Wandee Thamjaree

Analysis of X-ray diffraction line profiles of lead zirconate titanate using the Fourier method

Lead zirconate titanate (PZT) powder was prepared by a solid state reaction. The X-ray line broadening produced in PZT powder was analyzed by the Fourier method to estimate particle size and microstrain. It was found that an increase of the annealing temperature caused the microstrain to decrease owing to an increase in particle size. The Scherrer formula used to calculate the particle size yielded considerably smaller values.

Improvement in the Tensile Strength of Epoxy Resin and Hemp/Epoxy Resin Composites Using Carbon Nanotubes

An experimental was investigated the condition of reinforcement of epoxy resin and hemp fiber/epoxy resin composites with carbon nanotubes (CNTs). The CNTs adding nanopowder were vibrated via the vibration milling technique for 6-48 h. Different volume percentages of CNTs were dispersed for hemp/epoxy resin composites. To compare properties of composites sample, CNTs were also added into epoxy resin for reference. Tensile strength of both specimens was tested. The significantly adding of CNTs and its dispersion in polymer matrix were investigated by scanning electron microscope (SEM). The results indicate that adding the milled CNTs can improve tensile properties of composites.

Fabrication of 0-3 Non-Lead Based Piezoceramic/Polymer Composites Using Suction Technique

In this research, 0-3 composites between non-lead based piezoceramic and polymer were fabricated using the suction technique. Bismuth sodium titanate (Bi0.5Na0.5TiO3:BNT) which prepared from conventional mixed oxide method was used as active phase whereas epoxy resin was used as matrix phase. The 50% volumetric fraction of BNT/epoxy resin can obtain from suction technique. The physical and piezoelectric properties of composites samples were examined. It can be found that density of composite samples were about 1.78 g/cm3. Moreover, the piezoelectric coefficient (d33) of sample was 13 pC/N. Furthermore, the microstructure of composites was determined using SEM technique.

Effects of rare earth additive (Nd2O3) on microstructure and dielectric properties of lead zirconate titanate ceramics

This paper presents work on studying the structure and physical properties of PZT ceramics at a morphotropic phase boundary composition (Zr?:?Ti=52?:?48) which has been modified with different quantities of neodymium oxide, Nd2O3. Phase formation and microstructure development were examined by x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. Dielectric properties were measured, and the relationship between properties and the amount of Nd-dopant is discussed. It has been found that in the Nd-doped samples, the highest value of dielectric constant occurred for the 0.5?wt.% sample, sintered at 1200??C, and that the maximum d31 and kp values were obtained for the 0.5?wt.% Nd composition with values of 124?pC?N?1 and 0.53, respectively.

Structural and Physical Properties of Nd-Doped Pb(Zr0.52Ti0.48)O3 Ceramics

Lead zirconate titanate (PZT) ceramics (Zr/Ti = 52/48) have been modified with different quantities of neodymium oxide (Nd2O3). The preparation was carried out via the solid-state-reaction route. The samples were calcined and sintered at 850°C and 1200°C, respectively. The structural evolution and the microstructure were investigated using an X-ray diffractometer (XRD) and a scanning electron microscope (SEM), respectively. The physical properties such as dielectric constants, piezoelectric coefficients, density etc. were also studied. Communicated by Dr. George W. Taylor

Mechanical Properties and Microstructure of Aramid/Al2O3/Epoxy Resin Laminated Composites

Aramid/Al2O3/epoxy resin laminated composites were fabricated using ultrasonic mixing and casting technique. This novo material could be exhibited to the ideal mechanical properties such as high tensile strength, hardness, flexural strength and lightweight which may be used to replace metal parts in vehicles. Moreover, Al2O3 powder was mixed to epoxy resin to improve the scratch resistance. To improve the bending force and interaction between Al2O3 powder phase and epoxy resin phase, the ultrasonic mixing was used for fabricating these laminate composites. The physicals and mechanical properties such as density, hardness, impact test, wear resistance and tensile strength of the composites samples were investigated. It was found that the amounts of percent by volume of the Al2O3 have affected the properties of the laminated composites. Furthermore, microstructures of specimens were also investigated by scanning electron microscope (SEM). From the results, SEM images showed good distribution and adhesion between reinforced phase and epoxy resin matrix phase.

Mechanical Properties of Hemp Fiber Composites with Carbon Nanotubes Reinforcement

An experimental was investigated the condition of reinforcement of hemp fiber and hemp fiber/epoxy resin composites with carbon nanotubes (CNTs).The CNTs were mixed with several liquid such as ethanol, latex, water glue and epoxy resin. These mixtures were added to hemp fiber and prepared the hemp fiber/epoxy resin composites. The mechanical properties of both fiber and composite samples were measured. It was found that the mixture of epoxy resin and CNTs with CNTs ratio of 20 vol% in hemp fiber showed the highest tensile strength of 25.43 N. and the same mixture in hemp fiber/epoxy resin composites showed the highest tensile strength of 31.82 MPa and elongation of 7.40 %.

Optimization of Diamond-Like Carbon Thin Film on Copper Substrate for Carbon Nanotubes Synthesis by ACVD Technique

In this research, demonstrate plasma treatment on copper substrate by Radio Frequency Plasma (RF) using a mixture of 70%C2H2 + 30%H2 as the working gases. The plasma exposure time were varied from 10, 20 and 30 min under the electrical power of 50 Watts for synthesizing the diamond-like carbon (DLC) thin film on copper substrate. Thereafter, the substrates were used for synthesizing the carbon nanotubes (CNTs) via alcohol chemical vapor deposition technique (ACVD). It could be found that the plasma treatment for 10 min exhibited the small contact angle less than those of substrates treated with 20, 30 min and untreated sample which relate to the hydrophilic and affect to improve the adhesion and distribution of catalyst on substrate. The roughness of DLC film showed the different high and low level like hillock. After that, the 10 min treatment time sample was used for synthesizing the CNTs and the results found that the obtained CNTs showed good distribution on substrate.

Fabrication and Mechanical Properties of the Biocomposites between Water Hyacinth Fiber and Paper Mulberry

Fabrication and mechanical properties of the bio-composites between water hyacinth natural fiber and paper mulberry have been investigated. The fabrication was performed using the hand lay-up technique. Untreated and treated water hyacinth fiber were used as reinforcements, in the ratio of 5%, 10%, 15%, and 20% by weight, with paper mulberry as a biomatrix. It has been found that paper mulberry reinforced with 15 % treated WH fiber showed maximum tensile strength and impact energy. The optical and scanning electron microscopic morphology of the obtained composites displayed a rougher surface and the decrease in the fiber diameter when treated with sodium hydroxide (NaOH). This improved the interlocking between the matrix and its reinforcement.

Effect of added silicon carbide nanowires and carbon nanotubes on mechanical properties of 0–3 natural rubber composites

In this work, the mechanical properties of 0–3 nanocomposite materials containing silicon carbide nanowires (SiCNWs), carbon nanotubes (CNTs), and natural rubber were studied. The SiCNWs and CNTs were used as reinforcement fiber whereas natural rubber was used as the matrix phase. The chemical vapor depositions (CVD) was used for synthesizing the nanowire and nanotube phases. The volume fraction of reinforcement was varied from 0 to 10%. The nanophases were mixed in the natural rubber matrix and molded by the hand lay-up technique. The mechanical properties of the samples were examined and compared with those of neat natural rubber. From the results, it was found that the hardness and density of the samples increased with the quantities of nanophases. The nanocomposites with a volume fraction of 10% exhibited maximum hardness (50.5 SHORE A). The maximum tensile strength and extent of elongation at break of the samples were obtained from the 4% volume fraction sample, which were 16.13 MPa and 1,540%, respectively.