Banjuraizah Johar
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Banjuraizah Johar
Official Name
Banjuraizah, Johar
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Scopus Author ID
36782257500
Researcher ID
ELA-9787-2022

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  • Publication
    Formation of bio-based derived dicalcium silicate ceramics via mechanochemical treatment: physical, XRD, SEM and FTIR analyses
    ( 2023-07)
    Siti Nur Hazwani Yunus
    ;
    Khor Shing Fhan
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    Nur Hazlinda Jakfar
    ;
    Cheng Ee Meng
    ;
    Emma Ziezie Mohd Tarmizi
    ;
    Zainal Abidin Talib
    Beta-dicalcium silicate plays an important role in modern technology, but its tendency for polymorphic transformation results in the dusting phenomenon, is a major challenge. Therefore, mechanochemical treatment is used to reduce the particle size to retain the stability of the polymorph. In this study, pure dicalcium silicate ceramics of β-monoclinic structure with P 121/c1 space group were synthesized using calcium oxide and silicate powders derived from calcined eggshells and rice husks, respectively. The powders were mixed in a 2:1 molar ratio by mechanochemical treatment and heat-treated in the air at temperatures ranging from 900°C to 1100°C for 2 h. The results reveal that pure betadicalcium silicate formed at 1100°C without adding stabilizers. The properties of the pristine and sintered bodies were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). SEM revealed that the grain and pore sizes increase with rising sintering temperatures. FTIR spectra indicate the existence of Si-O bonds in -4 4 SiO tetrahedrons on all the samples. The sample sintered at 1000°C attains the lowest bulk density (1.2463 g/cm3), whereas the apparent porosity is the highest (62.5%). The reason for this trend is due to the decomposition of carbonate into CO2 gas. The densification onset for the sample sintered at 1100°C as the bulk density rises and grain size achieves 6.06 μm. This study further explains the effect of sintering temperatures on the physical, structural, and morphological properties of Ca2SiO4 which would also be useful for further optimization of its use.
  • Publication
    The effect of pressing load on 8 mol% Yttria stabilized Zirconia grade 204NS-G
    (Trans Tech Publications Ltd., 2020-09)
    Tinesha Selvaraj
    ;
    Banjuraizah Johar
    ;
    Khor Shing Fhan
    The aim of this study is to understand the compaction characteristics of as received granulated 8 mol% yttria-stabilized zirconia (8YSZ). The samples were compacted at different loads and sintered at 1550 °C with the heating rate of 5°C/min for 5 hours. The densification, morphology analysis and crystal structure of the sintered were compared. The densification of granulated 8YSZ achieved 67% as increasing pressing load (0.1 tonne to 0.4 tonne). Rietveld quantitative phase analysis demonstrates that the tetragonal-ZrO2 phase reduces in granulated 8YSZ. The amount of cubic-ZrO2 phase dramatically dropped for both granulated as the pressing load increased. From the morphology analysis, granulated sample found to be porous observed on the surface as compaction load applied. Compaction load has no significant effect on the densification of granule sintered 8YSZ in the current study. The maximum densification was only reached 67% by using granulated 8YSZ powder with 0.4 tonne pressing load.
  • Publication
    The thermal behavior of cordierite-based ceramic with the substitution of treated flue gas desulfurization sludge in the non-stoichiometric cordierite composition
    (Springer, 2023)
    Fatin Fatini Othman
    ;
    Banjuraizah Johar
    ;
    Khor Shing Fhan
    ;
    Nik Akmar Rejab
    ;
    Suffi Irni Alias
    The substitution of FGD sludge that is rich with a glass-forming agent in non-stoichiometric cordierite composition is able to crystallize α-cordierite at the low sintering temperature, 1250 °C via solid-state reaction methods. Even though the substitution of MgO with FGD sludge can reduce the sintering temperature, the physical and mechanical properties of cordierite-based ceramic with FGD sludge are depleted due to the decomposition of SO3 took place during the sintering process and thus lead to the formation of voids in the ceramic. Thus, this paper is focusing on the thermal properties of cordierite-based ceramic when subjected to a high sintering temperature, 1000 °C using a dilatometric test. Different wt% of treated FGD sludge substitution gave a different type of CTE value, but 3.0 wt% of FGD sludge is able to obtain the lowest CTE value, 2.26 × 10–6/°C, compared to other samples as this sample obtains a single phase of α-cordierite phases.
  • Publication
    The mechanochemical process and Hâ‚‚SOâ‚„ treatment on the rehydration of Anhydrite from FGD sludge into Gypsum and Hemihydrate
    (Springer, 2023)
    Fatin Fatini Othman
    ;
    Banjuraizah Johar
    ;
    Khor Shing Fhan
    ;
    Nik Akmar Rejab
    ;
    Suffi Irni Alias
    The rehydration of anhydrite (CaSO₄) leads to the crystallization of gypsum (CaSO₄⋅2H₂O) has been widely studied. Different process parameter had been conducted on anhydrite from the flue gas desulphurization (fgd) sludge to identify its ability to be reused as synthetic gypsum. A mechanochemical process using a high-energy planetary mill would break down the particle size and enhance the reaction of Ca²+ and SO₄ ²− with water while additives modify the number of ions present in the sample during the hydration. Difference hydrothermal temperatures (80 and 130 °C) for 30 min were conducted to dehydrate the synthetic gypsum from fgd sludge to hemihydrate (CaSO₄⋅0.5H₂O) to identify its potential to replace natural gypsum during the plaster of Paris production. The sample without a mechanochemical process wasn’t able to crystallize a high amount of gypsum while sample with 5 × 10–4 mol−1 of H₂SO₄ additive was able to crystallize a high amount of gypsum from the fgd sludge. After undergoing the hydrothermal process, all of the samples were able to crystallize hemihydrate at low-intensity peak due to the favourable of hemihydrate crystal’s growth at plane [31-3] only, which leads to the preferred orientation of hemihydrate crystal.
  • Publication
    Dielectric properties of Nephelium Lappaceum tropical wood
    ( 2020-03-25)
    Khor Shing Fhan
    ;
    Cheng Ee Meng
    ;
    Banjuraizah Johar
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Zaizul M.A.
    ;
    Wan Azani Wan Mustafa
    ;
    Nik Noriman Zulkepli
    ;
    Dahham O.S.
    Dielectric properties of rambutan wood (Nephelium Lappaceum) were investigated in three anisotropic directions, namely miters-cut, cross-cut, and rib-cut. Dielectric constants and dielectric loss factors were measured at ambient temperatures by using an impedance analyzer. The dielectric constant decreased as frequency increased from 4 to 1 MHz. Among the wood specimens, the rib-cut direction has the lowest dielectric constant, while the cross-cut direction has the highest value. A dielectric dispersion occurred within frequencies 100 Hz to 10 kHz, which corresponding to a relaxation peak as observed on dielectric loss factor spectra. The relaxation peak value of the dielectric loss factors shifted towards higher frequencies in the sequence of rib-cut, miters-cut, and cross-cut specimen. Above 500 Hz, the cross-cut specimen has the highest value conductivity than others. Generally, these variations were subjected to the anatomical structure in the wood, such as parenchyma, ray cell, vessel cell, and fiber cell.
      41  2
  • Publication
    Synthesis of sustainable binary Calcium monosilicate ceramics from bio-waste: effect of sintering temperature on microstructure and electrical properties
    (Universiti Malaysia Perlis (UniMAP), 2023-01)
    N. H. Jakfar
    ;
    Khor Shing Fhan
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    S. N. H. Mohd. Yunus
    ;
    Cheng Ee Meng
    ;
    E. Z. M. Tarmizi
    ;
    Z. A. Talib
    This study was conducted to synthesise calcium monosilicate ceramics using rice husks and raw eggshells and investigated the effect of sintering temperature on the physical, microstructure and electrical properties of the final product. The high content of calcium and silicon in eggshells and rice husks, respectively promote the use of waste materials in the production of calcium monosilicates by mixing in a molar ratio 1CaO:1SiO2 and fired at different sintering temperatures for 2 hours with a heating rate of 10°C/min. A good correlation between sintering temperature, structural, microstructure, and electrical properties of calcium silicate was observed. The structural and morphological evolutions were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with electron dispersive X-ray analysis (EDX). XRD analysis showed that the main crystalline phases of synthesised calcium monosilicate are pseudowollastonite (ICSD 98- 005-2598) at 1250°C, and the phases of SiO2 also exist in different types of minerals. Besides, a small amount of larnite, Ca2SiO4 was traced at 1100°C and 1200°C. Fourier Transforms Infrared (FTIR) spectra showed the presence of characteristic functional groups in the precursor powder. In Nyquist plots, the summit frequency of the dominant arc decreases with increasing sintering temperatures. It may be attributed to the co-effect of the grain size and pore. A larger value of impedance at a lower frequency suggests an essential role of boundaries in governing the electrical properties of the sintered ceramics. As the sintering temperature increases, the microstructure of the sintered samples becomes denser while conductivity performance decreases. This is due to the reduction of particle interfaces and charge transfer.
      1  17
  • Publication
    The effect of treated flue gas desulfurization (FGD) sludge addition on the properties of non-stoichiometric cordierite
    ( 2025-01)
    Fatin Fatini Othman
    ;
    Banjuraizah Johar
    ;
    Khor Shing Fhan
    ;
    Suffi Irni Alias
    ;
    Nik Akmar Rejab
    This study examines the incorporation of treated Flue Gas Desulphurization (FGD) by-products from the glass industry in Malaysia into non-stoichiometric cordierite compositions, focusing on its effects on the physical, mechanical, and microstructural properties. New ceramic samples were developed using a blend of kaolin, silica, talc, and treated FGD sludge. The results indicate that increasing the amount of treated FGD sludge leads to desirable properties such as a low thermal coefficient of expansion (2.62 – 3.64 x 10-6/ ℃), reduced density, and decreased average flexural strength (34.43 – 54.69 MPa), along with an increase in average porosity (17.04 - 31.90 %). Notably, ceramics that were treated with 3 wt% FGD sludge crystallized α-cordierite at a lower sintering temperature (1250 ℃), whereas traditional solid-state reaction methods need higher temperatures (>1350 ℃) to make α-cordierite. Overall, replacing feldspar with treated FGD sludge in non-stoichiometric cordierite formulations presents a sustainable strategy for recycling industrial waste and reducing the need for natural resources. The resulting materials exhibit characteristics suitable for lightweight construction applications, such as commercial bricks, due to their light weight, adequate flexural strength, and appropriate porosity.
      3  24
  • Publication
    Formation of Bio-based Derived Dicalcium Silicate Ceramics via Mechanochemical Treatment: Physical, XRD, SEM and FTIR Analyses
    ( 2023-07-01)
    Yunus S.N.H.
    ;
    Khor Shing Fhan
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    Jakfar N.H.
    ;
    Cheng Ee Meng
    ;
    Tarmizi E.Z.M.
    ;
    Talib Z.A.
    Beta-dicalcium silicate plays an important role in modern technology, but its tendency for polymorphic transformation results in the dusting phenomenon, is a major challenge. Therefore, mechanochemical treatment is used to reduce the particle size to retain the stability of the polymorph. In this study, pure dicalcium silicate ceramics of β-monoclinic structure with P 121/c1 space group were synthesized using calcium oxide and silicate powders derived from calcined eggshells and rice husks, respectively. The powders were mixed in a 2:1 molar ratio by mechanochemical treatment and heat-treated in the air at temperatures ranging from 900°C to 1100°C for 2 h. The results reveal that pure beta-dicalcium silicate formed at 1100°C without adding stabilizers. The properties of the pristine and sintered bodies were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). SEM revealed that the grain and pore sizes increase with rising sintering temperatures. FTIR spectra indicate the existence of Si-O bonds in tetrahedrons on all the samples. The sample sintered at 1000°C attains the lowest bulk density (1.2463 g/cm3), whereas the apparent porosity is the highest (62.5%). The reason for this trend is due to the decomposition of carbonate into CO2 gas. The densification onset for the sample sintered at 1100°C as the bulk density rises and grain size achieves 6.06 μm. This study further explains the effect of sintering temperatures on the physical, structural, and morphological properties of Ca2SiO4 which would also be useful for further optimization of its use.-4 SiO4.
      1
  • Publication
    Effect of sintering temperature on dielectric and electrical properties of bio-waste derived beta-dicalcium silicate
    ( 2023-11-01)
    Mohd Yunus S.N.H.
    ;
    Khor Shing Fhan
    ;
    Banjuraizah Johar
    ;
    Nur Maizatul Shima Adzali
    ;
    Jakfar N.H.
    ;
    Cheng Ee Meng
    ;
    Mohd Tarmizi E.Z.
    ;
    Talib Z.A.
    Beta-dicalcium silicate ceramics were synthesized by mechanochemical-assisted solid-state reaction route using rice husks and chicken eggshells as silica and calcium oxide sources. The ceramics were sintered at 900, 1000, and 1100 °C for 2 h in air. The effect of sintering temperature on these ceramics' morphological, breakdown strength, dielectric, and electrical properties was investigated. It was found that the ceramic sintered at the optimized temperature of 1100 °C formed the pure β-dicalcium silicate (β-Ca2SiO4). Scanning electron micrographs showed that with the increase in sintering temperature, the average grain size and pore size of the sintered ceramics increased while the grain boundary density decreased, which promoted the breakdown path and resulted in a decrease in breakdown strength. The dielectric behavior examined from 25 to 300 °C and in a frequency range of 4–5 MHz found that the dielectric constant and loss tangent decreased with increasing frequency. Nyquist plot of impedance confirmed a non-Debye type relaxation, and grain and grain boundary contributions were revealed from equivalent circuit fitting. Variations of impedance spectroscopy reflect the positive and negative temperature coefficient of resistance behavior for these ceramics. Electric modulus spectra revealed that with the sintering temperature increase, the samples' conductivity activation energies increased from 0.35 to 0.46 eV. All the sintered samples attained low dielectric loss (0.004 < tanδ < 0.1) above 103 Hz, which makes them suitable materials for capacitor application.
      2  42