The Effect of MgO Dopant and Laser Treatment on ZnO Ceramic

doi:10.4236/jmmce.2013.16045

Paper Menu >>

Journal Menu >>

Journal of Minerals and Materials Characterization and Engineering, 2013, 1, 301-306

Published Online November 2013 (http://www.scirp.org/journal/jmmce)

http://dx.doi.org/10.4236/jmmce.2013.16045

Open Access JMMCE

The Effect o f M g O Dopant a n d L aser Treatment on ZnO

Ceramic

Fadhil A. Chyad1, Shaymaa Q. Abul Hassan2, Zyad T. Al-Dahan3

1Department of Materials Engineering, University of Technology, Baghdad, Iraq

2Department of Physics, College of Ibn-Al-Haithm, Baghdad University, Baghdad, Iraq

3College of Engineering, University of Al-Nahrian, Baghdad, Iraq

Email: [email protected]

Received September 18, 2013; revised October 26, 2013; accepted November 6, 2013

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT

ZnO ceramic samples as pellets have been prepared and doped with (1, 2.5, 5, 10 wt%) of MgO powder, sintering at

1300˚C, these samples have been treated with laser at 400 J/cm2. X-ray diffraction spectra of the samples show some

changes in the X-ray parameters, where d-spacing and the intensities of the peaks are changed. FWMH of all the sam-

ples was altered due to MgO dopant and the laser influence microstructure was affected by the laser treatment, also, the

texture coefficient is affected.

Keywords: ZnO; Laser Treatment; Texture Coefficient; FWMH; X-Ray Diffraction

1. Introduction

Ceramic is an important class of materials which finds

increased applications as biomaterials, advanced structural

and engineering materials, where surface modifications

become important which were greatly influenced by the

surface microstructure defined by the morphology and

crystallographic texture of the surface grain [1].

ZnO is one of these ceramics with wide band gap

semiconductors which is used in optical devices near

ultraviolet region.

It has good optical, electrical and piezoelectric proper-

ties because it has high transparence in the visible wave

length range and low electric resistance and its band gap

is 3.3 eV at room temperature [2].

It has been used in many applications such as gas sen-

sors, bulk acoustic wave devices, transparent conductive

oxide, solar cell windows besides its applications as

biomaterials against bacteria (i.e. solution or powders for

skin ointment). Many studies have been conducted on

laser interaction with ceramic materials, for example,

ceramics welding with laser have been studied by Ikeda

[3]. For preventing crack for motion at the welded part, a

preheating at slow cooling was effective.

Mordike and Sivakumar [4] have used a laser beam to

locally melt and densify the ceramic coatings.

Harimkar and Dohotre [5] have discussed the micro-

structure development during surface modifications of

alumina ceramic using high power continuous wave

Nd:YAG laser.

Krasnikov et al. [6] have been studied the effect of la-

ser treatment with varying pulse duration and pumping

voltage on ceramic material. They found the amorphaza-

tion of the ceramic structure in the laser beam action

zone is established.

Ural et al. [7] have studied the effect of laser treatment

on the bonding between zirconia ceramic surface and

resin cement which has a clear effect on the microstruc-

ture of bonding region.

Abeidia et al. [8] have studied the realization of molt-

ed layers with the CO2 laser on sintered alumina cera-

mic.

Dyshlovenko et al. [9] have used CO2 laser to treat

plasma sprayed hydroxylapatite coating. The laser beam

was scanned with speed of 6.4 mm/s. SEM and X-ray

diffraction enabled the determination of quantitative

phase composition.

Dimitrov et al. [10] have used pulsed laser deposition

which can provide crystallization at relatively low sub-

strate temperature due to the higher energy of the ablated

particles in the laser—produce plume and relatively high

deposition rates.

Adawya et al. [11] have studied the deposition of

Al2O3 on glass substrate by PLD in 10−3 m bar oxygen

F. A. CHYAD ET AL.

302

ambient at different alumina concentration with laser

fluency energy 0.4 J/cm².

The aim of this work is to study the influence of Nd:

YAG laser on the microstructure and morphology of

ZnO ceramic with and without MgO.

2. Experimental Procedure

2.1. Materials Used

In the present study, ZnO powder used was obtained

from Fluka Company with 99.5% purity, and less than

25% µm particle size MgO obtained from Boh Company

with the purity 99.5%, and 25 µm particle size. PVA

(poly vinyl alcohol) is used as binder.

2.2. Equipments Used

1) Nd:YAG laser with 400 J/cm².

2) Digital balance (0.0001 gm) sensitivity.

3) Oven type cooper heat.

4) Hydraulic press type (BeGo) capacity 5 tons.

5) Electrical furnace (Ruhs Tral Co.) up to 1350˚C.

6) X-ray diffractions type (XRD 6000 SHIMADZU

JAPAN, λ = 1.5405A˚).

7) Optical microscope type (OLYMPUS OPTICAL

Co. LTD. JAPAN).

2.3. Samples Preparation

ZnO powder mixed thoroughly with 1.5% of PVA as a

binding material and pressed at 3 tons as a disc of 10 mm

diameter and 4mm thickness.

Other samples contain four percentages of MgO (1

wt%, 2.5 wt%, 5 wt% and 10 wt%) mixed and pressed as

the same above procedure.

All the samples dried at 80˚C in an oven for six hours

and then sintered in an electrical furnace at 1300˚C with

5˚C/min as a heating rate for 2 hrs and then cooling at the

same rate. All the samples have been treated with pulsed

laser.

3. Results and Discussion

3.1. Analysis of X-Ray Spectra

Laser surface modification of ZnO and ZnO doped MgO

ceramics with the range of laser influence (400 J/cm²)

employed in the present study.

X-ray diffraction patterns obtained at room tempera-

ture for ZnO sample before and after laser treatment are

shown in Figures 1 and 2.

After treatment, there was a change in the intensities

of the peaks with sharp altitude, also shift slightly to-

wards high 2



values which mean the d-spacing values

are decreased.

Figures 3-10 show the X-ray spectra of ZnO doped

Figure 1. XRD Spctrum of pure ZnO.

Figure 2. XRD Spctrum of treated ZnO by Laser.

Figure 3. XRD of ZnO doped with 1 wt% MgO sintered at

1300˚C.

Figure 4. XRD Spectrum of ZnO 1 wt% MgO treated by

Laser.

Open Access JMMCE

F. A. CHYAD ET AL. 303

Figure 5. XRD Spectrum of ZnO 2.5 wt% MgO.

Figure 6. XRD Spectrum of treated ZnO 2.5 wt% MgO.

Figure 7. XRD Spectrum of ZnO 5 wt% MgO.

Figure 8. XRD Spectrum of treated ZnO 5 wt% MgO.

Figure 9. XRD Spectrum of ZnO 10 wt% MgO.

Figure 10. XRD Spectrum of ZnO 10 wt% MgO treated by

Laser.

with different percentages of MgO (1 wt%, 2.5 wt%, 5

wt% and 10 wt%) before and after treatment by laser. At

1 wt% MgO dopant it is cleared that d-spacing is in-

creased by introducing the MgO oxide and the altitude of

peak intensities is increased again and the d-spacing val-

ues decreased at the laser treatment, but still higher than

those of pure ZnO as shown in Figure 4.

At 2.5 wt% MgO again sharp and high altitude of

peaks have shown with decreasing in d-spacing but after

treatment with laser the change in d-spacing values are

small with sharp peaks as shown in Figure 6.

Increasing the doping to 5 wt% MgO high peaks in-

tensities observed and the d-spacing values are decreased

sharply as shown in Figure 7. Figure 8 shows the spec-

tra of laser treatment of the samples have sharp peaks

and high intensities are observed with decreasing in d-

spacing values.

A small intensity peak at 2



equal 43.04 appeared in

this spectra which is belong to MgO according to N 1997

JCPAS No. 45-0946.

Figure 9 shows the spectra of 10 wt% MgO which has

very sharp peak with high intensity and high d-spacing

values , but at the treatment with laser the intensities are

decreased slightly with decreasing of d-spacing values , a

new peak with 2θ equal 42.63 which belong to MgO ob-

served with slight high intensity in Figure 10.

Open Access JMMCE

F. A. CHYAD ET AL.

304

In general, the analysis of X-ray spectra revealed a

systematic variation of relative intensities and d-spacing

values for all the spectra planes with MgO dopant and

laser influence.

3.2. Analysis of Texture Coefficient

Figure 11 shows the values of FWHM for all the sam-

ples which show that the addition of MgO is increased

the value of FWHM and the maximum is at 1 wt% and

then decreased, with treated the samples by laser the

value of pure ZnO is increased and the same behavior

with the doping of MgO.

The development of texture with the laser influence

can be quantified in terms of the texture coefficient (TC)

given by [3]:

 



I hklI hkl

Tc hklIhkl nIhkl





















where I(hkl) are measured intensities of (hkl) reflection,

Io(hkl) are powder reflection intensities of ZnO according

to ICDD PDF ≠ 36 - 1451 and (n)is the number of reflec-

tions used in the calculation.

Following (hkl) reflections corresponding (100,002,

101,102,110) of the samples the results of TC calculation

for (100) reflection are presented in Figure 12.

The figure indicates that the TC increased gradually

with increasing MgO content which reached maximum

value at 2.5 wt% and then decreased progressively; thus

substantiating the formation of strong (100) texture at the

intermediate MgO content, these two regimes of ex-

plored MgO contained less and greater than 2.5 wt%.

The variation of TCs and the relative intensity of (100)

plane corresponding closely with the regimes of MgO

content and laser influence which showed a distinct va-

riation in the morphology of surface grains in laser sur-

face modified ZnO ceramic as shown in Figure 12.

3.3. Analysis of Microstructures

The effect of laser irradiation on the surface microstruc-

ture of ZnO and ZnO doped MgO are illustrated in Fig-

ures 13-17. These figures present a set of optical surface

images which represent the untreated and treated samples

at laser influence of 400 J/cm².

The untreated samples consisted of irregular ZnO and

MgO grains with a degree of interconnected porosity.

It is evident that the surface microstructure of laser

modified ZnO ceramic is characterized by faceted po-

lygonal surface grains with varying size and the exten-

sion of surface faceting depend on MgO contend and

laser influence.

Some of the surface grains tend to deviate from po-

lygonal shapes transferred from irregular to near circular

shapes.

0.1

0.2

0.3

0.4

01020

FWHM

Content ofMgO

FWHM

FWHM laser

treatm ent

Fi gure 11. Variation of (100) FWHM of untreated and treat-

ed samples with laser influences.

1.2

1.25

1.3

1.35

1.4

051015

Conte nt ofMgO

Tcl

Figure 12. Variation of (100) TC of untreated and treated

samples with laser influences.

(a)

(b)

Figure 13. Micrograph optical microscope of (a) untreated

and (b) laser treated of pure ZnO.

Open Access JMMCE

F. A. CHYAD ET AL. 305

(a)

(b)

Figure 14. Micrograph optical microscope of (a) untreated

and (b) laser treated of ZnO with 1 wt% MgO.

(a)

(b)

Figure 15. Micrograph optical microscope of (a) untreated

(a)

(b)

Figure 16. Micrograph optiicroscope of (a) untreated cal m

and (b) laser treated of ZnO with 5 wt% MgO.

(a)

(b)

Figure 17. Micrograph optiicroscope of (a) untreated

and (b) laser treated of ZnO with 10 wt% MgO.

cal m

and (b) treated ZnO with 2.5 wt% MgO.

Open Access JMMCE

F. A. CHYAD ET AL.

Open Access JMMCE

306

fications of ZnO ceramic and ZnO

RENCES

[1] F. K. Shan anperties of Pure and

Al Doped ZnO with Plasma Pro-

Grown on Sapphire,” Journal

, Oberursel,

Laser-Dressed Alumina Grinding Wheel

ucture and

4. Conclusions

Laser surface modi

doped with different percentages of MgO with Nd-YAG

laser results in the formation of surface microstructure

consisted of faceted surface grain have been observed.

MgO dopant and laser influence have changed the pa-

rameters of microstructure of ZnO such as FWHM, d-

spacing, 2θ and intensities of the peaks besides the tex-

ture coefficient (TC)n.

REFE

d Y. S. Yu, “Optical Pro

Thin Films Fabricated

duced by Excimer Laser,” Thin Solid Films, Vol. 435, No.

1-2, 2003, pp. 174-178.

[2] A. Ashida, H. Ohta, J. Nagata and T. Ito, “Optical Propa-

gation Loss of ZnO Films

of Applied Physics, Vol. 95, No. 4, 2004, pp. 1673-1676.

[3] M. Iked, “Ceramics Welding with Laser,” Taikabutsu

Overseas, Vol. 5, No. 3, 1985, pp. 27-33.

[4] B. l. Mordike and R. Sivakumar, “Laser Treatment of

Materials,” DGM Information Sgesell Schaft

1987, p. 373.

[5] S. P. Harimkar and N. B. Dabotre, “Evolution of Surface

Morphology in

Material,” International Journal of Applied Ceramic

Technology, Vol. 3, No. 5, 2006, pp. 375-381.

[6] A. Krasnikov, A. Berezhnoi and L. Mrkim, “Str

Properties of Ceramic Material after Laser Treatment,”

Glass and Ceramic, Vol. 56, No. 5-6, 1999, pp. 172-176.

[7] C. Ural, T. Kulunk, S. Kulunk and M. Kurt, “The Effect

of Laser Treatment on Bonding between Zirconia Cera-

mic Surface and Resin Cement,” Acta Odontologica Scan-

dinavica, Vol. 68, No. 6, 2010, pp. 354-359.

http://dx.doi.org/10.3109/00016357.2010.51472

ealiza-

, L. Pawlowski, I. Smurove and V. Veiko,

imitrov, P. A. Atanasov and T. Vasiler, “Al-Doped

wiya, et al., “Effect of Alumina-Doping Struc-

[8] H. Abeidia, A. Issa, M. Robin and G. Faniossi, “R

tion of Melted Layers with CO2 Laser on Sintered Cera-

mic,” Journal de Physique IV, Vol. 1, No. C7, 1991, pp.

39- 42.

[9] S. Dyshlovenko

“Pulsed Laser Modification of Hydroxylapatite Ceramic,”

Surface and Coatings Technology, Vol. 201, 2006, pp. 2248-

2255.

[10] J. G. D

ZnO Thin Films for Gas Sensor Application,” Journal of

Physics: Conference Series, Vol. 113, 2008, Article ID:

012044.

[11] J. H. Ada

tural and Optics Properties of ZnO Thin Film by Pulsed

Laser Deposition,” Journal of Engineering & Technology,

Vol. 28, No. 14, 2010, pp. 4677-4686.