Borik asit katkılı pomza esaslı izolasyon malzemesi geliştirilmesi

Abstract

 Boric acid addition decreased thermal conductivity  Temperature higher than 700 °C provides lower conductivity  The addition of perlite and cenosphere increased the thermal conductivity of pumice Figure A. The effect of the materials mixed at 700 °C on the density and thermal conductivity of pumice Purpose: This study investigates the effects of additives on the thermal conductivity and density of pumicebased ceramic foams. Theory and Methods:Composition preparation was carried out by grinding the dried pumice, boric acid, perlite, and cenosphere in porcelain jars for 2 hours. Dry pressing of all samples was carried out using uniaxial pressing at a pressure of 1000 kg/cm 2 in steel molds. It was pressed using a circular die of 80 mm diameter and 20 mm thickness to measure thermal conductivity. Samples were heated with a heating rate of 5 °C/min to temperatures between 500 °C and 700 °C. When the specified temperatures were reached, they were kept for 24 hours in a furnace. Sintered densities were measured according to ASTM C518 by applying the Archimedes principle. The heat flow meter was used to measure the thermal conductivity. Density measurements were carried out with a scale with 0.1 gr sensitivity. Results:The temperature increase decreased the thermal conductivity of the Pumice-Boric acid mixture. The addition of boric acid to pumice, with sintering at 700 °C, decreased the thermal conductivity by 42%, decreased 0.236 W/m.K, and the density by 44.8%, reducing it to 0.64 g/cm3. As expected, adding boric acid lowered the melting temperature of pumice. Sintering performed at 700 ° C, adding perlite and fly ash to the pumice boric acid mixture in addition to the mixture increased the thermal conductivity and density. Perlite addition increased the thermal conductivity by 0.374 W/m.K, while the addition of fly ash decreased it to 0.359 W/m.K. While the density decreased to 1.06 g/cm3 with the addition of perlite, it decreased to 1.1 g/cm3 with the addition of the cenosphere. Conclusion:In order to decrease thermal conductivity further, higher temperatures of sintering and a higher amount of boric acid addition to pumice could be investigated in future studies.