Hamed Roghani - Academia.edu (original) (raw)
Papers by Hamed Roghani
Materials Chemistry and Physics, Jul 1, 2015
Composite prepared by combustion synthesis method in system of Si, C, B 2 O 3 and Mg. More than s... more Composite prepared by combustion synthesis method in system of Si, C, B 2 O 3 and Mg. More than stoichiometric Mg/B 2 O 3 molar ratio cause to more complete synthesis. Lower than 900 C furnace temperature cause to incomplete synthesis. Nanocomposite with a high homogeneity and lowest impurity synthesized.
Advanced Powder Technology, Jul 1, 2015
In this study, ultra fine B 4 C-SiC composite powder was prepared by mechanically activated self-... more In this study, ultra fine B 4 C-SiC composite powder was prepared by mechanically activated self-propagating synthesis (MASHS) method from the raw material of B 2 O 3 , Si, C and Mg. Initially the synthesized samples contained MgO, B 4 C, SiC and a small amount of magnesium borates, residual carbon and silicon. XRD analysis after acid leaching of combustion products showed a great effect of acid leaching on removing the impurities. The remaining substances significantly reduced by increasing the energy of milling. The comparison of diffraction patterns after synthesis and after acid leaching showed that acid leaching had moved the peaks to the lower angles. This is due to the development of solid solution and a decrease in contraction stress during the synthesis. Optimum sample prepared with milling parameter of ball to powder ratio of 20:1, rotation speed 300 rpm and milling time of 12 h and synthesized at 1000°C furnace temperature. The average crystallite size of B 4 C and SiC were calculated less than 15 nm. These values are consistent with the TEM results while most of grain size was less than 30 nm. The particle size analysis of optimum sample indicated that 99.7% of synthesized nanocomposite agglomerated particles were less than 1000 nm.
Ceramics International, Dec 1, 2020
Abstract The nano-sized B4C–SiC composite powders were in-situ synthesized with high purity in a ... more Abstract The nano-sized B4C–SiC composite powders were in-situ synthesized with high purity in a short time at low temperatures. In this study, the mechanically activated mixtures of C, B2O3, Mg, and Si were used as raw materials. The synthesis processes were performed in tubular and spark plasma furnaces. The synthesized nanocomposites were acid, being leached to remove the MgO byproducts. The purity of the acid leached composites was determined through the XRD, EDS, and FTIR analyses. The purity level of the nanocomposites, which were synthesized in spark plasma furnace, was 90%, which was increased to 98% by using higher amounts of raw materials. Moreover, the average crystallite size of B4C and SiC were 17 and 41 nm, respectively, in the high-purity nanocomposite. The SEM and TEM investigations confirmed the synthesis of nano-sized B4C–SiC nanocomposites.
Journal of Materials Research and Technology, 2022
We created AA2024-AA1050 and AA2024-AA1050/0.005 vol.% Al2O3 nanocomposites by six accumulative r... more We created AA2024-AA1050 and AA2024-AA1050/0.005 vol.% Al2O3 nanocomposites by six accumulative roll bonding (ARB) process stages. AA2024 and AA1050 sheets with a thickness of 0.7 mm were used to create a composite. Also, plate-shaped alumina nanoparticles were used in the composites. The two AA1050 and one AA2024 sheets (among the two AA1050 sheets) were ARB-ed up to six cycles with and without adding alumina nanoparticles. Also, a sample of the AA1050 without composite making was ARB-ed up to six cycles. Some composites were aged after the ARB process in the furnace at 110, 150, and 190°C. SEM, TEM, and EDS-MAP analyses, tensile strength, microhardness, and Pin-on-Disc tests were performed to study the ARB-ed sheets. The results of the tensile tests showed that the tensile strength of AA2024-AA1050 created by the six stages ARB process was two times more than primary AA1050. Also, the wear resistance of this composite was 74% more than six cycles ARB-ed the AA1050. Using 0.005 vol...
Materials Chemistry and Physics, 2015
Composite prepared by combustion synthesis method in system of Si, C, B 2 O 3 and Mg. More than s... more Composite prepared by combustion synthesis method in system of Si, C, B 2 O 3 and Mg. More than stoichiometric Mg/B 2 O 3 molar ratio cause to more complete synthesis. Lower than 900 C furnace temperature cause to incomplete synthesis. Nanocomposite with a high homogeneity and lowest impurity synthesized.
In this study, in situ synthesis of B4C-SiC nanocomposite powder (1 : 1 molar ratio) was performe... more In this study, in situ synthesis of B4C-SiC nanocomposite powder (1 : 1 molar ratio) was performed by mechanically activated volume combustion synthesis (MAVCS) method. Raw materials were included Si, C, B2O3 and Mg. Milling process was used to mechanically activate the raw materials. Synthesis of prepared samples was occurred in a tube furnace under argon atmosphere at 1000 C. The milling parameters were examined to optimize the activating of the raw materials process. Synthesized samples after mechanical activation with milling parameters of 300 rpm rotation speed, 20 to 1 ball to powder ratio and milling time of 9 and 12 h had best phase and morphology conditions. Average crystallite size of B4C and SiC compounds were calculated less than 15 nm for these two samples. Transmission electron microscopy (TEM) analysis of these two samples approved their formation from the grains in nanometers scale. The TEM analysis showed the sample with 12 h of milling the raw materials has formed ...
Journal of Materials Research and Technology
Advanced Powder Technology, 2015
In this study, ultra fine B 4 C–SiC composite powder was prepared by mechanically activated self-... more In this study, ultra fine B 4 C–SiC composite powder was prepared by mechanically activated self-propagating synthesis (MASHS) method from the raw material of B 2 O 3 , Si, C and Mg. Initially the synthesized samples contained MgO, B 4 C, SiC and a small amount of magnesium borates, residual carbon and silicon. XRD analysis after acid leaching of combustion products showed a great effect of acid leaching on removing the impurities. The remaining substances significantly reduced by increasing the energy of milling. The comparison of diffraction patterns after synthesis and after acid leaching showed that acid leaching had moved the peaks to the lower angles. This is due to the development of solid solution and a decrease in contraction stress during the synthesis. Optimum sample prepared with milling parameter of ball to powder ratio of 20:1, rotation speed 300 rpm and milling time of 12 h and synthesized at 1000 °C furnace temperature. The average crystallite size of B 4 C and SiC were calculated less than 15 nm. These values are consistent with the TEM results while most of grain size was less than 30 nm. The particle size analysis of optimum sample indicated that 99.7% of synthesized nanocomposite agglomerated particles were less than 1000 nm.
In this study, in situ synthesis of B 4 C-SiC nanocomposite powder (1 : 1 molar ratio) was perfor... more In this study, in situ synthesis of B 4 C-SiC nanocomposite powder (1 : 1 molar ratio) was performed by mechanically activated volume combustion synthesis (MAVCS) method. Raw materials were included Si, C, B 2 O 3 and Mg. Milling process was used to mechanically activate the raw materials. Synthesis of prepared samples was occurred in a tube furnace under argon atmosphere at 1000 o C. The milling parameters were examined to optimize the activating of the raw materials process. Synthesized samples after mechanical activation with milling parameters of 300 rpm rotation speed, 20 to 1 ball to powder ratio and milling time of 9 and 12 h had best phase and morphology conditions. Average crystallite size of B 4 C and SiC compounds were calculated less than 15 nm for these two samples. Transmission electron microscopy (TEM) analysis of these two samples approved their formation from the grains in nanometers scale. The TEM analysis showed the sample with 12 h of milling the raw materials has formed from more uniform grains than the sample with 9 h of milling the raw materials. Particle size analysis showed more than 99% of the particles from both samples have a size less than 1000 nm.
In this study, SiCeB4C nanocomposite has been synthesized in situ successfully by Mechanical acti... more In this study, SiCeB4C nanocomposite has been synthesized in situ successfully by Mechanical activated combustion synthesis method (MASHS). Initially Si, C, B2O3 and Mg powders as raw materials were weighed according to different molar ratio of Mg to B2O3. In next step theses materials were milled in a planetary mill under Ar atmosphere. The synthesis step was performed in a tube furnace equipped with controlled atmosphere system. The different furnace temperature was investigated on the phase synthesis and morphology of the products. The specimens in the various steps were studied by XRD analysis for evaluation of the phase compositions and calculation of the average crystallite size of them. The morphology of synthesized products was investigated by scanning and transmission electron microscopes (SEM&TEM). The final product contains main phases MgO, B4C and SiC. Also, In this sample byproducts were characterized such as Mg3B2O6, Mg2B2O5 and remaining carbon. XRD pattern of synthesized sample showed the considerable effect of increasing Mg to B2O3 molar ratio on reducing the amount of Mg3B2O6, Mg2B2O5 and remaining carbon. SiCeB4C composite was synthesized with more homogenous morphology by reducing the furnace temperature from 1000 to 900 C, but reduction of temperature up to 800 C give rise to uncompleted reaction whereas some unreacted Si remains. Average crystallite sizes of optimal sample were calculated 10.5 and 8 nm for SiC and B4C respectively. These values are consisted of the TEM results somehow while grain size was less than 70 nm. Also SEM observation showed fine grains with sizes falling in the nanometer range.
In this study, ultra fine B 4 C–SiC composite powder was prepared by mechanically activated self-... more In this study, ultra fine B 4 C–SiC composite powder was prepared by mechanically activated self-propagating synthesis (MASHS) method from the raw material of B 2 O 3 , Si, C and Mg. Initially the synthesized samples contained MgO, B 4 C, SiC and a small amount of magnesium borates, residual carbon and silicon. XRD analysis after acid leaching of combustion products showed a great effect of acid leaching on removing the impurities. The remaining substances significantly reduced by increasing the energy of milling. The comparison of diffraction patterns after synthesis and after acid leaching showed that acid leaching had moved the peaks to the lower angles. This is due to the development of solid solution and a decrease in contraction stress during the synthesis. Optimum sample prepared with milling parameter of ball to powder ratio of 20:1, rotation speed 300 rpm and milling time of 12 h and synthesized at 1000 °C furnace temperature. The average crystallite size of B 4 C and SiC were calculated less than 15 nm. These values are consistent with the TEM results while most of grain size was less than 30 nm. The particle size analysis of optimum sample indicated that 99.7% of synthesized nanocomposite agglomerated particles were less than 1000 nm.
Materials Chemistry and Physics, Jul 1, 2015
Composite prepared by combustion synthesis method in system of Si, C, B 2 O 3 and Mg. More than s... more Composite prepared by combustion synthesis method in system of Si, C, B 2 O 3 and Mg. More than stoichiometric Mg/B 2 O 3 molar ratio cause to more complete synthesis. Lower than 900 C furnace temperature cause to incomplete synthesis. Nanocomposite with a high homogeneity and lowest impurity synthesized.
Advanced Powder Technology, Jul 1, 2015
In this study, ultra fine B 4 C-SiC composite powder was prepared by mechanically activated self-... more In this study, ultra fine B 4 C-SiC composite powder was prepared by mechanically activated self-propagating synthesis (MASHS) method from the raw material of B 2 O 3 , Si, C and Mg. Initially the synthesized samples contained MgO, B 4 C, SiC and a small amount of magnesium borates, residual carbon and silicon. XRD analysis after acid leaching of combustion products showed a great effect of acid leaching on removing the impurities. The remaining substances significantly reduced by increasing the energy of milling. The comparison of diffraction patterns after synthesis and after acid leaching showed that acid leaching had moved the peaks to the lower angles. This is due to the development of solid solution and a decrease in contraction stress during the synthesis. Optimum sample prepared with milling parameter of ball to powder ratio of 20:1, rotation speed 300 rpm and milling time of 12 h and synthesized at 1000°C furnace temperature. The average crystallite size of B 4 C and SiC were calculated less than 15 nm. These values are consistent with the TEM results while most of grain size was less than 30 nm. The particle size analysis of optimum sample indicated that 99.7% of synthesized nanocomposite agglomerated particles were less than 1000 nm.
Ceramics International, Dec 1, 2020
Abstract The nano-sized B4C–SiC composite powders were in-situ synthesized with high purity in a ... more Abstract The nano-sized B4C–SiC composite powders were in-situ synthesized with high purity in a short time at low temperatures. In this study, the mechanically activated mixtures of C, B2O3, Mg, and Si were used as raw materials. The synthesis processes were performed in tubular and spark plasma furnaces. The synthesized nanocomposites were acid, being leached to remove the MgO byproducts. The purity of the acid leached composites was determined through the XRD, EDS, and FTIR analyses. The purity level of the nanocomposites, which were synthesized in spark plasma furnace, was 90%, which was increased to 98% by using higher amounts of raw materials. Moreover, the average crystallite size of B4C and SiC were 17 and 41 nm, respectively, in the high-purity nanocomposite. The SEM and TEM investigations confirmed the synthesis of nano-sized B4C–SiC nanocomposites.
Journal of Materials Research and Technology, 2022
We created AA2024-AA1050 and AA2024-AA1050/0.005 vol.% Al2O3 nanocomposites by six accumulative r... more We created AA2024-AA1050 and AA2024-AA1050/0.005 vol.% Al2O3 nanocomposites by six accumulative roll bonding (ARB) process stages. AA2024 and AA1050 sheets with a thickness of 0.7 mm were used to create a composite. Also, plate-shaped alumina nanoparticles were used in the composites. The two AA1050 and one AA2024 sheets (among the two AA1050 sheets) were ARB-ed up to six cycles with and without adding alumina nanoparticles. Also, a sample of the AA1050 without composite making was ARB-ed up to six cycles. Some composites were aged after the ARB process in the furnace at 110, 150, and 190°C. SEM, TEM, and EDS-MAP analyses, tensile strength, microhardness, and Pin-on-Disc tests were performed to study the ARB-ed sheets. The results of the tensile tests showed that the tensile strength of AA2024-AA1050 created by the six stages ARB process was two times more than primary AA1050. Also, the wear resistance of this composite was 74% more than six cycles ARB-ed the AA1050. Using 0.005 vol...
Materials Chemistry and Physics, 2015
Composite prepared by combustion synthesis method in system of Si, C, B 2 O 3 and Mg. More than s... more Composite prepared by combustion synthesis method in system of Si, C, B 2 O 3 and Mg. More than stoichiometric Mg/B 2 O 3 molar ratio cause to more complete synthesis. Lower than 900 C furnace temperature cause to incomplete synthesis. Nanocomposite with a high homogeneity and lowest impurity synthesized.
In this study, in situ synthesis of B4C-SiC nanocomposite powder (1 : 1 molar ratio) was performe... more In this study, in situ synthesis of B4C-SiC nanocomposite powder (1 : 1 molar ratio) was performed by mechanically activated volume combustion synthesis (MAVCS) method. Raw materials were included Si, C, B2O3 and Mg. Milling process was used to mechanically activate the raw materials. Synthesis of prepared samples was occurred in a tube furnace under argon atmosphere at 1000 C. The milling parameters were examined to optimize the activating of the raw materials process. Synthesized samples after mechanical activation with milling parameters of 300 rpm rotation speed, 20 to 1 ball to powder ratio and milling time of 9 and 12 h had best phase and morphology conditions. Average crystallite size of B4C and SiC compounds were calculated less than 15 nm for these two samples. Transmission electron microscopy (TEM) analysis of these two samples approved their formation from the grains in nanometers scale. The TEM analysis showed the sample with 12 h of milling the raw materials has formed ...
Journal of Materials Research and Technology
Advanced Powder Technology, 2015
In this study, ultra fine B 4 C–SiC composite powder was prepared by mechanically activated self-... more In this study, ultra fine B 4 C–SiC composite powder was prepared by mechanically activated self-propagating synthesis (MASHS) method from the raw material of B 2 O 3 , Si, C and Mg. Initially the synthesized samples contained MgO, B 4 C, SiC and a small amount of magnesium borates, residual carbon and silicon. XRD analysis after acid leaching of combustion products showed a great effect of acid leaching on removing the impurities. The remaining substances significantly reduced by increasing the energy of milling. The comparison of diffraction patterns after synthesis and after acid leaching showed that acid leaching had moved the peaks to the lower angles. This is due to the development of solid solution and a decrease in contraction stress during the synthesis. Optimum sample prepared with milling parameter of ball to powder ratio of 20:1, rotation speed 300 rpm and milling time of 12 h and synthesized at 1000 °C furnace temperature. The average crystallite size of B 4 C and SiC were calculated less than 15 nm. These values are consistent with the TEM results while most of grain size was less than 30 nm. The particle size analysis of optimum sample indicated that 99.7% of synthesized nanocomposite agglomerated particles were less than 1000 nm.
In this study, in situ synthesis of B 4 C-SiC nanocomposite powder (1 : 1 molar ratio) was perfor... more In this study, in situ synthesis of B 4 C-SiC nanocomposite powder (1 : 1 molar ratio) was performed by mechanically activated volume combustion synthesis (MAVCS) method. Raw materials were included Si, C, B 2 O 3 and Mg. Milling process was used to mechanically activate the raw materials. Synthesis of prepared samples was occurred in a tube furnace under argon atmosphere at 1000 o C. The milling parameters were examined to optimize the activating of the raw materials process. Synthesized samples after mechanical activation with milling parameters of 300 rpm rotation speed, 20 to 1 ball to powder ratio and milling time of 9 and 12 h had best phase and morphology conditions. Average crystallite size of B 4 C and SiC compounds were calculated less than 15 nm for these two samples. Transmission electron microscopy (TEM) analysis of these two samples approved their formation from the grains in nanometers scale. The TEM analysis showed the sample with 12 h of milling the raw materials has formed from more uniform grains than the sample with 9 h of milling the raw materials. Particle size analysis showed more than 99% of the particles from both samples have a size less than 1000 nm.
In this study, SiCeB4C nanocomposite has been synthesized in situ successfully by Mechanical acti... more In this study, SiCeB4C nanocomposite has been synthesized in situ successfully by Mechanical activated combustion synthesis method (MASHS). Initially Si, C, B2O3 and Mg powders as raw materials were weighed according to different molar ratio of Mg to B2O3. In next step theses materials were milled in a planetary mill under Ar atmosphere. The synthesis step was performed in a tube furnace equipped with controlled atmosphere system. The different furnace temperature was investigated on the phase synthesis and morphology of the products. The specimens in the various steps were studied by XRD analysis for evaluation of the phase compositions and calculation of the average crystallite size of them. The morphology of synthesized products was investigated by scanning and transmission electron microscopes (SEM&TEM). The final product contains main phases MgO, B4C and SiC. Also, In this sample byproducts were characterized such as Mg3B2O6, Mg2B2O5 and remaining carbon. XRD pattern of synthesized sample showed the considerable effect of increasing Mg to B2O3 molar ratio on reducing the amount of Mg3B2O6, Mg2B2O5 and remaining carbon. SiCeB4C composite was synthesized with more homogenous morphology by reducing the furnace temperature from 1000 to 900 C, but reduction of temperature up to 800 C give rise to uncompleted reaction whereas some unreacted Si remains. Average crystallite sizes of optimal sample were calculated 10.5 and 8 nm for SiC and B4C respectively. These values are consisted of the TEM results somehow while grain size was less than 70 nm. Also SEM observation showed fine grains with sizes falling in the nanometer range.
In this study, ultra fine B 4 C–SiC composite powder was prepared by mechanically activated self-... more In this study, ultra fine B 4 C–SiC composite powder was prepared by mechanically activated self-propagating synthesis (MASHS) method from the raw material of B 2 O 3 , Si, C and Mg. Initially the synthesized samples contained MgO, B 4 C, SiC and a small amount of magnesium borates, residual carbon and silicon. XRD analysis after acid leaching of combustion products showed a great effect of acid leaching on removing the impurities. The remaining substances significantly reduced by increasing the energy of milling. The comparison of diffraction patterns after synthesis and after acid leaching showed that acid leaching had moved the peaks to the lower angles. This is due to the development of solid solution and a decrease in contraction stress during the synthesis. Optimum sample prepared with milling parameter of ball to powder ratio of 20:1, rotation speed 300 rpm and milling time of 12 h and synthesized at 1000 °C furnace temperature. The average crystallite size of B 4 C and SiC were calculated less than 15 nm. These values are consistent with the TEM results while most of grain size was less than 30 nm. The particle size analysis of optimum sample indicated that 99.7% of synthesized nanocomposite agglomerated particles were less than 1000 nm.