scholarly journals Influence of Manufacturing Regimes on the Phase Transformation of Dental Zirconia

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4980
Author(s):  
Markus Wertz ◽  
Hieronymus Hoelzig ◽  
Gert Kloess ◽  
Sebastian Hahnel ◽  
Andreas Koenig
Keyword(s):  
Phase Transformation ◽  
Phase Composition ◽  
Low Temperature ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Dental Prostheses ◽  
Alumina Particles ◽  
History Of ◽  
Fixed Dental Prostheses

Background: The influence of typical manufacturing regimes for producing fixed dental prostheses (FDPs) from yttria partly-stabilized zirconia polycrystals (3Y/4Y/5Y-TZP) on the phase composition is quantified. Methods: Fixed dental prostheses (FDPs) were designed using a CAD process and machined from different Y-TZP blanks from two manufacturers differing in yttria contents. Subsequent to sintering, the FDPs were glaze fired and air-blasted using alumina particles. Phase composition was determined with X-ray diffraction and quantified with Rietveld refinement. Results: The blanks from VITA Zahnfabrik (VITA YZ HT, VITA YZ ST, VITA YZ XT) and Dental Direct (DD Bio ZX2, DD cube ONE, DD cube X2) featured a rhombohedral portion with rather small crystallites and a small monoclinic portion for 3Y/4Y-TZPs, which increased after machining and disappeared after sintering. Glaze firing and air-blasting with alumina particles had no significant influence on the phase composition. Conclusion: The phase history of dental zirconia is revealed, which may have implications on further processing and aging of the FDP (e.g. low temperature degradation) in mouth.

Displacive Phase Transformation in Vanadium - Substituted Lanthanum Niobate

1983 ◽  
Vol 24 ◽  
Author(s):  
A. T. Aldred ◽  
S.-K. Chan ◽  
M. H. Grimsditch ◽  
M. V. Nevitt
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Low Temperature ◽  
Raman Scattering ◽  
Transformation Temperature ◽  
Complex Oxides ◽  
Temperature Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order

ABSTRACTThe displacive transformations in complex oxides of the type LaNb1-xVxO4 has been studied by x-ray diffraction and Raman scattering for 0 < x < 0.3. X-ray diffraction results indicate that the transformation from the tetragonal high temperature structure (C4h6) to the monoclinic low-temperature structure (C2h6) is higher than first order and that the transformation temperature Tc is depressed significantly by V substitution. Raman scattering results show that the force constant between the nearest (Nb, V)O4 tetrahedral units behave uniquely compared to others. It softens at Tc as a function of composition and it also softens as a function of temperature as Tc is approached from above.

Texture on Ground, Fractured, and Aged Y-TZP Surfaces

1986 ◽  
Vol 78 ◽  
Author(s):  
Franz Reidinger ◽  
Philip J. Whalen
Keyword(s):  
Phase Composition ◽  
Transition Temperature ◽  
Diffraction Analysis ◽  
Surface Treatment ◽  
Tetragonal Phase ◽  
Surface Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
History Of

ABSTRACTThe phase composition of Y-TZP surfaces has been shown to vary greatly depending on the thermo-mechanical history of the surface. The orientation of these different phases in the surface region is not always random. There is speculation that the alignment of the tetragonal phase before fracturing may play a part in increasing the toughness of these materials. This article deals with an X-ray diffraction analysis of various Y-TZP surfaces with special emphasis on the texture of the different phases. Surfaces which have been ground (and polished), fractured, and aged (200°C) have been examined. In all cases, the monoclinic component that was formed was strongly oriented. The tetragonal phase may or may not be oriented depending on surface treatment. Annealing above the monoclinic-tetragonal transition temperature had little effect on the tetragonal orientation in most cases. Samples fractured at 1000°C have no unusual orientation on the fracture faces.

X-Ray Diffraction and Electric Measurements of Phase Transformation in Li-Mn Spinels

2007 ◽  
Vol 130 ◽  
pp. 63-68
Author(s):  
J. Pielaszek ◽  
J.R. Dygas ◽  
F. Krok ◽  
D. Lisovytskiy ◽  
Monika Kopeć ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Composition ◽  
Impedance Spectroscopy ◽  
Electric Conductivity ◽  
Weight Percent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Set Up ◽  
Additional Phase

Laboratory prepared and commercial Li-Mn spinels were studied. Making use of the dedicated XRD-impedance spectroscopy experimental set-up, direct correlations of the degree of phase transformation (expressed as change of the FWHM of the selected reflection) with electric conductivity was found. Independent XRD measurements and full pattern fitting allowed quantitative estimations of the phase composition of the spinels. It was found that commercial spinels were in fact multiphase, with the content of the additional phase of few weight percent.

Charles S. Barrett: X-Ray Metallurgist — An Informal Portrait

1987 ◽  
Vol 2 (3) ◽  
pp. 163-175
Author(s):  
R. N. Rose
Keyword(s):  
Physical Chemistry ◽  
Phase Transformation ◽  
Low Temperature ◽  
First Principles ◽  
Atomic Level ◽  
X Ray Diffraction ◽  
Wide Audience ◽  
X Ray

Charles Barrett's work in phase transformation at the atomic level helped redefine the underpinnings of the science and practice of metallurgy. His work in low temperature physical chemistry has extended its range. And, perhaps more than anyone else, as a teacher and author, he has helped introduce the technique of X-ray diffraction to the present generations of practicing metallurgists.The relevance of his contributions is demonstrated by the continuing utility of his widely translated metallurgical text, Structure of Metals, which, when it first appeared, made the understanding of metallurgy at the atomic level accessible to a wide audience. Today this book has become a compendium of first principles.

NANO-VANADIUM DOPING-DRIVEN LOW TEMPERATURE STRUCTURAL PHASE TRANSFORMATION IN TITANIA

2009 ◽  
Vol 23 (29) ◽  
pp. 3543-3549
Author(s):  
ANUJ KUMAR ◽  
BHASKER GAHTORI ◽  
NEERAJ KUMAR ◽  
V. P. S. AWANA ◽  
A. K. SRIVASTAVA ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Low Temperature ◽  
Structural Phase ◽  
Rutile Phase ◽  
Vanadium Content ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Vanadium Doping

Synthesis, X-ray diffraction (XRD), morphological, and magnetization studies of nano-vanadium doped TiO 2 are reported here. Commercially available anatase nano- TiO 2 and nano-vanadium powders were mixed and heat-treated in air at 600°C. X-ray diffraction revealed a complete anatase to rutile phase transformation at low vanadium content of 5%. Samples annealed under different environments such as Ar and O 2 also exhibited the same trend. Such a phase transformation at relatively low temperature (600°C) has been explained based on enhanced reactivity between vanadium and TiO 2 powders. Scanning electron micrographs elucidated the tunable microstructures from irregular-shaped, in the pristine TiO 2 (x=0.0), to well-faceted polyhedra V-doped (x=0.05 to 0.15) samples. Room temperature magnetization results revealed that upto 10% vanadium doping the samples are diamagnetic in nature and exhibit a paramagnetic transition for higher V content which presumably can be attributed to the presence of vanadium pentaoxide observed in the XRD.

Microstructure and Phase Composition of (Ce, Mg)-PSZ Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1194-1196
Author(s):  
Zhi Ping Shen ◽  
Shu Cai ◽  
Zhen Dong
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Monoclinic Phase ◽  
Processing Method ◽  
Nanoporous Structure ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
Heat Treated

Magnesia, ceria partially stabilized zirconia (Ce,Mg)-PSZ ceramics with net shape microstructure are prepared using a processing method similar to that of conventional Mg-PSZ ceramics, then heat-treated at 1500°C for different time. Microstructure and phase composition of (Ce, Mg)-PSZ samples with different amount of CeO2 doped were investigated using SEM and X-ray diffraction. The addition of CeO2 could impede the formation of monoclinic phase and inhibit the growth of cubic grains. A microstructure with net-shape cubic grains, in which tetragonal precipitates interweave to a nanoporous structure is obtained by adding 4∼8 mol% CeO2 in 10mol% MgO doped zirconia matrix and then heat treatment at 1500°C for different time. The precipitate morophology might be related with the addition of CeO2 and the heat treatment temperatures.

A Study of Rhombohedral Phase in Y2 O3 -Partially Stabilized Zirconia

1986 ◽  
Vol 78 ◽  
Author(s):  
Jukishige Kitano ◽  
Y. Mori ◽  
A. Ishitani ◽  
T. Masaki
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Hot Isostatic Pressing ◽  
Tetragonal Zirconia ◽  
Rhombohedral Phase ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
The Stability

ABSTRACTTetragonal to rhombohedral phase transformation was studied by X-ray diffraction technique on the ground surfaces of tetragonal zirconia polycrystals (Y-TZP) and partially stabilized zirconia (Y-PSZ) with 2.0 to 5.0 mol% Y2 O3 contents prepared by hot isostatic pressing. The rhombohedral phase increased with increase of Y2 O3 content from 2.0 to 5.0 mol%, and also with the increase of HIPing temperature from 1400 to 1600°C. The stability of the phase was also studied with regard to the surface finish and annealing. The subsequent heat treatment of the samples was found to promote the reverse rhombohedral to tetragonal transformation.

Sign in / Sign up

Export Citation Format

Share Document