Synthesis and Characterization of Porous ZrO2-Y2O3-TiO2 Ceramics Prepared by Coprecipitation

2012 ◽  
Vol 727-728 ◽  
pp. 1387-1392 ◽  
Author(s):  
Luan M. Medeiros ◽  
Fernando S. Silva ◽  
Juliana Marchi ◽  
Walter Kenji Yoshito ◽  
Dolores Ribeiro Ricci Lazar ◽  
...  
Keyword(s):  
Ceramic Composite ◽  
High Strength ◽  
Ceramic Composites ◽  
Rice Starch ◽  
X Ray Diffraction ◽  
Zirconia Ceramics ◽  
Pore Former ◽  
X Ray ◽  
Cold Pressed

Zirconium dioxide (zirconia) ceramics are known by its high strength and toughness and titanium dioxide (titania) ceramics has outstanding surface properties. The ceramic composite formed between the two oxides are expected to have advantages of both ceramics, especially when its surface area is increased by pores. In this work, ceramic composites of ZrO2-Y2O3-TiO2were synthesized by coprecipitation and rice starch was added as pore former in 10, 20 and 30 wt%. Powders were cold pressed as cylindrical pellets and sintered at 1500 °C for 01 hour and ceramics were characterized by techniques as Archimedes method for density measurements, X-ray diffraction and scanning electron microscopy. Results showed that pores are inhomogeneously distributed through ceramic bodies.

Fabrication and Characterization of Novel Bone Void Filler Made from Hydroxyapatite-Rice Starch Composite

2018 ◽  
Vol 779 ◽  
pp. 45-49
Author(s):  
Sittiporn Punyanitya ◽  
Warangkul Punyanitya ◽  
Sakdiphon Thiansem ◽  
Rungsarit Koonawoot
Keyword(s):  
Bone Cells ◽  
Rice Starch ◽  
Bovine Bone ◽  
X Ray Diffraction ◽  
Pore Former ◽  
X Ray ◽  
Bone Void Filler ◽  
Fabrication And Characterization ◽  
Bone Void

The aim of this study is fabricated bone void filler (BVF) made from hydroxyapatite (HA)-rice starch (RS) composite. We provided HA derived from cockle shells and RS derived from Thai rice starch. BVF was prepared by adding the pore former method to mimic the pore structure of bones. The samples were heated at 1250°C for 3 hours. Then, the composites were prepared by dipping and coating surface of the samples with RS gel. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) confirmed that bovine bone and BVF are made of HA phase. Film of RS gel coated on surface of samples indicated that BVF without toxicity and would increased the proliferation of bone cells. Moreover, it was found that BVF after coated RS gel had water absorption value higher than before coated as 25% that exhibited a good capacity of regeneration bone.

Devitrification in SiO2-B2O3-Al2O3-La2O3-TiO2 Glass during the Infiltration of Ceramic Composite

2016 ◽  
Vol 881 ◽  
pp. 77-82
Author(s):  
Afonso Chimanski ◽  
Amanda Martins Jordão ◽  
Paulo Francisco Cesar ◽  
Humberto Naoyuki Yoshimura
Keyword(s):  
Ceramic Composite ◽  
Raw Materials ◽  
Porous Alumina ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
Infiltration Process ◽  
X Ray ◽  
Dental Prostheses ◽  
Devitrification Process ◽  
Natural Teeth

Dental prostheses made of ceramic composites infiltrated with glasses have been used due to their biocompatibility and possibility to mimic the natural teeth. In this study, the devitrification behavior of 20SiO2-25B2O3-25Al2O3-15La2O3-15TiO2 glass during the infiltration process in a porous alumina preform was investigated. Glass frits were prepared by melting the raw materials at 1500 °C for 60 min. The glass was infiltrated into the alumina preform at 1,150 or 1,200 °C for 60 min. The specimens were characterized by X-ray diffraction analysis and scanning electron microscopy. After the infiltration, it was possible to note that the devitrification process occurred in the remaining glass (excess glass that did not infiltrate in the preform), forming mostly aluminum borate and mullite crystalline phases. However, within the infiltrated composite no devitrification was noticed in the infiltrated glass. Possible explanations for this behavior are discussed.

Synthesis and Characterization of CeO2 Doped ZrO2 Ceramics by a Simple Sol-Gel Route

2017 ◽  
Vol 907 ◽  
pp. 56-60
Author(s):  
Ummuhanı Hilal Özer ◽  
Kerim Emre Öksüz ◽  
Ali Özer
Keyword(s):  
Tetragonal Phase ◽  
Sol Gel ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Zirconia Ceramics ◽  
Simple Method ◽  
X Ray ◽  
Gel Technique

It is well known that sol-gel technique is a simple method to produce nano sized ceramic powders. In this study, cerium oxide doped zirconia samples, with 10 mol%-12mol% and14mol% CeO2, were synthesized by sol-gel technique and characterized. The surface morphology, elemental composition, microstructure, and phase analysis, of the sintered CeO2 doped ZrO2 ceramics were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDS) analysis, and X-ray diffraction (XRD) respectively. X-ray diffraction for samples sintered at 1550 °C for 4h revealed that the zirconia ceramics have a tetragonal phase structure. The addition of CeO2 can raise the content of the tetragonal phase, but the minor monoclinic phase exists even at the CeO2 content of 10 mol%. The effect of dopant concentration on the lattice parameter, average primary crystallite size and micro-strain was studied. Relative densities for CeO2 doped ZrO2 bulk ceramics varied between 95% and 99 %, depending on the CeO2 addition.

Development and Characterization of the Al2O3-YAG Ceramic Composites

2014 ◽  
Vol 798-799 ◽  
pp. 383-388 ◽  
Author(s):  
Eduardo Sousa Lima ◽  
A.P.O. Santos ◽  
L.M. Itaboray ◽  
C. Santos ◽  
R.F. Cabral
Keyword(s):  
Relative Density ◽  
Microstructural Characterization ◽  
Ceramic Composites ◽  
Oxide Ceramic ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Resistance To Oxidation ◽  
Oxidation And Corrosion

YAG (Y3Al5O12) and Al2O3 ceramics have high resistance to oxidation and corrosion in harsh environments and high temperatures, which turns into a quite attractive material as compared to other ceramics. Thus, lately oxide ceramic YAG has been extensively used as reinforcement phase to Al2O3 in order to obtain a composite with improved mechanical properties. This research focused on the development of sintered Al2O3-Y2O3 powder mixtures for the production of Al2O3-YAG composite. Powder mixtures composed of 63.65:36.35wt.% and 80.00:20.00wt.% of Al2O3 and Y2O3, respectively, were milled by planetary milling for 2h. The compositions were compacted by cold uniaxial pressing, at 70 MPa, for 30s. The two mixtures were sintered at 1500 and 1600°C for 3h. The samples were evaluated for relative density, shrinkage, weight loss, and X-Ray Diffraction (XRD). Scanning Electron Microscopy (SEM) was used for microstructural characterization. The X-Ray Diffraction showed the presence of Al2O3 and Y3Al5O12 as crystalline phases in both compositions. Samples composed by 80:20wt.% of Al2O3/Y2O3 powder sintered at 16000C-3h presented the higher relative density ranging around 86% of theoretical density.

Characterization of Microstructure in High Strength Microalloyed Steels Using Quantitative X-Ray Diffraction

2008 ◽  
Author(s):  
X. Li ◽  
J. B. Wiskel ◽  
H. Henein ◽  
D. G. Ivey ◽  
O. Omotoso
Keyword(s):  
Mechanical Properties ◽  
Rietveld Method ◽  
Domain Size ◽  
High Strength ◽  
Preferred Orientation ◽  
Microalloyed Steels ◽  
X Ray Diffraction ◽  
X Ray ◽  
X80 Steels

The mechanical properties of microalloyed steels used in pipelines are strongly affected by microstructure. In this paper, X-ray diffraction (Rietveld method) was used to quantify the microstructure — specifically domain size, microstrain and preferred orientation — for four X80 steels and three experimental X100 steels. Measurements were made at the surface and at several positions below the surface. Nano-sized domains were obtained for all steels tested. A smaller domain size, higher microstrain and stronger preferred orientation were observed in the X100 samples relative to the X80 steels.

Fracture Stress Analysis in Ceramic Composites of Alumina Matrix with Zirconia 3Y-TZP Nanograins for Mechanical Shielding of Satellites

2016 ◽  
Vol 869 ◽  
pp. 64-68
Author(s):  
Eron Fernandes da Silva ◽  
Daniel Alessander Nono ◽  
Sergio Luiz Mineiro ◽  
Francisco Piorino Neto ◽  
Maria do Carmo de Andrade Nono
Keyword(s):  
Fracture Stress ◽  
Ceramic Composite ◽  
Space Debris ◽  
Tetragonal Zirconia ◽  
Ceramic Composites ◽  
Bending Test ◽  
Alumina Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mechanical Bending

This paper presents the analysis results of fracture stress values for ceramic composites of alumina matrix mixed with nanoparticulate zirconia (3Y-TZP) ((tetragonal zirconia polycrystalline doped with 3 mol% yttria), which will be used in parts of the Brazilian satellites to act as mechanical shield for micrometeoroid and space debris impacts. The ceramic composites were obtained by mixing dispersed suspensions of alumina powders and 18.5 wt % of nanoparticulate zirconia, compacted with isostatic pressure and sintered at 1550 °C. After sintering, the ceramic composite was analyzed by SEM, X-ray diffraction and subjected to 4 points mechanical bending test. The microstructure analyses were performed and rupture stress values with Weibull distribution. The results were compared to previous works obtained after mechanical mixture of same powders. The results analyses showed that the greater homogeneity distribution of zirconia nanograins on alumina matrix contributes to increased fracture stress values.

Processing and Characterization of Tissue Adhesive from Rice Starch Nanocomposites

2010 ◽  
Vol 123-125 ◽  
pp. 363-366 ◽  
Author(s):  
Watee Puntuwat ◽  
Sathiya Wongsa ◽  
Jiraporn Poonyawatpornkul ◽  
Sittiporn Punyanitya ◽  
Anirut Raksujarit
Keyword(s):  
Adhesive Bond ◽  
Raw Material ◽  
Tissue Adhesive ◽  
Rice Starch ◽  
X Ray Diffraction ◽  
Tissue Adhesives ◽  
Health Ministry ◽  
X Ray ◽  
Standard Product

The objective of this work is make tissue adhesives agent from Thai rice starch, then test the final products for scientific and medical properties following the laws of Thai health ministry, to demonstrate that this product can be used safely, as same as the standard product. The principal raw material is pharmaceutical grade, Thai rice starch powder. The additives are hydroxyapatite (HA) nanopowder, carboxymethylcellulose, lactic acid, gelatin, polyvinylalcohol and glycerol. All materials will be mixed in distilled water under high temperature, and dried into starch tissue adhesives plate hydrogel. The final product will be kept in medical package and sent for sterilization by gamma radiation. These products will be characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), stability in water, and adhesive bond strength test in wet environment.

Development and Characterization of Al2O3-ZrO2 Composites Using ZrO2(Y2O3)-Recycled as Raw Material

2018 ◽  
Vol 912 ◽  
pp. 124-129
Author(s):  
Caio Marcelo Felbinger Azevedo Cossu ◽  
Manuel Fellipe Rodrigues Pais Alves ◽  
Luiz Cláudio Lemos de Assis ◽  
Roberto de Oliveira Magnago ◽  
José Vitor Candido de Souza ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Relative Density ◽  
Raw Materials ◽  
Ceramic Composites ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dental Prostheses ◽  
Scanning Electron

The objective of this work was the development of Al2O3-ZrO2 ceramic composites using recycled-source of ZrO2(Y2O3). Al2O3 powder was mixed with different proportions of ZrO2(Y2O3) arising from pre-sintered blocks used in dental prostheses manufacturing. The mixtures containing 3wt% to 15wt% ZrO2(Y2O3) were uniaxially pressed at 80MPa and sintered at 1600°C-2h. Raw materials and sintered samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), relative density, hardness and fracture toughness. The results of X-ray diffraction showed α-Al2O3 and tetragonal-ZrO2 as crystalline phases after sintering. Furthermore, the relative density in all compositions was higher than 95%. The samples presented Vickers hardness and fracture toughness higher than 1300HV and 3.5MPa. m1/2, respectively.

Influence of Addition of Polysiloxane on Sintering of Al2O3

2014 ◽  
Vol 798-799 ◽  
pp. 696-702
Author(s):  
Ana Lucia Exner Godoy ◽  
José Carlos Bressiani ◽  
Ana Helena de Almeida Bressiani
Keyword(s):  
Electron Microscopy ◽  
Ceramic Composites ◽  
Nitrogen Atmosphere ◽  
Processing Route ◽  
Sintering Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polymer Precursors ◽  
Transmission Electron ◽  
Cold Pressed

The effects of adding polysiloxane (polymethylsilsesquioxane) on the sintering behavior, microstructure and hardness of alumina ceramics have been studied. The sintering kinetics of cold-pressed specimens was studied by dilatometry. Polymer sintering aid was used for alumina based ceramics sintered at 1650o C. The sintered materials were characterized using helium picnometry, x-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, energy dispersive x-ray spectrometry and Vickers indentation. The addition of polymethylsilsesquioxane yielded alumina/Si2Al4O4N4 composites. The sintering studies in nitrogen atmosphere (1650 °C/1h) revealed that the highest densities were obtained for specimens with 1wt% PMS. The materials prepared with ceramic polymer precursors had higher hardness than the standard specimen. The preparation of ceramic composites using small amounts of polymer precursors is suited for alumina based ceramics. The processing route being simple, it has the potential to enable the manufacture of complex shaped pieces.

Mechanical and structural characterization of uniaxially cold-pressed Fe2Mo powders

2002 ◽  
Vol 17 (8) ◽  
pp. 1954-1959 ◽  
Author(s):  
R. Morales ◽  
S. Seetharaman ◽  
V. Agarwala
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bragg Peak ◽  
X Ray Diffraction ◽  
Vickers Hardness Number ◽  
X Ray ◽  
Transmission Electron ◽  
Cold Pressed ◽  
Logarithmic Relation

In this work, Fe2Mo intermetallic powder, produced by H2 gas reduction of Fe2MoO4 was characterized by techniques like x-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM studies confirmed the presence of nano- and microcrystalline grains of Fe2Mo. The above powders when compressed uniaxially showed a logarithmic relation with “relative density”, δr, of the compacts. The multiple compaction mechanisms were analyzed by Kawakita's and Balshin's models. Vickers hardness number, VHN, was found to increase linearly with δr of the compacts. The hardness of Fe2Mo intermetallic when δr = 1 was estimated as 343 VHN. Using Tabor's analysis, the yield strength of Fe2Mo was found to be about 1100 MPa. This value was further confirmed from the details of relative broadening (112) Bragg peak of Fe2Mo obtained from XRD analyses of Fe2Mo at different compaction pressures.

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