Advanced Materials Research Vols. 488-489

Abstract: The Eu²⁺ doped barium aluminate (BaAl2O4:Eu²⁺) and strontium aluminate (SrAl2O4:Eu²⁺) with high brightness were synthesized by self-propagating high temperature synthesis (SHS) method. The influence of doping rare earth ions (Eu²⁺) on the luminescence of MAl2O4:Eu²⁺ were described in this study. The reactions were carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The morphologies and the phase structures of the products have been characterized by X-ray diffraction (XRD) and scanning electron microscope technique (SEM). The emission spectra of the products have been measured by an Ocean optics spectrometer at room temperature. Broad band UV excited luminescence was observed for BaAl2O4:Eu²⁺ and SrAl2O4:Eu²⁺ in the green region peak at λmax = 501 nm and 523 nm, respectively. The optimum Eu²⁺ doping ratio were 10.5 mol% and 6 mol% for BaAl2O4:Eu²⁺ and SrAl2O4:Eu²⁺, respectively

Abstract: Steel substrate was coated by Fe-Al₂O₃ composite using self-propagating high-temperature synthesis (SHS) reaction of reactant coating paste. The green composite paste were prepared by mixing of Fe₂O₃, Al and polyvinyl alcohol solution. It coated on the steel substrate. The effect of sustrate conditions on the Fe-Al₂O₃ composite coating were studied. The SHS reaction of the coated green composite was ignited by oxy-acethylene flame. The reaction between precursors happen step by step along the coated green composite length, to form Fe-Al2O3 composite coating on the steel plate. The Fe-Al₂O₃ composite coating was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) couple with dispersive X-ray (EDS)

Abstract: 82% Ni-Fe films have been prepared using Radio frequency (R.F) sputtered, R.F induced substrate bias. The results presented are of study of sputter films deposition at various RF substrate bias conditions so that suitable sputtering rate with optimum (target) composition could be determined for magnetoresistive sensing applications. Films have been sputtered with substrate temperature of 200^° C, sputter gas (argon) pressure of 10mTorr with film thicknesses near 1000 ^°A. Substrate bias potential in the range 0 V to -400 V is varied in order to determine its dependence upon film composition and deposition rate. The result presented indicates the strong bias dependence upon film composition and deposition rate with most useful films for the application in concern could be produced at substrate bias potential in the range of -80 V to -120 V.

Abstract: Aluminum 6061 is a common alloy which is widely used in aerospace and yacht construction industry. Generally machining of aluminum alloys inherently generates high chip sticking on tool face and changes the tool edge geometry, which not only reduces tool life but also impairs the product surface quality. This study investigated the tool life and tool wear mechanisms besides evaluating surface roughness in various cutting conditions to attain finest possible surface with minimum tool wear. Turning experiments performed under dry orthogonal cutting of Al6061 using carbide CVD tri-phase coated inserts with constant depth of cut, various cutting speeds and feed rates. Insert’s flank and rake faces analyzed to assess wear mechanisms. Additionally Scanning electron microscope (SEM) employed to clarify different types of wear. Surface integrity and effect of built up edge in deviating surface roughness were studied in each cutting condition. Additionally results of experiments demonstrated that built up edge took over cutting edge and with sacrificing surface roughness, tool life increased by decreasing pace of abrasive wear propagation on flank face. According to these experiments the main reasons of flank wear were abrasive and adhesion of aluminum on tool face.

Abstract: This paper presents the results of experimental investigation conducted on a vertical machining centre (VMC) to ascertain the effectiveness of TiAlN/AlCrN multilayer coated carbide inserts in end milling of AISI D2 hardened steel (58-62 HRC) In high-speed dry hard milling, different cutting speed (v) and radial depth of cut (d_r) were applied. Tool failure modes and wear mechanisms were examined at various cutting parameters. Flank wear, chipping and breakage at cutting edge were found to be the predominant tool failure for the cutting tools. Built-up edge, adhesion and abrasive are the wear mechanisms observed on the cutting tools. The highest volume of material removed, VMR attained was 1500 mm3, meanwhile the highest tool life (T) was 4.97 min. The surface roughness, Ra values from 0.20 to 0.45 μm can be attained in the workpiece with a high volume material removed. The relationship of tool wear performance and surface integrity was established to lead an optimum parameter in order to have high volume material removed, maximum tool life as well as acceptable surface finish.

Abstract: Steel pipe lined Fe-Al intermetallic-TiB₂-Al₂O₃ composite were prepared by centrifugal-self-propagating high temperature synthesis (centrifugal-SHS) process from FeTiO₃, B₂O₃, Fe₂O₃, Al and CaF₂ as raw materials. The standard Gibbs energy minimization method was used to calculate the equilibrium compositions of the reacting species. The effect of adding CaF₂ to the precursors on the result product were investigated. The phase separation between less porosity Fe-Al intermetallics-TiB₂ with Al₂O₃ layer were affected greatly by adding CaF₂. The phase compositions and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) couple with energy dispersive X-ray (EDX), respectively.

Abstract: This study investigated the effect of the organic phthalocyanine blue and inorganic ultramarine blue pigments on nucleation of polypropylene (PP). The PP/pigment pellets containing various concentrations of each pigment (0.0001-0.1 wt %) were prepared by a melt blending process using a single-screw extruder, followed by fabricating into thin sheets using a single-screw plastic sheet extruder. The nucleation effects of both pigments were characterized by wide angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC) techniques. The WAXD patterns revealed that the addition of phthalocyanine blue or ultramarine blue did not affect the crystal structure of PP. The DSC results indicated that both pigments were able to nucleate PP, where the organic phthalocyanine blue pigment was a very efficient nucleating agent, increasing the crystallization temperature of PP by 15oC. The results of tensile and optical tests showed that the tensile strength and clarity of PP were improved with phathalocyanine blue addition.

Abstract: The waste natural rubber latex was treated with natural rubber latex (TWNRL) prior to blend with polystyrene (PS). The blend was conducted with the ratio of 30/70, 50/50 and 70/30 TWNRL/PS using Haake internal mixer at 140 °C and 60 rpm. The waste natural rubber latex/PS (WNRL/PS) was prepared in the similar procedure. The complex modulus (E*) at various temperature and tensile properties were investigate. The tensile fracture surface was observed using Scanning Electron Microscope (SEM). The results show that the E* of WNRL/PS blends are higher at any temperature compared to TWNRL/PS blend for similar compositiondue to higher network molecules. At 30/70 blends show the tensile strength, Young’s modulus and elongation at break of TWNRL/PS are higher than WNRL/PS blend due to a better molecule entanglement. Improvement of elongation at break was shown for70/30 TWNRL/PS blend, because of the rearrangement of molecule chains under stress. The SEM observation show the successful improvement of blend morphologies by latex treatment at all composition. Moreover, the SEM micrograph also imply the fracture behavior; more tendril on fracture surface indicating the higher strain needed before failure.

Abstract: Fiberglass-Polyester Paving Mat is a new compound synthetic material, and a compound of fiberglass and polyester, which advantages include high strength, low elongation, good compatibility with bitumen, resistance of high temperature and corrosiveness. This paper mainly elaborated the performance of Fiberglass-Polyester Paving Mat, such as delaying cracking, alleviating the crack development, which can effectively prevent the road surface water infiltration and improve the pavement performance in asphalt pavement construction and transformation. Based on the forming mechanism of reflective cracks, this article describes the engineering application of fiberglass-polyester paving mat in the prevention of reflection crack of bituminous pavement and in waterproofing of the paving layer in tunnels, thus providing the basis for the application of Fiberglass-Polyester Paving Mat in highway construction and maintenance engineering.

Abstract: The composite materials have been synthesized in situ by self-propagating high temperature synthesis (SHS) from natural precursors. The studied natural resources are ilmenite, kaolin, sand and rice husk ash. The reactions were carried out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium compositions of the reacting species. The composites results have been characterized by scanning electron microscope (SEM), image analysis and X-ray diffraction (XRD). The results showed that the production of composite materials using SHS process is feasible and agree well with the thermodynamics calculations.