Gadolinium Doped Ceria Lab Report
Abstract— The present work is about preparation and characterization of high temperature oxygen sensing composite material consisting of Gadolinium doped Ceria (GDC) together with a relatively low temperature melting, ionic conducting glass to facilitate lower sintering and operating temperature. This paper reports the physical and ionic conductivity properties of this sintered composite as a function of operating temperature.
Keywords—Gadolinium doped Ceria, oxygen sensor, composite, glass, ionic conductivity
I. INTRODUCTION
Gadolinium doped Ceria (GDC) is one of the promising oxygen ion conductor in the operating temperature range of 500-700 ˚C [1-4]. Due to the ionic conductivity properties, it has been extensively studied for electrolyte …show more content…
RESULTS AND DISCUSSION
The pellets were first characterized by XRD to identify the phase and crystal structure. The obtained XRD pattern is shown in Figure 1. The XRD pattern matches well with JCPDS card of pure GDC [Card No. 01-075-0162], having Face Centered Cubic (FCC) crystal structure. No additional peaks were observed due to addition of the glass. However, as seen in figure inset for the highest intensity peak, the peaks have shifted towards higher 2θ values due to a compressive strain induced by recrystallization of doped glass in lattice planes of GDC matrix [10].
The density of the sintered composite pellet was measured using standard weight volume method. This density was compared to the theoretically calculated density of the composite, viz. 7.8 gms cm-3 [11]. It was found that the pellets were sintered to about 95% of theoretical density. The shrinkage in diameter calculated for the pellet before and after shrinkage was about 9.8%. This shrinkage value is comparable to most commercial LTCC tapes and far higher than that of GDC-Bi2O3 pellet which showed 3% shrinkage when fired at 1000 °C.
Figure 2 presents Nyquist plot of the sample measured at different operating temperatures from 500 – 700
Keywords—Gadolinium doped Ceria, oxygen sensor, composite, glass, ionic conductivity
I. INTRODUCTION
Gadolinium doped Ceria (GDC) is one of the promising oxygen ion conductor in the operating temperature range of 500-700 ˚C [1-4]. Due to the ionic conductivity properties, it has been extensively studied for electrolyte …show more content…
RESULTS AND DISCUSSION
The pellets were first characterized by XRD to identify the phase and crystal structure. The obtained XRD pattern is shown in Figure 1. The XRD pattern matches well with JCPDS card of pure GDC [Card No. 01-075-0162], having Face Centered Cubic (FCC) crystal structure. No additional peaks were observed due to addition of the glass. However, as seen in figure inset for the highest intensity peak, the peaks have shifted towards higher 2θ values due to a compressive strain induced by recrystallization of doped glass in lattice planes of GDC matrix [10].
The density of the sintered composite pellet was measured using standard weight volume method. This density was compared to the theoretically calculated density of the composite, viz. 7.8 gms cm-3 [11]. It was found that the pellets were sintered to about 95% of theoretical density. The shrinkage in diameter calculated for the pellet before and after shrinkage was about 9.8%. This shrinkage value is comparable to most commercial LTCC tapes and far higher than that of GDC-Bi2O3 pellet which showed 3% shrinkage when fired at 1000 °C.
Figure 2 presents Nyquist plot of the sample measured at different operating temperatures from 500 – 700