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Study the affect of Silica on the physical and electrical properties of Alumina (Al2O3) | ||
| journal of al-qadisiyah for pure science(quarterly) | ||
| Article 1, Volume 9, Issue 1, 2009, Pages 139-153 PDF (0 K) | ||
| Author | ||
| Hani mahmood hussien | ||
| Abstract | ||
| The research concerns with physical properties (linear firing shrinkage ,bulk density ,open porosity , and water absorption ) and electrical properties up to 1 MHz ( dielectric constant ,electrical conductivity and power factor ) of samples prepared from Alumina powder with Quartz additives .Samples were pressed at pressure 50 MPa by using a mould has diameter 5 cm and fired at temperature 1500 OC with maturing time 2.5 hr . The research ,in the course of studying the above properties , aims to an accurate clarifying to the effect of Quartz additives percentage (5 %, 10% , 20 % , and 30 % )on the physical and electrical properties Alumina.It was found that the water absorption and open porosity decreased with increasing of Quartz additives .Also ,it was found clearly decreasing in linear shrinkage (from 5 % to 4.2 % ) at Quartz additives 5 % and 10 % ; while the variation was a trace at 20 % and 30 % ( from 4.6 % to 4.5 % ) respectively .Also , it was found decreasing of bulk density with increasing of Quartz additives up to 10 % from 1.518 gm/cm3 to 1.434 gm/cm 3 then it increased with increasing of Quartz up to 30 % from 1.541 gm/cm3 to 1.586 gm/cm 3 . In relation to electrical properties ,at the frequency 1 KHz , it was found that 5 % of Quartz additives result in maximum values of dielectric constant and power factor and electrical conductivity. The same behavior was found at 1 MHz except dielectric constant; while the 30 % of Quartz additives gave maximum dielectric constant(3.15 ) and minimum electrical conductivity and power factor (4.47*10 -8ohm-1.cm-1 ,0.0255) respectively .In general it was found ,through the curves of electrical properties with increasing of Quartz additives , that the ratio 5 % gave larger values of electrical conductivity within the extent of frequency from 200 Hz to 1 MHz ,then it decreased at the additives 10 % and 20 % .While at ratio 30 % gave minimum values of electrical conductivity compared to Alumina. The same behavior was found relative to power factor curves. | ||
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