Effects of mixing proportions and firing temperature on properties of electric porcelain from Ugandan minerals
2008 (English)In: Industrial ceramics, ISSN 1121-7588, Vol. 28, no 1, 1-10 p.Article in journal (Refereed) Published
Five sample mixtures of Ugandan kaolin, ball clay, feldspar and flint were formulated and porcelain samples fabricated by extrusion through a vacuum pugmill. Samples were evaluated for formability. The degree of densification of sintered specimens fired at 1200 to 1350 degrees C was evaluated by measuring the firing shrinkage, bulk density, water absorption and bending strength. Crystalline phases and mullite morphology were studied using XRD and SEM respectively. Dielectric strength measurements were carried out on disc specimens. Dielectric and bending strength properties deteriorated at high temperatures because of pore formation and decreasing amount of undissolved quartz in the crystalline phase. An optimum composition of 30% kaolin, 15% ball clay, 30% feldspar and 25% quartz yielded an unglazed body with highest bending strength of 72MPa and dielectric strength of 19MVm(-1) after firing at 1250 degrees C. The body consisted of small, closely packed mullite needles and undissolved quartz crystals embedded in a glass matrix.
Place, publisher, year, edition, pages
2008. Vol. 28, no 1, 1-10 p.
rice husk ash, whiteware compositions, bending strength, mechanical-behavior, raw-materials, silica fume, fly-ash, quartz, substitution, constitution
IdentifiersURN: urn:nbn:se:kth:diva-17593ISI: 000256573400001ScopusID: 2-s2.0-45749156420OAI: oai:DiVA.org:kth-17593DiVA: diva2:335637
QC 201005252010-08-052010-08-052010-11-22Bibliographically approved