Effect of Dispersant Agent Amount in Colloidal Processing of Zirconia Dental Ceramic

2012 ◽  
Vol 622-623 ◽  
pp. 215-219 ◽  
Author(s):  
Noor Faeizah Amat ◽  
Andanastuti Muchtar ◽  
Norziha Yahaya ◽  
Mariyam Jameelah Ghazali
Keyword(s):  
Sintered Density ◽  
Sintering Temperature ◽  
Slip Casting ◽  
Casting Process ◽  
Processing Technique ◽  
Colloidal Processing ◽  
Optimum Amount ◽  
Rotational Viscometer ◽  
Agglomeration Of Nanoparticles ◽  
Zirconia Suspension

The effects of a polyelectrolyte dispersant agent, polyethyleneimine (PEI), on the rheology of zirconia 3Y-TZP suspensions and the densification characteristics of sintered zirconia were investigated. The colloidal processing technique was used to minimize the agglomeration of nanoparticles during the fabrication of the samples. Five batches of 10% zirconia suspensions containing different amounts of PEI at 0.3, 0.4, 0.5, 0.6, and 0.7 wt% were prepared. The rheological properties of the zirconia suspensions were determined using a rotational viscometer. The optimum amount of PEI that can maximize powders dispersion was determined. The green samples were then prepared using the slip casting process. The samples were densely sintered at a final sintering temperature of 1300 °C. The result revealed that the zirconia suspension with 0.5 wt% PEI was the most optimum amount to obtain a well-dispersed suspension. The sintered density of zirconia 3Y-TZP reached its maximum by adding 0.5 wt% PEI.

scholarly journals Mekanisme Penyerakan Zarah dalam Pemprosesan Berkoloid Oksida Seramik (Al2O3–ZrO2–MgO) Menggunakan DAXAD 19TM

2012 ◽  
Author(s):  
Andanastuti Muchtar ◽  
Husna Osman ◽  
Siti Masrinda Tasirin
Keyword(s):  
Key Words ◽  
Slip Casting ◽  
Casting Process ◽  
Processing Technique ◽  
Particle Dispersion ◽  
Optimum Concentration ◽  
Rotational Viscometer ◽  
Optimum Quantity ◽  
Oxide Particles ◽  
Zirconia Powders

Dalam kajian ini, kesan agen penyerak komersil Daxad 19TM terhadap sifat reologi dan pemadatan ampaian seramik alumina–zirkonia–magnesia telah dikenalpasti. Komposisi serbuk yang digunakan adalah berasaskan kepada 85% isipadu alumina (ketulenan 99.99%) dan 15% isipadu zirkonia (ketulenan 99.5%). Penambahan serbuk magnesia (ketulenan 99.99%) pula adalah pada kuantiti yang kecil iaitu 0.25% berat daripada jumlah berat alumina dan zirkonia. Untuk mengelakkan masalah pengaglomeratan zarah, teknik pemprosesan berkoloid dipilih dalam pembikinan sampel. Untuk ini, Daxad 19TM dicampurkan ke dalam ampaian dengan tujuan untuk menyerakkan zarah. Kuantiti penyerak Daxad 19TM yang digunakan ialah dalam julat 0 hingga 0.60% berat. Kajian reologi menggunakan alat meter kelikatan dilakukan bagi mengenalpasti kuantiti Daxad 19TM yang optimum bagi penyerakan zarah. Setelah itu, sampel anum dihasilkan melalui proses penuangan buburan. Sampel diprasinter pada suhu 800°C selama 45 minit sebelum disinter pada suhu 1600°C selama 2 jam. Kajian ini secara keseluruhannya telah mendapati julat penggunaan optimum penyerak Daxad 19TM di dalam ampaian seramik yang dihasilkan adalah di antara 0.4875% hingga 0.525% berat daripada berat keseluruhan serbuk seramik yang digunakan. Kertas ini juga membincangkan mekanisme penyerakan zarah dalam ampaian alumina–zirkonia–magnesia melalui penggunaan Daxad 19TM. Kata kunci: Penyerakan zarah, reologi, ketumpatan, alumina, zirkonia The effects of a commercially available dispersant, Daxad 19TM, on the rheology and densification characteristics of alumina–zirconia–magnesia suspensions have been investigated. The compositions of powders used are based on 85% volume of alumina (99.99% purity) and 15% volume of zirconia (99.95% purity). The addition of a small amount of magnesia is based on 0.25% weight of the combined weight of both alumina and zirconia powders. In an effort to avoid the agglomeration of particles, colloidal processing technique is used to produce samples. For this, Daxad 19TM is added to the suspensions to disperse the oxide particles. The Daxad 19TM addition is within the range of 0–0.60% weight. Rheological investigation is carried out using a rotational viscometer to determine the optimum quantity of dispersant (Daxad 19TM) that can best disperse the powders. Green samples are then prepared using the slip casting process. The sample are pre–sintered at a constant temperature of 800°C for 45 minutes before being sintered at 1600°C with a holding time of 2 hours. The optimum concentration of Daxad 19TM for a successful dispersion of powders is found to be between 0.4875–0.525% weight of the combined weight of alumina and zirconia powders. This paper also discusses the mechanisms for particle dispersion in alumina–zirconia–magnesia suspensions. Key words: Particle dispersion, rheology, density, alumina, zirconia

Evaluation of Bone Ingrowth in Free Form Fabricated Scaffolds

2007 ◽  
Vol 361-363 ◽  
pp. 919-922
Author(s):  
Erik Adolfsson ◽  
Johan Malmström ◽  
Peter Thomsen
Keyword(s):  
Bone Tissue ◽  
Sintered Density ◽  
Bone Ingrowth ◽  
Casting Process ◽  
Tissue Response ◽  
Free Form ◽  
Bone Area ◽  
Colloidal Processing ◽  
Sintering Condition ◽  
Rabbit Femur

Colloidal processing was used to cast zirconia and hydroxyapatite materials. The cast materials reached densities around 99% when sintered at 1500°C and 1200°C respectively. By controlling the colloidal process the sintered density of hydroxyapatite was also reduced to around 80% when the same sintering condition was used. The casting process was combined with free form fabrication to prepare designed scaffolds with identical macroporosity. These scaffolds were used to evaluate the early bone tissue response in rabbit femur. After six weeks of implantation the bone area in scaffolds of zirconia and hydroxyapatite were compared. In scaffolds of hydroxyapatite the bone area was roughly three times larger compared to corresponding scaffolds of zirconia. When the scaffolds of hydroxyapatite also contained an open microporosity of around 20% the amount of bone was even more pronounced. The results showed the importance of the material composition and the microstructure on the bone regenerating performance of scaffolds.

Effect of Sintering Temperature on the Mechanical Properties of Nanostructured Ceria-Zirconia Prepared by Colloidal Process

2015 ◽  
Vol 1125 ◽  
pp. 401-405
Author(s):  
Mohamed M. Aboras ◽  
Andanastuti Muchtar ◽  
Noor Faeizah Amat ◽  
Che Husna Azhari ◽  
Norziha Yahaya
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Slip Casting ◽  
Tetragonal Zirconia ◽  
Cold Isostatic Pressing ◽  
Sintering Process ◽  
Colloidal Processing ◽  
Tooth Color ◽  
Biological Compatibility ◽  
Nanostructured Ceria

The demand for tetragonal zirconia as a dental restorative material has been increasing because of its excellent mechanical properties and resemblance to natural tooth color, as well as its excellent biological compatibility. Cerium oxide (CeO2) has been added to yttria-stabilized zirconia (Y-TZP), and studies have demonstrated that the stability of the tetragonal phase can be significantly improved. Y-TZP with 5wt% CeO2 as a second stabilizer was developed via colloidal process, followed by a suitable sintering process. According to the literature, the sintering process is the most crucial stage in ceramic processing to obtain the most homogeneous structure with high density and hardness. This study aims to investigate the effect of sintering temperature on the mechanical properties of nanostructured ceria–zirconia fabricated via colloidal processing and slip casting process with cold isostatic pressing (CIP). Twenty-five pellet specimens were prepared from ceria–zirconia with 20 nm particle size. CeO2 nanopowder was mixed with Y-TZP nanopowder via colloidal processing. The consolidation of the powder was done via slip casting followed by CIP. The samples were divided into five different sintering temperatures with. Results from FESEM, density and hardness analyses demonstrated statistically significant increase in density and hardness as the sintering temperature increased. The hardness increased from 4.65 GPa to 14.14 GPa, and the density increased from 4.70 to 5.97 (g/cm3) as the sintering temperature increased without changing the holding time. Sintering Ce-Y-TZP at 1600 °C produced samples with homogenous structures, high hardness (14.14 GPa), and full densification with 98% of the theoretical density.

Effect of Sintering Temperature on the Mechanical Properties of Nanostructured Zirconia Fabricated via Colloidal Processing

2013 ◽  
Vol 686 ◽  
pp. 44-48 ◽  
Author(s):  
Noor Faeizah Amat ◽  
Andanastuti Muchtar ◽  
Norziha Yahaya ◽  
Mariyam Jameelah Ghazali
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Tetragonal Zirconia ◽  
Sintered Specimen ◽  
Full Density ◽  
Colloidal Processing ◽  
Zirconia Powder ◽  
Dental Ceramic

This study aims to evaluate the effects of sintering temperature on the density and hardness of tetragonal zirconia polycrystals stabilized with 3 mol% 3Y-TZP dental ceramic type. Five cylindrical specimens were fabricated from zirconia powder of particle size 50 nm via colloidal processing. The specimens were sintered densely at the final sintering temperatures of 1000, 1100, 1200, and 1300 °C, respectively. The sintered density and hardness of the sintered specimen were then examined. The results showed that the sintered densities and hardness of the specimen increased as the temperature increased from 1000 °C to 1300 °C. Zirconia 3Y-TZP could gain near full density and reach hardness of as high as 11.30 GPa at the final sintering temperature of 1300 °C. The density and hardness of zirconia structured from 3Y-TZP can be improved by controlling the final sintering temperature.

INFLUENCE OF PROCESSING ON MECHANICAL PROPERTIES OF 3Y-TZP FOR DENTAL APPLICATIONS

2016 ◽  
Vol 78 (11-3) ◽  
Author(s):  
Mohamed Aboras ◽  
Andanastuti Muchtar ◽  
Che Husna Azhari ◽  
Norziha Yahaya ◽  
Chin Chuin Hao
Keyword(s):  
Mechanical Properties ◽  
Phase Distribution ◽  
Slip Casting ◽  
Tetragonal Zirconia ◽  
Casting Process ◽  
Cold Isostatic Pressing ◽  
Colloidal Processing ◽  
X Ray Diffraction ◽  
Consolidation Process ◽  
Dental Applications

Purpose: This study aimed to investigate the influence of processing on the mechanical properties of 3 mol% yttrium–tetragonal zirconia (3Y–TZP) for dental applications. In this study, cold isostatic pressing (CIP) was adopted as a second consolidation process to enhance the mechanical properties of slip-cast 3Y–TZP. Methods: Two batches were prepared. The first batch of 3Y–TZP suspension was fabricated via colloidal processing. Then, the suspension was subjected to the slip casting process. Simultaneously, the second batch was prepared via colloidal processing, followed by CIP. The specimens were sintered at 1600 °C.  Sintered density, hardness, microstructure, and phase distribution were examined and analyzed. Results showed that the specimens fabricated via slip casting and CIP had the highest density of 99% of the theoretical density (6.1 g/cm3) and hardness of 14.4 GPa. The microstructure of the CIP samples was homogeneous with low porosity. According to X-ray diffraction examination, both batches exhibited a single phase (tetragonal phase). Conclusion(s): The density, hardness, and homogeneity of the microstructure of Y–TZP fabricated via slip casting and CIP improved. Using CIP as the second consolidation method improved the quality of green bodies

Effect of Sintering Temperature on Properties of Setiu Clay Sediments

2020 ◽  
Vol 1010 ◽  
pp. 206-210
Author(s):  
Mohd Al Amin Muhamad Nor ◽  
Noor Asliza Ismail Adnen ◽  
Mohamad Zaky Noh ◽  
A.R.M. Warikh ◽  
Julie Juliewatty Mohamed
Keyword(s):  
Sintering Temperature ◽  
Slip Casting ◽  
Casting Process ◽  
Production Costs ◽  
Ceramic Samples ◽  
Before And After ◽  
Different Temperatures ◽  
Clay Sediment ◽  
Quality Of Products ◽  
Increasing Temperature

The effect of sintering temperature on physical properties of Setiu clay sediment was studied. The ceramic samples were prepared via slip casting method, and sintered at different temperatures ranging from 900 to 1100°C, with 2 hours soaking time. Morphologies of ceramic samples were characterized using Tabletop Microscope. Shrinkage was determined from measurement of samples before and after sintering process. A good ceramic sample without warping or cracks obtained after casting process and after sintered at different temperatures. The results show that sintering temperatures greatly influence morphology of samples. As sintering temperature increased the grain boundaries between particles become smoother and compacted while pores shrunk due to the densification behavior. A considerable increased in shrinkage from 5 to 20% were observed with increasing temperature from 900 to 1100°C. As conclusion, Setiu clay sediment are suitable for production ceramic products and 1000°C can be consider the best sintering temperature in terms of quality of products and production costs.

scholarly journals Optimization of Sintering Process of Alumina Ceramics Using Response Surface Methodology

2021 ◽  
Vol 13 (12) ◽  
pp. 6739
Author(s):  
Darko Landek ◽  
Lidija Ćurković ◽  
Ivana Gabelica ◽  
Mihone Kerolli Mustafa ◽  
Irena Žmak
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Nonlinear Models ◽  
Slip Casting ◽  
Holding Time ◽  
Alumina Ceramics ◽  
Aqueous Suspensions ◽  
Temperature Heating

In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were prepared with different amounts of the ammonium salt of a polycarboxylic acid, Dolapix CE 64, as an electrosteric dispersant. The stability of highly concentrated Al2O3 aqueous suspensions was monitored by viscosity measurements. Green bodies (ceramics before sintering) were obtained by pouring the stable Al2O3 aqueous suspensions into dry porous plaster molds. The obtained Al2O3 ceramic green bodies were sintered in the electric furnace. Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface methodology (RSM), based on experimental data obtained according to Box–Behnken experimental design, using the software Design-Expert. From the statistical analysis, linear and nonlinear models with added first-order interaction were developed for prediction and optimization of density-dependent variables: sintering temperature, heating rate and holding time.

Effects of Sintering Conditions on Properties of a Warm Compacted Stainless Steel Powder

2012 ◽  
Vol 217-219 ◽  
pp. 483-486
Author(s):  
Mei Yuan Ke
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Steel Powder ◽  
Stainless Steel Powder ◽  
Sintering Atmosphere ◽  
Comprehensive Properties ◽  
Ammonia Atmosphere ◽  
Sintering Conditions

Effects of Sintering atmosphere and temperature on properties of warm compacted 410L stainless steel powder were studied. Sintered density, hardness, tensile strength and elongation were measured. Results showed that in order to achieve high comprehensive properties, the optimal sintering temperature was 1230°C for 410L stainless steel powder. At the same sintering temperature, density and hardness sintered in vacuum were much higher than that sintered in cracked ammonia while tensile strength sintered in cracked ammonia were much higher than that in vacuum. When sintered in vacuum at 1230°C, sintered density was 7.45 g•cm-3, hardness was 65 HRB, tensile strength was 410 MPa and elongation was 29.5%. When sintered in cracked ammonia atmosphere at 1230°C, sintered density was 7.26 g•cm-3, hardness was 97 HRB, tensile strength was 515 MPa and elongation was 3.8%.

scholarly journals Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Xianjie Yuan ◽  
Xuanhui Qu ◽  
Haiqing Yin ◽  
Zaiqiang Feng ◽  
Mingqi Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Velocity ◽  
Sintered Density ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
High Velocity Compaction ◽  
Sintered Temperature

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

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