The Influence of Zirconia Powder Dispersion Technique on Microstructure and Properties of Al2O3 – ZrO2 Ceramic

2014 ◽  
Vol 682 ◽  
pp. 109-112
Author(s):  
Sergey Veselov ◽  
N.Yu. Cherkasova ◽  
R.S. Timarevskiy
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Bending Strength ◽  
Preliminary Treatment ◽  
Zirconia Powder ◽  
Powder Dispersion ◽  
Dispersion Technique ◽  
Zirconia Toughened Alumina ◽  
Zirconia Suspension

The results of microstructure and mechanical properties investigation for alumina and zirconia toughened alumina (ZTA) with 20 wt. % 3Y-ZrO2is presented. It was stated that the technique of preliminary treatment for zirconia suspension makes significant influence on sintered specimen microstructure. Introduction of the alloying additive treated with ball milling reduces Al2O3grain size in ceramic from 2-5 μm to 0.2-1 μm. The reduction of grain size increases the bending strength of ceramic material from 270 MPa up to 350 MPa. However fracture toughness of alumina and ZTA is 3.4 and 2.5 MPa·m1/2, respectively. It was shown that the low level of mechanical properties is related to the occurrence of major defects in the form of granule boundaries preserved at the forming stage.

Pressureless Sintering and Properties Investigation of Silicon Nitride

2011 ◽  
Vol 194-196 ◽  
pp. 1464-1469
Author(s):  
Bin Li ◽  
Yi Feng ◽  
Hui Qiang Liu ◽  
Yan Fang Zhu ◽  
Dong Bo Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Bending Strength ◽  
Fracture Morphology ◽  
Pressureless Sintering ◽  
Sintering Aids ◽  
Α Phase ◽  
Different Grain Size ◽  
Si3n4 Ceramics

Different grain size of starting powder was choosed and different sintering additives were used to fabricate Si3N4 ceramics by pressureless sintering. Samples’ relative density and mechanical properties including Vickers hardness, bending strength and fracture toughness were tested. Then XRD, SEM and EDS were carried out to identify phase and observe microstructure and fracture morphology. The result shows that high purity α phase Si3N4 powder of 5 μm is suitable for sintering and combination of 5 wt.% MgO +5 wt.% Y2O3 is most effective within six kinds of sintering aids.

Simultaneous Synthesis and Sintering of Al2O3/Mo2N Composites Using Capsule-Free Nitrogen Hot Isostatic Pressing and their Characterization

2010 ◽  
Vol 62 ◽  
pp. 197-202
Author(s):  
Hirota Ken ◽  
Takaoka Katsuya ◽  
Murase Yasushi ◽  
Kato Masaki
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Hot Isostatic Pressing ◽  
Isostatic Pressing ◽  
Simultaneous Synthesis ◽  
Powder Compacts ◽  
Al2o3 Matrix

Synthesis of dense materials with the compositions of Al2O3/Mo2N=100/0 ~ 40/60 vol% has been attempted directly from Al2O3/Mo mixed raw powder compacts using capsule-free N2 hot isostatic pressing (HIP). During HIPing [1500°C/(16~20)MPa]/1h], solid/gas reaction between Mo and N2 was introduced to form Mo2N. Most sintered composites consisting of only Al2O3 and Mo2N phases reached a higher relative density than 98.0% with closed pores nevertheless capsule-free HIPing. Distribution of Mo2N particles just formed suppressed the grain growth of Al2O3 during sintering. Mechanical properties, such as bending strength (Σb), Vickers hardness (HV), fracture toughness (K1C), and other properties have been evaluated as a function of their compositions. The best mechanical values of Σb (c.a. 573 MPa), HV (c.a. 20.3 GPa) and K1C (c.a. 5.00 MPa･m1/2) were attained at the composition of Al2O3/Mo2N=90/10 vol%, due to a high density (98.6%) and small grain size of Al2O3 matrix (Gs c.a. 4.70 μm). Further addition of Mo2N reduced the sinterability of matrix grains, resulting in low densities of around 90% at the 40/60 vol% composition.

Densification Behaviour and Mechanical Properties on MgO Doped Zirconia Toughened Alumina (ZTA) Prepared by Two-Stage Sintering

2021 ◽  
Vol 1030 ◽  
pp. 3-10
Author(s):  
Teow Hsien Loong ◽  
Ananthan Soosai ◽  
Suresh Muniandy
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Total Hip Arthroplasty ◽  
Young’S Modulus ◽  
Vickers Hardness ◽  
Young's Modulus ◽  
Two Stage ◽  
Positive Effect ◽  
Zirconia Toughened Alumina

The effect of doping small amounts of Magnesium Oxide ranging between 0 to 1 vol% on Zirconia Toughened Alumina (ZTA) composites which is one of main biomaterial used for production of total hip arthroplasty were investigated. The samples were produced via conventional two-stage sintering with T1 varies between 1450°C and 1550°C with heating rate of 20°C/min. The samples were then rapid cooled to T2 set at 1400°C with holding time of 12 hours. The microstructural and mechanical properties of the two-stage sintered ZTA are then investigated to determine the feasibility of MgO addition. Combination of two-stage sintering at T1 above 1500 and also small amount of MgO up to 0.5 vol% were shown to have positive effect on ZTA which exhibited improvement on its grain size, mechanical properties such as Vickers hardness, Young’s modulus and fracture toughness compared to undoped ZTA composites. The sample with 0.5 vol% MgO addition sintered at T1 of 1500°C and T2 1400°C was able to achieve Vickers hardness of 19.6 GPa, Young’s modulus of 408 GPa and fracture toughness of 6.8 MPam1/2 without significant grain growth compared to undoped ZTA composites.

Microstructure and Mechanical Properties of Al2O3/ZrO2 Composites Prepared by Gelcasting

2007 ◽  
Vol 280-283 ◽  
pp. 1057-1060
Author(s):  
Bao Xiang Jiao ◽  
Tai Qiu ◽  
Chun Cheng Li ◽  
Chun Ying Shen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Solid Loading ◽  
Zro2 Content ◽  
Zro2 Particle ◽  
Microstructure And Mechanical Properties ◽  
Dry Pressing ◽  
Gelcasting Process ◽  
Zirconia Toughened Alumina

Microstructure and mechanical properties of zirconia-toughened alumina (ZTA) composite ceramics prepared by gelcasting process were investigated. The results indicated that Al2O3-ZrO2 composites have high bending strength and fracture toughness for the solid loading of the suspension ³ 50vol.%. The bending strength and fracture toughness of sintered ZTA ceramics reach values as high as 631.5 MPa and 7.64 MPa·m1/2, respectively, with solid loading of suspension being 55vol.%. The t-ZrO2 content is increased, and the uniformity of ZrO2 particle distribution is improved in sintered samples prepared by gelcasting compared with those by dry pressing.

Mechanical Properties of ZrB2-Based Ceramics Reinforced by Nano-SiC Whiskers

2007 ◽  
Vol 353-358 ◽  
pp. 1564-1567 ◽  
Author(s):  
Hai Long Wang ◽  
Chang An Wang ◽  
Rui Zhang ◽  
Xing Hu ◽  
Dai Ning Fang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Relative Density ◽  
Hot Pressing ◽  
Bending Strength ◽  
Sintering Process ◽  
Homogeneous Microstructure ◽  
Sic Whiskers ◽  
Xrd Techniques

In this paper, ZrB2-based ceramics containing up to 15 vol% nano-SiC whiskers were prepared by hot pressing at 1950°C under 20MPa pressure in flow argon. SEM and XRD techniques were used to characterize the sintered compacts. A fine and homogeneous microstructure was observed. The relative density of ZrB2-based ceramic containing 10vol% SiC whiskers reached to 97.7%. The bending strength and fracture toughness of the composite were 550 MPa and 8.08 MPa·m1/2 respectively, while those of the monolithic ZrB2 ceramic (0 vol% SiC whiskers added) were 424 MPa and 4.52 MPa·m1/2 respectively. The grain size of the ZrB2-based ceramics was reduced greatly by the addition of nano-SiC whiskers during the sintering process.

Mechanical Properties and Microstructure of Partially Sintered Zirconia Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1252-1254 ◽  
Author(s):  
Shi Bao Li ◽  
Zhao Hui Chen ◽  
Yi Min Zhao ◽  
Zhong Yi Wang ◽  
Li Hui Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Bending Strength ◽  
Target Material ◽  
Dental Restoration ◽  
Diameter Distribution ◽  
Zirconia Ceramics ◽  
Grain Sizes ◽  
Cad Cam

Partially sintered zirconia ceramics (PSZCs) for dental uses were prepared from zirconia nanopowder via isostatic pressing and partially sintering. The open porosities, pore diameters, grain sizes and mechanical properties of the ceramics with different densities were studied. The results show that the pores formed in the PSZCs are all open pores, with a diameter distribution of 60nm~130nm and a grain size distribution of 120~170nm. The machinability becomes worse when the density of PSZC is higher than 75% of the theoretical density, so a ceramic named PSZC-70% with density of 70%TD was selected as the target material. Its bending strength is 168 MPa and fracture toughness is 1.8 MPa·m1/2. A dental restoration framework can be obtained via machining the PSZC-70% on a dental CAD/CAM system.

scholarly journals Effect of Grain Size on Hardness, Bending Strength and Indentation Toughness of Multi-Doped Zirconia Ceramics

2018 ◽  
Author(s):  
Y.G. Hoo ◽  
Yusheng Shi ◽  
Wenzhong Lu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Size Effect ◽  
Bending Strength ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
Partially Stabilized Zirconia ◽  
Indentation Toughness ◽  
Wide Range

Partially stabilized zirconia (PSZ) is a promising material with superior combination properties in a wide range of industries. In this study, the effect of grain size on the mechanical properties such as hardness, bending strength and fracture toughness (named as ‘indentation toughness’ in this study) was investigated. The multi-doped zirconia ceramics were prepared by powder processing and pressure-less sintered following four sintering schedules. The measured mechanical properties results show that the polymorph structure sintered at a higher temperature has a lower bending strength and hardness. But 300% more indentation toughness (30.54 Kg/mm) of samples sintered at 1600 °C +1150 °C relative to others was estimated due to the grain size effect by our suggested equation. By contrast, the fracture toughness was calculated with an existing method. The results showed that similar trends were obtained. It appeared to be a novel method for evaluating the toughness of partially stabilized zirconia ceramics with micron grains based on the size effect.

Effects of Calcium Hexaluminate Addition on the Mechanical Properties of Zirconia-Toughened-Alumina

2013 ◽  
Vol 544 ◽  
pp. 286-290 ◽  
Author(s):  
Mei Ling Hu ◽  
Ming Hao Fang ◽  
Shu Sen Chen ◽  
Tao Yang ◽  
Zhao Hui Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Alumina Ceramic ◽  
Pressureless Sintering ◽  
Composite Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Calcium Hexaluminate ◽  
Zirconia Toughened Alumina

The effects of calcium hexaluminate addition on the microstructure and mechanical properties of zirconia-toughened-alumina ceramic were investigated. Zirconia-toughened-alumina (ZTA) composite ceramics which have different additions of calcium hexaluminate were successfully fabricated by pressureless sintering at 1600°C for 3h. The result shows that the bending strength and abrasive wearing improved with the increasing of CaAl12O19addition while the fracture toughness declined.

Mechanical Properties of Nanostructured Zirconia

2010 ◽  
Vol 660-661 ◽  
pp. 757-761 ◽  
Author(s):  
C.P. Silva ◽  
C. Santos ◽  
Cosme Roberto Moreira Silva
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Bending Strength ◽  
Tetragonal Zirconia ◽  
Physical And Mechanical Properties ◽  
Volumetric Fraction ◽  
Reliability Improvement ◽  
Four Point Bending ◽  
Dental Applications

In this work itria stabilized ZrO2 based ceramics for dental applications has been sintered and characterized in terms of physical and mechanical properties. Nanostructured blocks were sintered at 1400 0C and microstrutured blocks sintered at 1600 0C. Both nanostructured and microstructured materials were characterized in terms of densification, crystalline phases, mechanical properties and microstructure. Fracture toughness and four point bending strength were evaluated and compared. For the nanostructured zirconia, the reduced grain size allowed the increase of its toughening capacity, generated from maximization of volumetric fraction of retained tetragonal zirconia particles. For this material higher bending flexural strength is related to induced nucleation of microcracks, increase of energy absorption during crack propagation and developed compressive surface stress. The fracture toughness obtained at nanostructured samples sintered at 1400 0C is approximately 20% higher when compared to microstrucutured samples. These results represent the toughening ability of nanostructured zirconia, originated from higher amount of retained tetragonal phase and grain boundary microcracks. The higher Weibull moduli in this case are indicative of material reliability improvement and these results are correlated to grain size and its influence at mechanical strength.

Synthesis of Coloured Dental Zirconia Ceramics and their Mechanical Behaviors

2014 ◽  
Vol 602-603 ◽  
pp. 594-597 ◽  
Author(s):  
Jing Li ◽  
Shi Ming Liu ◽  
Yuan Hua Lin
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Phase Composition ◽  
Bending Strength ◽  
Linear Shrinkage ◽  
Zirconia Ceramic ◽  
Mechanical Behaviors ◽  
Zirconia Ceramics ◽  
Dental Zirconia Ceramics

The effects of Pr6O11 and Er2O3 dopants on microstructure and mechanical properties of zirconia ceramics were investigated. The phase composition and microstructure analysis indicate that samples are all tetragonal phase and grain size is about 50-100 nm. The relative density of zirconia ceramics was above 99.1%, linear shrinkage was nearly 20%, while Vickers hardness was over 12.5 GPa. Three-points bending strength was over 850 MPa which was slightly lower than that of the pure samples, and fracture toughness was above 4.9 MPa*m1/2. The results show that the dopants can be used to obtain the colored zirconia ceramic, and also have effects on its mechanical properties.

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