Enhancing the Value of Local Silica Sand from Bancar as a Fuel-Cell Sealing Material

Abstract:

A prospective fuel cell sealing material using silica sand from Bancar, Tuban, East Java has been investigated. The investigation was aimed to enhance the value of such natural sand and was started by a treatment using magnetic separation and immersion with HCl to produce pure silica powder. Ceramic composites were then synthesized by a solid state reaction method by mixing the silica powder, magnesia (MgO), and 5-20wt% of boria (B₂O₃), pressing the mixture into pellets and finally sintering them at 1150 °C for 4 hours. By Archimedes method, it was found that the addition of B₂O₃ is favorable to reduce the porosity of composites with a maximum value reaching 0.68(0)% for the composite with 20% B₂O₃. An X-ray diffraction technique revealed that a liquid phase sintering had occurred, indicated by the appearance of quartz (SiO₂), forsterite (Mg₂SiO₄) and protoenstatite (MgSiO₃) in the sample without B₂O₃ and quartz and protoenstatite in the composites with 5 and 10 wt% of B₂O₃. Meanwhile, the composite SMB15h, in addition to quartz and protoenstatit, also contains a new phase, namely suanite (Mg₂B₂O₅). In SMB204h, there are quartz and suanite.The phase compositions were determined using the Rietveld method from which thermal expansion coefficient values of 9.5-12 ppm °C^-1 had been predicted. These results showed that natural-sand-based composites could fairly satisfy the required conditions of fuel-cell sealing materials.

• Periodical: Advanced Materials Research (Volume 1112)
• Pages: 262-265
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1112.262
• Online since: July 2015
• Authors: Egidius Dewa, Musyarofah Musyarofah, Upik Nurbaiti, Triwikantoro Triwikantoro, Sukma Firdaus, Pratapa Suminar
• Keywords: Fuel-Cell Sealing Materials, Local Silica Sand, Porosity, Silica-Magnesia-Boria Ceramic Composites, Thermal Expansion Coefficient

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