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.

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 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 Sintering Temperature on the Translucency of Sintered Zirconia by Cold Isostatic Pressing

2014 ◽  
Vol 896 ◽  
pp. 591-595
Author(s):  
Chuin Hao Chin ◽  
Andanastuti Muchtar ◽  
Noor Faeizah Amat ◽  
Mariyam Jameelah Ghazali ◽  
Norziha Yahaya
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Tetragonal Zirconia ◽  
Hardness Test ◽  
Cold Isostatic Pressing ◽  
Light Transmittance ◽  
Isostatic Pressing ◽  
Different Temperatures ◽  
Pellet Form ◽  
Dental Applications

Zirconia-based ceramics exhibit excellent mechanical properties and biocompatibility in dental applications. However, the production of translucent zirconia that offers resemblance to real teeth remains a challenge. This study aims to fabricate zirconia compacts by cold isostatic pressing (CIP) and investigate the influence of sintering temperature on translucency, microstructure, hardness, and density of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP). Zirconia stabilized with 3 mol% yttria (3Y-TZP) was pressed by uniaxial pressing and later by CIP to produce green bodies in pellet form. Subsequently, the green bodies were sintered at different temperatures (1100 °C to 1300 °C). The specimens were then investigated in terms of translucency, density, and hardness. X-ray diffraction was also performed and the microstructure of the specimens was observed under a scanning electron microscope (SEM). Density and light transmittance tests results showed that zirconia sintered at 1200 °C exhibits the highest density (5.957 g/cm3) and light transmittance intensity. Vickers hardness test showed that higher sintering temperatures result in higher hardness of the sintered zirconia. SEM micrographs illustrate the effect of microstructural changes on the translucency of zirconia. A temperature of 1200 °C is found to be the recommended sintering temperature at which zirconia exhibiting optimum translucency and mechanical properties is produced. CIP is found to be a suitable consolidation method to produce high-density translucent zirconia.

IMPROVEMENT OF MECHANICAL PROPERTIES OF Y-TZP VIA CERIA ADDITION AND COLD ISOSTATIC PRESSING METHOD

2015 ◽  
Vol 77 (6) ◽  
Author(s):  
Mohamed Aboras ◽  
Andanastuti Muchtar ◽  
Che Husna Azhari ◽  
Norziha Yahaya ◽  
Chin Chuin Hao
Keyword(s):  
Mechanical Properties ◽  
Slip Casting ◽  
Tetragonal Zirconia ◽  
Xrd Analysis ◽  
Cold Isostatic Pressing ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
Pressing Method ◽  
Isostatic Pressing ◽  
Lower Porosity

Fabrication and composition of tetragonal zirconia have been extensively studied to enhance its mechanical properties. The present study aims to investigate the mechanical properties of yttrium-stabilized zirconia (Y-TZP) with ceria addition consolidated via cold isostatic pressing (CIP). 3Y-TZP was prepared by slip casting. Another batch of samples was fabricated via slip casting with the addition of 5 wt% of ceria, followed by CIP. All samples were sintered at 1600 °C. Results showed that the density and hardness of Y-TZP increased with the addition of ceria and use of CIP. The density increased from 91.8% to 98% of theoretical density, and the hardness increased from 10.33 GPa to 14.14 GPa. Field-emission scanning electron microscopy (FESEM) images showed that Y-TZP with ceria and consolidated via CIP had more homogenous grain structure with lower porosity. The X-ray diffraction (XRD) analysis showed that the phase was 100% tetragonal for both materials. Ceria addition consolidated via CIP are an effective method to improve the mechanical properties of Y-TZP. 

Effects of Sintering Process on the Properties of Ti3SiC2/Cu Composite

2012 ◽  
Vol 512-515 ◽  
pp. 377-381 ◽  
Author(s):  
Jin Rong Lu ◽  
Yang Zhou ◽  
Yong Zheng ◽  
Shi Bo Li ◽  
Zhen Ying Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Sintering Process ◽  
Vacuum Sintering ◽  
New Type ◽  
Sintering Conditions ◽  
The Relationship ◽  
Better Than

In this paper, a new type of Ti3SiC2/Cu composites with the volume fractions of 30% Ti3SiC2 particle was prepared by hot pressing and vacuum sintering respectively. The effects of sintering temperature and holding time on the density, resistance and Vickers hardness of Cu-30vol%Ti3SiC2 composite were investigated. The results show that the mechanical properties of the composites prepared by hot pressing are better than that prepared by vacuum sintering. The relative densities of Cu-30vol% Ti3SiC2 composites are rather high in suitable sintering conditions. It achieved 100% for the composites prepared by hot pressing at 930°C for 2h, and 98.4% for the composites prepared by vacuum sintering at 1250°C for 1h. At the same time, the maximum Vickers hardness reached 1735MPa at 900°C by hot pressing. The resistance and Vickers hardness of the composites decreased with an increase in sintering temperature, whereas the density increased. Scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) were used to observe the microstructure of the composites. The relationship between microstructure and mechanical properties was discussed.

scholarly journals The Influence of Co Additive on the Sintering, Mechanical Properties, Cytocompatibility, and Digital Light Processing Based Stereolithography of 3Y-TZP-5Al2O3 Ceramics

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2789 ◽  
Author(s):  
Margarita Goldberg ◽  
Tatiana Obolkina ◽  
Sergey Smirnov ◽  
Pavel Protsenko ◽  
Dmitriy Titov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Ceramic Powder ◽  
Tetragonal Zirconia ◽  
Specific Area ◽  
Precipitation Method ◽  
Temperature Phase ◽  
Sintered Ceramic ◽  
Digital Light Processing

Nanocrystalline 3 mol% yttria-tetragonal zirconia polycrystal (3Y-TZP) ceramic powder containing 5 wt.% Al2O3 with 64 m2/g specific area was synthesized through precipitation method. Different amounts of Co (0–3 mol%) were introduced into synthesized powders, and ceramic materials were obtained by heat treatment in the air for 2 h at 1350–1550 °C. The influence of Co addition on the sintering temperature, phase composition, microstructure, mechanical and biomedical properties of the obtained composite materials, and on the resolution of the digital light processing (DLP) printed and sintered ceramic samples was investigated. The addition of a low amount of Co (0.33 mol%) allows us to decrease the sintering temperature, to improve the mechanical properties of ceramics, to preserve the nanoscale size of grains at 1350–1400 °C. The further increase of Co concentration resulted in the formation of both substitutional and interstitial sites in solid solution and appearance of CoAl2O4 confirmed by UV-visible spectroscopy, which stimulates grain growth. Due to the prevention of enlarging grains and to the formation of the dense microstructure in ceramic based on the tetragonal ZrO2 and Al2O3 with 0.33 mol% Co the bending strength of 720 ± 33 MPa was obtained after sintering at 1400 °C. The obtained materials demonstrated the absence of cytotoxicity and good cytocompatibility. The formation of blue CoAl2O4 allows us to improve the resolution of DLP based stereolithographic printed green bodies and sintered samples of the ceramics based on ZrO2-Al2O3. The developed materials and technology could be the basis for 3D manufacturing of bioceramic implants for medicine.

Physical, Mechanical and Electrical Properties of W-20 wt.% Cu Composite Produced by Liquid Phase Sintering Process

2014 ◽  
Vol 879 ◽  
pp. 21-26
Author(s):  
Fauzi Ismail ◽  
Mohd Asri Selamat ◽  
Norhamidi Muhamad ◽  
Abu Bakar Sulong ◽  
Nurzirah Abdul Majid
Keyword(s):  
Particle Size ◽  
Liquid Phase ◽  
Electrical Properties ◽  
Microstructure Evolution ◽  
Sintering Temperature ◽  
Cold Isostatic Pressing ◽  
Liquid Phase Sintering ◽  
Sintering Process ◽  
Composite Powders ◽  
Mechanical And Electrical Properties

In this study, the effect of sintering temperature on the properties of tungsten-copper (W-Cu) composite produced by liquid phase sintering (LPS) process has been investigated. W-20 wt.% Cu composite powders with particle size less than 1 μm was prepared by cold compaction and followed by cold isostatic pressing. The green specimens were then sintered under nitrogen based atmosphere in the temperature range of 1100°C to 1300°C. The sintering studies were conducted to determine the extent of densification and corresponding to microstructure changes. In addition, the properties of the sintered specimens such as physical appearance, microstructure evolution, mechanical and electrical properties were presented and discussed.

A Review of the Low-Temperature Degradation of Dental Zirconia

2014 ◽  
Vol 606 ◽  
pp. 85-88
Author(s):  
Mohamed M. Aboras ◽  
Kai Yuan Theng ◽  
Andanastuti Muchtar ◽  
Che Husna Azhari ◽  
Norziha Yahaya
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Low Temperature ◽  
Tetragonal Zirconia ◽  
Dental Restoration ◽  
Restorative Material ◽  
Dental Restorations ◽  
Biological Compatibility ◽  
Oral Environment ◽  
Dental Restorative

The use of tetragonal zirconia as a dental restorative material has recently increased because of its unique mechanical and optical properties, as well as high biological compatibility with the oral cavity environment. However, the mechanical properties of zirconia can be severely degraded, which leads to the failure of dental restorations. This review focuses on the low-temperature degradation of dental zirconia and its effects on the properties of zirconia and on the oral environment. The purpose is to show the importance of this negative phenomenon and suggest guidelines for minimizing the aging of zirconia that is used as a dental restoration material.

scholarly journals Effects of Reinforcement Ratios and Sintering Temperatures on the Mechanical Properties of Titanium Nitride/Nickel Composites

2020 ◽  
Author(s):  
Yi-Cheng Chen ◽  
Shih-Fu Ou
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Compressive Strength ◽  
Titanium Nitride ◽  
Sintering Temperature ◽  
Hot Forging ◽  
Titanium Content ◽  
Reduction Reaction ◽  
Cold Isostatic Pressing ◽  
Nickel Metal

Abstract In this study, powder metallurgy was used to fabricate titanium nitride/nickel metal-matrix composites. First, Ti and Ni powders with weight ratios of 20:80, 50:50, and 80:20 were dry mixed for 24 h. After cold isostatic pressing, the green compacts were soaked in a water-based hot forging lubricant and sintered at 850, 950, and 1050°C for 1.5 h in an air atmosphere. The effects of the amount of titanium powder and the sintering temperature on the mechanical properties (hardness, wear resistance, and compressive strength) of the composites were investigated. The results indicated that titanium gradually transformed into titanium nitride near the surface after sintering due to the carbothermal reduction reaction; this transformation was observed to significantly increase the hardness. In addition, a titanium oxide film was observed to form between the titanium particles and the nickel matrix. The optimum sintering temperature of 950°C provides the composites with titanium-nickel weight ratios of 20:80 and 50:50, the latter of which exhibited the best mechanical properties (wear resistance and compressive strength). Furthermore, increasing the titanium content to 80% in the composite increased the hardness; however, the wear resistance and compressive strength were observed to reduce.

scholarly journals Yttria- Stabilized Tetragonal Zirconia with Superior Mechanical Properties Prepared Using Gel Casting Technology and a Two-Stage Sintering Process

2021 ◽  
Author(s):  
Jing-Siang Jhan ◽  
Chih-Cheng Chen ◽  
Yu-Chi Liu ◽  
Hsing-I Hsiang
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Grain Growth ◽  
Tetragonal Zirconia ◽  
Solid Content ◽  
Sintering Process ◽  
Two Stage ◽  
Casting Technology ◽  
Gel Casting ◽  
Superior Mechanical Properties

Abstract Yttria-stabilized tetragonal zirconia (YTZP) ceramics with high densification and superior mechanical properties were obtained using gel casting technology and a two-stage sintering process. Well-dispersed Nano-sized (94 nm) zirconia slurry with high solid content (45vol%) was prepared for gel casting using Dolapix CE64 as the dispersant. As the dispersed slurry was added epoxy monomer (EGDGE) and polymerization initiator (DPTA), Dolapix CE64 promoted gelling, leading to an abrupt increase in the slurry viscosity. As Dolapix CE64 was added into the slurry, its functional carboxyl groups reacted with EGDGE, resulting in a decrease in gelling incubation time and an increase in viscosity, hence, leading to gel casting failure. The addition of hydroquinone (HQ) into the slurry can be used to delay the polymerization and extend the gel casting working time. After gel casting, the temperature was raised to above 60o C to promote the polymerization, leading to an increase in the green strength.A two-stage sintering process was used to control the grain growth. The first stage sintering temperature was chosen at 1300oC, where the relative density reached 83%. In the second sintering stage, the temperature was lowered to 1240°C and soaked for 24 h to inhibit grain growth (mean grain size of 195 nm) and continue densification to a relative density of above 99%. Vickers hardness of 15.2GPa, fracture toughness of 7.8MPa.m1/2, and flexural strength of 771MPa can be obtained for the sample prepared using gel casting technology with a two-stage sintering process.

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