Influence of manganese on the sintering properties of tetragonal zirconia (original) (raw)
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Densification Studies of Tetragonal Zirconia with Manganese as Sintering Additive
The effects of small additions of MnO 2 on the sinterability of tetragonal zirconia (Y-TZP) over the temperature range from 1250ºC to 1500ºC was studied. The results indicated that the mechanical properties of Y-TZP were dependent on the dopant amount and sintering temperature. It was found that relative densities above 98% of theoretical could be obtained in bodies sintered at low temperatures of 1250ºC and 1300ºC with the additions of ≥ 0.3 wt% MnO 2 . In comparison to the undoped samples, the additions of up to 1 wt% MnO 2 and for sintering up to 1350ºC was found to be beneficial in enhancing the Vickers hardness of the ceramic. The fracture toughness of Y-TZP however, was found to increase only in the 1 wt% MnO 2 -doped samples when sintered above 1400ºC.
Sintering and Ageing Properties of Manganese Doped Y-TZP Ceramics
The sinterability of 3 mol% yttria-tetragonal zirconia polycrystals (Y-TZP) containing small amounts of manganese oxide (MnO2) as sintering aid was investigated over the temperature range of 1250°C to 1500°C. Sintered samples were evaluated to determine bulk density, Young’s modulus, Vickers hardness and fracture toughness. In addition, the tetragonal phase stability of selected samples was evaluated by subjecting the samples to hydrothermal ageing in superheated steam at 180°C/10 bar for periods up to 525 hours. The research showed that the addition of MnO2, particularly ³ 0.3 wt%, was effective in aiding densification and improving the matrix stiffness and hardness when compared to the undoped Y-TZP sintered at temperatures below 1350°C. On the other hand, the fracture toughness of Y-TZP was unaffected by MnO2 addition except for the 1 wt% MnO2-doped Y-TZP samples sintered above 1400°C. The hydrothermal ageing resistance of Y-TZP was significantly improved with the additions of Mn...
Sintering of Commercial Yttria-Stabilized Zirconia
The sinterability of three different commercially available 3 mol% Y-TZP powders was investigated. The powders were designated after the manufacturers as Kyoritsu, Dai-ichi and Stanford Y-TZPs. Green samples were compacted and cold isostatically pressed at 200 MPa prior to sintering at temperatures ranging from 1200ºC to 1500°C in air atmosphere. The sintered bodies were examined where appropriate to determine the phase present, bulk density, Young's modulus, hardness and fracture toughness. The results showed that although all the sintered bodies were tetragonal structure, they behave differently with increasing sintering temperature. In general, the Kyoritsu and Dai- ichi Y-TZPs exhibited higher bulk density coupled with better mechanical properties particularly when sintered at temperatures 1350°C to 1450°C. The influence of sintering temperature on the mechanical properties of these ceramics is deliberated in this paper.
Influence of sintering profile on the mechanical properties of manganese oxide doped 3Y-TZP
IOP Conference Series: Earth and Environmental Science, 2020
Zirconia ceramic has been identified as one of the advanced ceramic material with great mechanical properties which is used as engineering and implant materials. However, the great potential of the ceramic is hindered by low temperature degradation (LTD) where the ceramic experiencing t-m phase transformation that weakens the properties of 3Y-TZP in the presence of moisture. Two-step sintering was found to be effective in producing fully resistance 3Y-TZY but very long holding time is required. Manganese Oxide (MnO2) is reported as good densification aid at low sintering temperature for 3Y-TZP but the LTD issue is not fully resolved. In this study, the effects of different sintering profiles and dwell time on 3Y-TZP added with 0.5 wt.% of MnO2 were studied in order to improve the resistance towards LTD without affecting the intrinsic properties of the ceramic. The effects of adding 0.5 wt.% of manganese oxide (MnO2) into 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-...
Effect of sintering protocols on zirconia with various YTTRIA concentrations
2021
OBJECTIVES: To compare the effects of different sintering protocols on density, translucency, microstructure, crystallography, and biaxial flexural strength of different yttria concentrations of Tosoh zirconia materials (TZ-3YSB-E, TZ-3YB-E, Zpex, and Zpex Smile). MATERIALS AND METHODS: A total of 242 zirconia discs were manufactured from commercially available Tosoh zirconia powders. Zpex smile, Zpex, TZ-3YB-E, and TZ-3YSB-E were uniaxially dry pressed into cylindrical blocks using a 5/8-inch internal diameter steel die set under a hydraulic press load of 3,000 N (Carver Press). Blocks were partially sintered at 1000 °C and sectioned into discs with a thickness of 2 mm x 15 mm by an IsoMet 5000 section machine. The discs were fully sintered using three protocols: 1) regular sintering using Vita Zyrcomat T furnace at 1520 °C for 2 h (total cycle time of 7 h); 2) fast sintering using Sirona inFire HTC SPEED at 1540 °C for 30 min (total cycle time of ~1.5 h). 3) speed sintering using ...
Journal of Materials Engineering and Performance, 2014
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The sintering of yttria-tetragonal zirconia polycrystals (Y-TZP) is commonly carried at a predefined temperature using a long holding time of 2 hours. This often has resulted in grain coarsening which affects the mechanical properties of the sintered body and low temperature degradation (LTD) behaviour of the ceramic when exposed to moist environment. In this research, the effect of using a short holding time of 1 min. during sintering coupled with small amounts (0.5 and 1 wt%) of manganese oxide, MnO2 as dopant on the mechanical properties and LTD behaviour of 3 mol% Y-TZP were investigated. The results showed that the mechanical properties improved significantly with the addition of 0.5 wt% MnO2 for the 1-min. and 12-min. holding time samples when compared to 2 hours holding time sintered at the same temperature of 1350 degrees C. Nevertheless, regardless of the holding time employed, the 1 wt% MnO2 addition was not effective in improving the mechanical properties and ageing resistance of Y-TZP ceramic. Link to Full-Text Articles : http://jcpr.kbs-lab.co.kr/file/JCPR\_vol.16\_2015/JCPR16-2/\_032014-099\_193-198.pdf
Your article is protected by copyright and all rights are held exclusively by ASM International. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to selfarchive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Journal of the Australian Ceramic Society
The effect of additions of Al 2 O 3 and CeO 2 (up to 1 wt %) on the sintering behavior of yttria-stabilized Tetragonal Zirconia Polycrystals (Y-TZP) were studied. The effects of Al 2 O 3 and CeO 2 on the Vickers hardness, bulk density, fracture toughness and Young's modulus were carried out on the sintered samples. The sintering temperature was ranging from 1250 °C to 1450 °C with the ramp rate of 10°C/min. The results revealed that the doped samples demonstrated a stronger effect in contrast with the undoped samples. The relative densities were above 97.5 % of theoretical (i.e. > 6.1 gcm-3) could be obtained in Y-TZPs sintered at low temperatures, 1350 °C. The hardness's value of Y-TZP was increased in the 1 wt % Al 2 O 3 and CeO 2-doped samples when sintered above 1400 °C.
2015
The aim of this study is to obtain yttria-stabilized zirconia ceramics with possible applications in dentistry. Firstly, it was obtained zirconia powders doped with different amounts of yttrium oxide (2 mol%, 2.5 mol% and 3 mol%), using the sol-gel method. After synthesis, the powders were dried at 100°C and then heat treated to 500°C for 3 hours. In order to obtain dense ceramics, powders were uniaxial pressed and then the compact green bodies were isostatically hotpressed for 1h and 2h, at temperatures between 1200°C-1300°C, under 150MPa, in argon atmosphere. After the sintering process, the phase composition and microstructure were determined through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Were also studied ceramic properties like apparent density and compressive strength. Scopul acestei lucrări este de a obţine ceramică zirconică cu posibile aplicaţii în stomatologie. În primul rând, s-au obţinut pulberile de zirconă dopată cu oxid de ytriu (2 mol%, 2.5 m...