scholarly journals Influence of mechanical activation on microstructure and crystal structure of sintered MgO-TiO2 system

2010 ◽  
Vol 42 (2) ◽  
pp. 143-151 ◽  
Author(s):  
S. Filipovic ◽  
N. Obradovic ◽  
V.B. Pavlovic ◽  
S. Markovic ◽  
M. Mitric ◽  
...  

Mixtures of MgO-TiO2 were mechanically activated using high-energy planetary ball mill during 5, 10, 20, 40, 80 and 120 minutes. Sintering process was preformed in air at 1100o-1400oC for 2h. The decrease in powder?s particle size was noticed as the time of mechanical activation increased and confirmed by particle size analyzer. XRD analyses were performed in order to acquire the information about phase composition. Different ratio mixtures of MgTiO3 and Mg2TiO4 are present within all sintered samples. The effect of tribophysical activation on microstructure was investigated by scanning electron microscopy. The differential thermal gravimetric analysis has been performed in order to investigate thermal behaviour of the mixtures.

2012 ◽  
Vol 44 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Darko Kosanovic ◽  
N. Obradovic ◽  
J. Zivojinovic ◽  
A. Maricic ◽  
V.P. Pavlovic ◽  
...  

In this article the influence of mechanical activation on sintering process of bariumstrontium-titanate ceramics has been investigated. Both non-activated and mixtures treated in a planetary ball mill for 5, 10, 20, 40, 80 and 120 minutes were sintered at 1100-1400?C for 2 hours in presence of air atmosphere. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100?C was too low to induce final sintering stage for this system. Electrical measurements have been conducted for the densest ceramics sintered at 1400?C for 2 hours.


2014 ◽  
Vol 625 ◽  
pp. 38-41
Author(s):  
Rashidah Mohammed Hamidi ◽  
Zakaria Man ◽  
Khairun Azizi Azizli ◽  
Lukman Ismail ◽  
Mohd Fadhil Nuruddin

Fly ash has a high potential to be converted into geopolymeric material due to its abundant supplies and low cost. However, large particle size of the fly ash caused low reactivity which results in low properties of the end product. The improvement on the fly ash properties by mechanical activation allows it as a new possible raw material in wider application besides solving the low reactivity issue which hindered its range of utilization. In this study, fly ash was mechanically activated by high energy planetary ball mill for 1 hour at different speed, ranging from 100 to 350 rpm and with varied ball to powder ratio (2:1, 3:1 and 4:1). The effects towards its particle size, specific surface area and morphology were determined by particle size analyzer and SEM. It was observed that, increasing of speed to 350 rpm and 4:1 ball to powder ratio (BPR) results in finest size of fly ash where at d (0.1), d (0.5) and d (0.9) the sizes were 1.861, 6.765 and 17.065μm respectively and largest surface specific area (1.46 m2/g).


2011 ◽  
Vol 43 (2) ◽  
pp. 145-151 ◽  
Author(s):  
N. Obradovic ◽  
S. Filipovic ◽  
V.B. Pavlovic ◽  
A. Maricic ◽  
N. Mitrovic ◽  
...  

In this article the influence of mechanical activation on sintering process of magnesium-titanate and barium-zinc-titanate ceramics has been investigated. Both nonactivated and mixtures treated in planetary ball mill for 80 minutes were sintered at 1100?C and 1300?C. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100?C was to low to induce final sintering stage for both systems. Moreover, we concluded that barium-zinc-titanate ceramics exhibited better sinterability than magnesium-titanate ceramics.


2011 ◽  
Vol 477 ◽  
pp. 10-15
Author(s):  
Zhong Yuan Lu ◽  
Xun Xu ◽  
Jun Li

In this study, coarse fly ash was ground with laboratory ball mill, vibration mill and jet mill respectively. The powder characteristic of ground fly ash was tested by laser particle size analyzer and scanning electron microscope. And the performance of cement containing different ground fly ash was also studied. It was observed that the characteristic value of fly ash ground by ball mill, vibration mill and jet mill was 13.543 μm, 13.403 μm and 17.344 μm, respectively, when average particle size was about 25μm. And the uniformity coefficient of fly ash ground by ball mill, vibration mill, and jet mill was 1.26, 1.24 and 1.38, respectively. Specially, the mortar strength was increased when 10 to 20 percent of ground fly ash was added. And the highest fluidity of mortar was obtained when 30 percent of fly ash ground by jet mill was added.


2011 ◽  
Vol 306-307 ◽  
pp. 261-264
Author(s):  
Shu Ai Chen ◽  
Jing Kun Xu ◽  
Dan Hua Zhu ◽  
Xue Min Duan

Conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) has been synthesized by solid-state polymerization of 2,5-diiodo-3,4-ethylenedioxythiophene under normal conditions. The resulting iodine-doped PEDOT is completely insoluble in common organic solvents and retained partial crystal structure of monomer as indicated by scanning electron microscopy. Electrical conductivity measurement showed that PEDOT exhibited conductivity in the range of 0.16–0.23 S/cm (pressed powder pellet) with temperature dependence. Thermogravimetric and differential thermal gravimetric analysis of PEDOT indicated that its main chain was stable up to ca. 200 °C.


2009 ◽  
Vol 41 (2) ◽  
pp. 117-123 ◽  
Author(s):  
S. Filipovic ◽  
N. Obradovic ◽  
V. Pavlovic ◽  
V. Petrovic ◽  
M. Mitric

The aim of this work was to analyze the influence of mechanical activation on the MgCO3-TiO2 system. Mixtures of MgCO3-TiO2 were mechanically activated for 15, 30, 60 and 120 minutes in a planetary ball mill and after that sintered at 1100?C for 1h. XRD analyses were performed in order to give information about the phase composition and to determine a variety of microstructure parameters using Scherrer's method. Also, the effect of tribophysical activation and sintering process on microstructure was investigated by scanning electron microscopy. Electrical measurements were performed in order to determine electrical properties of sintered samples. Our conclusions are that the sample activated for 120 min showed the best electrical properties ( ? r=23.86, Q=233, ?=0.38) and exhibited the best sinterability.


2020 ◽  
Vol 12 (2) ◽  
pp. 87-91
Author(s):  
Ranjan K. Bhuyan ◽  
D. Pamu ◽  
Basanta K. Sahoo ◽  
Ashish K. Sarangi

Background: Mg2TiO4 – based ceramics have proven their potentiality in the field of wireless communication systems. In the past, Mg2TiO4 ceramics was considered a quite optical response material in thin film form. Moreover, there is very few studies have been done whatever the proposed work in the present study. Objective: To prepare Mg2TiO4 nano-powders with the help of High Energy Ball Mill (HEBM) and intend to investigate its effect on crystal structure, microstructure and on thermodynamic behavior of MgO-TiO2 system. Methods: Mg2TiO4 ceramics were synthesized using Mechanical alloying method from high- purity oxides MgO and TiO2 (99.99%) of Sigma Aldrich (St. Louis, MO). Results: From the experimental studies it is observed that the powder’s particle size decreases with an increase of milling time. XRD analysis is carried out for phase confirmation of the mixed Mg2TiO4 powder. Further, the result also showed that there is structural changes occurred in the sample by high energy ball milling process, milled at different times. The nanocrystalline nature Mg2TiO4 powder was confirmed from microstructure taken by Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM). Further, differential thermal gravimetric analysis has been carried out to investigate the thermal behavior of milled Mg2TiO4 -powder (35 hours). Conclusion: In work, the effect of mechanical alloying on structural, microstructural and thermal properties of nanocrystalline Mg2TiO4 powders has been investigated systematically. The effect of milling time on particle size, crystal structure and the microstructure was studied using XRD, FE-SEM, TEM and DSC/TGA analysis. The microstructural analysis (FE-SEM and TEM) reveals the nanocrystallinity nature of MTO ceramics prepared by mechanical alloying method. The thermal decomposition behavior of the milled powders was examined by a Thermo-Gravimetric Analyzer (TGA) in argon atmosphere.


2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>


2017 ◽  
Vol 6 (1) ◽  
pp. 31 ◽  
Author(s):  
Dessy Kurniasari ◽  
Sri Atun

Tujuan penelitian ini adalah untuk membuat dan mengetahui karakteristik nanopartikel dari ekstrak etanol temu kunci (Boesenbergia pandurata) dan rasio optimal variasi konsentrasi kitosan dan NaTPP dalam pembuatan nanopartikel temu kunci.            Pembuatan ekstrak temu kunci (Boesenbergia pandurata) menggunakan metode maserasi menggunakan etanol teknis 96% dilanjutkan evaporasi hingga terbentuk ekstrak kental temu kunci. Koloid nanopartikel dibuat dengan mencampurkan ekstrak temu kunci dalam etanol p.a, akuades, larutan kitosan dalam asam asetat glasial, dan larutan NaTPP. Ada 9 variasi komposisi antara larutan kitosan dan  NaTPP yakni rasio (5:1); (10:1); (15:1); (20:1); (3,33:1); (8:1); (9:1); (11:1); dan (12:1). Padatan dalam koloid nanopartikel dipisahkan dengan cara sentrifugasi. Endapan yang didapatkan disimpan dalam freezer. Koloid nanopartikel yang terbentuk dikarakterisasi menggunakan Particle Size Analyzer (PSA) dan Zeta Sizeruntuk mengetahui ukuran partikel dan nilai zeta potensial. Padatan yang didapatkan dari proses sentrifugasi selanjutnya dikarakterisasi menggunakan Scanning Electron Microscopy (SEM) untuk mengetahui kondisi morfologi padatan tersebut. Karakterisasi dengan KLT pada padatan yang didapatkan bertujuan untuk mengetahui kesamaan kandungan senyawa antara ekstrak etanol temu kunci dan ekstrak etanol temu kunci dalam sediaan berukuran nano.            Koloid nanopartikel yang telah dibuat berwarna kuning dan setelah di sentrifugasi terbentuk padatan berwarna kuning kecokelatan. Karakterisasi menggunakan PSA menunjukkan ukuran partikel pada rentang 389-877 nm sebanyak 98,1% pada rasio konsentrasi kitosan dan NaTPP = (8:1). Nilai rerata zeta potensial adalah 41,87 mV. Hasil foto SEM menunjukkan morfologi partikel yang memiliki permukaan yang tidak rata. Rf keenam sampel menunjukkan hasil bahwa senyawa yang terkandung dalam ekstrak etanol temu kunci maupun ekstrak etanol temu kunci dalam sediaan nanopartikel adalah sama. Kata Kunci : kitosan, NaTPP, ekstrak etanol temu kunci, KLT, SEM, PSA, zeta sizer


2013 ◽  
Vol 45 (2) ◽  
pp. 157-164 ◽  
Author(s):  
A. Peles ◽  
N. Djordjevic ◽  
N. Obradovic ◽  
N. Tadic ◽  
V.B. Pavlovic

Mechanical activation is a commonly used and relatively fast and inexpensive procedure for sample preparation before the sintering process. Cordierite, a stoichiometric mixture of three different oxides (2MgO?2Al2O3?5SiO2) is a very attractive, widely used high-temperature ceramic material. The mechanical activation of the starting mixtures with 5.00 mass% TiO2 was performed in a high energy ball mill during 10-80 min. The applied compaction pressure before the sintering process was 2t/cm2, based on our recent investigation. The sintering process was performed at 1350oC for 2h and 4h in air atmosphere. X-ray diffraction was used to analyze the phase composition of non-activated and 80 min activated samples, sintered for 2 and 4h, respectively. Scanning electron microscopy was performed to analyze the microstructure of both compacted and sintered samples. Atomic force microscope was used to investigate the surface of the sintered samples. This paper investigates the influence of prolonged sintering time on the densities of the sintered samples, along with electrical properties.


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