Fabrication of Structural Leucite Glass–Ceramics from Potassium‐Based Geopolymer Precursors

Abstract

Leucite glass–ceramics were fabricated by cold isostatically pressing K2O·Al2O3·4SiO2·11H2O geopolymer powders into pellets followed by firing at 950°–1200°C, every 50°C in air. Leucite formation was observed in specimens heat treated to ≥1000°C. The relative density, Vickers hardness, fracture toughness, and biaxial flexural strength of sintered samples ranged approximately 96%–98%, 767–865 kg/mm2, 0.94–2.36 MPa·m1/2, and 90–140 MPa, respectively. The toughness and biaxial flexure strength increased with the firing temperature, while the density and hardness were relatively constant. Scanning electron microscopic and transmission electron microscopic analysis revealed that the sintered geopolymer formed leucite crystals and a compositionally variable glassy phase. Samples heated to 1200°C attained the highest biaxial flexure strength and toughness. This higher strength is believed to arise from an optimum in density, leucite content, and crystal size distribution.

XRD and FTIR study of the effect of ultra high molecular weight polyethylene (UHMWPE) as binder on kaolin geopolymer ceramics

“…The figure shows that significant amount of amorphous phase exist in kaolin as indicates by humps between 20 ° to 40 °. Generally pure kaolin consists of kaolinite as main mineral [12]. The characteristic kaolinite peaks are at 2θ values of 24.9° and 26.7°.…”

“…Many studies have concentrated on the use of metakaolin [4,9,10] because of its higher reactivity, which lead to optimal performance, slightly than the less reactive of kaolin [11]. In addition, the use of metakaolin instead of other materials has been found to produce more homogeneous geopolymers [12]. As a result, there is limited study on green polymeric composites by using kaolin.…”

Kaolin Geopolymer as Precursor to Ceramic Formation

“…Despite being used in refractory and high temperature applications, geopolymers is gaining interest as precursors to ceramic formation. Cesium based geopolymers often used to produce pollucite ceramic [18,19] and potassium based geopolymers as precursor to leucite ceramic [20,21]. However, limited research was founded on using kaolin as the source materials and sodium based geopolymers.…”

Properties and Microstructural Characteristic of Kaolin Geopolymer Ceramics with Addition of Ultra High Molecular Weight Polyethylene

“…Several studies have focused on the use of metakaolin [11 -13] because of its higher reactivity, which contributes to optimal performance, slightly than the less reactive of kaolin [14]. Besides, the use of metakaolin instead of other materials has been found to produce more homogeneous geopolymers [15]. Thus, there is a lack of study on green polymeric composites by using kaolin.…”