Nur Bahijah Mustapa, Romisuhani Ahmad, Mohd Mustafa Al Bakri Abdullah, Wan Mastura Wan Ibrahim, Andrei Victor Sandu, Ovidiu Nemes, Petrica Vizureanu, Christina W. Kartikowati, Puput Risdanareni
This research aims to study the effects of the sintering mechanism on the crystallization kinetics when the geopolymer is sintered at different temperatures: 200 °C, 400 °C, 600 °C, 800 °C, 1000 °C, and 1200 °C for a 3 h soaking time with a heating rate of 5 °C/min. The geopolymer is made up of kaolin and sodium silicate as the precursor and an alkali activator, respectively. Characterization of the nepheline produced was carried out using XRF to observe the chemical composition of the geopolymer ceramics. The microstructures and the phase characterization were determined by using SEM and XRD, respectively. The SEM micrograph showed the microstructural development of the geopolymer ceramics as well as identifying reacted/unreacted regions, porosity, and cracks. The maximum flexural strength of 78.92 MPa was achieved by geopolymer sintered at 1200 °C while the minimum was at 200 °C; 7.18 MPa. The result indicates that the flexural strength increased alongside the increment in the sintering temperature of the geopolymer ceramics. This result is supported by the data from the SEM micrograph, where at the temperature of 1000 °C, the matrix structure of geopolymer-based ceramics starts to become dense with the appearance of pores. © 2023 by the authors.
Faculty of Mechanical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Perlis, Arau, 02600, Malaysia; Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), Universiti Malaysia Perlis (UniMAP), Perlis, Arau, 02600, Malaysia; Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Perlis, Arau, 02600, Malaysia; Faculty of Material Science and Engineering, Gheorghe Asachi Technical University of Iasi, Iasi, 700050, Romania; Romanian Inventors Forum, Str. Sf. P. Movila 3, Iasi, 700089, Romania; Academy of Romanian Scientists, 54 Splaiul Independentei St., Sect. 5, Bucharest, 050094, Romania; Department of Environmental Engineering and Sustainable Development Entrepreneurship, Faculty of Materials and Environmental Engineering, Technical University of Cluj-Napoca, B-dul Muncii 103-105, Cluj-Napoca, 400641, Romania; Technical Sciences Academy of Romania, Dacia Blvd 26, Bucharest, 030167, Romania; Department of Chemical Engineering, Universitas Brawijaya, Malang, 65145, Indonesia; Department of Civil Engineering, Faculty of Engineering, Universitas Negeri Malang, Malang, 65145, Indonesia