2024-03-29T02:33:46Z
https://www.acerp.ir/?_action=export&rf=summon&issue=9023
Advanced Ceramics Progress
ACERP
2423-7477
2423-7477
2015
1
1
Effect of Milling Time and Microwave Sintering on Microhardness and Electrical Properties of Nano and Micro Structured Cordierite
Marzieh
Kiani
Touraj
Ebadzadeh
The purpose of this research is to investigate the mechanical and electrical properties of nano structured cordierite. Nano grain size powders were synthesized through mechanical activation by high-energy ball milling of the starting powders containing 34.86 wt% Al2O3, 51.36 wt% SiO2, and 13.78 wt% MgO. Samples were prepared by conventional and microwave sintering at 1390°C. SEM observations illustrated the equiaxed nano-grains of cordierite with an average grain size of 40 nm for samples sintered in microwave. With the increase of milling time, samples sintered at 1390°C in microwave furnace obtained higher micro-hardness and density than those sintered at the same temperature in conventional furnace. Sample milled for 30 h and sintered in microwave furnace at 1390°C obtained the maximum dielectric constant of 5.5±0.1.
Microwave sintering
Mechanical activation
Dielectric Constant
bending strength
Cordierite
2015
03
01
1
5
https://www.acerp.ir/article_69993_22b90c58299d7ee0aa6409f6b445dfac.pdf
Advanced Ceramics Progress
ACERP
2423-7477
2423-7477
2015
1
1
Luminescence Properties of Oxyfluoride Glass and Glass Ceramic Doped with Y3 + Ions
Laleh
Farahinia
Mohammad
Rezvani
Oxyfluoride glass ceramics containing CaF2 nano-crystals doped with Y3+ ions were prepared by one-step crystallization of SiO2- Al2O3- CaO- CaF2 glasses at different temperatures. X- ray diffraction (XRD) results have revealed that CaF2 was the only precipitated crystalline phase in glass ceramic samples. According to the XRD results, a glass ceramic was selected as the best sample in order to compare its optical properties with basic glass. Photoluminescence (PL) and UV-Vis spectra have been employed to study optical properties of glass and glass ceramic samples. A broad band emission in the visible region was observed, which was stronger in the glassy sample. Scanning electron microscopy (SEM) observation and EDX (Energy-dispersive X-ray spectroscopy) results proved the entrance of Y3+ ions into only some of the crystals embedded in the glassy matrix, which was the rational reason of photoluminescence intensity decrease in glass-ceramic.
oxyfluoride glass-ceramic
CaF2 nanocrystals
yttrium emission
luminescence
2015
03
01
6
10
https://www.acerp.ir/article_70000_dbb187562ff352a3d2b65c1d398dd047.pdf
Advanced Ceramics Progress
ACERP
2423-7477
2423-7477
2015
1
1
Determining the Optimal Conditions for Calcium Titanate Nanostructures Synthesized by Mechanical Alloying Method
Sahebali
Manafi
Mojtaba
Jafarian
In this research, calcium titanate nanoparticles have been synthesized via mechanical alloying (MA). By changing the parameters of mechanical alloying, optimal conditions for synthesis of this compound was determined. For synthesis of this compound, a mixture of calcium hydroxide and titanium dioxide, rotation speed of 250 rpm and differnet ball to powder weight ratio was used. Phase investigation, morphology and structure of calcium titanate powder obtained were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) respectively.The results of the X-ray diffraction analysis confirmed the formation of single-phase calcium titanate nanoparticles with cubic crystal structure. The agglomeration of powder has been shown in SEM images. According to the results, the minimum of ball to powder weight ratio for synthesizing this compound via mechanical alloying and without using heat treatment was 50:1 and milling time of 60 h. In this situation the range of grain size (apparent size) using Williamson-Hall equation is 70 nm. The results of Zetasizer showed that the major part of the particle size distribution was in the range between 60 to 80 nm and this confirms the results of Williamson-Hall equation and SEM images. Also, by using of Nelson-Riely and Cohen equations for assessing the lattice parameter, it was found that by increasing milling time to 60 h, lattice parameter values has been closed to ideal values of calcium titanate phase.
mechanical alloying
Calcium titanate
Nanoparticle
Perovskite
2015
03
01
11
16
https://www.acerp.ir/article_69994_457c5d3c5332c30ae521f1f22c28720a.pdf
Advanced Ceramics Progress
ACERP
2423-7477
2423-7477
2015
1
1
Molecular Dynamics Simulation of Straight-chain Alkanes Adsorption and Diffusion in Zeolite
Hamidreza
Rahimipour
Reza
Tafreshi
Mahdi
Davoodpour
Y.
Mortazavi
A. A.
khodadadi
Molecular dynamics simulations were applied to calculate self-diffusion coefficients (Di,self) and heats of adsorption for ethane, propane and n-butane. Simulations were done in temperature range of 300-525 K for various concentrations inside the pores of silicalite type zeolite. Calculated values of selfdiffusion coefficients and heats of adsorption resulted from the current work, were in better agreement with experimental estimated values found in literature than those resulted from simulations reported by other authors. For instance, at temperature of 300K and loading of 5 molecules/unit cell, self-diffusion coefficients of 16.56×10-5, 7.62×10-5 and 5.81×10-5 cm2/s were calculated for C2H6, C3H8, n-C4H10 respectively was compared to experimental reported values of 10×10-5, 9×10-5 and 6×10-5 cm2/s. At the same conditions, adsorption energies of 9.2, 11.48, and 13.66 kcal/mol. were calculated for ethane,propane, and n-butane respectively, while the experimental reported values found to be6.93, 9.7 and12.7 kcal/mol. Simulations showed that the diffusion decreases when loading increases and the heatsof adsorptions were increase by molecular weight of hydrocarbons for all adsorbates studied.
Molecular Dynamics Simulation
Alkanes
SiO2 ceramic
Adsorption and self
Diffusion
2015
03
01
17
26
https://www.acerp.ir/article_69995_6674f7d92e9f142fe6d6ef9c1d563b38.pdf
Advanced Ceramics Progress
ACERP
2423-7477
2423-7477
2015
1
1
Comparison of Thermal Expansion Coefficient in Ln0.6Sr0.4Co0.2M0.8O3-δ (Ln=La,Nd,Sm and M=Fe,Ni,Mn) as Cathode Materials for Solid Oxide Fuel Cell
Fatemeh
Heydari
Amir
Maghsoudipour
Masoud
Alizadeh
Zahra
Khakpour
Masoumeh
Javaheri
In this study, Thermal expansion coefficient (TEC) variation of Ln0.6Sr0.4Co0.2M0.8O3−δ (Ln=La,Nd,Sm and M= Fe,Ni,Mn) perovskite oxide have been evalouated. Different compounds have been prepared and thermal expansion coefficient have been meseaured in different temperature by means of dilatometer analysis. Structural parameters of compounds have been determined by X-ray diffraction and Field Emission Scanning Electron Microscopy (FE-SEM) has been used for the morphological study. Experimental results have shown TEC decreases favorably with substitution of Nd3+ and Mn3+ ions in the lattice
Thermal expansionc oefficient
Perovskite oxide
lattice parameter
2015
03
01
27
31
https://www.acerp.ir/article_69996_4ae4d99123151b53873f055ca547ee2e.pdf
Advanced Ceramics Progress
ACERP
2423-7477
2423-7477
2015
1
1
Affectability of Low Frequency Electrophoretically Deposited Patterns of WO3 and TiO2 Nanoparicles in the Presence of Modifier
Mahsa
Navidirad
Babak
Raissi
Reza
Riahifar
Maziar
Sahba Yaghmaee
Asghar
Kazemzadeh
Fatemeh
Taati-Asil
In this work, the result of additives on electrophoretically deposited patterns of ceramic nanoparticles with totally different chemical composition in the case of using AC electrical field are studied. For this purpose, by the assistance of coplanar electrodes with an interelectrode gap size of 150 µm, heterogeneous AC electrical field was applied to the suspensions of TiO2-acetone and WO3-acetone in the presence and absence of Polyethylenimine (PEI) as an additive at the frequency of 1Hz. The results verified that whereas WO3 nanoparticles tend to fill the gap once additive was not used, they show no tendency to enter it within the presence of PEI. However, TiO2 nanoparticles that leave the gap once additive was not applied, fill it in the presence of PEI.
AC electrophoretic deposition
TiO2 nanoparticles
WO3 nanoparticles
Modifier
2015
03
01
32
35
https://www.acerp.ir/article_69997_406c89522e4897d0cca6bb03ced90fd6.pdf
Advanced Ceramics Progress
ACERP
2423-7477
2423-7477
2015
1
1
Effects of Time, Temperature and Precursor on Solid State Synthesis of α-TCP
Roshanak
Asadi Tabrizi
Ali
Zamanian
Saeed
Hesaraki
In this study, the correlation between impurity content of reagents used (monetite and brushite both from Merck), soaking time and firing temperature in the solid state synthesis of α-tricalcium phosphate (α -TCP) has been established. Mg impurity promoted formation of β-polymorph as a second phase in the resultant product. The extension of firing operation also led to an increase in the amount of α-TCP, higher firing temperature with an Equivalent soaking time resulted in a more purely synthesized αTCP. The amount of α and β phases at each heating program were investigated throughMatch software system. The highest percentage of obtained α-TCP in the resultant product with the monetite precursor containing 0.43 wt.% magnesium impurity at 1350°C and 16 hours of soaking time was about 94%.
Calcium phosphate cement
solid state synthesis
α-tricalcium phosphate
Magnesium
2015
03
01
36
39
https://www.acerp.ir/article_69998_67ab35c3848501d5195817792f2257bc.pdf
Advanced Ceramics Progress
ACERP
2423-7477
2423-7477
2015
1
1
Simulation of the Effect of Sub-Micron Interface Roughness on the Stress Distribution in Functionally Graded Thermal Barrier Coatings
Nasim
Nayebpashaee
Seyed Hossein
Seyedein
M.R.
Aboutalebi
H.
Sarpoolaky
Mohammad Mehdi
Hadavi
In this research, a numerical modeling method was utilized to calculate the stresses occurring during the thermal cycling in a functionally graded thermal barrier coating (FG - TBC). The temperature –dependent material response of this protective material was taken into account and the effects of the thermal cycle and interface morphology of the ceramic /metallic layer in a functionally graded coating system was investigated. Sinusoidal mode of asperity with specific wavelength and amplitude was used to model the two dimensional geometry of interface profile between layers. A finite element model was used to model the effect of the thermal loading imposed on the thermo-mechanical response and stress distribution. In this regard, different observable facts were taken into account in the model such as: non- homogenous temperature distribution, periodic boundary condition and convective heat transfer. These phenomena depict the most real world situation in numerical simulation of multi-layer coating during cooling and thermal cycling, specifically near the ceramic/metal interface. In addition, regions which are potent to crack initiation and propagation in the system and the subsequent delamination places of the TBCs system were predicted.
Finite element method
Functionally graded thermal barrier coating
sinusoidal interface
Residual Stress
2015
03
01
40
47
https://www.acerp.ir/article_69999_6c5f28ece8c8d838b7fac75cd961db6b.pdf