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.

scholarly journals New Perspectives on Zirconia Composites as Biomaterials

2021 ◽  
Vol 5 (9) ◽  
pp. 244
Author(s):  
Giuseppe Magnani ◽  
Paride Fabbri ◽  
Enrico Leoni ◽  
Elena Salernitano ◽  
Francesca Mazzanti
Keyword(s):  
Mechanical Properties ◽  
Dental Implants ◽  
High Performance ◽  
Bending Strength ◽  
Ceramic Powder ◽  
Orthopedic Implants ◽  
Forming Process ◽  
Digital Light Processing ◽  
Zirconia Composites ◽  
Alumina Composites

Zirconia–alumina composites couple the high toughness of zirconia with the peculiar properties of alumina, i.e., hardness, wear, and chemical resistance, so they are considered promising materials for orthopedic and dental implants. The design of high performance zirconia composites needs to consider different aspects, such as the type and amount of stabilizer and the sintering process, that affect the mechanics of toughening and, hence, the mechanical properties. In this study, several stabilizers (Y2O3, CuO, Ta2O5, and CeO2) were tested together with different sintering processes to analyze the in situ toughening mechanism induced by the tetragonal–monoclinic (t–m) transformation of zirconia. One of the most important outcomes is the comprehension of the opposite effect played by the grain size and the tetragonality of the zirconia lattice on mechanical properties, such as fracture toughness and bending strength. These results allow for the design of materials with customized properties and open new perspectives for the development of high-performance zirconia composites for orthopedic implants with high hydrothermal resistance. Moreover, a near-net shape forming process based on the additive manufacturing technology of digital light processing (DLP) was also studied to produce ceramic dental implants with a new type of resin–ceramic powder mixture. This represents a new frontier in the development of zirconia composites thanks to the possibility to obtain a customized component with limited consumption of material and reduced machining costs.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

Effects of TiN Content on Mechanical Properties and Microstructure of ATN Materials

2013 ◽  
Vol 589-590 ◽  
pp. 590-593 ◽  
Author(s):  
Min Wang ◽  
Jun Zhao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Hot Press ◽  
Hot Press Sintering ◽  
Tin Content

In order to investigate the effects of TiN content on Al2O3/TiN ceramic material (ATN), the ATN ceramic materials were prepared of TiN content in 30%, 40%, 50%, 60% in the condition of hot press sintering. The sintering temperature is 1700°C, the sintering press is 32MPa, and the holding time are 5min, 10min, 15min. The effects of TiN content on mechanical properties and microstructure of ATN ceramic materials were investigated by analyzing the bending strength, hardness, fracture toughness. The results show that ATN50 has the best mechanical property, its bending strength is 659.41MPa, vickers hardness is 13.79GPa, fracture toughness is 7.06MPa·m1/2. It is indicated that the TiN content has important effect on microstructure and mechanical properties of ATN ceramic materials.

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.

scholarly journals Si3N4-SiCpComposites Reinforced byIn SituCo-Catalyzed Generated Si3N4Nanofibers

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Juntong Huang ◽  
Zhaohui Huang ◽  
Shaowei Zhang ◽  
Minghao Fang ◽  
Yan’gai Liu
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Network Connection ◽  
Opposite Trend ◽  
Low Sintering Temperature ◽  
Co Addition

Si3N4-SiCpcomposites reinforced byin situcatalytic formed nanofibers were prepared at a relatively low sintering temperature. The effects of catalyst Co on the phase compositions, microstructures, and physicochemical-mechanical properties of samples sintered at 1350°C–1450°C were investigated. The results showed that the catalyst Co enhanced the nitridation of Si. With the increase of Co addition (from 0 wt% to 2.0 wt.%), the apparent porosity of as-prepared refractories was initially decreased and subsequently increased, while the bulk density and the bending strength exhibited an opposite trend. TheSi3N4-SiCpcomposites sintered at 1400°C had the highest strength of 60.2 MPa when the Co content was 0.5 wt.%. The catalyst Co facilitated the sintering ofSi3N4-SiCpcomposites as well as the formation of Si3N4nanofibers which exhibited network connection and could improve their strength.

Fabrication of TiAl Intermetallic by Spark Plasma Sintering

2007 ◽  
Vol 336-338 ◽  
pp. 1050-1052 ◽  
Author(s):  
Hai Tao Wu ◽  
Yun Long Yue ◽  
Wei Bing Wu ◽  
Hai Yan Yin
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compounds ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Three Point Bending ◽  
The Poor ◽  
High Relative Density ◽  
Plasma Sintering ◽  
Spark Plasma

The γ-TiAl intermetallic compounds were produced at the temperature ranging from 850°C to 1050°C by the Spark Plasma Sintering (SPS) process. The effects of sintering temperature and holding time on the mechanical properties of γ-TiAl intermetallic compounds were investigated. The γ-TiAl intermetallic compounds sintered at 1050°C for 10 min showed a high relative density more than 98%, and had the best three-point bending strength of 643MPa, fracture toughness of 12 MPa·m1/2 and microhardness of 560MPa. The microstructural observations indicated typical characteristics of intergranular fracture, which meant the poor ductility of γ-TiAl intermetallic compounds.

Microstructure and Properties of Al2O3-ZrO2 Ceramics Prepared by Microwave Sintering

2014 ◽  
Vol 633 ◽  
pp. 193-197 ◽  
Author(s):  
Yun Long Ai ◽  
Xiang Hua Xie ◽  
Wen He ◽  
Bing Liang Liang ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Intergranular Fracture ◽  
Fracture Mode ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Transgranular Fracture ◽  
Submicron Scale ◽  
Main Fracture ◽  
Sintering Processes

ZrO2 doped with 7.5% (volume percent) nanoalumina ceramics were prepared by microwave sintering processes. The effects of nanoalumina additions and various sintering temperature on densification, phase composition, microstructure and mechanical properties of Al2O3-ZrO2 ceramics were investigated. The results show that the m-ZrO2 phase transformed into t-ZrO2 during the process of microwave sintering. Relative densities between 95% and 99% were attained in the different conditions. In any cases the grain size was maintained at a submicron scale at a processing microwave sintering. The presence of Al2O3 grains had an effect of hindering grain growth of ZrO2 grains. When the microwave sintering temperature was 1500°C, 7.5Al2O3-ZrO2 composite ceramics presented excellent mechanical properties: HV=12.0 GPa, σf=715.7 Mpa, KIC=11.9 MPa·m1/2. Compared with that of pure ZrO2 ceramic, the bending strength and the fracture toughness were improved 45% and 23% at least, respectively. The fracture mode was associated with sintering temperature: when the sintering temperature was 1350°C~1450°C, the intergranular fracture and transgranular fracture coexisted; when the sintering temperature was 1500°C, intergranular fracture was the main fracture mode.

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.

Study of the mechanical properties and toughening mechanism of ZrO2 particles toughened Si3N4 ceramics

2020 ◽  
Vol 10 (6) ◽  
pp. 928-933
Author(s):  
Liang Tian ◽  
Qinglin Hou ◽  
Yingxia Wang ◽  
Yihui Hou
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
High Hardness ◽  
Fracture Morphology ◽  
Xrd Analysis ◽  
High Thermal Stability ◽  
Toughening Mechanism ◽  
Temperature Resistance ◽  
Si3n4 Ceramics

Si3N4 ceramic has excellent properties such as high temperature resistance, high hardness, and high thermal stability, but it has the disadvantages of high hardness and brittleness and difficulty in later processing. In this paper, ZrO2 was used as toughening phase, and ZrO2 toughened Si3N4 ceramics was prepared by injection molding. The effects of ZrO2 sintering temperature and content on the mechanical properties and fracture morphology were studied. Experiments show that when the ZrO2 content is 10 wt.% and the sintering temperature reaches 1650 °C, the bending strength and fracture toughness of Si3N4 ceramics reach the maximum at the same time, which are 767 MPa and 8.7 MPa·m1/2, respectively. The density is high. XRD analysis revealed that if the sintering temperature is too high, the ZrO2/Si3N4 system will generate a large number of ZrN impurity phases that cannot be phase-transformed, which ultimately affects the ceramic properties. According to fracture morphology, the toughening mechanism of ZrO2 is stress-induced phase transition.

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