Impact of high-speed sintering and choice of preshaded monochrome or multilayered blanks on fatigue behavior of 4 mol% yttria-stabilized tetragonal zirconia polycrystal

2021 ◽  
Author(s):  
Xenia Antón ◽  
Anja Liebermann ◽  
Rüdiger Hampe ◽  
Tim Joda ◽  
Bogna Stawarczyk
Keyword(s):  
High Speed ◽  
Fatigue Behavior ◽  
Tetragonal Zirconia ◽  
Tetragonal Zirconia Polycrystal

Analysis about Vibration and Noise of Ceramic Electrical Spindle

2011 ◽  
Vol 189-193 ◽  
pp. 1696-1699 ◽  
Author(s):  
Yu Hou Wu ◽  
Li Xiu Zhang
Keyword(s):  
High Speed ◽  
Tetragonal Zirconia ◽  
Major Elements ◽  
High Speed Machining ◽  
Ball Bearings ◽  
High Productivity ◽  
Spindle Shaft ◽  
Ferrous Metals ◽  
High Speed Grinding ◽  
Tetragonal Zirconia Polycrystal

High speed machining (HSM) technology is used in a broad range of applications to machine ferrous metals and nonmetallic material. The electrical spindle is one of the major elements to keep the machine running at high productivity. In recently years, the requirement of rotational speed and rigidity of electrical spindle is getting higher and higher in order to satisfy the high speed processing. So a high speed grinding electrical spindle equipped with hot isostatic pressed silicon nitride (HIPSN) fully-ceramic ball bearings without inner rings and yttria partially stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic spindle shaft is designed for higher speed and rigidity. Because the processing precision is relevant to the vibration of electrical spindle, it is necessary the vibration and noise of the ceramic electrical spindle is detected. This paper presents results of vibration and noise of the ceramic electrical spindle and analysis the reason of phenomenon. The analysis shows the vibration and noise of the ceramic electrical spindle is up to the standard.

Influence of CAD/CAM Grinding in the Performance of Sintered Dental Zirconia Framework

2012 ◽  
Vol 727-728 ◽  
pp. 1081-1084
Author(s):  
Carlos Nelson Elias ◽  
Andréa Mattos Melo ◽  
Claudinei dos Santos
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Surface Defects ◽  
Tetragonal Zirconia ◽  
Surface Cracks ◽  
Brittle Behavior ◽  
Dental Prostheses ◽  
Cad Cam ◽  
Ceramic Restorations ◽  
Tetragonal Zirconia Polycrystal

The brittle behavior of ceramics limits the use of these materials under conditions of cyclic loading, as is the case of fixed partial dentures. To improve toughness and biocompatibility of ceramics is necessary to employ powders with better purities, adjust the conditions of compaction and sintering, microstructure control and explore mechanisms for increasing the toughness. Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is generally used for dental ceramic restorations. The zirconia framework is fabricated using the CAD/CAM system. The ceramic mechanical properties are determined by testing polished sample. Previous work did not analyze the influence of surface defects induced during dentures grinding. Ceramic restorations manufacturing are made with coarse grinding high-speed diamond rotatory cutting instruments. This process induces residual stresses and the high temperature induces surface cracks. Consequently, a lower strength and reliability of the material is observed. In this work the mechanical properties of yttria stabilized zirconia were determined with the use of samples of dental prostheses molded in patients and machined with the use of a dental laboratory CAD/CAM system. The results showed that the mechanical properties of pre-sintered blocks are different from prosthetics machined by CAD/CAM and sintered under the same conditions used in the laboratories of the prosthesis. The defects created during machining reduce the mechanical properties of zirconia.

Parameter Optimization for Oil/Air Lubrication of High Speed Ceramic Motorized Spindle without Bearing Inner Rings

2010 ◽  
Vol 37-38 ◽  
pp. 839-843 ◽  
Author(s):  
Song Hua Li ◽  
Yu Hou Wu ◽  
Ke Zhang
Keyword(s):  
Temperature Increase ◽  
High Speed ◽  
Tetragonal Zirconia ◽  
Motorized Spindle ◽  
Operating Life ◽  
Spindle Shaft ◽  
Air Supply ◽  
Air Lubrication ◽  
Hybrid Ceramic ◽  
Tetragonal Zirconia Polycrystal

Recently, hybrid ceramic bearings and oil/air lubrication have been used more and more on high speed spindles. However, applying an appropriate lubrication and the hybrid bearings can’t be overemphasized, and the oil/air supply with inadequate parameters is undesirable. In this study, a high speed ceramic spindle equipped with HIPSN (Hot Isostatically Pressed Silicon Nitride) full-ceramic ball bearing and Y-TZP (Yttria partially stabilized Tetragonal Zirconia Polycrystal) ceramic spindle shaft was designed for higher speed, stiffness, precision and longer operating life. Furthermore, the performance of a high-speed ceramic motorized spindle under different lubrication parameters was investigated. The optimum lubrication conditions that create the smallest temperature increase were obtained by the applying of the Taguchi method. The results show that oil volume per lubrication cycle, interval time per lubrication cycle and air pressure are three pacing factors that affect the temperature increase most significantly in ceramic motorized spindle with oil/air lubrication.

Behavior of 3mol% yttria-stabilized tetragonal zirconia polycrystal film prepared by slurry spin coating

2009 ◽  
Vol 186 (1) ◽  
pp. 128-132 ◽  
Author(s):  
Kongfa Chen ◽  
Yanting Tian ◽  
Zhe Lü ◽  
Na Ai ◽  
Xiqiang Huang ◽  
...  
Keyword(s):  
Spin Coating ◽  
Tetragonal Zirconia ◽  
Tetragonal Zirconia Polycrystal

Role of secondary phase particles in fatigue behavior of high-speed railway gearbox material

2020 ◽  
Vol 131 ◽  
pp. 105336 ◽  
Author(s):  
Yinan Jiao ◽  
Yifan Zhang ◽  
Shiqing Ma ◽  
Deli Sang ◽  
Yang Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Fatigue Behavior ◽  
Secondary Phase ◽  
High Speed Railway

Transformation behavior of yttria stabilized tetragonal zirconia polycrystal–TiB2 composites

2001 ◽  
Vol 16 (7) ◽  
pp. 2158-2169 ◽  
Author(s):  
B. Basu ◽  
J. Vleugels ◽  
O. Van Der Biest
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Low Temperature ◽  
Tetragonal Zirconia ◽  
Mechanical Analysis ◽  
Transformation Behavior ◽  
Thermal Expansion Data ◽  
Thermally Induced ◽  
First Time ◽  
Tetragonal Zirconia Polycrystal

The objective of the present article is to study the influence of TiB2 addition on the transformation behavior of yttria stabilized tetragonal zirconia polycrystals (Y-TZP). A range of TZP(Y)–TiB2 composites with different zirconia starting powder grades and TiB2 phase contents (up to 50 vol%) were processed by the hot-pressing route. Thermal expansion data, as obtained by thermo-mechanical analysis were used to assess the ZrO2 phase transformation in the composites. The thermal expansion hysteresis of the transformable ceramics provides information concerning the transformation behavior in the temperature range of the martensitic transformation and the low-temperature degradation. Furthermore, the transformation behavior and susceptibility to low-temperature degradation during thermal cycling were characterized in terms of the overall amount and distribution of the yttria stabilizer, zirconia grain size, possible dissolution of TiB2 phase, and the amount of residual stress generated in the Y-TZP matrix due to the addition of titanium diboride particles. For the first time, it is demonstrated in the present work that the thermally induced phase transformation of tetragonal zirconia in the Y-TZP composites can be controlled by the intentional addition of the monoclinic zirconia particles into the 3Y-TZP matrix.

scholarly journals Effect of Al2O3 Sandblasting Particle Size on the Surface Topography and Residual Compressive Stresses of Three Different Dental Zirconia Grades

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 610
Author(s):  
Hee-Kyung Kim ◽  
Byungmin Ahn
Keyword(s):  
Particle Size ◽  
Residual Stresses ◽  
Surface Topography ◽  
Tetragonal Zirconia ◽  
Peak Shift ◽  
Confocal Laser ◽  
Compressive Stresses ◽  
Surface Topographies ◽  
Altered Surface ◽  
Tetragonal Zirconia Polycrystal

This study investigated the effect of sandblasting particle size on the surface topography and compressive stresses of conventional zirconia (3 mol% yttria-stabilized tetragonal zirconia polycrystal; 3Y-TZP) and two highly translucent zirconia (4 or 5 mol% partially stabilized zirconia; 4Y-PSZ or 5Y-PSZ). Plate-shaped zirconia specimens (14.0 × 14.0 × 1.0 mm3, n = 60 for each grade) were sandblasted using different Al2O3 sizes (25, 50, 90, 110, and 125 μm) under 0.2 MPa for 10 s/cm2 at a 10 mm distance and a 90° angle. The surface topography was characterized using a 3-D confocal laser microscopy and inspected with a scanning electron microscope. To assess residual stresses, the tetragonal peak shift at 147 cm−1 was traced using micro-Raman spectroscopy. Al2O3 sandblasting altered surface topographies (p < 0.05), although highly translucent zirconia showed more pronounced changes compared to conventional zirconia. 5Y-PSZ abraded with 110 μm sand showed the highest Sa value (0.76 ± 0.12 μm). Larger particle induced more compressive stresses for 3Y-TZP (p < 0.05), while only 25 μm sand induced residual stresses for 5Y-PSZ. Al2O3 sandblasting with 110 μm sand for 3Y-TZP, 90 μm sand for 4Y-PSZ, and 25 μm sand for 5Y-PSZ were considered as the recommended blasting conditions.

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