Cost-Effective Grinding of Zirconia Using the Dense Vitreous Bond Silicon Carbide Wheel

2003 ◽  
Vol 125 (2) ◽  
pp. 297-303 ◽  
Author(s):  
Albert J. Shih ◽  
Ronald O. Scattergood ◽  
Adam C. Curry ◽  
Thomas M. Yonushonis ◽  
Darryl J. Gust ◽  
...  
Keyword(s):  
Monoclinic Phase ◽  
Base Material ◽  
Ground Surface ◽  
Cost Effective ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Wheel Wear ◽  
X Ray ◽  
Fine Grain ◽  
Measurement Results

Results of grinding zirconia using wheels with fine grain size SiC and dense vitreous bond are presented. Wheel wear results demonstrated that this type of SiC wheel could grind fully and partially stabilized zirconia (PSZ) very effectively. X-ray diffraction was used to analyze the percentage of monoclinic phase in the PSZ base material, ground surface, and debris. As expected, due to the stress- and temperature-induced phase transformation during grinding, the percentage of monoclinic phase on the ground surface was increased relative to the base material. However, X-ray diffraction showed no monoclinic phase in the PSZ debris. This suggests that, during grinding, the low thermal conductivity of zirconia and SiC, compared to that of diamond, facilitates heat retention in the chip and softens the work-material. This makes the efficient grinding of PSZ possible. Grinding temperature measurement results supported this hypothesis.

Microstructure and Phase Composition of (Ce, Mg)-PSZ Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1194-1196
Author(s):  
Zhi Ping Shen ◽  
Shu Cai ◽  
Zhen Dong
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Monoclinic Phase ◽  
Processing Method ◽  
Nanoporous Structure ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
Heat Treated

Magnesia, ceria partially stabilized zirconia (Ce,Mg)-PSZ ceramics with net shape microstructure are prepared using a processing method similar to that of conventional Mg-PSZ ceramics, then heat-treated at 1500°C for different time. Microstructure and phase composition of (Ce, Mg)-PSZ samples with different amount of CeO2 doped were investigated using SEM and X-ray diffraction. The addition of CeO2 could impede the formation of monoclinic phase and inhibit the growth of cubic grains. A microstructure with net-shape cubic grains, in which tetragonal precipitates interweave to a nanoporous structure is obtained by adding 4∼8 mol% CeO2 in 10mol% MgO doped zirconia matrix and then heat treatment at 1500°C for different time. The precipitate morophology might be related with the addition of CeO2 and the heat treatment temperatures.

Microdomains in BaFeO3-y (0.35 < y < 0.50)

1990 ◽  
Vol 48 (4) ◽  
pp. 780-781
Author(s):  
M. Vallet-Regí ◽  
M. Parras ◽  
J.M. González-Calbet ◽  
J.C. Grenier
Keyword(s):  
Electron Diffraction ◽  
Chemical Analysis ◽  
Monoclinic Phase ◽  
Orthorhombic Phase ◽  
Total Iron ◽  
Zone Axis ◽  
Electron Micrograph ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compositional Variations

BaFeO3-y compositions (0.35<y<0.50) have been investigated by means of electron diffraction and microscopy to resolve contradictory results from powder X-ray diffraction data.The samples were obtained by annealing BaFeO2.56 for 48 h. in the temperature range from 980°C to 1050°C . Total iron and barium in the samples were determined using chemical analysis and gravimetric methods, respectively.In the BaFeO3-y system, according to the electron diffraction and microscopy results, the nonstoichiometry is accommodated in different ways as a function of the composition (y):In the domain between BaFeO2.5+δBaFeO2.54, compositional variations are accommodated through the formation of microdomains. Fig. la shows the ED pattern of the BaFeO2.52 material along thezone axis. The corresponding electron micrograph is seen in Fig. 1b. Several domains corresponding to the monoclinic BaFeO2.50 phase, intergrow with domains of the orthorhombic phase. According to that, the ED pattern of Fig. 1a, can be interpreted as formed by the superposition of three types of diffraction maxima : Very strong spots corresponding to a cubic perovskite, a set of maxima due to the superposition of three domains of the monoclinic phase along [100]m and a series of maxima corresponding to three domains corresponding to the orthorhombic phase along the [100]o.

Characterizations of Synthetic 8mol% YSZ with Comparison to 3mol %YSZ for HT-SOFC

2020 ◽  
Vol 38 (4A) ◽  
pp. 491-500
Author(s):  
Abeer F. Al-Attar ◽  
Saad B. H. Farid ◽  
Fadhil A. Hashim
Keyword(s):  
Ionic Conductivity ◽  
Electrochemical Impedance ◽  
Structural Information ◽  
Impedance Analysis ◽  
High Energy ◽  
Yttria Stabilized Zirconia ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Powder Morphology ◽  
X Ray

In this work, Yttria (Y2O3) was successfully doped into tetragonal 3mol% yttria stabilized Zirconia (3YSZ) by high energy-mechanical milling to synthesize 8mol% yttria stabilized Zirconia (8YSZ) used as an electrolyte for high temperature solid oxide fuel cells (HT-SOFC). This work aims to evaluate the densification and ionic conductivity of the sintered electrolytes at 1650°C. The bulk density was measured according to ASTM C373-17. The powder morphology and the microstructure of the sintered electrolytes were analyzed via Field Emission Scanning Electron Microscopy (FESEM). The chemical analysis was obtained with Energy-dispersive X-ray spectroscopy (EDS). Also, X-ray diffraction (XRD) was used to obtain structural information of the starting materials and the sintered electrolytes. The ionic conductivity was obtained through electrochemical impedance spectroscopy (EIS) in the air as a function of temperatures at a frequency range of 100(mHz)-100(kHz). It is found that the 3YSZ has a higher density than the 8YSZ. The impedance analysis showed that the ionic conductivity of the prepared 8YSZ at 800°C is0.906 (S.cm) and it was 0.214(S.cm) of the 3YSZ. Besides, 8YSZ has a lower activation energy 0.774(eV) than that of the 3YSZ 0.901(eV). Thus, the prepared 8YSZ can be nominated as an electrolyte for the HT-SOFC.

Room Temperature Screw Form Rolling of AZ91D Magnesium Alloy through Processing by Extrusion-Torsion Simultaneous Working

2014 ◽  
Vol 783-786 ◽  
pp. 375-379
Author(s):  
Mitsuaki Furui ◽  
Shouyou Sakashita ◽  
Kazuya Shimojima ◽  
Tetsuo Aida ◽  
Kiyoshi Terayama ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Room Temperature ◽  
Hardness Measurement ◽  
Rolling Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Az91d Magnesium Alloy ◽  
Microstructure Observation ◽  
Fine Grain ◽  
Simultaneous Processing

Extrusion-torsion simultaneous processing is a very attractive technique for fabricating a rod-shape material with fine grain and random texture. We have proposed a new screw form rolling process combined with preliminary extrusion-torsion simultaneous working. Microstructure evolution and mechanical property change of AZ91D magnesium alloy during extrusion-torsion simultaneous processing was examined through microstructure observation, X-ray diffraction analysis and micro-Vickers hardness measurement. By the addition of torsion, the crystal orientation of AZ91D magnesium alloy workpiece was drastically changed from basal crystalline orientation to the random orientation. Crystal grain occurred through the dynamic recrystallization and tended to coarsen with an increase of extrusion-torsion temperature. Grain refinement under 2 um was achieved at the lowest extrusion-torsion temperature of 523 K. M8 gauge AZ91D magnesium alloy screw was successfully formed at room temperature using the extrusion-twisted workpiece preliminary solution treating at 678 K for 345.6 ks. It was found that the extrusion-torsion temperature of 678 K must be selected to fabricate the good screw without any defects.

The Use of the Pseudo-Voigt Function in the Variance Method of X-ray Line-Broadening Analysis

1997 ◽  
Vol 30 (4) ◽  
pp. 427-430 ◽  
Author(s):  
F. Sánchez-Bajo ◽  
F. L. Cumbrera
Keyword(s):  
Crystallite Size ◽  
Original Form ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Variance Method ◽  
The Mean ◽  
Voigt Function

A modified application of the variance method, using the pseudo-Voigt function as a good approximation to the X-ray diffraction profiles, is proposed in order to obtain microstructural quantities such as the mean crystallite size and root-mean-square (r.m.s.) strain. Whereas the variance method in its original form is applicable only to well separated reflections, this technique can be employed in the cases where there is line-profile overlap. Determination of the mean crystallite size and r.m.s. strain for several crystallographic directions in a nanocrystalline cubic sample of 9-YSZ (yttria-stabilized zirconia) has been performed by means of this procedure.

Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

2011 ◽  
Vol 479 ◽  
pp. 54-61 ◽  
Author(s):  
Fei Wang ◽  
Ya Ping Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Method ◽  
X Ray ◽  
Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

Effect of Yttria-Stabilized Zirconia Concentration in an Electroless Bath on Microstructure and Composition of Ni/Yttria-Stabilized Zirconia Nanocomposite

2021 ◽  
Vol 21 (11) ◽  
pp. 5592-5602
Author(s):  
Samira Almasi ◽  
Ali Mohammad Rashidi
Keyword(s):  
High Performance ◽  
Yttria Stabilized Zirconia ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Nickel Ion ◽  
Nanocomposite Particles ◽  
X Ray ◽  
Ni Content ◽  
Naoh Solution ◽  
Average Size

The effect of the yttria-stabilized zirconia (YSZ) nanoparticle loading in an electro-less bath was considered as one of the vital synthesis variables for control Ni content and microstructure of prepared nanocomposite particles, which are two crucial factors to achieving high-performance SOFC anode. Nanocomposite particles were prepared using a simple electroless method without any expensive pretreatment of sensitizing by Sn2+ ions as well as activating by Pd2+ ions that are usually used to apply nickel coating on the surface of a non-conductive substrate. The process was performed by adding YSZ nanoparticles into NaOH solution, separating them from the solution by the centrifugal method, then providing several water-based nanofluids with different concentrations of activated YSZ nanoparticles, mixing them with NiCI2 solution, followed by adding the hydrazine and then NaOH solution. X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray analysis were used to analyze the prepared nanocomposite particles. It is observed that after adding YSZ nanoparticles into the NaOH solution, the pH of the solution varied gradually from a starting pH of 10.2 to 9. Also, by increasing the YSZ nanoparticles loading in the electroless bath from 76 mg/l to 126 mg/l, the grain size of Ni deposits, the Ni content and the average size of the prepared nanocomposite particles decreased. The electrochemical mechanism previously proposed for the nickel ion reduction was modified, and a novel analytical model was proposed for variation of the efficiency of Ni deposition with YSZ nanoparticles loading.

Removeal of Arsenic(III) from Water by Using a New Class of Zero-Valent Iron Modified Mesoporous Silica Molecular Sieves SBA-15

2011 ◽  
Vol 356-360 ◽  
pp. 423-429
Author(s):  
Meng Ye ◽  
Jin Huang ◽  
Rui Chen ◽  
Qi Zhuang He
Keyword(s):  
Molecular Sieves ◽  
Cost Effective ◽  
Zero Valent Iron ◽  
Preparation Process ◽  
X Ray Diffraction ◽  
Wet Impregnation ◽  
X Ray ◽  
New Class ◽  
Transmission Electron ◽  
Removal Of Arsenic

An elevated arsenic (As) content in groundwater imposes a great threat to people worldwide. Thus, developing new and cost-effective methods to remove As from groundwater and drinking water becomes a priority. Using Zero-Valent iron (ZVI) to remove As from water is a proven technology. In this study, ZVI modified SBA-15 mesoporous silicamolecular sieves (ZVI-SBA-15), was prepared, characterized, and used for removing arsenic from water. Wet impregnation, drying, and calcination steps led to iron inclusion within the mesopores. Iron oxide was reduced to ZVI by NaBH4, and the ZVI modified SBA-15 was obtained. Fourier-transform infrared spectroscopy confirmed the preparation process of the nitrate to oxide forms. The structure of the materials was confirmed by Powder X-ray diffraction. Its data indicated that the structure of ZVI-SBA-15 retained the host SBA-15 structure. Brunauer-Emmett-Teller analysis revealed a decrease in surface area and pore size, indicating ZVI-SBA-15 coating on the inner surfaces. Transmission electron micrographs also confirmed that modified SBA-15 retained the structure of the parent SBA-15 silica.It has a high uptake capability(more than 90 pecent) make it potentially attractive absorbent for the removal of arsenic from water.

scholarly journals Equimolar Yttria-Stabilized Zirconia and Samaria-Doped Ceria Solid Solutions

Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 343-352 ◽  
Author(s):  
Reginaldo Muccillo ◽  
Daniel de Florio ◽  
Eliana Muccillo
Keyword(s):  
Tetragonal Phase ◽  
Room Temperature ◽  
Single Phase ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Ceria Solid Solutions ◽  
Attrition Milling

Compositions of (ZrO2)0.92(Y2O3)0.08 (zirconia: 8 mol % yttria—8YSZ) and (CeO2)0.8(Sm2O3)0.2 (ceria: 20 mol % samaria—SDC20) ceramic powders were prepared by attrition milling to form an equimolar powder mixture, followed by uniaxial and isostatic pressing. The pellets were quenched to room temperature from 1200 °C, 1300 °C, 1400 °C and 1500 °C to freeze the defects configuration attained at those temperatures. X-ray diffraction analyses, performed in all quenched pellets, show the evolution of the two (8YSZ and SDC20) cubic fluorite structural phases to a single phase at 1500 °C, identified by Rietveld analysis as a tetragonal phase. Impedance spectroscopy analyses were carried out in pellets either quenched or slowly cooled from 1500 °C. Heating the quenched pellets to 1000 °C decreases the electrical resistivity while it increases in the slowly cooled pellets; the decrease is ascribed to annealing of defects created by lattice micro-tensions during quenching while the increase to partial destabilization of the tetragonal phase.

scholarly journals Формирование и трансформация моноклинной и орторомбической фаз в реакторных порошках сверхвысокомолекулярного полиэтилена

2018 ◽  
Vol 60 (9) ◽  
pp. 1847
Author(s):  
М.В. Байдакова ◽  
П.В. Дороватовский ◽  
Я.В. Зубавичус ◽  
Е.М. Иванькова ◽  
С.С. Иванчев ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Room Temperature ◽  
Monoclinic Phase ◽  
Orthorhombic Phase ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Polymer Synthesis ◽  
X Ray Diffraction ◽  
Reactor Powder ◽  
X Ray ◽  
The One

AbstractUsing powerful synchrotron X-ray radiation of the beamline “Belok” operated by the National Research Center “Kurchatov Institute,” we perform X-ray diffraction (XRD) study of an intact, virgin (not subjected to any external mechanical loads) particle isolated from reactor powder of ultrahigh molecular weight polyethylene. Along with the peaks originating from the orthorhombic phase, we detect the peaks characteristic of the monoclinic phase that is stable only under mechanical stress, suggesting that the mechanical stress that leads to the formation of the monoclinic phase and persists at room temperature develops during the polymer synthesis. The monoclinic phase gradually disappears when the particle is heated stepwise in increments of 5 K, and its peaks become undetectable when the temperature reaches 340 K. We contrast the results obtained for the phase composition of the virgin particle to those for a tablet prepared by compaction of the same reactor powder at room temperature. XRD analyses of the tablet were performed on D2 Phaser (Bruker) instrument. The monoclinic phase that originates during the polymer synthesis and the one that forms in the tablet during compaction have different parameters. We discuss the mechanisms by which these two different monoclinic phases originate during the processes involved.

Sign in / Sign up

Export Citation Format

Share Document