Papers by Author: Che Mohd Ruzaidi Ghazali

Abstract: This paper reports a detail study of the effect of NaOH concentration on flexural strength, phase formation and microstructural development of kaolin geopolymer ceramic. The NaOH concentration used ranged from 6 M to 14 M. The flexural strength showed the optimum value when NaOH concentration is 12 M. XRD analysis showed the formation of crystalline nepheline in all samples. Microstructural analysis showed formation of homogenous and denser structure in kaolin geopolymer ceramic as the NaOH concentration increase.

Abstract: Kaolin, a geopolymer raw material that is rich with aluminosilicate materials is mixed with alkaline activator solution to produce geopolymer based coating material. Geopolymer technology is stil under studied in terms of coating applications especially using kaolin as raw material. Till date, there are no similar work as our effort in this research. Lumber wood is used as our subtrates as it has low grade wood properties such as low resistance to heat, impact or even durability. In this work, optical microscopy data are analysed in support of flexural properties of kaolin coated lumber woods. As discussed in our previous work, flexural properties shows that at solid/liquid ratio of 0.7, silicate/NaOH ratio of 0.40 and 8M of NaOH, kaolin coated lumber is at its best. Our findings on interfacial micrographs of kaolin geopolymer coating and wood substrates are further observed and studied.

Abstract: The wettability of Sn-Cu-Ni with Germanium (Ge) additions of 0 ppm, 10 ppm, 60 ppm, 100 ppm and 200 ppm were investigated with Gen3 machine. The range of the wettability shows the lowest and the highest reading of wetting time and maximum force. Three different conditions were investigated which consist of as soldered, reflowed and aged. Further interfacial IMC observation was done for 0 ppm and 60 ppm of Ge to investigate the growth of interfacial IMC after thermal aging. From the measurement, the thickness of IMC for 0 ppm Ge is 2.075μm, 3.936μm and 4.502μm with aging time at 24,120 and 240 hours respectively. While for 60 ppm Ge, the IMC thickness are much lower with 1.8μm, 3.11μm and 4.154μm at the same aging time with 0ppm Ge. The results indicate that 60 ppm of Ge in Sn-Cu-Ni has the lowest wetting time, higher maximum force and slow IMC growth.

Abstract: Kaolin, an abundantly available material that mainly contains alumina and silica is now being used in geopolymer system. Kaolin based geopolymer has been proven to acquire remarkable thermal resistance, chemical resistance, and mechanical properties. Geopolymer materials have become the new favorite, especially for the carbon conscious end users as a potential replacement for widely used Ordinary Portland Cement (OPC). This works shares the effect of various mix designs, especially in terms of altering the solid/liquid ratio, sodium silicate/sodium chloride ratio and sodium chloride molarity on the flexural properties of kaolin coated lumber woods via geopolymer technology.

Abstract: In this study, the mechanical behavior of white clay based geopolymer filled epoxy composites was studied through compressive test. The morphology of white clay based geopolymer and origin was characterized using scanning electron microscopy (SEM). A series of epoxy composites with various white clay based geopolymer filler loadings varying from 0 to 7phr of was prepared. The assessments showed the presence of white clay based geopolymer in the composite system has improved the compressive properties of the epoxy. This indicated the potential of epoxy / white clay based geopolymer composites in structural applications.

Abstract: Properties of geopolymer coating on nonmetallic substrates, especially glass fiber-reinforced epoxy (GRE) have been considered based on the effect of Si/Al ratio and surface treatment at a determined proportion of solid to liquid (S/L) and curing temperature.Kaolin and white clay have been used as geopolymer raw material in study of adhesive strength in geopolymer coating. Effect Si/Al ratio and surface treatment on adhesive strength has been tested from 0.40-0.60using Elcometer 106 Pull Off. The answer shows that Si/Al ratio and surface treatment were effecting the adhesive strength of geopolymer coating. The highest adhesive strength 6.0 MPa was found ina Si / Al ratio of 3.5 with surface treatment.

Abstract: In this study, the effect of geopolymer materials in epoxy hardener was studied under mechanical testing which is using flexural test. A series of epoxy filled with 10%-30% weight percentage geopolymer materials which are white clay, fly ash and silica sand was prepared. Flexural strength of the epoxy filled geopolymer materials is determined using Instron Universal Testing under flexural mode. It was found that the addition of these geopolymer materials into epoxy at the beginning with 10% weight percentage showing lower flexural strength than epoxy without geopolymer materials filled. However, flexural properties suddenly increased at 20% weight percentage of white clay and fly ash based geopolymer but tend to decrease at 30% weight percentage compared to silica sand based geopolymer which the strength is continue to decline with the increasing of weight percentage of silica sand. The results indicated that the blending of geopolymer materials in epoxy system can be obtained in this study.

Abstract: SN100C lead-free solder coating wettability on SN100C solder has been investigated on as soldered samples and exposed intermetallic compound (IMC). In addition, the effect of oxidation on its wettability has also been investigated. Oxidation layer on the coated copper surface was developed after 120 hours of exposure on as soldered samples and exposed IMC samples. GEN3 solderability test machine in globule mode was used to determine the wettability of each sample. The influence of oxidation and the effect of exposed IMC were established. Results show that oxidation affected wettability by increasing the wetting time. On the other hand, exposed IMC had increased the wetting time and decreased the maximum force.

Abstract: Geopolymer is cementitious binders that do not require the presence of ordinary Portland cement (OPC). Fly ash with geopolymer formulations prepared with mixing alumino-silicate with the alkaline activator solution has been applied as protective coating material that suitable for high temperature applications such as fire resistant panel. Geopolymer coating samples were cured at 70 °C for 24 hours before sintered using temperatures range from 600 °C to 1500 °C in order to increase strength and improve thermal properties. Curing conditions also have a significant effect on the development of mechanical strength in most cementitious systems. The chemical compositions, microstructure and FTIR were studied. Geopolymer coating samples cures to a glassy texture and effectively used to create a resistant surface. Fly ash geopolymer coating was improved the compressive strength of the coatings materials as high as 40 MPa. This technology develop a geopolymeric mix design that superior use as cementitious coatings with high thermal application.

Abstract: The development of asbestos free brake pad composites using different fillers was investigated with a intention to substitute asbestos which is known hazardous and carcinogenic. Mechanical and morphology studies were made to clarify the mechanism for compressive strength, hardness and wear rate behavior of different filler of brake pad which were prepared by compression molding of mixture of filler (palm slag, calcium carbonate and dolomite) with phenolic as binder, metal fiber as reinforcement, graphite as lubricant and alumina as abrasive. The result showed that palm slag has significant potential to use as filler material in brake pad composite. The wear rate of palm slag composite was comparable with the conventional asbestos based brake pad. The result also supported by SEM micrograph.