cil training

7/31/2019 cil training

1/19

A Presentation

On

Manufacturing and

Application of

Peizo

CeramicCrystal

at

Presented by:

Yash Agarwal

EN F

IV Year


2/19

About CEL

Introduction

ManufacturingProcess

Application


3/19

Central Electronics Limited is a Public Sector Enterprise under theDepartment of Scientific and Industrial Research (DSIR), Ministry of Science

& Technology, Government of India. It was established in 1974 with an

objective to commercially exploit the indigenous technologies developed by

National Laboratories and R&D Institutions in the country. CEL is one of the

rare companies, which utilized the homegrown technologies during all these

years of its existence. CEL is the largest manufacturer ofSolar Photo Voltaic

Cells in India. CEL is also a pioneer in manufacturing of: Railway Electronics Microwave Electronics Cathodic Protection Ceramics


4/19

Piezo Electric Materials:

These are those materials which when subjected to mechanical stress

and strain develops a electric field and a voltage is introduced

OR

These are those materials in which when a charge is made to flow, mechStress and Strain are developed leading to deformation of material.


5/19

PZT Crystal

P Z T

PbO(Lead Oxide)

Zinc Oxide

Titanium Oxide

The word PZT is a Abbreviation for words under:

The PZT Crystal is made from three organic compounds namely Lead Oxide,

Zinc Oxide and Titanium oxide. PZT crystals have properties of peizo electricity.The manufacturing of this crystal involves a series of steps and have some crucial

applications too. The Crystal can used as :

1. Sensor2. Transducer3. Actuator


6/19


7/19

The flowchart shown below illustrates the process of manufacturing of

PZT Crystal:

[1] Raw Materials [2] Mixing [3] Calcining [4] Milling

[5] Spray Drying [6] Pressing [7] Binder Burnout [8] Sintering

[9] Grinding/ Polishing [10] Electroding [11] Poling [12] Final Inspection


8/19

1. Raw Materials and Mixing

Batch Preparation :

Under this three key organic oxides namely lead oxide, zinc oxide

and titanium oxide are mixed .

The composition of oxides in mixture is:

Zinc Oxide : 65%Lead Oxide : 25%

Titanium Oxide : 10%

The raw materials are now mixed using electrical strirrer or manually.


9/19

2. Milling :

Milling is a unit operation designed to break a solid materialinto smaller pieces. There are many different

types of grinding mills and many types of materials processed

in them. Historically mills were powered

by hand (mortar and pestle), working animal

(horse mill), wind (windmill) or water (watermill).

Today they are also powered by electricity.

The Milling may serve the following purposes in engineering:

increase of the surface area of a solid manufacturing of a solid with a desired grain size pulping of resources
http://en.wikipedia.org/wiki/Unit_operationhttp://en.wikipedia.org/wiki/Mortar_and_pestlehttp://en.wikipedia.org/wiki/Working_animalhttp://en.wikipedia.org/wiki/Horse_millhttp://en.wikipedia.org/wiki/Windmillhttp://en.wikipedia.org/wiki/Watermillhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Watermillhttp://en.wikipedia.org/wiki/Windmillhttp://en.wikipedia.org/wiki/Horse_millhttp://en.wikipedia.org/wiki/Working_animalhttp://en.wikipedia.org/wiki/Mortar_and_pestlehttp://en.wikipedia.org/wiki/Unit_operation


10/19

3. Calcination:

Calcination is carried out in furnaces or reactors (sometimes

referred to as kilns or calciners) of various designs includingshaft furnaces, rotary kilns, multiple hearth furnaces, and

fluidized bed reactors. A very high temperature of about 960C is

maintained inside the furnace. This is done to

bring uniformity of oxides and during calcination the components

react to form the polycrystalline phase.

After Calcination the mixture is sent to milling again.
http://en.wikipedia.org/wiki/Furnacehttp://en.wikipedia.org/wiki/Kilnhttp://en.wikipedia.org/w/index.php?title=Shaft_furnace&action=edit&redlink=1http://en.wikipedia.org/wiki/Rotary_kilnhttp://en.wikipedia.org/w/index.php?title=Multiple_hearth_furnace&action=edit&redlink=1http://en.wikipedia.org/wiki/Fluidized_bed_reactorhttp://en.wikipedia.org/wiki/Fluidized_bed_reactorhttp://en.wikipedia.org/w/index.php?title=Multiple_hearth_furnace&action=edit&redlink=1http://en.wikipedia.org/wiki/Rotary_kilnhttp://en.wikipedia.org/w/index.php?title=Shaft_furnace&action=edit&redlink=1http://en.wikipedia.org/wiki/Kilnhttp://en.wikipedia.org/wiki/Furnace


11/19

4. Spray Drying

The calcined powder is spray dried to add binder in order to increaseit's reactivity and to improve pressing properties.

Spray drying is an essential unit operation for the manufacture of

many products with specific powder properties. It is characterized by

atomization of a solution or suspension into droplets, followed by

subsequent drying of these droplets by evaporation of water or other

solvents. Spray drying results in agglomeration.

Before Spray

drying

After Spray

drying


12/19

5. Pressing

Dry pressing is used to manufacture mass-produced precision ceramic

products. Non-clumping granulates are compressed in steel dies designedappropriately for the part to be manufactured.


13/19

6. Binder Burnout

The binder material used is burned out in a furnace at temperature

of about 650-700C. The binder burnout causes decarbonation of the

agglomerated material

7. Sintering

This is done to provide strength to the agglomerate formed. In this the

material is heated in another furnace at about 1300C.

A lead Tablet is used to cover the agglomerate because at temperature

Above 1300C , lead from PZT disc began to evaporate.Due to sintering the size of disc decreases. So some tolerance is taken

during the Pressing.


14/19

8. Grinding/Polishing

The dimensional tolerance of fired parts ( 3%) is improved by cutting, grinding

and lapping.

The action is similar to that of a mechanical file. Water is used to soften the

Material because ceramic is hard


15/19

9. Electroding

The PZT disc formed need to form electrodes so as to develop a voltage

after polarization.

This electroding is done by applying silver paste.

After the application to silver paste, PZT discs are heated in oven at

about 650C so that the silver do not get removed rather gets stuffed.

This process is called Firing Process.

10. Polarization

The Polarization is done by placing the PZT disc having electrodes

between parllel plate capacitor. The voltage applied is decidedaccording to the thickness.

The maximum voltage that can be applied is 2.5KV/mm.


16/19

11. Testing

Normally two test are performed on polarized PZT crytal.

1. Measurement of capacitanceThis is done using LCR(inductance, Capacitance and Resistance) Bridge.

The capacitance of PZT disc is checked by placing the disc under LCR

Bridge. The range of permissible capacitance varies from 1 nF to 1.3 nF.


17/19

2. Measurement of Voltage:The voltage is tested using ball drop method.

In this a ball is dropped on PZT disc which provides mechanical

stress andstrain to the disc and a since it is polarized a voltage is

produced which is

Measured by a calibrated CRO.


18/19


19/19

The PZT manufactured from process described in very widely used in

Arms and ammunition. The PZT discs are mounted on circular disc and

A electronic circuit is made. This disc is placed either at the top of bombs

or inside the gun. When the bomb is thrown or the the gun is fired, aMechanical impact is received by the PZT disc . This mechanical impact

produces a voltage or arc which are required for the combustion of

explosives.

Earlier these disc were imported but are now manufactured in India only

by CEL and are supplied to various ordinance factories across the country

A Prototype of PZT Disc

Polarised

PZT

Metal

frame

Documents

cil training