Crystallisation of PFA glasses

Glasses with various compositions, falling in the CaO-AI20rSi02 and MgO-CaOAI20rSi02 systems were made, using pulverised fuel ash and silica, hydrated lime, kaolin and magnesium carbonate. Titania or ferric oxide and chromia were used as nucleants. Various crystallisation heat treatments were carried out and the nucleation and crystallisation behaviour was studied. A minimum MgO:CaO was found to be necessary for bulk nucleation to occur. The activation energy for viscous flow decreased with increased MgO:CaO ratios. This was accompanied by an increase in the surface crystal growth rates and a decrease in the activation energy for surface crystal growth. Titania also lowered the activation energies for viscous flow and surface crystal growth and caused an increase in the surface crystal growth rates.

Grantor dc:publisher.institution

Department of Mechanical Engineering

Year dc:date.issued

1994

Author dc:creator

• Emms, S

Advisor dc:contributor.advisor

• Heckroodt, R O

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/8485

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/8485