Processing and Characterization of Porous Silica-Ag-Nanoparticle Composites Produced by Pulsed Electric Current Sintering

Abstract:

This paper studies influence of the process temperature and time on the properties of the compacts made of Ag-SiO2 powder by the pulsed electric current sintering (PECS). Silica particles doped with Ag nanoparticles were prepared by modified Stöber method, and calcinated at 573 K in air resulting in average silica particle size of ~1.1 µm and agglomerate size up to 32 µm. There was about 7 wt.% of silver in the structure and the diameter of the silver particles on the silica carriers was 30 ±7 nm on average. The composite powder was sintered into porous compacts by PECS at 873, 973, 1073, or 1173 K for 10, 20, or 30 min under pressure of 50 MPa. Samples were characterized by SEM, XRD, UV-vis-spectrometer, and laser diffraction. During PECS compaction grain growth of silver particles was observed and the measured average size of Ag in 873 K and in 1173 K samples were 65 nm and 170 nm, respectively. The porosity of the materials did not show remarkable change, as the relative density ranged from 76 to 79 %. Thus, it is possible to produce porous silica based materials with controlled Ag-nanoparticle size by PECS. These materials may be optimized for, e.g., different kinds of antibacterial filters.

• Periodical: Key Engineering Materials (Volume 527)
• Pages: 38-43
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.527.38
• Online since: November 2012
• Authors: Juha Larismaa, Outi Söderberg, Jesse Syrén, Eero Haimi, Simo Pekka Hannula
• Keywords: Electron Microscopy, Porous Material, Powder metallurgy, Sintering, X-Ray Diffraction (XRD)

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