Sinterability of Alumina-Dispersed 3Y-TZP

2006 ◽  
Vol 317-318 ◽  
pp. 37-40
Author(s):  
Bum Rae Cho ◽  
Dong Guk Yeoum
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
Micro Hardness ◽  
Drying Method ◽  
Hardness Tester ◽  
Pinning Effect ◽  
High Relative Density ◽  
Al2o3 Particles ◽  
Vickers Micro Hardness ◽  
Tetragonal Zirconia Polycrystal

The effect of Al2O3 addition on sinterability of Tetragonal Zirconia Polycrystal powders including 3mol% Y2O3 (3Y-TZP) was investigated. Each 3Y-TZP powder dispersed with 0.3, 0.6, 0.9 and 1.2wt.% of Al2O3 was prepared by the spray-drying method. The prepared powders were pressed into a disk type and sintered at 1350, 1400, 1450 and 1500 for 2 hours in the air. Resultant microstructures and mechanical properties of specimens were investigated by using Vickers/Micro hardness Tester, FE-SEM and XRD. Most of the specimens showed high relative density over 99% and a higher fracture toughness than pure 3Y-TZP. Al2O3 particles dispersed in 3Y-TZP microstructure depressed grain growth of 3Y-TZP by the pinning effect. Increase in fracture toughness of 3Y-TZP was explained by the crack deflection due to dispersed Al2O3 particles.

Characterisation of WC-17Co and WC-9Ni HVOF Sprayed Cermet Coatings

2016 ◽  
Vol 840 ◽  
pp. 331-335
Author(s):  
Nur Amira Mohd Rabani ◽  
Zakiah Kamdi
Keyword(s):  
Steel Substrate ◽  
Optical Microscope ◽  
Binder Phase ◽  
High Porosity ◽  
Tungsten Carbides ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardness Tester ◽  
Vickers Micro Hardness

Cemented tungsten carbides have been paid much attention due its better mechanical properties with excellent combination of hardness and toughness characteristics. The hard WC particles in the coating provide hardness and wear resistance, while the ductile binder such as Co and Ni contribute to toughness and strength. WC-17wt.% Co and WC-9wt.% Ni powders have been sprayed by the HVOF method to form coatings approximately 300μm and 150μm thick onto AISI 1018 steel substrate. Both coatings have been prepared and supplied by an external vendor. The coatings were examined using optical microscope (OM), scanning electron microscope (SEM), and X-Ray diffraction (XRD). The hardness of both coatings were also measured using Vickers micro-hardness tester. The microstructure of the coatings has been analyzed and found to consist of WC, brittle W2C phase, metallic W phase, and amorphous binder phase of Co and Ni. It is found that WC-Ni has a higher hardness value compared to WC-Co due to high porosity distribution.

Effect of TiN Addition on Microstructure and Mechanical Properties of Zirconia Matrix Ceramic Tool Material

2004 ◽  
Vol 471-472 ◽  
pp. 321-325 ◽  
Author(s):  
Jing Sun ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Sui Lian Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Monoclinic Phase ◽  
Tetragonal Zirconia ◽  
Tool Material ◽  
Strengthening Mechanisms ◽  
Microstructure And Mechanical Properties ◽  
Ceramic Tool Material ◽  
Tetragonal Zirconia Polycrystal

In this paper, 3mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) and TiN/3Y-TZP(adding TiN particles to 3Y-TZP) composites were fabricated by hot-pressing technique. Phase composition, microstructure and mechanical properties of the composites were investigated. It is shown that the flexural strength, fracture toughness and Vickers hardness of TiN/3Y-TZP was significantly improved by the addition of TiN particles compared with 3Y-TZP. The flexural strength of ZYT2 (20wt% TiN addition) is 1318 MPa. The fracture toughness of ZYT4 (40wt% TiN addition) is 16.8MPa·m1/2. The toughening and strengthening mechanisms were analyzed. The XRD results show that the additing of TiN can hinder the transformation from tetragonal phase to monoclinic phase of 3Y-TZP during fabrication process.

Laser-Assisted Milling of Zirconia with Systematically Determined Machining Conditions

2017 ◽  
Vol 11 (2) ◽  
pp. 258-269
Author(s):  
Toru Kizaki ◽  
◽  
Yusuke Ito ◽  
Naohiko Sugita ◽  
Mamoru Mitsuishi
Keyword(s):  
Fracture Toughness ◽  
Unique Feature ◽  
Elevated Temperatures ◽  
Thrust Force ◽  
Tetragonal Zirconia ◽  
Systematic Method ◽  
Processing Efficiency ◽  
Diamond Tools ◽  
Dental Restoratives ◽  
Tetragonal Zirconia Polycrystal

Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is a promising material for dental restoratives. Although grinding or polishing with diamond tools is widely used to machine Y-TZP, the processing efficiency and cost of the process are problematic. In this study, we applied laser-assisted machining (LAM) to Y-TZP, in which non-diamond tools were used. Unlike LAM applied to other materials, decrease of the fracture toughness at elevated temperatures which is a unique feature of the Y-TZP was adopted as a key mechanism for machinability enhancement. In addition, a systematic method to determine the LAM conditions was proposed. In this study, we explain the LAM condition-determining method, which is based on numerical simulations of the temperature distribution. Secondly, the determining method was evaluated through a series of LAM experiments to obtain the appropriate LAM conditions. Using the determined conditions, LAM of Y-TZP was demonstrated to be effective; the thrust force was reduced by 51.3% and the tool wear was significantly reduced, while no cracks formed on the Y-TZP.

A Study on Effect of Beginning V Concentration in TD Process

2014 ◽  
Vol 624 ◽  
pp. 134-137
Author(s):  
Shi Nan Li ◽  
Hui Chen ◽  
Yan Jie Zhang ◽  
Zhang Yu Gao ◽  
Li Zhen Liu ◽  
...  
Keyword(s):  
Thermal Diffusion ◽  
Salt Bath ◽  
Reducing Agent ◽  
Micro Hardness ◽  
Hardness Tester ◽  
Vital Factor ◽  
Vickers Micro Hardness

Procedures of thermal diffusion (TD) process are carried out on two specimens of Cr12MoV steel using the same salt bath formula. For the two specimens, the beginning V concentration, V concentration at the time specimen is added, are different, the level of which is controled by changing the interval between the specimen are added and the time reducing agent of Al meeting with vanadizing source of V2O5. The interval for Specimen 1 and Specimen 2 are 10 and 30 minutes respectively. Consequently, different changes are happened on the surface of the substrates. The microstructures of coatings are observed by optical metallographic microscope and SEM/EDS, the hardness are tested by Vickers micro-hardness tester. Results show that: VC coating formed on Specimen 2 is of better performances than Specimen 1, microhardness of Specimen 2 reaches as much as 2400HV. It can be concluded that level of V concentration at the beginning of TD process is a vital factor for the forming of VC layer.

scholarly journals Determination of Hardness and Fracture Toughness of Y-TZP Manufactured by Digital Light Processing through the Indentation Technique

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ziyu Mei ◽  
Yuqing Lu ◽  
Yuxin Lou ◽  
Ping Yu ◽  
Manlin Sun ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
Milling Process ◽  
Control Group ◽  
Digital Light Processing ◽  
Hardness Values ◽  
3D Printing Technique ◽  
True Hardness ◽  
Tetragonal Zirconia Polycrystal

Objective. The purpose of the study was to determine the hardness and fracture toughness of dental yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) manufactured by digital light processing (DLP) technology to study its clinical prospects. Methods. The experimental group was DLP-manufactured zirconia, and the control group was milled zirconia. The hardness was investigated under a range of test loads (0.49 N, 0.98 N, 1.96 N, 4.90 N, 9.81 N, 29.42 N, 49.03 N, 98.07 N, and 196.1 N). Meyer’s law was applied to describe the indentation size effect (ISE). Meanwhile, the PSR model and MPSR model were utilized to generate true hardness values. The cracks were observed to be induced by indentation under loads above 49.03 N, while the cracks showed the radial-median type under the load of 196.1 N, under which the fracture toughness was calculated. Results. The true hardness of DLP-manufactured zirconia was 1189 HV based on the PSR model and 1193 HV based on the MPSR model, a bit lower than that of milled zirconia. The fracture toughness was 3.43 ± 0.29   MPa √ m , which showed no statistical difference with the milled zirconia. Conclusion. The dental zirconia manufactured by the DLP 3D printing technique is similar to that manufactured by the conventional milling process in hardness and fracture toughness, thus having a promising future of clinical use.

scholarly journals Yttria stabilized tetragonal zirconia ceramics: preparation, characterization and applicationspplications

2018 ◽  
Vol 53 (2) ◽  
pp. 111-116 ◽  
Author(s):  
N Sultana ◽  
K Bilkis ◽  
R Azad ◽  
MR Qadir ◽  
MA Gafur ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Tetragonal Zirconia ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Zirconia Ceramics ◽  
X Ray ◽  
Hardness Tester ◽  
Maximum Value ◽  
Different Temperatures ◽  
Temperature Water

In this study, yttria stabilized tetragonal zirconia (YSTZ) ceramics were prepared and were sintered at different temperatures to find out the optimum sintering temperature for their better tetragonality and mechanical properties for their application as optical ferrule. Vicker’s hardness was performed by micro hardness tester and it was found to increase with the increase of sintering temperature to a maximum value, then it was decreased with higher sintering temperature. Water absorptivity and porosity were also seen to decrease as the densities of the specimens were increased. X-ray diffraction was employed to determine crystal structure of sintered samples. Surface morphology of the sintered samples was examined through field emission scanning electron microscope.Bangladesh J. Sci. Ind. Res.53(2), 111-116, 2018

Effects of CeO2 Addition on Slip - Cast Yttria Tetragonal Zirconia Polycrystals Toughened Alumina (ZTA)

2019 ◽  
Vol 814 ◽  
pp. 340-346 ◽  
Author(s):  
Sivakumar Sivanesan ◽  
Teow Hsien Loong ◽  
Satesh Namasivayam ◽  
Mohammad Hosseini Fouladi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Growth ◽  
Tetragonal Zirconia ◽  
Solubility Limit ◽  
Pinning Effect ◽  
A Value ◽  
Maximum Value ◽  
Slip Cast

Addition of CeO2 into ZTA and its effects on microstructure and mechanical properties were investigated. CeO2 was detected with significant amounts only above 10 wt%. Viscosity was measured for slurry preparartions and characterization of mechanical properties of ZTA. Additions of CeO2 of more than 10 wt% surpassed the solubility limit and formed Ce2Zr3O10. Ce2Zr3O10 increased the tetragonality factor, prevented excessive grain growth through a pinning effect, which is attributed to the segregation of Ce2Zr3O10 to the grain boundaries and showed a peak in fracture toughness with a value of 9.3 MPam1/2 with 10 wt% additions of CeO2. Further additions of CeO2 reduced ZTA’s mechanical strength. Maximum value of Hv was 17700 MPa with 10 wt% CeO2. Porosities have been attributed as the underlying reason as to why theoretical density were always higher than measured densities.

Effects of NiO Nanoparticles on Physical and Mechanical Properties of BNKT Lead-Free Ceramics

2017 ◽  
Vol 866 ◽  
pp. 282-286 ◽  
Author(s):  
Chatchai Kruea-In ◽  
Suchittra Inthong ◽  
Wilaiwan Leenakul
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Micro Hardness ◽  
Nio Nanoparticles ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Hardness Tester ◽  
Lead Free Ceramics ◽  
Vickers Micro Hardness

In this research, The effects of NiO nanoparticles on the physical and mechanical properties of Bi0.5(Na0.81,K0.19)0.5TiO3 (BNKT) were investigated. The ceramics were synthesized by solid state reaction technique. The powder of BNKT was calcined at 850 °C for 4 h. The ceramics of BNKT/x NiO vol.% ( i.e. x= 0.0, 1.0, 2.0 and 3.0) were sintered at 1000-1150 °C for 2 h for optimize condition. Densification, phase formation, microstructure and micro hardness of samples were characterized via Archimedes method, X-ray diffraction techniques (XRD), scanning electron microscope (SEM) and Vickers micro hardness tester. The X-ray diffraction analysis of the ceramics suggests that all samples exhibited a perovskite structure. Densification of samples tended to increase with increasing amount of NiO content with minimun at 1.0 vol.% NiO additive. The NiO additive influenced densification as well as the mechanical properties of the samples. The results of this research suggest that NiO nanoparticles have influence on physical and mechanical properties of BNKT ceramics.

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