Rietveld Quantitative Phase Analysis of Non-Stoichiometric Cordierite Synthesised from Mainly Talc and Kaolin: Effect of Sintering Temperature

2010 ◽  
Vol 173 ◽  
pp. 190-195
Author(s):  
Johar Banjuraizah ◽  
Mohamad Hasmaliza ◽  
Zainal Arifin Ahmad
Keyword(s):  
Sintering Temperature ◽  
Raw Materials ◽  
Rietveld Method ◽  
Quantitative Phase Analysis ◽  
Secondary Phases ◽  
Grinding Media ◽  
Heat Treated ◽  
Higher Temperature ◽  
New Phase ◽  
Rietveld Quantitative Phase Analysis

Indialite or α-cordierite was synthesized by glass crystallization method using mainly talc and kaolin and with small amount of MgO, Al2O3, SiO2 to compensate the chemical formulation of non-stoihiometric compositions of cordierite. (3MgO.1.5Al2O3.5SiO2). B2O3, P2O5 and CaO was also added to decrease the melting and sintering temperature of cordierite. The glasses were pelletized and sintered from 850oC up to 1050oC. Phase compositions of both heat treated glass was quantified by X-ray powder diffraction data by the Rietveld method using TOPAS Ver 3 software. Result shows that about 60wt% of α cordierite has successfully crystallized at 850oC. Beside secondary phases (forsterite) which come from initial raw materials, phases from grinding media were also presents in the sample. The contamination was considered high since it has reacted with existence phases to form a new phase at higher temperature. Without any contamination from grinding it was expected to obtain more than 90wt% α cordierite using the same composition.

Conductivity Characterizationof Iron Oxide Doped 8 mol% Yttria Stabilized Zirconia

2018 ◽  
Vol 280 ◽  
pp. 58-64
Author(s):  
Tinesha Selvaraj ◽  
Johar Banjuraizah ◽  
S.F. Khor ◽  
M.N. Mohd Zainol
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Solid Electrolytes ◽  
Electrode Materials ◽  
Rietveld Method ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Solid Electrode ◽  
Short Sample ◽  
X Ray ◽  
Rietveld Quantitative Phase Analysis

A facile strategy was proposed to incorporate the dopant Fe into 8YSZ-based material, which can be potentially applied as solid electrode materials for Solid Oxide Fuel Cells (SOFC). In this study, 8YSZ powder was investigated in terms of densification, conductivity and thecrystal structure as a solid electrolytes. Therefore, varying mol% of Fe included 1, 2, and 3 were prepared for investigation. The crystalline structure of the pristine and Fe doped samples were characterized by X-ray diffraction (XRD) and the phase contents were evaluated by using the Rietveld method. Rietveld quantitative phase analysis demonstrates that the monoclinic-ZrO2phase increases (12.8 wt% to 39.7 wt%) as the concentration of Fe increases, while the amount of tetragonal-ZrO2phase drop (40.4 wt% to 11.9 wt%) dramatically. Sintering activity was applied to improve incorporation of the 8YSZ powder and the dopant Fe where the relative density increases from 77% to 92%. Sample YSZ-2Fe has been fitted with CPE equivalent circuit and achieved 6.251 x 10-6S/cm at 300 °C in air. However, it was found that conductivity levels decreased as the mol% of Fe increased. In short, sample YSZ-2Fe ceramic demonstrated good results in terms of densification (92.09%), cubic ZrO2phase (22 wt%) and conductivity 6.251 x 10-6S/cm.

Selected applications of Rietveld-XRD analysis for raw materials of the aluminum industry

2013 ◽  
Vol 28 (2) ◽  
pp. 112-123 ◽  
Author(s):  
Frank R. Feret
Keyword(s):  
Red Mud ◽  
Aluminum Industry ◽  
Raw Materials ◽  
Rietveld Method ◽  
Xrd Analysis ◽  
Rietveld Analysis ◽  
Quantitative Phase Analysis ◽  
Calibration Methods ◽  
Phase Quantification ◽  
The Aluminum Industry

In the last few decades, X-ray diffraction (XRD) systems have been paramount and irreplaceable in controlling bauxite exploration, as well as Bayer and reduction processes. XRD quantitative phase analysis in the aluminum industry witnessed a steady deployment of the Rietveld method, which at present progressively replaces existing methodologies in research and plant laboratories. Rietveld analysis not only helped to surpass traditional XRD calibration methods, it also opened the door for new applications previously not possible. The use of the Rietveld method to characterize selected materials unique to the aluminum industry, such as bauxite, red mud, and alumina is demonstrated and discussed. This paper also presents how synchrotron-based diffractograms obtained for bauxite and red mud samples allowed a much better understanding of mineralogical representation, and made it possible to leverage their Rietveld quantification. Despite clear advantages, the Rietveld method also has limitations that are revealed. For alumina phase quantification, a dedicated Rietveld analytical program was built with structure data for eight alumina mineralogical phases: alpha, beta (β-Al2O3 = Na2O•11Al2O3), delta, gamma (2), kappa, sigma, and theta. The paper gives unique examples of phase quantification in aluminas of various origins and phase composition.

Phase Analysis in the Crystallization of Cordierite

2012 ◽  
Vol 501 ◽  
pp. 91-95
Author(s):  
Ibrahim Norfadhilah ◽  
Zainal Arifin Ahmad ◽  
Mohamad Hasmaliza
Keyword(s):  
Quantitative Analysis ◽  
Phase Analysis ◽  
Glass Composition ◽  
Raw Materials ◽  
Rietveld Method ◽  
Total Weight ◽  
Quantitative Phase Analysis ◽  
Crystalline Fraction ◽  
Weight Percentage ◽  
Amorphous Content

In this study, α-Cordierite was synthesized via glass-route using kaolin, talc and dolomite as starting raw materials. All the materials were mixed using non-stoichiometric xCaO.21-xMgO-26Al2O3-53SiO2 and melted at 1540°C for 4 h followed by quenching. Various weight percentage (wt%) of CaO (0, 1, 3, 5, 6, 7, 8, 10, 15 wt %) from dolomite was used to study their effects on the formation of α-cordierite. Quantitative phase analysis of sintered samples was carried out using Rietveld method and the results demonstrated total weight percentage of α-cordierite as a function of various composition of CaO. The Rietveld results were normalized to 100 wt% of crystalline fraction, so the hypothetical amorphous content of samples was assumed to be negligible. Quantitative analysis showed that amount of α-cordierite decreased with increasing CaO. Forsterite phase increased with increasing amount of CaO and anorthite phase start to crystallize at 5 wt% CaO. The precipitation of anorthite may be attributing to the glass composition locating in the field of anorthite phase.

Impact of Secondary Phases Content on the Mechanical Properties of Cordierite

2016 ◽  
Vol 723 ◽  
pp. 650-655 ◽  
Author(s):  
Eing Kuan Kok ◽  
Johar Banjuraizah ◽  
Li Ngee Ho ◽  
Zabar Yahidah
Keyword(s):  
Mechanical Properties ◽  
Phase Analysis ◽  
Sintering Temperature ◽  
Ceramic Body ◽  
Stoichiometric Composition ◽  
Hardness Test ◽  
Quantitative Phase Analysis ◽  
Secondary Phases ◽  
Structural Refinement ◽  
Α Phase

The Cordierite ceramic body had been synthesized through conventional techniques solid state reaction by using non-stoichiometric composition (2.5 MgO. 1.8 Al2O3. 5 SiO2). The sintering temperature study was carried out by heat treated the samples at several degree of sintering temperature (1250 °C, 1275 °C, 1300 oC, 1325 °C, 1350 °C and 1375 °C). The qualitative and quantitative of crystalline phase analysis was accomplished by using X-ray Diffraction (XRD) technique and Rietveld structural refinement. The Scanning electron microscopy (SEM) was employed for morphology analysis. The mechanical properties of samples were determined by Vicker’s Hardness test. Rietveld quantitative phase analysis results show that α phase Cordierite constitutes up to 96.4 wt% when the samples was sintered for 2 hours at sintering temperature of 1375 °C and obtained densified and orderly crystal structure arrangement in SEM micrograph except the mechanical strength. The sample obtained the uppermost α phase Cordierite content gained the lowest hardness values (4.00.8GPa). Conversely, the sample contains 90 wt% α-cordierite and 1.4 wt% magnesium titatnate achieve highest hardness which is about 4.90.79GPa.

Influence of Sintering Temperature on Electrical Properties of Modified-PZT Piezoelectric Ceramics

2016 ◽  
Vol 872 ◽  
pp. 97-102
Author(s):  
Pharatree Jaita ◽  
Ratabongkot Sanjoom ◽  
Chatchai Kruea-In ◽  
Tawee Tunkasiri ◽  
Gobwute Rujijanagul
Keyword(s):  
Electrical Properties ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Secondary Phases ◽  
Xrd Pattern ◽  
Mechanical And Electrical Properties ◽  
Low Field ◽  
Higher Temperature ◽  
Dominant Phase ◽  
Ferroelectric And Piezoelectric Properties

In this research, the effects of sintering temperature on phase structure, densification, microstructure, mechanical and electrical properties of modified-PZT ceramics were investigated. All ceramics were prepared by a conventional mixed oxide amend sintered at various temperatures from 1150 - 1250°C. XRD pattern indicated that completely solid solution occurred for all samples and the ceramics exhibited a single perovskite without any secondary phases. At lower sintering temperature, the dominant phase was rhombohedral while tetragonal phase became dominant at higher temperature. Grain size tended to increase with increasing sintering temperature. The dielectric, ferroelectric and piezoelectric properties were also increased with increasing sintering temperature. In addition, the highest low field d33 of 620 pC/N of was observed for the 1250°C sample.

Synthesis and Characterization of LaMgAl11O19 as Thermal Barrier Coatings Material

2016 ◽  
Vol 697 ◽  
pp. 390-394 ◽  
Author(s):  
Ze Ya Huang ◽  
Hao Ran Lu ◽  
Chang An Wang
Keyword(s):  
Thermal Barrier Coatings ◽  
Raw Materials ◽  
Laser Flash ◽  
Flash Method ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Heat Treated ◽  
Higher Temperature ◽  
Thermal Diffusivities ◽  
Thermal Conductivities

LaMgAl11O19 was synthesized at 1550 °C using La2O3, MgO and Al2O3 as raw materials. The samples were characterization by XRD and SEM. The tablet shaped crystals free of impurity phase formed under this condition. The thermal diffusivities were measured by laser flash method and the determined intrinsic thermal conductivities decreased as temperature increases from 25 °C to 1000 °C. As comparison, intrinsic thermal conductivities of LaMgAl11O19 are lower than that of 7YSZ. The synthesized LaMgAl11O19 was heat treated at higher temperature from 1600 °C to 1700 °C and no change in the phase indicates that the LaMgAl11O19 phase is stable under 1700 °C, which is very important for thermal barrier coatings (TBCs) serving at elevated temperature.

Accuracy in Rietveld quantitative phase analysis of Portland cements

2003 ◽  
Vol 36 (5) ◽  
pp. 1169-1176 ◽  
Author(s):  
A. G. De la Torre ◽  
M. A. G. Aranda
Keyword(s):  
Rietveld Method ◽  
High Energy ◽  
Tricalcium Silicate ◽  
Dicalcium Silicate ◽  
Cement Industry ◽  
Quantitative Phase Analysis ◽  
Portland Cements ◽  
X Ray ◽  
Relative Errors ◽  
Rietveld Quantitative Phase Analysis

The polymorphs that constitute most Portland cements have been synthesized: tricalcium silicate, dicalcium silicate, aluminate, ferrite, gypsum, bassanite and calcite. They have been used to prepare artificial mixtures,i.e.white Portland clinker, grey Portland clinker and two types of grey Portland cements. Quantitative mineralogical analyses of these mixtures have been obtained by laboratory X-ray powder diffraction (λ = 1.54 Å) and the Rietveld method. To assess the accuracy of these analyses, high-energy synchrotron X-ray powder data (λ = 0.40 Å) for the same mixtures have also been studied. Furthermore, synchrotron X-ray powder data were collected for binary mixtures of the polymorphs and a corundum standard. This was done to determine the presence of impurity crystalline phases in the synthesized samples and to check the presence of non-negligible amorphous phase contents. The errors in the synchrotron X-ray analyses are quite low (usually smaller than 1 wt%). The relative errors in the laboratory X-ray analyses are of the order of 2% for the main phases and increase to approximately 5–10% for the low-content components. These errors are acceptable in the factory environment and the routine application of this methodology in the cement industry is being implemented.

scholarly journals (Cu0.4Al0.3)TaSe2: PREPARATION AND CRYSTAL STRUCTURE ANALYSIS FROM X-RAY POWDER DIFFRACTION

2020 ◽  
Vol 28 (29) ◽  
pp. 01-06
Author(s):  
Pedro GRIMA-GALLARDO ◽  
Sonia DURÁN ◽  
Marcos MUÑOZ ◽  
Dibya P RAI ◽  
Gerzon E. DELGADO
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Rietveld Method ◽  
Alloy System ◽  
Crystal Structure Analysis ◽  
Partial Ordering ◽  
Secondary Phases ◽  
X Ray ◽  
Cell Parameters ◽  
New Phase

A new phase of the (CuAlSe2)1-x(TaSe)x alloy system was synthesized by the melt and annealing technique and studied by SEM, DTA, and XRPD techniques. Its structure has been refined by the Rietveld method using X-ray powder diffraction data. The new alloy corresponds with the stoichiometry Cu0.4Al0.3TaSe2. This compound crystallizes in the hexagonal space group 𝑃6ത𝑚2 (Nº 187) with a MoS2-type structure, and unit cell parameters a = 3.455(2) Å, c = 13.423(4) Å, V = 138.7(1) Å3, Z =2. The crystal structure is based on the MoS2- type of stacking of TaSe2 layers with a partial ordering of Cu and Al cations over the tetrahedral sites. The powder pattern was composed of 63.1% of the principal phase Cu0.4Al0.3TaSe2 and 29.9% of CuAlSe2, 7.0% of TaSe3, as the secondary phases.

scholarly journals Pressureless Sintering of YIG Ceramics from Coprecipitated Nanopowders

2021 ◽  
Vol 7 (5) ◽  
pp. 56
Author(s):  
Yimin Yang ◽  
Xiaoying Li ◽  
Ziyu Liu ◽  
Dianjun Hu ◽  
Xin Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Calcination Temperature ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Secondary Phase ◽  
Coprecipitation Method ◽  
Pressureless Sintering ◽  
Densification Behavior ◽  
Sintering Process

Nanoparticles prepared by the coprecipitation method were used as raw materials to fabricate Y3Fe5O12 (YIG) ceramics by air pressureless sintering. The synthesized YIG precursor was calcinated at 900–1100 °C for 4 h in air. The influences of the calcination temperature on the phase and morphology of the nanopowders were investigated in detail. The powders calcined at 1000–1100 °C retained the pure YIG phase. YIG ceramics were fabricated by sintering at 1200–1400 °C for 10 h, and its densification behavior was studied. YIG ceramics prepared by air sintering at 1250 °C from powders calcinated at 1000 °C have the highest in-line transmittance in the range of 1000-3000 nm. When the sintering temperature exceeds 1300 °C, the secondary phase appears in the YIG ceramics, which may be due to the loss of oxygen during the high-temperature sintering process, resulting in the conversion of Fe3+ into Fe2+.

Effect of copper incorporation on phase transformation behavior of electroless nickel–phosphorous coating and its effect on the tribological behavior

2020 ◽  
pp. 146442072098160
Author(s):  
Abhijit Biswas ◽  
Suman Kalyan Das ◽  
Prasanta Sahoo
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Tribological Behavior ◽  
Electroless Nickel ◽  
Two Phase ◽  
Microstructural Changes ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Higher Temperature ◽  
Effect Of Copper

The microstructural changes of electroless Ni–P–Cu coating at various heat-treatment conditions are investigated to understand its implications on the tribological behavior of the coating. Coatings are heat-treated at temperatures ranging between 200°C and 800 °C and for 1–4 h duration. Ni–P–Cu coatings exhibit two-phase transformations in the temperature range of 350–450 °C and the resulting microstructural changes are found to significantly affect their thermal stability and tribological attributes. Hardness of the coating doubles when heat-treated at 452 °C, due to the formation of harder Ni3P phase and crystalline NiCu. Better friction and wear performance are also noted upon heat treatment of the coating at the phase transformation regime, particularly at 400 °C. Wear mechanism is characterized by a mixed adhesive cum abrasive wear phenomena. Heat treatment at higher temperature (600 °C and above) and longer duration (4 h) results in grain coarsening phenomenon, which negatively influences the hardness and tribological characteristics of the coating. Besides, diffusion of iron from the ferrous substrate as well as greater oxide formation are noticed when the coating is heat-treated at higher temperatures and for longer durations (4 h).

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