- Restrictions on Access:
- Restricted (Penn State Only).
- Pure Nanocrystallite akermanite powder was synthesized using initial materials: calcium carbonate, magnesium carbonate, and silica. Initial materials were mechanically activated and subsequently annealed at various temperatures. Resultant powders were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) mass spectrometry (MS), X-ray diffractometry (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results showed that pure nanocrystallite akermanite was synthesized from calcium carbonate, magnesium carbonate, and silica powders mechanically activated for 50 h and subsequently heat treated at 900 C for 1 h. Nanostructured akermanite had a crystallite size of 67 nm. Additionally, the formation mechanism of akermanite was evaluated. Results showed that akermanite forms through several transition compounds such as enstatite, wollastonite, larnite, and merwinite. Furthermore, pure nanocrystallite akermanite was synthesized via mechanical activation and heat treatment of talc, calcium carbonate, and silica. The formation mechanism was studied. The results showed that akermanite was synthesized through two parallel mechanisms. One was directly, and the other was through the formation and consumption of transitionary compounds. Pure akermanite synthesized through mechanical activation for 20 hours and subsequent heat treatment of 900 C for 1 h resulted in a crystallite size of 34 nm. Increased mechanical activation or heat treatment had no significant effect on the crystallite structure of akermanite. Mechanical properties of the synthesized akermanite was also evaluated. Akermanite synthesized with 20 h mechanical activation and heat treated at 900 C for 1 h resulted in a Youngs modulus of 3800 MPa, an ultimate compressive strength of 24.7 MPa, and a density of 2.489 g/cm3.
- Dissertation Note:
- M.S. Pennsylvania State University 2019.
- Technical Details:
- The full text of the dissertation is available as an Adobe Acrobat .pdf file ; Adobe Acrobat Reader required to view the file.
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