N. Hidayat, Istiqomah, M.Y.H. Widianto, A. Taufiq, Sunaryono, Triwikantoro, M. Zainuri, M.A. Baqiya, G. Aristia, S. Pratapa
An attempt has been developed to establish the prospect of the useful application of Indonesian natural silica sand, instead of commercially expensive materials, as a future fuel-cell sealant. The sand was initially washed and ball-milled at 150 rpm for 60 minutes and then heated at 1000 °C for the same duration. The resulting powder was then mixed with alumina powder at various amounts and shaped into discs before sintering at 1150 °C and 1250 °C to produce compact ceramics. The diameter shrinkage, porosity, and density of the ceramics were evaluated by Archimedes method. Their crystalline phase composition was quantified by Rietveld refinement analysis on the X-ray diffraction (XRD) data and the phase weight fraction was then used for coefficient of thermal expansion (CTE) evaluation. It was observed that the bulk density increased while the porosity decreased with alumina addition. The XRD data analysis revealed that the prepared silica sand contains a very high purity of quartz-SiO2, i.e. 97.8(18)%. The sintering temperatures of 1150 °C and 1250 °C transformed some quartz-SiO2 to crystobalite-SiO2. All the calcite-CaCO3 exhibited reaction sintering with SiO2 forming wollastonite-CaSiO3. Therefore, the ceramic composites contained SiO2/Al2O3/CaSiO3. Regarding CTE, all of the composites meet the criteria for fuel-cell sealants, in the range of 9-12 ppm/°C. © Published under licence by IOP Publishing Ltd.
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, State University of Malang, Jl. Semarang 5, Malang, 65145, Indonesia; National Standardization Agency of Indonesia, Jl. M. H. Thamrin No 8, Kebon Sirih, Jakarta Pusat, 10340, Indonesia; Department of Physics, Faculty of Mathematics and Natural Sciences, Institute of Technology Sepuluh Nopember, Jl. Arif Rachman Hakim, Surabaya, 60111, Indonesia; Center for Minerals and Advanced Materials, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, State University of Malang, Jl. Semarang 5, Malang, 65145, Indonesia; Department of Physical and Theoretical Chemistry, Institute of Chemistry and Biochemistry, Freie Universitat, Kaiserswerther Str. 16-18, Berlin, 14195, Germany
