Materials and Energy Research Center (MERC)
Iranian Ceramic Society (ICERS)Advanced Ceramics Progress2423-74772420161101The Effect of Rotation Speed on the Microstructure and Hardness of Synthesized Al-WC Nano-Composite by Centrifugal Casting167003110.30501/acp.2016.70031ENMagid ArefkhaniCeramic Division, Materials and Energy Research CenterMansour RazaviCeramic Division, MERC0000-0003-0622-6775Mohammad Reza RahimipoorCeramic Division, MERC0000-0001-5840-0339Aida FaeghiniaCeramic Division, Materials and Energy Research Center0000-0001-6288-7178Journal Article19700101The aim of this work was WC distribution in base Al-Si-Mg (A356) alloy as reinforcing agent. WC Solid particles in the sub-23-nm size range added to melted alloy by centrifuge casting. The cylinder tube without gap was obtained. FESEM and OPM results show that the distribution depends upon the rotational speeds of the mould and centrifugal casting conditions. According to the MAP results, during solidification, Nano size WC phase, by the Eutectic Silicon and around primary Aluminum phase, was precipitated and distributed significantly. The wear tests were carried out using pin on disk method. Results revealed the 0.0272g wear rate by 500gr load at 1200 m for samples that are casted at 1500RPM centrifugal casting speed. According to SEM micrographs, the sliding load transfer by Nano WC particles occurred.https://www.acerp.ir/article_70031_133f2af9dae6a8f98238833f8fc1842a.pdfMaterials and Energy Research Center (MERC)
Iranian Ceramic Society (ICERS)Advanced Ceramics Progress2423-74772420161101Effects of particles size distribution and occupied area of CdS photosensitizer on photovoltaic performance7127003710.30501/acp.2016.70037ENBenyamin YarmandNanotechnology and Advanced Materials Department, , Materials and Energy Research Center (MERC)0000-0002-6771-314XJournal Article19700101Cadmium sulfide (CdS) photosensitizers were successfully formed on the mesoporous titania films using the successive ionic layer adsorption and reaction (SILAR) method in five cycles, and the effects of particles size distribution and their occupied surface area on the morphology, topography, optical property, and photovoltaic performance were investigated. Scanning electron microscope (SEM) images demonstrated that the increase in the number of SILAR cycles increased the number of deposited particles as well as their sizes so that the surface morphology after the third SILAR cycle changed from non-uniform particles to a uniform layer. The surface topography of all layers was hill-valley like, the roughness of which decreased as homogeneous layers formed. The absorbance spectra measured by UV-Vis spectrophotometer revealed that the absorbance spectra of the films increased and shifted towards longer wavelengths as the number of SILAR cycles increased, which is due to the increase in the particles size distribution. Photovoltaic measurements clarified that increase in the particles size distribution had the dominant effect up to the third SILAR cycle and increased the power conversion efficiency to a maximum of 4.65 %. However, as the occupied surface area increased due to the extreme formation of CdS particles and blocking of porosities in the mesoporous titania film, the efficiency dropped to 2.64 %.https://www.acerp.ir/article_70037_b10996b309c8c43fd1663fd548b5bc7e.pdfMaterials and Energy Research Center (MERC)
Iranian Ceramic Society (ICERS)Advanced Ceramics Progress2423-74772420161101Nb2O5 Nanoparticles Synthesis by Chemical Surfactant-Free Methods: ltrasonic Assisted Approach13179083610.30501/acp.2016.90836ENMahshid MohammadifarSemiconductors, Material and Energy Research Center (MERC)0000-0001-9516-8890Abouzar MassoudiSemiconductor, Merc0000-0002-4203-7376Nima NaderiSemiconductors, Materials and Energy Research Center (MERC)0000-0002-4071-5516Mohamad Javad EshraghiSemiconductor, MERC0000-0001-9432-3596Journal Article20161025<span>In this study, spherical Nb2O5 nanoparticles were synthesized by a novel chemical method as a simple, robust, surfactant-free, non-toxic and widely applicable approach. In order to investigate the effect of initial concentration on particle sizes, nanoparticles with different initial concentration were synthesized. Ultrasonic assisted method was applied and the effects of ultrasonic treatment and concentration on particle sizes have been investigated. The structure and morphology of Nb2O5 nanoparticles were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FE-SEM). Particle size measurement was estimated by Digimizer software and particle size distribution was plotted. The results showed that ultrasonic treatment and different suspension concentration impact on particle sizes. Nanoparticles with average particle size of 41 nm in diameter were achieved by using 2 gr/L of Nb2O5 in initial suspension with ultrasonic assist. </span>https://www.acerp.ir/article_90836_a68664936ac20ff95f836c30960ef44a.pdfMaterials and Energy Research Center (MERC)
Iranian Ceramic Society (ICERS)Advanced Ceramics Progress2423-74772420161101Investigation of Macroporous Calcium Phosphate Cement Obtained by Foamed Gelatin Polymer18247003210.30501/acp.2016.70032ENZiba OrsheshNano-Techology and Advanced Materials, MERCSaeed HesarakiNano-Techology and Advanced Materials, MERC0000-0001-9147-5850Ali KhanlarkhaniNano-Technology and Advanced Materials, Materials and Energy Research CenterJournal Article19700101This study deals with the effect of gelatin on physical and mechanical properties of calcium phosphate bone cements. The mixture of tetracalcium phosphate (TTCP) and dicalcium phosphate (DCPA) as the cement powder was mixed with 6 wt% Na2HPO4 solution containing different amount (0, 2, 5 and 8% in w/w) of foamed gelatin as liquid phase. The physical properties were determined in the terms of setting time and macroporosity. The compressive strength was also checked before and after soaking the cements in simulated body fluid (SBF). The phase composition, microstructure and chemical groups were respectively determined using X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier transformation Infrared Spectroscopy (FTIR). The results showed that gelatin accelerated hydroxyapatite (HA) precipitation during setting and reduced the initial setting time from 35 min for cement without gelatin to 23 min for cement with the most amount of gelatin. Moreover, 17% (in v/v) macroporosity was induced in the cement structure using 8% solution of gelatin as the cement liquid. Gelatin addition promoted compressive strength of the set cement from 1.13 MPa (for gelatin-free cement) to 5.8 MPa.https://www.acerp.ir/article_70032_cc52bcf81534b0a4bf363bbd31852313.pdfMaterials and Energy Research Center (MERC)
Iranian Ceramic Society (ICERS)Advanced Ceramics Progress2423-74772420161101Investigation of HF/H2O2 Concentration Effect on Structural and Antireflection Properties of Porous Silicon Prepared by Metal-Assisted Chemical Etching Process for Photovoltaic Applications25317003310.30501/acp.2016.70033ENShirin MahmoudiSemiconductors, Materials and Energy Research Center (MERC)Mohammad EshraghiSemiconductors, Materials and Energy Research Center (MERC)Benyamin YarmandNanotechnology and Advanced Materials Department, , Materials and Energy Research Center (MERC)0000-0002-6771-314XNima NaderiSemiconductors, Materials and Energy Research Center (MERC)0000-0002-4071-5516Journal Article19700101Porous silicon was successfully prepared using metal-assisted chemical etching method. The Effect of HF/H2O2 concentration in etching solution as an affecting parameter on the prepared porosity type and size was investigated. Field emission electron microscopy (FE-SEM) confirmed that all etched samples had porous structure and the sample which was immersed into HF/H2O2 withmolar ratio of 7/3.53 had the smallest porosities. The average roughness of 288 nm and reflectivity as low as 7% could be achieved using this molar ratio. The Raman peak appeared at 520.09 cm-1 confirmed that there weren’t any defect and stress in the porous structure. The prepared porous silicon had potential candidate for replacement with antireflective layer in photovoltaic devices because of their low production cost, high antireflective property, and possibility of integration process relative to other antireflection layers.https://www.acerp.ir/article_70033_e4a665a618facc6a618932b7c17fe08b.pdfMaterials and Energy Research Center (MERC)
Iranian Ceramic Society (ICERS)Advanced Ceramics Progress2423-74772420161101Characterization and Phase Transformation of Spherical YSZ Powders Fabricated Via air Plasma Spray Method32387003410.30501/acp.2016.70034ENMohammad Reza DadfarCeramic Department, Materials and Energy Research Center (MERC)0000-0000-0000-0000Mohammad Reza RahimipoorCeramic Division, MERC0000-0001-5840-0339M.R. VaeziNanotechnology and Advanced Materials, Material and Energy Research Center (MERC)A. GholamzadehDepartment of Materials Science and Engineering, Sharif University of TechnologyJournal Article19700101Air plasma spray (APS) process is used to produce high density and flowability spherical powders. Phase transformation that occurred in this process isn’t well known. In this paper, the YSZ powders have been sprayed in water to investigate the morphology changes and phase transformations via air plasma spray (APS) method. Phase analysis of powders was examined by XRD and the crystallite size and lattice strain of YSZ calculated by the Williamson-Hall method. Morphology and particle size measurement observed by scanning electron microscope. Therefore, results showed the good spherical YSZ powders morphology and also phase transformations were in order to improve the properties of the fabricated powders. During the YSZ powders plasma process, some monoclinic phases transform to stable tetragonal phase.https://www.acerp.ir/article_70034_4b1aa3274f4977e360a683eff1681ee7.pdfMaterials and Energy Research Center (MERC)
Iranian Ceramic Society (ICERS)Advanced Ceramics Progress2423-74772420161101Effect of Surface Roughness Morphology on Bond Strength of Thermal Sprayed WC-10Co-4Cr Ceramic/Metal Coating39437003510.30501/acp.2016.70035ENFarid NaeimiEngineering, Islamic Azad UniversityMostafa TahariEngineering, Esfarayen University of TechnologyJournal Article19700101In this study, the effect of surface roughness and roughness morphology on the bond strength of WC-Co-Cr coatings has investigated. The three different surfaces morphology are use for this purpose. The first and tow samples sandblasted with alumina and silicon carbide respectively. Other sample no sandblasted before spraying process. The same WC-10Co-4Cr coating deposited on the substrates with HVOF methods. The morphology of powder, coating and substrate surface roughness has investigated with scanning electron microscopy (SEM) and the surface roughness meter used for measurement of surface roughness. The phase study of powder and coating are doing with X-ray diffractometry. Coatings bond strength has investigated with pull off test. The phase investigated show that decomposition of WC phase is very low during thermal spray process. Porosity in the WC-10Co-4Cr coating that calculated with image analysis is about %1.6, whereas the hardness is 1180 HV. The pull off test results show the non-sandblasted substrate after coating process shows higher bond strength. Probably work hardening during sandblasting prevent of WC particles penetration into copper substrate. This phenomenon to cause the fracture mode in alumina and SiC was adhesion and cohesion respectively, while Fracture in the non-sandblasted coating occurs in epoxy.https://www.acerp.ir/article_70035_d4fdeda250c7bfb41045c9f52c0c6ad7.pdfMaterials and Energy Research Center (MERC)
Iranian Ceramic Society (ICERS)Advanced Ceramics Progress2423-74772420161101Correlation Between Surface Morphology and Optical Properties of Quasi-Columnar Porous Silicon Nanostructures44497003610.30501/acp.2016.70036ENSanaz RasiSemiconductors, Materials and Energy Research CenterMorteza MoradiSemiconductors, Materials and Energy Research Center (MERC)Nima NaderiSemiconductor, Merc0000-0002-4071-5516Journal Article19700101In the current work, the effect of surface morphology on light emission property and absorption behavior of quasi-columnar macro-porous silicon (PS) was investigated. PS structures with different morphology were synthesized using photo-electrochemical etching method by applying different etching current densities. SEM micrographs showed that empty macro-pores size and porosity of PS layers were increased by increasing the current density due to passivity breakdown in initiated pore walls. Also, a decrease in pore density and a diminishing of nanocrystallites density on PS samples surface was observed. By increasing etching current density, a red shift in Raman peak position of PS samples was observed which was due to the residual stress and quantum confinement (QC) effect in the PS structures. PL peak position was also shifted to higher frequencies and it was in good agreement with Raman red shift due to QC effect in finite size crystallites. Maximum PL intensity was observed for sample with higher pore density and smaller pore size. Although, the PS structure with maximum pore size had the maximum porosity, but it showed a remarkable decrease in PL intensity because of trapping of irradiated light in quasi-columnar empty macropores. We report that porosity is not necessarily increase in order of creation more pores and more nanocrystallites formation in PS structures. Therefore porosity can not the only effective parameter for determination of optical properties such as photoluminescence efficiency. The morphology and size of pores can also be outstanding parameters for changing optical behavior of PS nanostructures.https://www.acerp.ir/article_70036_cf87d3783a612c07357afd629514eee8.pdf