The Effect of SiO2 AdditionThe Effect of SiO2 Additionon the Characteristics of CuFe2O4 Ceramicson the Characteristics of CuFe2O4 Ceramics

for NTC Thermistorsfor NTC Thermistors

Wiendartun Wiendartun 11), Dani Gustaman Syarif ), Dani Gustaman Syarif 22))

11)) Department of Physics, UPI, Bandung. Department of Physics, UPI, Bandung. 22 )Nuclear Technology Center for Materials and )Nuclear Technology Center for Materials and

Radiometry Radiometry –– BATAN, Bandung.BATAN, Bandung.

INTRODUCTIONINTRODUCTION

THERMISTORTHERMISTOR Thermally Sensitive Resistor.Thermally Sensitive Resistor.NTC CHARACTERISTIC : PRODUCT EXAMPLES:NTC CHARACTERISTIC : PRODUCT EXAMPLES:

INTRODUCTIONINTRODUCTION (Continuation)(Continuation)

Important electronic component. Important electronic component. -- Sectors: Biomedical, aerospace, instrumentation, communications, Sectors: Biomedical, aerospace, instrumentation, communications,

automotive and HVACR (Heating, Ventilation, Air conditioning and automotive and HVACR (Heating, Ventilation, Air conditioning and Refrigeration).Refrigeration).--Application : Temperature measurement, circuit compensation, Application : Temperature measurement, circuit compensation,

suppression of in rushsuppression of in rush--current, flow rate sensor and pressure sensor. current, flow rate sensor and pressure sensor. Most, thermistors are produced from spinel ceramics based on Most, thermistors are produced from spinel ceramics based on Most, thermistors are produced from spinel ceramics based on Most, thermistors are produced from spinel ceramics based on transition metal oxides forming general formula AB2O4.transition metal oxides forming general formula AB2O4.Need alternative (Expecially based on abundant material (mineral) Need alternative (Expecially based on abundant material (mineral) in Indonesia) in Indonesia) CuFeCuFe22OO44 is proposed, including that added with is proposed, including that added with SiOSiO22..Predicted that the SiOPredicted that the SiO22 addition can improve the characteristics of addition can improve the characteristics of the CuFethe CuFe22OO44 ceramic for NTC thermistors.ceramic for NTC thermistors.

EXPERIMENTEXPERIMENT

CuO Fe3O4 SiO2

MIXING

XRD

CALCINATION

CRUSHING

SIEVING

PRESSING

SINTERING1100oC/2h

CHARACTERIZATION-XRD-Electrical-Microstructural

3,9 ton/cm2

800oC/2h

Sintering Furnace

Optical Microscope

RESULTS (XRD)RESULTS (XRD)

0 w/o SiO20.25 w/o SiO2

0

50

100

150

200

250

300

350

15 25 35 45 55 65 75

2q (Derajat)

Inte

ns

ita

s (

Cp

s)

101 202 220

303

224 413404

112

211

312

XRD profiles of CuFe2O4 based-ceramics.

0 w/o SiO20.25 w/o SiO2

0.75 % SiO2

2q (Derajat)

Inte

ns

ita

s (

a.u

.)

0.50 w/o SiO2

0

50

100

150

200

250

15 25 35 45 55 65 75

2q (Derajat)

Inte

nsi

tas

(Cp

s)101

112/200

211

103

202220

312

303224

413 404

RESULTS (Microstructure)RESULTS (Microstructure)

Microstructure of the CuFe2O4 based-ceramics.

0 w/o SiO2

0.75 w/o SiO2

0.25 w/o SiO2

50 m

RESULTSRESULTS(Electrical Characteristics)(Electrical Characteristics)

6

7

8

9

10ln

Res

isti

vit

y li

stri

k, r

(ln

Oh

m-c

m)

0 w/o SiO2

0.25 w/o SiO2

Ln resistivity () vs 1/T of SiO2 added- CuFe2O4 ceramics.

2

3

4

5

0.0025 0.003 0.0035

1/T (1/oK)

ln R

esis

tiv

ity

list

rik,

0.50 w/o SiO2

0.75 w/o SiO2

RESULTSRESULTS(Electrical Characteristics)(Electrical Characteristics)

CuFe2O4 ceramics.

NoNo..Additive Additive of SiOof SiO22

(w/o)(w/o)

BB((ooK)K)

(%/(%/ooK)K)

RTRT(Ohm(Ohm--cm)cm)

Market requirement for B is ≥ 2000 oK and is ≥ 2.2 %/oK[7], market requirement for RT = 10 ohm.cm -1 Mohm.cm [4].

1.1.2.2.3.3.4.4.

0,000,000.250.250.500.500,750,75

25482548

23582358

28842884

33083308

2,832,83

2,622,62

3,203,20

3,683,68

291291

10791079

47884788

9400 9400

CONCLUSIONSCONCLUSIONSThe CuFeThe CuFe22OO4 4 ceramics can be applied as NTC ceramics can be applied as NTC Thermistor.Thermistor.

The grain size of the CuFeThe grain size of the CuFe22OO4 4 ceramics tends to ceramics tends to decrease by addition of SiOdecrease by addition of SiO22. .

The addition of SiOThe addition of SiO22 increased the room increased the room The addition of SiOThe addition of SiO22 increased the room increased the room temperature resistivity (temperature resistivity (RT) and the thermistor RT) and the thermistor constant (B) of the CuFeconstant (B) of the CuFe22OO44 ceramics due to the ceramics due to the segregated SiOsegregated SiO22. .

The value of (The value of (RTRT) and (B) of the CuFe) and (B) of the CuFe22OO44ceramics made in this work fits the market ceramics made in this work fits the market requirement.requirement.

THANK YOUTHANK YOU

ACKNOWLEGMENTACKNOWLEGMENTTheThe authorsauthors wishwish toto acknowledgeacknowledge theirtheir deepdeep gratitudegratitudetoto DIKTI,DIKTI, DepartmentDepartment ofof NationalNational EducationEducation ofofIndonesianIndonesian GovernmentGovernment forfor financialfinancial supportsupport underunderhibahhibah PekertiPekerti programprogram withwith contractcontracthibahhibah PekertiPekerti programprogram withwith contractcontractNoNo..014014/SPP/PP/DP/SPP/PP/DP22M/II/M/II/20062006