Title of Invention	A PROCESS FOR THE PREPARATION OF BARIUM TITANATE BASED COMPOSITION WITH HIGH DIELECTRIC CONSTANT AND TEMPERATURE STABILITY
Abstract	A process for the preparation of barium titanate based composition with high dielectric constant and temperature stability: The invention relates to a process for the preparation of barium titanate based composition with high dielectric constant and temperature stability. The composition is used for making low-fire multilayer ceramic capacitors. The process steps are: a) adding 0.3 - 1.5 wt.% ( of BaTiO3) fluxes containing Li2C2O4, Bi2O3 and CuO to BaTiO3 powder, b) adding 0.3 - 9.0 wt. % of CaZrO3, Nb2O5 and BaCO3 to the mixture obtained in step a), which acts as grain growth inhibitors and Curie peak suppressors, c) mixing the said composition obtained in step b) in a ball mill with 60-80 wt.% ( of powder mix) distilled water for 10 - 20 h, d) drying the mixture at 100 - 150°C in an oven for 2 - 4 h, e) calcining the mixture at 600 - 800°C for 5 - 10 h and f) dry grinding of the calcined powder in a ball mill for 5 - 10 h to obtain the product.

Title of Invention

A PROCESS FOR THE PREPARATION OF BARIUM TITANATE BASED COMPOSITION WITH HIGH DIELECTRIC CONSTANT AND TEMPERATURE STABILITY

Abstract

A process for the preparation of barium titanate based composition with high dielectric constant and temperature stability: The invention relates to a process for the preparation of barium titanate based composition with high dielectric constant and temperature stability. The composition is used for making low-fire multilayer ceramic capacitors. The process steps are: a) adding 0.3 - 1.5 wt.% ( of BaTiO3) fluxes containing Li2C2O4, Bi2O3 and CuO to BaTiO3 powder, b) adding 0.3 - 9.0 wt. % of CaZrO3, Nb2O5 and BaCO3 to the mixture obtained in step a), which acts as grain growth inhibitors and Curie peak suppressors, c) mixing the said composition obtained in step b) in a ball mill with 60-80 wt.% ( of powder mix) distilled water for 10 - 20 h, d) drying the mixture at 100 - 150°C in an oven for 2 - 4 h, e) calcining the mixture at 600 - 800°C for 5 - 10 h and f) dry grinding of the calcined powder in a ball mill for 5 - 10 h to obtain the product.

Full Text	This invention relates to a process for the preparation of barium titanate based composition with high dielectric constant and temperature stability. The invention also relates to a composition having high dielectric constant and temperature stability. This invention particularly relates to improved barium titanate based composition which is lead and boron free, showing high dielectric constant value and temperature stability over a wide range and are useful for making low-fire multilayer ceramic capacitors. The uniqueness of the present invention lies in the fact that i) the improved composition eliminates the necessity of any hazardous lead compound in the powder mix, whereas similar existing compositions contain toxic lead compounds and ii) the improved composition eliminates the necessity of any boron compound in the powder mix and hence environment-friendly water based binders can be used during fabrication of the capacitors from the powder mix. Various dielectric compositions standardized and coded have got typical applications. Low-fire high dielectric constant: capacitor compositions showing temperature stability within a specific range (variation of capacitance between + 10°C to + 85°C should be within + 20 to - 56% of room temperature value) are generally coded as Z5U type. They offer very high capacitance per unit volume and are particularly preferred for decoupling and filtering applications. These capacitors show relatively wide variations of capacitance with temperture than those of X7R type capacitors (for which the capacitance value between - 55°C and + 125°C should not change over +/- 15%). In this connection, reference may be made to the following publications and patents: 1. TAM Ceramics Inc., Niagara Falls, New York, Product Data Sheet, Product no. 52604, Grade Z5U, 502L. 2. I.Burn "Flux-sintered BaTi03 dielectrics" J. Mat.Sc. 1398 (1982) 3. G.G.Mahar, U.S.Patent no. 4,066,426 (1978) 4. D.A.Payne and S.M.Park, U.S.Patent no. 4,218,723 (1980) All of the above works are based on modification of pure BaTi03 by suitable doping. However, all of them use either highly toxic lead compounds or binder incompatible (water based) boron compounds or both. The main object of the present invention is to provide a composition having high dielectric constant and temperature stability useful for making low-fire multilayer ceramic capacitors which obviates the drawbacks as mentioned above. Another object of the present invention is to provide an improved barium titanate ( BaTiO-j) based composition which is free of toxic lead and problematic boron compounds. Yet another object is to provide lead and boron free barium titanate based dielectric compositions showing room temperture (~30°C) dielectric constant values ranging from 5500 to 7500 (in the disc form) and dissipation factors 0.04 to 0.01 (at 1kHz and IV RMS). Still another object is to provide lead and boron free barium titanate based dielectric compositions showing dielectric constant variations ( from its room temperature value ) over the temperature range + 10°C to + 85°C within + 15 to -55%. Yet another object is to provide lead and boron free barium titanate based dielectric compositions which can be sintered at Another object is to provide a process for preparing a powder mix of the composition of the present invention. Accordingly, the present invention provides a composition having high dielectric constant and temperature stability useful for making low-fire ceramic capacitors which comprises: (i) barium titanate (BaTi03) ; (ii) 0.3 - 1.5 wt.% (of BaTiO3) flux containing Li2C204, Bi203, and CuO; (iii) 0.3 - 9.0 wt. % (of BaTiO3) grain growth inhibitors and Curie peak suppressors containing CaZrO-,, Nb^O^ and BaC03. The flux used in the composition of the present invention may be of laboratory reagent grade and may consist of 0.5 - 1 wt.% Li2C204, 0.5 - 0.9 wt. % Bi203 and 0.1 - 0.3 wt. % CuO(of barium titanate). The grain growth inhibitors and Curie peak suppressors used in the composition of the present invention may be of laboratory reagent grade and may consist of 4-9 wt. % CaZr03, 0.3-1 wt. % Nb90c and 2.5-5 wt.% BaCO-, (of barium titanate). £, O -3 \ / The composition of the present invention is not a mere admixture but a synergistic mixture having properties which are different from the mere aggregated properties of the individual ingredients. Accordingly the present invention provides a process for the preparation of barium titanate based composition with high dielectric constant and temperature stability which comprises: a) adding 0.3 - 1.5 wt.% (of BaTiOa) fluxes containing I^CaCU, Bi2O3 and CuO in a ratio in the range of 1:1:0.2 to 1:1:0.3 to BaTiO3 powder, b) adding 4.0 - 9.0 wt. % CaZrO3,0.3-1.0 wt % Nb2O5 and 2.5-5.0 wt % BaCOs to the mixture obtained in step a), which acts as grain growth inhibitors and Curie peak suppressors, c) mixing the said composition obtained in step b) in a ball mill with 60- 80 wt.% ( of powder mix) distilled water for 10 - 20 h, d) drying the mixture at 100 - 150°C in an oven for 2 - 4 h, e) calcining the mixture at 600 - 800°C for 5 - 10 h and f) dry grinding of the calcined powder in a ball mill for 5 - 10 h to obtain the product. The following examples illustrate the invention and the manner in which it may be carried out in practice; however, this should not be construed to limit the scope of the present invention. Example -1 A batch composition containing 10.00 g CaCOa and 12.30 g ZrO2 along with 14 g of distilled water was mixed in a ball mill for 10 h. The mixture after drying ( at 150°C ) was calcined at 1350°C for 4 h to get CaZr03. The calcined mass was ground (dry) in a ball mill for 5 h. A batch composition containing 15.00 g BaTiCU, 0.90 g CaZr03(prepared as above), 0.09 g Nb205, 0.10 g Li2C204, 0.10 g Bi00-,, 0.02 g CuO and 0.50 g BaCCU along with 10 g distilled £1 J J water was prepared by mixing the aforesaid powders in a ball mill for 15 h. The mixed slurry was dried at 150°C in an oven for 4 h. The dried mixture was calcined at 750°C for 10 h followed by dry grinding in a ball mill for 5 h to get the capacitor composition (mixed powder) . For testing, pellets of mixed powder (10 mm dia. and 2-3 mm thickness) were prepared by uniaxial pressing (pressure 50 MPa) using 1.5 wt. % (of mixed powder) ethyl cellulose binder. The samples were kept on a dense zirconia plate and were sintered at 1150°C for 3 h. The density of the sintered pellets was found to be ~ 5.61 g/cc, the room temperature dielectric constant ~ 5700, dissipation factor ~ 0.020 and variation of dielectric constant from +10°C to +85°C was found to be within +12 to -18%. Example 2. A batch composition containing 15.00 g BaTiO3, 0.90 g CaZr03 (prepared as in example 1), 0.09 g Nb205, 0.10 g Li2C204, 0.10 g Bi203, 0.03 g CuO and 0.50 g BaC03 along with 10 g distilled water was prepared by mixing the aforesaid powders in a ball mill for 15 h. The mixed slurry was dried at 150°C in an oven for 4 h. The dried mixture was calcined at 750°C for 10 h followed by dry grinding in a ball mill for 5 h to get the capacitor composition (mixed powder). For testing, pellets of mixed powder (10 mm dia. and 2-3 mm thickness) were prepared by uniaxial pressing (pressure 50 MPa) using 1.5 wt. % (of mixed powder) ethyl cellulose binder. The samples were kept on a dense zirconia plate and were sintered at 1150°C for 3 h. The density of the sintered pellets was found to be ~ 5.71 g/cc, the room temperature dielectric constant ~ 6400, dissipation factor ~ 0.025 and variation of dielectric constant from +10°C to +85°C was found to be within +10 to -23%. Example 3. A batch composition containing 15.00 g BaTi03, 0.90 g CaZrOo (prepared as in example 1), 0.09 g Itt^O,-, 0.13 g Li^C^O^, 0.10 g Bi203, 0.03 g CuO and 0.60 g BaC03 along with 10 g distilled water was prepared by mixing the aforesaid powders in a ball mill for 15 h. The mixed slurry was dried at 150°C in an oven for 4 h. The dried mixture was calcined at 750°C for 10 h followed by dry grinding in a ball mill for 5 h to get the capacitor composition (mixed powder). For testing, pellets of mixed powder (10 mm dia. and 2-3 mm thickness) were prepared by uniaxial pressing (pressure 50 MPa) using 1.5 wt.% (of mixed powder) ethyl cellulose binder. The samples were kept on a dense zirconia plate and were sintered at 1150°C for 3 h. The density of the sintered pellets was found to be ~ 5.03 g/cc, the room temperature dielectric constant ~ 7215, dissipation factor ~ 0.025 and variation of dielectric constant from +10°C to +85°C was found to be within +8 to -40%. Example 4_ A batch composition containing 15.00 g BaTiO3, 0.90 g CaZrO3 (prepared as in example 1), 0.09 g Nb2O5, 0.10 g Li2C2O4, 0.10 g Bi203, 0.03 g CuO and 0.55 g BaC03 along with 10 g distilled water was prepared by mixing the aforesaid powders in a ball mill for 15 h. The mixed slurry was dried at 150°C in an oven for 4 h. The dried mixture was calcined at 750°C for 10 h followed by dry grinding in a ball mill for 5 h to get the capacitor composition (mixed powder). For testing, pellets of mixed powder (10 mm dia. and 2-3 mm thickness) were prepared by uniaxial pressing (pressure 50 MPa) using 1.5 wt.% (of mixed powder) ethyl cellulose binder. The samples were kept on a dense zirconia plate and were sintered at 1150°C for 3 h. The density of the sintered pellets was found to be ~ 5.33 g/cc, the room temperature dielectric constant ~ 6630, dissipation factor ~ 0.030 and variation of dielectric constant from +10°C to +85°C was found to be within + 9 to -28%. The main advantages of the improved composition of the present invention are as follows: 1. The improved composition eliminates the necessity of any toxic lead compound in the dielectric formulations. 2. The improved composition eliminates the necessity of any boron compound in the dielectric formulations and hence environment - friendly water based binders can be used during fabrication of the capacitors from the powder mix. 3. The lead and boron free barium titanate based composition of the present invention satisfy the requirements of high dielectric constant, temperature stable Z5U type capacitors and can be used as better and safe alternative of existing dielectric compositions. We Claim: 1. A process for the preparation of barium titanate based composition with high dielectric constant and temperature stability which comprises: a) adding 0.3 - 1.5 wt.% ( of BaTiO3) fluxes containing Li2C2O4, Bi2O3 and CuO in a ratio in the range of 1:1:0.2 to 1:1:0.3 to BaTiO3 powder, b) adding 4.0 - 9.0 wt. % CaZrO3,0.3-1.0 wt % Nb2O5 and 2.5-5.0 wt % BaCO3 to the mixture obtained in step a), which acts as grain growth inhibitors and Curie peak suppressors, c) mixing the said composition obtained in step b) in a ball mill with 60-80 wt.% ( of powder mix) distilled water for 10 - 20 h, d) drying the mixture at 100 - 150°C in an oven for 2 - 4 h, e) calcining the mixture at 600 - 800°C for 5 - 10 h and f) dry grinding of the calcined powder in a ball mill for 5 - 10 h to obtain the product. 2. A process for the preparation of barium titanate based composition with high dielectric constant and temperature stability substantially as herein described with reference to the examples.

Full Text

This invention relates to a process for the preparation of barium titanate based composition with high dielectric constant and temperature stability. The invention also relates to a composition having high dielectric constant and temperature stability.
This invention particularly relates to improved barium titanate based composition which is lead and boron free, showing high dielectric constant value and temperature stability over a wide range and are useful for making low-fire multilayer ceramic capacitors.
The uniqueness of the present invention lies in the fact that i) the improved composition eliminates the necessity of any hazardous lead compound in the powder mix, whereas similar existing compositions contain toxic lead compounds and ii) the improved composition eliminates the necessity of any boron compound in the powder mix and hence environment-friendly water based binders can be used during fabrication of the capacitors from the powder mix.
Various dielectric compositions standardized and coded have got typical applications. Low-fire high dielectric constant: capacitor compositions showing temperature stability within a specific range (variation of capacitance between + 10°C to + 85°C should be within + 20 to - 56% of room temperature value) are generally coded as Z5U type. They offer very high capacitance per unit volume and are particularly preferred for decoupling and filtering applications. These capacitors show relatively wide variations of capacitance with temperture than those of X7R type capacitors (for which the capacitance value between - 55°C

and + 125°C should not change over +/- 15%).
In this connection, reference may be made to the following publications and patents:
1. TAM Ceramics Inc., Niagara Falls, New York, Product Data
Sheet, Product no. 52604, Grade Z5U, 502L.
2. I.Burn "Flux-sintered BaTi03 dielectrics" J. Mat.Sc. 1398
(1982)
3. G.G.Mahar, U.S.Patent no. 4,066,426 (1978)
4. D.A.Payne and S.M.Park, U.S.Patent no. 4,218,723 (1980)
All of the above works are based on modification of pure BaTi03 by suitable doping. However, all of them use either highly toxic lead compounds or binder incompatible (water based) boron compounds or both.
The main object of the present invention is to provide a composition having high dielectric constant and temperature stability useful for making low-fire multilayer ceramic capacitors which obviates the drawbacks as mentioned above.
Another object of the present invention is to provide an improved barium titanate ( BaTiO-j) based composition which is free of toxic lead and problematic boron compounds.
Yet another object is to provide lead and boron free barium titanate based dielectric compositions showing room temperture (~30°C) dielectric constant values ranging from 5500 to 7500 (in the disc form) and dissipation factors 0.04 to 0.01 (at 1kHz and IV RMS).
Still another object is to provide lead and boron free

barium titanate based dielectric compositions showing dielectric constant variations ( from its room temperature value ) over the temperature range + 10°C to + 85°C within + 15 to -55%.
Yet another object is to provide lead and boron free barium titanate based dielectric compositions which can be sintered at Another object is to provide a process for preparing a powder mix of the composition of the present invention.
Accordingly, the present invention provides a composition having high dielectric constant and temperature stability useful for making low-fire ceramic capacitors which comprises:
(i) barium titanate (BaTi03) ;
(ii) 0.3 - 1.5 wt.% (of BaTiO3) flux containing Li2C204, Bi203, and CuO;
(iii) 0.3 - 9.0 wt. % (of BaTiO3) grain growth inhibitors and Curie peak suppressors containing CaZrO-,, Nb^O^ and BaC03.
The flux used in the composition of the present invention may be of laboratory reagent grade and may consist of 0.5 - 1 wt.% Li2C204, 0.5 - 0.9 wt. % Bi203 and 0.1 - 0.3 wt. % CuO(of barium titanate).
The grain growth inhibitors and Curie peak suppressors used in the composition of the present invention may be of laboratory reagent grade and may consist of 4-9 wt. % CaZr03, 0.3-1 wt. % Nb90c and 2.5-5 wt.% BaCO-, (of barium titanate).
£, O -3 \ /
The composition of the present invention is not a mere admixture but a synergistic mixture having properties which are different from the mere aggregated properties of the individual ingredients.
Accordingly the present invention provides a process for the preparation of barium titanate based composition with high dielectric constant and temperature stability which comprises:
a) adding 0.3 - 1.5 wt.% (of BaTiOa) fluxes containing I^CaCU, Bi2O3 and
CuO in a ratio in the range of 1:1:0.2 to 1:1:0.3 to BaTiO3 powder,
b) adding 4.0 - 9.0 wt. % CaZrO3,0.3-1.0 wt % Nb2O5 and 2.5-5.0 wt %
BaCOs to the mixture obtained in step a), which acts as grain growth
inhibitors and Curie peak suppressors,
c) mixing the said composition obtained in step b) in a ball mill with 60-
80 wt.% ( of powder mix) distilled water for 10 - 20 h,
d) drying the mixture at 100 - 150°C in an oven for 2 - 4 h,
e) calcining the mixture at 600 - 800°C for 5 - 10 h and
f) dry grinding of the calcined powder in a ball mill for 5 - 10 h to obtain
the product.
The following examples illustrate the invention and the manner in which it may be carried out in practice; however, this should not be construed to limit the scope of the present invention.
Example -1
A batch composition containing 10.00 g CaCOa and 12.30 g ZrO2 along with 14 g of distilled water was mixed in a ball mill

for 10 h. The mixture after drying ( at 150°C ) was calcined at 1350°C for 4 h to get CaZr03. The calcined mass was ground (dry) in a ball mill for 5 h.
A batch composition containing 15.00 g BaTiCU, 0.90 g CaZr03(prepared as above), 0.09 g Nb205, 0.10 g Li2C204, 0.10 g Bi00-,, 0.02 g CuO and 0.50 g BaCCU along with 10 g distilled
£1 J J
water was prepared by mixing the aforesaid powders in a ball mill for 15 h. The mixed slurry was dried at 150°C in an oven for 4 h. The dried mixture was calcined at 750°C for 10 h followed by dry grinding in a ball mill for 5 h to get the capacitor composition (mixed powder) .
For testing, pellets of mixed powder (10 mm dia. and 2-3 mm thickness) were prepared by uniaxial pressing (pressure 50 MPa) using 1.5 wt. % (of mixed powder) ethyl cellulose binder. The samples were kept on a dense zirconia plate and were sintered at 1150°C for 3 h. The density of the sintered pellets was found to be ~ 5.61 g/cc, the room temperature dielectric constant ~ 5700, dissipation factor ~ 0.020 and variation of dielectric constant from +10°C to +85°C was found to be within +12 to -18%.
Example 2.
A batch composition containing 15.00 g BaTiO3, 0.90 g CaZr03 (prepared as in example 1), 0.09 g Nb205, 0.10 g Li2C204, 0.10 g Bi203, 0.03 g CuO and 0.50 g BaC03 along with 10 g distilled water was prepared by mixing the aforesaid powders in a
ball mill for 15 h. The mixed slurry was dried at 150°C in an oven for 4 h. The dried mixture was calcined at 750°C for 10 h followed by dry grinding in a ball mill for 5 h to get the capacitor composition (mixed powder).
For testing, pellets of mixed powder (10 mm dia. and 2-3 mm thickness) were prepared by uniaxial pressing (pressure 50 MPa) using 1.5 wt. % (of mixed powder) ethyl cellulose binder. The samples were kept on a dense zirconia plate and were sintered at 1150°C for 3 h. The density of the sintered pellets was found to be ~ 5.71 g/cc, the room temperature dielectric constant ~ 6400, dissipation factor ~ 0.025 and variation of dielectric constant from +10°C to +85°C was found to be within +10 to -23%.
Example 3.
A batch composition containing 15.00 g BaTi03, 0.90 g CaZrOo (prepared as in example 1), 0.09 g Itt^O,-, 0.13 g Li^C^O^, 0.10 g Bi203, 0.03 g CuO and 0.60 g BaC03 along with 10 g distilled water was prepared by mixing the aforesaid powders in a ball mill for 15 h. The mixed slurry was dried at 150°C in an oven for 4 h. The dried mixture was calcined at 750°C for 10 h followed by dry grinding in a ball mill for 5 h to get the capacitor composition (mixed powder).
For testing, pellets of mixed powder (10 mm dia. and 2-3 mm thickness) were prepared by uniaxial pressing (pressure 50 MPa) using 1.5 wt.% (of mixed powder) ethyl cellulose binder. The
samples were kept on a dense zirconia plate and were sintered at 1150°C for 3 h. The density of the sintered pellets was found to be ~ 5.03 g/cc, the room temperature dielectric constant ~ 7215, dissipation factor ~ 0.025 and variation of dielectric constant from +10°C to +85°C was found to be within +8 to -40%.
Example 4_
A batch composition containing 15.00 g BaTiO3, 0.90 g CaZrO3 (prepared as in example 1), 0.09 g Nb2O5, 0.10 g Li2C2O4, 0.10 g Bi203, 0.03 g CuO and 0.55 g BaC03 along with 10 g distilled water was prepared by mixing the aforesaid powders in a ball mill for 15 h. The mixed slurry was dried at 150°C in an oven for 4 h. The dried mixture was calcined at 750°C for 10 h followed by dry grinding in a ball mill for 5 h to get the capacitor composition (mixed powder).
For testing, pellets of mixed powder (10 mm dia. and 2-3 mm thickness) were prepared by uniaxial pressing (pressure 50 MPa) using 1.5 wt.% (of mixed powder) ethyl cellulose binder. The samples were kept on a dense zirconia plate and were sintered at 1150°C for 3 h. The density of the sintered pellets was found to be ~ 5.33 g/cc, the room temperature dielectric constant ~ 6630, dissipation factor ~ 0.030 and variation of dielectric constant from +10°C to +85°C was found to be within + 9 to -28%.
The main advantages of the improved composition of the present invention are as follows:
1. The improved composition eliminates the necessity of any toxic
lead compound in the dielectric formulations.
2. The improved composition eliminates the necessity of any boron
compound in the dielectric formulations and hence environment -
friendly water based binders can be used during fabrication of
the capacitors from the powder mix.
3. The lead and boron free barium titanate based composition of
the present invention satisfy the requirements of high
dielectric constant, temperature stable Z5U type capacitors
and can be used as better and safe alternative of existing
dielectric compositions.

We Claim:
1. A process for the preparation of barium titanate based composition with
high dielectric constant and temperature stability which comprises:
a) adding 0.3 - 1.5 wt.% ( of BaTiO3) fluxes containing Li2C2O4, Bi2O3 and
CuO in a ratio in the range of 1:1:0.2 to 1:1:0.3 to BaTiO3 powder,
b) adding 4.0 - 9.0 wt. % CaZrO3,0.3-1.0 wt % Nb2O5 and 2.5-5.0 wt %
BaCO3 to the mixture obtained in step a), which acts as grain growth inhibitors and Curie peak suppressors,
c) mixing the said composition obtained in step b) in a ball mill with 60-80
wt.% ( of powder mix) distilled water for 10 - 20 h,
d) drying the mixture at 100 - 150°C in an oven for 2 - 4 h,
e) calcining the mixture at 600 - 800°C for 5 - 10 h and
f) dry grinding of the calcined powder in a ball mill for 5 - 10 h to obtain the
product.
2. A process for the preparation of barium titanate based composition with
high dielectric constant and temperature stability substantially as herein
described with reference to the examples.

Documents:

750-del-1998-abstract.pdf

750-del-1998-claims.pdf

750-del-1998-correspondence-others.pdf

750-del-1998-correspondence-po.pdf

750-del-1998-description (complete).pdf

750-del-1998-form-1.pdf

750-del-1998-form-19.pdf

750-del-1998-form-2.pdf

750-del-1998-form-3.pdf

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Patent Number

215162

Indian Patent Application Number

750/DEL/1998

PG Journal Number

10/2008

Publication Date

07-Mar-2008

Grant Date

21-Feb-2008

Date of Filing

24-Mar-1998

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI 110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	NIHARENDU HALDER	CGCRI INDIA.
2	ABHIJIT DAS SHARMA	CGCRI INDIA.
3	SANTA KUMAR KHAN	CGCRI INDIA.
4	AMARNATH SEN	CGCRI INDIA.
5	HIMADRI SEKHAR MAITI	CGCRI INDIA.

PCT International Classification Number

H01G 4/018

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA