Pengoptimunan Proses Pengkalsinan Dan Pensinteran Untuk Manghasilkan Kalsium Kuprum Mangan Oksida (Cacu3mn4o12) Melalui Kaedah Tindakbalas Keadaan Pepejal [TK7871.15.C4 W276 2008 f rb].

Penghasilan bahan elektroseramik CaCu3Mn4O12 telah dijalankan dengan menggunakan kaedah tindakbalas pepejal. Preparation of CaCu3Mn4O12 electroceramic was carried out via solid state method. The solid state method was employed as it has many advantages such as minimum consumption of raw materials, short preparation duration and exclusion of pressure parameter in producing CaCu3Mn4O12

Formation of Cr23C6 During the Sensitization of AISI 304 Stainless Steel and its Effect to Pitting Corrosion

The metallic carbide precipitation was observed after the sensitization of AISI 304 stainless steel specimens in neutral flame by using oxy-fuel and slowly cooled in the air. Correlation between corrosion and X-Ray Diffraction (XRD) shows that the enrichment of Cr23C6 in the microstructure of AISI 304 worsens the pitting corrosion resistance properties as the sensitization time increases from 5 to 60 s. However, the precipitation dissolved and corrosion resistance properties improved after the specimens treated in solution quenching treatment at 1130 oC, soaked from 24 – 120 min, then rapidly cooled in water

Mechanical and Thermal Properties of Single-Walled Carbon Nanotube Filled Epoxidized Natural Rubber Nanocomposite

The use of Single-Walled Carbon Nanotube (SWCNT) as a reinforcement in rubber nano composite nowadays attracts a great deal of attention. Rubber used in this study was Epoxidized Natural Rubber (ENR) and was incorporated with SWCNT as nano filler. The influence of SWCNT nanofiller on mechanical and thermal properties of the produced nanocomposite was studied. The nanocomposite were prepared by using Haake internal mixer with 0, 5, 10 and 15 parts per hundred rubber of the SWCNT and the detailed preparation method is presented. Mechanical properties were evaluated by means of tensile and hardness tests under different SWCNT composition. As results, the strength and elongation at break of the nanocomposite decreased and simultaneously, the strength modulus and hardness increased. Moreover, from the differential scanning calorimetry analysis, the value of melting temperature (Tm), crystalline temperature (Tc) and heat transition (ΔH) were found increased with the increasing ratio of SWCNT

Hygrothermal Effect on Mechanical and Thermal Properties of Filament Wound Hybrid Composite

This study focused on the hygrothermal effect on filament wound glass-carbon/epoxy hybrid composite. Non-geodesic pattern of filament winding with a winding speed of 15.24–30.48 lm/min was used. Fiber tensioning weight of one kg and a winding angle of 30° were created to produce wound samples of the hybrid composite. The hybrid composite was wound by using a ±30° orientation with a total of six layers. Hygrothermal effect was conducted in a humidity chamber for three days (72 h). Control temperatures of 60 and 80°C were established, and humidity percentages of 50%, 70%, and 90% were used. Moisture absorption test showed that heat and humidity in most of the hybrid samples gradually increased. As a result, glass-carbon 80°C/90% showed the highest absorbed moisture at 0.77%. The involvement of highest heat and humidity showed the decline in the values of tensile and flexure strengths at 75.80 and 157.15 MPa, respectively. Fractography analysis using Stereo Microscope Stemi 2000-C indicated that glasscarbon/ epoxy 80°C/90% showed catastrophic damage, large crack, and longest delamination of fiber pullout at 10.39 mm. The fracture criterion revealed that the involvement of heat and humidity significantly affected the mechanical and physical properties of hybrid composite material

Transparent Coating Oxide - Indium Zinc Oxide As Conductive Coating : A Review

: This paper reviews the transparent conductive oxide with emphasis on indium doped zinc oxide (TCO-IZO). TCO has been growing faster year by year, especially in semiconductor,solar devices and electronic field. There are many methods that can be used to produce IZO coating such as dip coating, sol-gel, magnetron sputtering, thermal evaporation and atomic layer deposition. IZO has gained significant attention for transparent electrodes due to its good electrical conductivity, high visible transmittance in the range from 400 to 900 nm, large work function, excellent surface smoothness, and low deposition temperature. Many studies have been done on the IZO coating onto glass substrate, but there is still less study on the low processing temperature substrates such as polymers and natural fibres. Parameters such as coating thickness, annealing temperature and number of cycles have to be considered in order to achieve the desired electrical conductivity and optical properties of IZO

A preliminary study of porous ceramics with carbon black contents

This paper is a study of porous ceramics from a mixture of clay (kaolinite), silica (silicon dioxide), and feldspar by adding the carbon black (CB) with different contents. The results were presented in terms of apparent porosity, relative density, microstructure and porous characteristic, flexural strength and phase formation. As observed, the sintering at 1200 ℃ is the optimum temperature in this work. In comparison to the samples without CB content, the apparent porosity and relative density of ceramics are highly dependent on the CB contents. This might be attributed to the presence of porous structure as seen in SEM images on the fracture surface of ceramics. It also revealed that the addition of CB resulted in smaller pore sizes and a more uniform pore distribution. The creation of pores in porous ceramics was mainly attributed to the loss of shape of CB microspheres at high temperatures, as observed from SEM. The flexural strength of the sintered samples exhibited an average decrease from 60 to 55 MPa due to the presence of CB, which is typically known to reduce the mechanical properties with high porosity. In XRD results, the muscovite phase is represented by a few of peaks with significant intensities, while the rest peaks are of undetermined phase. The strongest peak at a 26° of 2θ angle, suggesting the presence of potassium and aluminium in the form of silicate minerals

Potassium sodium niobate (KNN) lead-free piezoceramics: A review of phase boundary engineering based on KNN materials

Lead zirconia titanate (PZT) is the most often used piezoelectric material in various electronic applications like energy harvesters, ultrasonic capacitors and motors. It is true that PZT has a lot of significant drawbacks due to its 60% lead content, despite its outstanding ferroelectric, dielectric and piezoelectric properties which influenced by PZT's morphotropic phase boundary. The recently found potassium sodium niobate (KNN) is one of the most promising candidates for a new lead-free piezoelectric material. For the purpose of providing a resource and shedding light on the future, this paper provides a summary of the historical development of different phase boundaries in KNN materials and provides some guidance on how to achieve piezoelectric activity on par with PZT through a thorough examination and critical analysis of relevant articles by providing insight and perspective of KNN, which consists of detailed evaluation of the design, construction of phase boundaries and engineering for applications

HYGROTHERMAL EFFECT ON MECHANICAL AND THERMAL PROPERTIES OF FILAMENT WOUND HYBRID COMPOSITE

This study focused on the hygrothermal effect on filament wound glass-carbon/epoxy hybrid composite. Nongeodesic pattern of filament winding with a winding speed of 15.24–30.48 lm/min was used. Fiber tensioning weight of one kg and a winding angle of 30° were created to produce wound samples of the hybrid composite. The hybrid composite was wound by using a ±30° orientation with a total of six layers. Hygrothermal effect was conducted in a humidity chamber for three days (72 h). Control temperatures of 60 and 80°C were established, and humidity percentages of 50%, 70%, and 90% were used. Moisture absorption test showed that heat and humidity in most of the hybrid samples gradually increased. As a result, glass-carbon 80°C/90% showed the highest absorbed moisture at 0.77%. The involvement of highest heat and humidity showed the decline in the values of tensile and flexure strengths at 75.80 and 157.15 MPa, respectively. Fractography analysis using Stereo Microscope Stemi 2000-C indicated that glasscarbon/ epoxy 80°C/90% showed catastrophic damage, large crack, and longest delamination of fiber pullout at 10.39 mm. The fracture criterion revealed that the involvement of heat and humidity significantly affected the mechanical and physical properties of hybrid composite material

Structural evolution and dopant occupancy preference of yttrium-doped potassium sodium niobate thin films

Sodium potassium niobate (KNN) is the most promising candidate for lead-free piezoelectric material, owing to its high Curie temperature and piezoelectric coefficients among the non-lead piezoelectric. Numerous studies have been carried out to enhance piezoelectric properties of KNN through composition design. This research studied the effects of yttrium concentrations and lattice site occupancy preference in KNN films. For this research, the yttrium-doped KNN thin films (mol% = 0, 0.1, 0.3, 0.5, 0.7 and 0.9) were fabricated using the sol-gel spin coating technique and had revealed the orthorhombic perovskite structures. Based on the replacement of Y3+ ions for K+/ Na+ ions, it was found that the films doped with 0.1 to 0.5 mol% of yttrium had less lattice strain, while films with more than 0.5 mol% of Y3+ ions had increased strain due to the tendency of Y3+ to occupy the B-site in the perovskite lattice. Furthermore, by analysing the vibrational attributes of octahedron bonding, the dopant occupancy at A-site and B-site lattices could be identified. O-Nb-O bonding was asymmetric and became distorted due to the B-site occupancy of yttrium dopants at high dopant concentrations of >0.5 mol%. Extra conduction electrons had resulted in better resistivity of 2.153× 106 Ω at 0.5 mol%, while higher resistivity was recorded for films prepared with higher concentration of more than 0.5 mol%. The introduction of Y3+ improved the grain distribution of KNN structure. Further investigations indicated that yttrium enhances the surface smoothness of the films. However, at high concentrations (0.9 mol%), the yttrium increases the roughness of the surface. Within the studied range of Y3+ , the film with 0.5 mol% Y3+ represented a relatively desirable improvement in dielectric loss, tan δ and quality factor, Qm