Preparation of nano-gypsum from anhydrite nanoparticles: Strongly increased Vickers hardness and formation of calcium sulfate nano-needles
The preparation of calcium sulfate by flame synthesis resulted in the continuous production of anhydrite nanoparticles of 20–50 nm size. After compaction and hardening by the addition of water, the anhydrite nanoparticles reacted to nano-gypsum which was confirmed by X-ray diffraction, diffuse reflectance IR spectroscopy and thermal analysis. Mechanical properties were investigated in terms of Vickers hardness and revealed an up to three times higher hardness of nano-gypsum if compared to conventional micron-sized construction material. The improved mechanical properties of nano-gypsum could in part be due to the presence of calcium sulfate nano-needles in the nano-gypsum as showed by electron microscopy.
Key wordsVickers hardness gypsum nanoparticles compaction construction material nano-needle nanocomposites
Unable to display preview. Download preview PDF.
This work was financed by the ETH Zurich. The authors would like to thank Dr. F. Krumeich for transmission electron microscopy and Prof. L. J. Gaukler for SEM measuring time.
- Bushuew N., Maselnnikow B.M., Borisov V.M. (1983). Phase transformations in the dehydration of CaSO4 2· H2O. Russ. J. Inorg. Chem. 28:1404Google Scholar
- Hand R.J. (1997). Calcium sulphate hydrates: A review. Br. Ceram. Trans. 96(3):116–120Google Scholar
- Huber M., W.J. Stark, S. Loher, M. Maciejewski, F. Krumeich & A. Baiker, 2005. Flame synthesis of calcium carbonate nanoparticles. Chem. Commun. 648–650Google Scholar
- Madler L., Stark W.J., Pratsinis S.E. (2002b). Flame-made ceria nanoparticles. J. Mater. Res. 17(6):1356–1362Google Scholar
- Olsen D.W., 2004. Mineral Commodity Summaries. U.S. Geological Survey, pp. 76–77Google Scholar
- Peters C.P., Hines J.L., Bachus K.N., Craig M.A., Bloebaum R.D. (2005). Biological effects of calcium sulfate as bone graft substitute in ovine metaphyseal defects. J. Biomed. Mater. Res. A. 76A(3):456–462Google Scholar
- Sandler S.I. (1999). Chemical and Engineering Thermodynamics. John Wiley & Sons, New YorkGoogle Scholar
- Stark W.J., L. Mädler & S.E. Pratsinis, 2004. Metal oxides prepared by flame pyrolysis, WO2004/005184 2004Google Scholar
- Xu C.H. (2005). Research and application of ceramic die materials. Rare Metal Mater. Eng. 34:262–265Google Scholar
- Zhan G.D., Mukherjee A.K. (2005). Processing and characterization of nanoceramic composites with interesting structural and functional properties. Rev. Adv. Mater. Sci. 10(3):185–196Google Scholar