Preparation of Bimodal Porous Apatite Ceramics through Slip Casting Using Fine Hydroxyapatite Powders

2006 ◽  
Vol 317-318 ◽  
pp. 723-728 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama
Keyword(s):  
Flexural Strength ◽  
Size Range ◽  
Slip Casting ◽  
Fine Powder ◽  
Total Porosity ◽  
Solid Loading ◽  
Wet Milling ◽  
Hydrogen Phosphate ◽  
Optimum Amount ◽  
Porous Hydroxyapatite

A bimodal porous hydroxyapatite (HAp) body with high flexural strength was prepared through slip casting. HAp fine powder used in this study was synthesized by wet milling, drying and heating of a mixture of calcium hydrogen phosphate di-hydrate and calcium carbonate. The synthesized HAp powder was 0.320.05 μm in size and 38.10.8m2/g in specific surface area. The slip was prepared by adding deflocculant and foaming reagent. The optimum value for the minimum viscosity in the present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were studied. The total porosity of the specimens obtained from a slip of 48 wt% HAp solid loading is in the range of 49 – 61vol %, and the resultant porous HAp sintered body had large spherical pores of 300 -m with interconnecting rectangular voids. Many small pores in the size range of 2-3 -m or below were observed in the specimen obtained by heating at 1100, and 1200 . The flexural strength of the bimodal porous HAp ceramics sintered at 1200 C showed a large value of 17.6 MPa, with a porosity of 60.5vol.

Influence of Powder Particle Size of Slurries on Mechanical Properties of Porous Hydroxyapatite Ceramics

2005 ◽  
Vol 284-286 ◽  
pp. 365-368 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama
Keyword(s):  
Particle Size ◽  
Flexural Strength ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Particle Sizes ◽  
Wet Milling ◽  
Median Particle Size ◽  
Powder Characteristics ◽  
Median Particle

The effect of different particle sizes on the flexural strength and microstructure of three different types of hydroxyapatite (HAp) powders was studied. The powder characteristics of laboratory synthesized HAp powder (Lab1 and Lab2) were obtained through a wet milling method, and the median particle size and the specific surface area of powders are different with the dryness period. The median particle sizes of Lab1 and Lab2 are 0.34 µm and 0.74 µm, and the specific surface areas of Lab1 and Lab2 are 38.01 m2/g and 19.77 m2/g. The commercial HAp had median particle size of 1.13 µm and specific surface area of 11.62m2/g. The different powder characteristics affected the slip characteristics, and the flexural strength and microstructure of the sintered porous HAp bodies are also different. The optimum value for the minimum viscosity in these present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were investigated. The flexural strengths of the porous HAp ceramics prepared by heating at 1200°C for 3 hrs in air were 17.59 MPa for Lab1 with a porosity of 60.48％, 10.51 MPa for Lab2 with a porosity of 57.75％, and 3.92 MPa for commercial HAp with a porosity of 79.37％.

Fabrication of an All-Ceramic Implant by Slip Casting of Nanoscale Zirconia Powder

2020 ◽  
Vol 20 (9) ◽  
pp. 5703-5706
Author(s):  
Dae Sung Kim ◽  
Jong Kook Lee
Keyword(s):  
High Surface ◽  
Slip Casting ◽  
Tetragonal Zirconia ◽  
Solid Content ◽  
Solid Loading ◽  
Forming Process ◽  
Surface Cracking ◽  
All Ceramic ◽  
Mechanical Machining ◽  
Zirconia Implants

Dental implants are typically composed of 3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystals). Most dental zirconia implants are currently fabricated via mechanical machining. However, during the machining of zirconia green bodies, many cracks form on the surface. To prevent surface crack formation on the implants, shape forming of the zirconia is necessary using methods such as slip casting. Herein, we fabricated green compacts using slip casting, candidate forming process to reduce surface cracking. To fabricate an optimal 3Y-TZP implant by slip casting and sintering, we prepared a suitable 3Y-TZP slurry for slip casting by adjusting the viscosity via pH, dispersant agent content, and solid loading refinement. Green compacts were prepared by the slip casting of all-ceramic zirconia implants fabricated using optimal slurry conditions, for example, 60 wt% solid content, 1 wt% dispersant, pH 12 and post-sintering at 1450 °C for 2 h. All sintered bodies contained a tetragonal phase with a high sintered density of approximately 6.07 g/cm3, good mechanical hardness of approximately 1367 Hv, grain size of 220 nm, and high surface roughness without cracks.

The Study on Mechanical Properties of the Graded Broken Stone Mixed with Cement and Fine Powder

2014 ◽  
Vol 905 ◽  
pp. 230-234
Author(s):  
Jun Lei Tian ◽  
Yan Ke Yang ◽  
Yi Ping Hu ◽  
Jian Qiang Cheng
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Regression Analysis ◽  
Flexural Strength ◽  
High Speed ◽  
Fine Powder ◽  
Frozen Soil ◽  
Power Exponent ◽  
High Speed Railway ◽  
Railway Passenger

Ha Tai railway passenger dedicated line is a national key project of the eleventh five-year plan. Its different from other construction of high-speed railway because there is many frozen soil over the place. The requirement of the subgrade material is higher.We proposed a idea that gradred broken stone mixed with cement and fine powder applied in the project.The compressive strength,splitting tensile strength and flexural strength were studied and analyzed through laboratory test.And regression analysis between compressive strength and flexural strength was made .According to the regression analysis,a power exponent function between flexural strength and compressive strength was got.Based on this,the corresponding relationship table was deduced,which can be used in practical projects.

Preparation of Complicated SiC Green Bodies via Aqueous Slip Casting

2010 ◽  
Vol 434-435 ◽  
pp. 88-91
Author(s):  
Yuan Li ◽  
Ji Qiang Gao ◽  
Jian Feng Yang
Keyword(s):  
Particle Size ◽  
Slip Casting ◽  
Solid Loading ◽  
Reaction Sintering ◽  
Processing Parameter ◽  
Suspension Viscosity ◽  
Effects Of Ph ◽  
Depth Study ◽  
Packing Ability ◽  
Coke Powder

Two domestic silicon carbide powders with different particle size distribution and one petroleum coke powder were blended in proportion and then dispersed in aqueous medium. Green bodies were solidified from these suspensions via conventional slip casting. The effects of pH, solid loading, and the amount of dispersant on the formability and packing ability were evaluated. The results showed that the pH within 9.5-10.5, solid loading of 42vol%, aging time more than 24h, and 0.3wt% of dispersant were optimal. Complicated green bodies with height of 300mm and thickness of 3.5mm were obtained. The corresponding suspension viscosity was 1200mPa∙s and the relative packing density was 64.8%. The density is 3.01g∙cm-3 and the flexural strength is 305±15 MPa after reaction sintering. These results may be attributed to accurately using of dispersant and in-depth study of processing parameter.

New Low-Toxic PEG(200)DMA/AM Gel System for 3YSZ Gel-Casting

2014 ◽  
Vol 602-603 ◽  
pp. 159-163
Author(s):  
Hai Yan Wu ◽  
Heng Lu ◽  
Zhi Jie Liao ◽  
Feng Xia ◽  
Jian Zhong Xiao
Keyword(s):  
Flexural Strength ◽  
Ceramic Body ◽  
Monomer Concentration ◽  
Solid Loading ◽  
Green Body ◽  
Gel Casting ◽  
Body Strength ◽  
Low Toxic ◽  
Poly Ethylene ◽  
Gel System

Gel-casting is promising in fabricating uniform and complex-shaped ceramic body, but it is confined in industrial application for the neurotoxic acrylamid (AM) gel system. Ether-contained oligomer poly(ethylene glycol)(200) dimethacrylate (PEG(200)DMA) with methacrylate end-group on either side of the long chain can act as cross-linking agent in free radical polymerization to form branchy gel network structure, which improves the green body strength. In this study, low-toxic PEG(200)DMA was chosen as the main binder and crosslinker and small dosage AM was applied to adjust the viscosity of the ceramic slurry to gel-cast 3YSZ (PEG(200)DMA: AM = 4:1, mass ratio). Influence of monomer concentration, dispersant concentration and solid loading on the rheological behavior of the slurry and the flexural strength of the green body were investigated using aqueous PEG(200)DMA/AM gel system to gel-cast 3YSZ. The results show that the flexural strength of green bodies notably increases with the increasing of monomer concentration and reaches high up to 14.4 MPa when gel-cast 3YSZ ceramics using PEG(200)DMA/AM gel system with appropriate amount of PAA-NH4, monomer and solid loading. This gel system obviously reduces the toxicity of the conventional AM system and, at the same time, ensures high flexural strength of green bodies.

scholarly journals Mechanical Investigation of a Novel Ceramic Composite Consisting of the YAG Matrix With Alumina Nanoparticles Fabricated by Slip Casting and the Conventional Sintering Process

2020 ◽  
Author(s):  
Mohammad Torki ◽  
behrooz movahedi ◽  
S S. ghazanfari ◽  
M. Milani
Keyword(s):  
Relative Density ◽  
Slip Casting ◽  
Ceramic Composites ◽  
Alumina Nanoparticles ◽  
Solid Loading ◽  
Sintering Process ◽  
The Matrix ◽  
Conventional Sintering ◽  
Mechanical Investigation ◽  
Composite Hardness

Abstract The aim of this study was to fabricate YAG/Al2O3 ceramic composites with different alumina nanoparticles using slip casting and the atmospheric sintering process. In addition, some mechanical properties such as hardness and elastic modules of this novel ceramics were evaluated using the nanoindention technique. The results showed that the rheological behavior of the slurry was optimized to the solid loading of 55 wt% and the relative density of the green body was enhanced up to 65%. Relative density was increased after sintering at 1700 °C for 12 h to 99.5% and the pore size (150 nm) was reduced to half of that of powder particles. It should be noted that the optimum amount of alumina nanoparticles as a reinforcing agent in the matrix was less than 5%wt and the composite hardness was increased to 7.3%, as compared to the pure YAG ceramic.

scholarly journals Properties of Mortar with Recycled Aggregates, and Polyacrylonitrile Microfibers Synthesized by Electrospinning

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3849 ◽  
Author(s):  
Manuel J. Chinchillas-Chinchillas ◽  
Manuel J. Pellegrini-Cervantes ◽  
Andrés Castro-Beltrán ◽  
Margarita Rodríguez-Rodríguez ◽  
Víctor M. Orozco-Carmona ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Total Porosity ◽  
Cementitious Materials ◽  
Effective Porosity ◽  
Recycled Aggregates ◽  
Capillary Absorption ◽  
Fine Aggregate ◽  
Water Penetration

Currently it is necessary to find alternatives towards a sustainable construction, in order to optimize the management of natural resources. Thus, using recycled fine aggregate (RFA) is a viable recycling option for the production of new cementitious materials. In addition, the use of polymeric microfibers would cause an increase in the properties of these materials. In this work, mortars were studied with 25% of RFA and an addition of polyacrylonitrile PAN microfibers of 0.05% in cement weight. The microfibers were obtained by the electrospinning method, which had an average diameter of 1.024 µm and were separated by means of a homogenizer to be added to the mortar. Cementing materials under study were evaluated for compressive strength, flexural strength, total porosity, effective porosity and capillary absorption, resistance to water penetration, sorptivity and carbonation. The results showed that using 25% of RFA causes decreases mechanical properties and durability, but adding PAN microfibers in 0.05% caused an increase of 2.9% and 30.8% of compressive strength and flexural strength respectively (with respect to the reference sample); a decrease in total porosity of 5.8% and effective porosity of 7.4%; and significant decreases in capillary absorption (approximately 23.3%), resistance to water penetration (25%) and carbonation (14.3% after 28 days of exposure). The results showed that the use of PAN microfibers in recycled mortars allowed it to increase the mechanical properties (because they increase the tensile strength), helped to fill pores or cavities and this causes them to be mortars with greater durability. Therefore, the use of PAN microfibers as a reinforcement in recycled cementitious materials would be a viable option to increase their applications.

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