The Effect of Iron Oxide on the Mechanical and Ageing Properties of Y-TZP Ceramic

2016 ◽  
Vol 701 ◽  
pp. 225-229 ◽  
Author(s):  
Sivanesan Sivakumar ◽  
Hsien Loong Teow ◽  
Ramesh Singh ◽  
Ali Niakan ◽  
Nobuyuki Mase
Keyword(s):  
Fracture Toughness ◽  
Iron Oxide ◽  
Bulk Density ◽  
Phase Stability ◽  
Vickers Hardness ◽  
Tetragonal Phase ◽  
Superheated Steam ◽  
Matrix Stiffness ◽  
Sintering Aid ◽  
The Matrix

A small amount of iron oxide (Fe2O3) was added to the commercially available 3 mol% Y-TZP as a sintering aid over a temperature range of 1250°C to 1500°C. Sintered samples were then evaluated to determine the bulk density, Vickers hardness, and fracture toughness. In addition, hydrothermal ageing experiments to determine the tetragonal phase stability were performed on selected sintered samples in superheated steam at 180°C / 10 bar for up to 24 hours. Based on the work carried out, it was revealed that additions of Fe2O3 particularly 0.3 wt% was indeed beneficial in aiding densification, improving the matrix stiffness and hardness when compared to undoped Y-TZP sintered at temperatures below 1350°C. Addition of Fe2O3 was found to have negligible effects on the fracture toughness of all samples with the exception of the 0.5 and 1 wt% doped Y-YZP sintered above 1400°C. Hydrothermal ageing resistance of Y-TZP was found to be enhanced with the addition of Fe2O3 in the Y-TZP matrix.

Sintering and Densification Behavior of ZnO-Doped Y-TZP Ceramics

2011 ◽  
Vol 83 ◽  
pp. 197-203 ◽  
Author(s):  
Umma Sankar ◽  
Meenaloshini Satgunam ◽  
Mahdi Amiriyan ◽  
Ramesh Singh ◽  
Wan Dung Teng
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Zinc Oxide ◽  
Vickers Hardness ◽  
Superheated Steam ◽  
Matrix Stiffness ◽  
Phase Content ◽  
Densification Behavior ◽  
Ramp Rate ◽  
The Matrix

The effect on densification and mechanical properties of 3 mol% Y-TZP ceramics doped with zinc oxide (0.1 wt.% to 1 wt.%), has been investigated in this study. Green samples were compacted by uniaxial pressing and cold isostatically pressed at 200 MPa. All samples have been sintered over the temperature range of 1250°C to 1500°C with a ramp rate of 10°C/ minute and 2 hours of holding time. In addition to that, the tetragonal phase stability of the samples was also studied in superheated steam at 180°C/10 bar for up to 50 h. The sintered bodies were examined to determine the phase content, bulk density, Young’s modulus, Vickers hardness and fracture toughness. The results showed that the addition of 1 wt.% ZnO was effective in aiding densification (~99% theoretical density). It also improved the matrix stiffness (~208 GPa) and Vickers hardness (~13 GPa), when the samples were sintered below 1300°C comparing to the undoped Y-TZP sintered at the same temperature. In contrast, ZnO addition to the Y-TZP matrix displayed a tendency to change hydrothermal ageing behavior as it was noticed that the monoclinic content increased with increasing content of dopant. The undoped samples showed a better hydrothermal ageing behavior at 1300°C compared to the doped samples.

Synthesis of High Fracture Toughness of Hydroxyapatite Bioceramics

2011 ◽  
Vol 264-265 ◽  
pp. 1849-1855 ◽  
Author(s):  
Chou Yong Tan ◽  
Ramesh Singh ◽  
R. Tolouei ◽  
Iis Sopyan ◽  
Wan Dung Teng
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Magnesium Oxide ◽  
Phase Stability ◽  
Vickers Hardness ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Sintering Additive

The sinterability of magnesium oxide (MgO) doped hydroxyapatite (HA) ranging from 1 to 10 wt% when sintered at 1150°C was investigated in terms of phase stability, bulk density, Young’s modulus, Vickers hardness and fracture toughness. The addition of up to 1 wt% MgO as sintering additive was found to be beneficial in promoting the densification of HA. Further addition of MgO in the HA matrix would deteriorate its densification properties. Similar results were observed for its stiffness and Vickers hardness. Nevertheless, the fracture toughness of HA was greatly enhanced by the incorporation of 5 wt% MgO. An increased toughness of up to 35% was obtained for the MgO-doped HA when compared to the undoped HA. This improvement is associated to the smaller grain size of the doped sample as compared to the undoped HA.

Machinability Evaluation of Ce-ZrO2/CePO4 Ceramics with Digraph Method

2007 ◽  
Vol 280-283 ◽  
pp. 1079-1082
Author(s):  
Ai Bing Yu ◽  
L.J. Zhong ◽  
Xin Li Tian ◽  
F. Zou
Keyword(s):  
Mechanical Property ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Vickers Hardness ◽  
Material Removal ◽  
Ceramic Materials ◽  
Experimental Results ◽  
The Matrix ◽  
Machinability Index ◽  
Machinable Ceramic

A new method is proposed for machinability evaluation of machinable ceramic materials. The relation of machinability attributes is modeled as a digraph, and machinability attribute matrix is defined. Machinability indexes are calculated with permanent function of the matrix, and machinabilities of machinable ceramics are ranked. Five composites consisting of CePO4 and zirconia were fabricated, measured and drilled with tungsten-cobalt carbide bits. Mechanical property parameters of Ce-ZrO2/CePO4 composites, including Vickers hardness, fracture toughness and Elastic modulus, are selected as machinability attributes. The experimental results of material removal rates are consistent with the ranking of machinability index values of Ce-ZrO2/CePO4 ceramics. The machinabilities of Ce-ZrO2/CePO4 ceramics improve with the increase of CePO4 proportions. Machinability of machinable ceramics can be evaluated with digraph method.

Sinterability and Mechanical Properties of MnO2-Doped Y-TZP: The Effects of Holding Time Variations

2011 ◽  
Vol 110-116 ◽  
pp. 1284-1288 ◽  
Author(s):  
Mahdi Amiriyan ◽  
Meenaloshini Satgunam ◽  
Sivanesan Sivakumar ◽  
Singh Ramesh ◽  
Ranna Tolouei
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Beneficial Effect ◽  
Bulk Density ◽  
Vickers Hardness ◽  
Time Variation ◽  
Sintering Temperature ◽  
Tetragonal Zirconia ◽  
Holding Time ◽  
Time Variations

The effect of holding time variation and sintering temperature on the mechanical properties and sinterability of yttria stabilized tetragonal zirconia doped with 1 wt. % MnO2 was investigated. Samples were sintered at 1150-1500 °C with holding times varying from 12 and 120 minutes. Comparing to the MnO2-doped Y-TZP, longer holding time resulted in enhanced densification of the undoped Y-TZP samples. In the case of MnO2-doped Y-TZP however, Bulk density, Young’s modulus, Vickers hardness and fracture toughness results show the beneficial effect of MnO2 in enhancing the densification of Y-TZP ceramics.

scholarly journals THE EFFECT OF COLD ISOSTATIC PRESSING ON THE SINTERABILITY OF SYNTHESIZED HA

2004 ◽  
Vol 16 (04) ◽  
pp. 199-204 ◽  
Author(s):  
S. RAMESH ◽  
P. CHRISTOPHER ◽  
C. Y. TAN ◽  
W. D. TENG
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Bulk Density ◽  
Phase Stability ◽  
Vickers Hardness ◽  
Linear Shrinkage ◽  
Cold Isostatic Pressing ◽  
Low Temperature Sintering ◽  
Cold Isostatic Press ◽  
Isostatic Pressing

The effect of cold isostatic pressing (CIP) on the sinterability of a laboratory synthesized hydroxyapatite (HA) powder was investigated. The starting powder was initially uniaxially diepressed at about 6 kN force to form disk and rectangular green compacts. Two batches of green samples were prepared, i.e. one batch was in the as-compacted state (Un-CIP) and another batch samples was subjected to cold isostatic press at 200 MPa (CIP). The latter samples exhibited alinear shrinkage of ∼16% prior to sintering. All the samples were sintered in air at temperatures ranging from 700°C to 1400°C. The densification behaviour of HA was evaluated in terms of linear shrinkage, phase stability, bulk density, Vickers hardness and Young's modulus. The results revealed that green samples subjected to cold isostatic pressing exhibited better sinterability and possessed excellent mechanical properties. This effect is more pronounced particularly for the low temperature sintering regime i.e. < 1100°C.

The Effect of Sintering Profiles on Zirconia Toughened Alumina (ZTA) Prepared by Two-Stage Sintering

2021 ◽  
Vol 904 ◽  
pp. 174-180
Author(s):  
Teow Hsien Loong ◽  
Sivakumar Sivanesan ◽  
Se Yong Eh Noum
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Heating Rate ◽  
Vickers Hardness ◽  
Young's Modulus ◽  
Holding Time ◽  
Two Stage ◽  
Zirconia Toughened Alumina

The effects of sintering profiles on the Zirconia Toughened Alumina (ZTA) composite containing 0 vol% Y-TZP (pure alumina) to 20 vol% Y-TZP content prepared by a sintering method known as two-stage sintering were investigated. The heating rate was set between 10°C/min to 20°C/min, T1 set between 1400°C to 1500°C, T2 at 1350°C and holding time was set at 12 hours. The samples’ microstructural properties and mechanical properties, including bulk density, Vickers hardness, Young’s modulus and fracture toughness, were evaluated. Based on the data obtained, the ZTA composites with 10 vol% Y-TZP sintered at a heating rate of 10°C/min and holding time of 12 hours were able to achieve mechanical properties requirements set by the industry standard. In addition, the maximum ZTA composite’s bulk density was recorded to be above 90% T.D, while the Vickers hardness of the composite was recorded to be exceeding 17 GPa. The ZTA composite also recorded maximum Young’s modulus exceeding 380 GPa and fracture toughness above 6 MPam1/2.

Effects of Bismuth Oxide on the Properties of Calcium Phosphate Bioceramics

2011 ◽  
Vol 264-265 ◽  
pp. 1839-1848
Author(s):  
Wei Hong Yeo ◽  
Ramesh Singh ◽  
Chou Yong Tan ◽  
K.L. Aw ◽  
R. Tolouei ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Calcium Phosphate ◽  
Bulk Density ◽  
Young’S Modulus ◽  
Bismuth Oxide ◽  
Vickers Hardness ◽  
Sintering Temperature ◽  
Young's Modulus ◽  
Xrd Analysis ◽  
The Stability

The aim of this work is to study the phase stability and sinterability of bismuth oxide (Bi2O3) doped HA ranging from 0.05 wt% to 1 wt%. The green samples were sintered in air at temperature ranging from 1000oC to 1400oC. In this experiment, the results from XRD analysis revealed that the stability of HA phase was disrupted when addition of 0.3, 0.5 and 1.0 wt% Bi2O3 were used and when samples sintered above 1100oC, 1000oC and 950oC, respectively. In general, HA containing 0.5 wt% of Bi2O3 and when sintered at 1000oC was found to be beneficial in enhancing densification, Young’s modulus, Vickers hardness and fracture toughness. Throughout the sintering regime, the highest value of relative bulk density of 98.7% was obtained for 0.5 wt% Bi2O3-doped HA when sintered at 1000oC. A maximum Young’s modulus of 119.2 GPa was observed for 0.1 wt% Bi2O3-doped HA when sintered at 1150oC. Additionally, 0.5 wt% Bi2O3-doped HA was able to achieve highest hardness of 6.04 GPa and fracture toughness of 1.21 MPam1/2 at sintering temperature of 1000oC. Furthermore, the Young’s modulus of HA was found to vary linearly with bulk density.

scholarly journals Microwave Vitrification of Uranium Tailings: Microstructure and Mechanical Property

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Wei Wei ◽  
Keyou Shi ◽  
Yupeng Xie ◽  
Shoufu Yu ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Vickers Hardness ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Homogeneous Distribution ◽  
Sintering Process ◽  
Sintering Aid ◽  
Ft Ir ◽  
Uranium Tailings

In this work, the dense glass matrix of uranium tailings was successfully fabricated via microwave sintering process with Na2CO3 as a sintering aid. The effects of Na2CO3 additive and sintering temperature on the microstructure and mechanical properties of as-prepared solids were systematically investigated. XRD results confirmed the vitrified forms can be achieved at 1200°C within 30 min with 20 wt.% Na2CO3 addition. Importantly, the Na2CO3 additive significantly reduced the firing temperature from 1500°C to 1200°C and promoted densification. FT-IR analysis demonstrated that the main characteristic peaks of the sintered samples were attributed to the vibration of Si-O-Si. Microstructural studies presented the homogeneous distribution of glass phases. The results of mechanical properties of the sintered forms show that bulk density and Vickers hardness increased with increasing Na2CO3 content as well as sintering temperature, and the highest bulk density (2.45 ± 0.01 g/cm3) and Vickers hardness (823 ± 25 HV) were obtained at the temperature of 1300°C with 20 wt.% Na2CO3 addition, the heating rate of 20°C/min, and the soaking time of 30 min. It implied that the combination of microwave sintering with the appropriate addition of Na2CO3 would provide an efficient method for the immobilization of radionuclides in uranium tailings.

scholarly journals Efficient Improvement in Fracture Toughness of Laminated Composite by Interleaving Functionalized Nanofibers

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2509
Author(s):  
Seyed Mohammad Javad Razavi ◽  
Rasoul Esmaeely Neisiany ◽  
Moe Razavi ◽  
Afsaneh Fakhar ◽  
Vigneshwaran Shanmugam ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Behavior ◽  
Laminated Composite ◽  
Carbon Phase ◽  
Reinforced Composite ◽  
Reinforcing Agent ◽  
The Matrix ◽  
As Stress ◽  
Double Cantilever Beam Test ◽  
Pan Nanofiber

Functionalized polyacrylonitrile (PAN) nanofibers were used in the present investigation to enhance the fracture behavior of carbon epoxy composite in order to prevent delamination if any crack propagates in the resin rich area. The main intent of this investigation was to analyze the efficiency of PAN nanofiber as a reinforcing agent for the carbon fiber-based epoxy structural composite. The composites were fabricated with stacked unidirectional carbon fibers and the PAN powder was functionalized with glycidyl methacrylate (GMA) and then used as reinforcement. The fabricated composites’ fracture behavior was analyzed through a double cantilever beam test and the energy release rate of the composites was investigated. The neat PAN and functionalized PAN-reinforced samples had an 18% and a 50% increase in fracture energy, respectively, compared to the control composite. In addition, the samples reinforced with functionalized PAN nanofibers had 27% higher interlaminar strength compared to neat PAN-reinforced composite, implying more efficient stress transformation as well as stress distribution from the matrix phase (resin-rich area) to the reinforcement phase (carbon/phase) of the composites. The enhancement of fracture toughness provides an opportunity to alleviate the prevalent issues in laminated composites for structural operations and facilitate their adoption in industries for critical applications.

Mechanical Properties of Zirconia Toughened Alumina Composites with TZP Partially Nanostructured Sintered by Liquid Fase

2008 ◽  
Vol 591-593 ◽  
pp. 436-440
Author(s):  
João Marcos K. Assis ◽  
Francisco Piorino Neto ◽  
Francisco Cristóvão Lourenço de Melo ◽  
Maria do Carmo de Andrade Nono
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Weibull Modulus ◽  
Bending Test ◽  
Sintering Aid ◽  
Zirconia Composites ◽  
Alumina Composites ◽  
Grain Size And Shape ◽  
Zirconia Toughened Alumina ◽  
Zirconia Powders

A comparative study between alumina added niobia ceramics and two alumina zirconia composites from nanostructured TZP (7% and 14% weight) was made. On this composites the zirconia were yttria stabilized and the alumina were submicron structured. As sintering aid a mixture of magnesia, niobia and talc were used on all samples. The sintering was performed at 1450 oC during 60 minutes. The characteristic grain size and shape of an alumina and zirconia powders, aggregates and agglomerates were characterized. The sintering ceramics were evaluated through hardness, fracture toughness and 4 point bending test. Weibull statistic was applied on the flexural results. Although the fracture toughness result from ZTA were lower, and seems to be affected by the liquid fase, the hardness and Weibull modulus were higher than alumina niobia. The grains size and the homogeneity of its distributions on the microstructure of this ceramics was correlated to these higher values. The results from these alumina zirconia composites showed a potential to apply as a ballistic armor material.

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