windows. The dip

coating technique is also applied for optical

coatings, e.g. on bulbs, for optical filters or

dielectric mirrors by various SMEs and other

companies, fabricating multilayer systems with up

to 30 or 40 coatings with very high precision.

What is Electro deposition? Electro deposition is the process of coating

a thin layer of one metal on top of adifferent metal to modify its surface properties.

Done to achieve the desired electrical and corrosion resistance, reduce wear & friction, improve heat tolerance and for decoration.

E.D. is a surface coating method that formsan adherent layer of one metal on another.

Electrodeposition is a key method for making the materials used in computer chips and magnetic data storage systems; every day it helps lower the cost and improve the performance of our information society.

However, electrodeposition is also emerging as a uniquely capable method for making materials and structures needed for a nanotechnology- and nanobiotechnology based future.

It also provides some unique opportunities for directly writing materials onto a surface without going through the photoresist masking steps that are used in conventional electrochemical microfabrication.

Electrodeposition has three main attributes that make it

so well suited for nano-, bio- and

microtechnologies:

• It can be used to grow functional material through

complex 3D masks.

• It can be performed near room temperature from

water-based electrolytes.

• It can be scaled down to the deposition of a few

atoms or up to large dimensions.

Automotive parts Printed circuitry and electrical contacts General engineering components Gold-Silver wares and Jewelry Musical Instruments and Trophies Soft metal gaskets Anti-seize bearings Decorative door, light & bathroom

fittings Production of micro parts for MEMS

(MicroElectroMechanical systems)