Effects of Monoclinic ZrO2 with Different Particle Size on Properties of Zirconia Refractories

2011 ◽  
Vol 335-336 ◽  
pp. 721-727
Author(s):  
Hong Gang Sun ◽  
Shuang Zhi Yan ◽  
Peng Tao Li ◽  
Qing Hua Tan ◽  
Ai Jun Wu
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Grain Boundaries ◽  
Bulk Density ◽  
Modulus Of Rupture ◽  
Monoclinic Zirconia ◽  
Stabilized Zirconia ◽  
Zirconia Powder ◽  
Partially Stabilized Zirconia ◽  
The Matrix

The zirconia refractories were prepared using partially stabilized zirconia grain and monoclinic zirconia powder as the matrix, partially stabilized zirconia particles as the aggregate, and phenolic resin as the binder, and four sizes of monoclinic zirconia powder (D50=1 μm, 3 μm, 6 μm, 10 μm) were used as additives. Besides, an improved specimen was prepared using a specific monoclinic zirconia powder as additive. Properties of specimens with different sizes of m-ZrO2powders were researched, including apparent porosity, bulk density, cold modulus of rupture, pore size distribution. Moreover, phase composition and microstructure were analyzed. The results show that, particle size of monoclinic zirconia powders greatly affect the sintering of materials. The specimens with finer m-ZrO2powder have lower porosity, higher bulk density and cold modulus of rupture, and the grain boundaries of zirconia particles were fuzzy, showing that the matrix of the specimens were almost sintered completely. While in specimens using coarser m-ZrO2powder, the grain boundaries of zirconia particles were clear, showing that the matrix of the specimens were not sintered completely.. Though finer monoclinic zirconia powder promoted the sintering of materials in the test, it had negative impact on the microporus structure, for large pores were observed in the specimen with fine m-ZrO2powder. Finally, the improved specimen with promoted sintering and optimized microstructure as well as phase composition was obtained by using specific monoclinic zirconia powder as additive.

Corrosion Resistance of Partially Stabilized Zirconia Materials to Alkaline Steel Slag

2020 ◽  
Vol 852 ◽  
pp. 119-128
Author(s):  
Liang Zhao ◽  
Qian Huang ◽  
Hua Yin Sun ◽  
Xiang Li
Keyword(s):  
Corrosion Resistance ◽  
Steel Slag ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Zirconia Powder ◽  
Slag Film ◽  
Partially Stabilized Zirconia ◽  
Stabilizing Agents ◽  
The Relationship

Partially stabilized zirconia (PSZ) materials were fabricated using 4 wt% CaO, 3 wt% MgO, and 5.4 wt% Y2O3 as stabilizing agents together with monoclinic zirconia powder. The physical properties, phase compositions, and microstructures of the Ca-PSZ, Mg-PSZ, and Y-PSZ samples were investigated by X-ray diffraction, scanning electron microscopy, and energy spectrum analysis. A crucible method was used to explore the relationship between the stabilizing agent and erosion resistance to alkaline steel slag. The results revealed that the zirconia materials stabilized by different stabilizing agents showed obvious differences in their bulk densities, apparent porosities, microstructures, and erosion resistances to alkaline steel slag. The structure of Y-PSZ showed highest density, containing a small number of uniformly distributed pores. In terms of Mg-PSZ, the intergranular bonding in its structure was observed to not be close, and the sample contained some cracks, but no pores. A large number of intragranular pores and a small number of overall pores was observed in Ca-PSZ, resulting in this material having the lowest bulk density. The pores and cracks provide the path to penetrate and diffuse for alkaline steel slag, which weakens the corrosion resistance of PSZ materials. The phase composition of the affected layers in all of the samples after corrosion was almost completely transformed from monoclinic phase to cubic phase, and the phase transition of both the original and transition layers was not obvious due to the formation of a slag film. Y-PSZ did not react with components of the steel slag such as SiO2 and Al2O3, showing the best corrosion resistance to alkaline steel slag.

Microwave Absorbency Change of Zirconia Powder and Fiber during Vacuum Heating

2010 ◽  
Vol 63 ◽  
pp. 85-90 ◽  
Author(s):  
Saburo Sano ◽  
Shoji Kawakami ◽  
Yasumasa Takao ◽  
Sadatsugu Takayama ◽  
Motoyasu Sato
Keyword(s):  
Microwave Absorption ◽  
Stoichiometric Composition ◽  
Wave Guide ◽  
Stabilized Zirconia ◽  
Zirconia Powder ◽  
Partially Stabilized Zirconia ◽  
Zro2 Powder ◽  
Zirconia Fiber ◽  
Vacuum Heating ◽  
Absorption Measurements

Stabilized zirconia shows rather high microwave absorbency at room temperature, and the absorbency become higher with increasing temperature. In this study, stabilized zirconia powder, partially stabilized zirconia powder and zirconia fiber were subjected for microwave absorption measurements at elevated temperature. Microwave absorption measurements were done by using a system consists of a microwave vector network analyzer, a circular wave-guide fixture and a vacuum furnace. Microwave absorbency was evaluated by the reflection power change from the sample in the circular wave-guide fixture under vacuum heating. Microwave absorbency of stabilized zirconia powder, partially stabilized zirconia powder and zirconia fiber gradually increased with the increase of temperature. We supposed that the increase of microwave absorbency is related to the ionic (oxygen) conduction behavior of stabilized zirconia. Stoichiometric composition ZrO2 powder was also subjected for a measurement to consider the relation between microwave absorbency and ion conduction of zirconia. As the result, stoichiometric composition ZrO2 powder was not absorbed microwave power even when the powder was heated up to 900oC because it isn’t an oxygen ion conductor.

Structure and phase composition studies of partially stabilized zirconia

2011 ◽  
Vol 5 (1) ◽  
pp. 166-171 ◽  
Author(s):  
M. A. Borik ◽  
V. T. Bublik ◽  
M. A. Vishnyakova ◽  
E. E. Lomonova ◽  
V. A. Myzina ◽  
...  
Keyword(s):  
Phase Composition ◽  
Composition Studies ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia

scholarly journals Improving the mechanical properties of zirconia in instrument bearings

2020 ◽  
Vol 329 ◽  
pp. 02023
Author(s):  
V. V. Alisin ◽  
B. A. Diethelm ◽  
A. V. Kulebyakin ◽  
V. A. Myzina ◽  
N. Yu. Tabachkova
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Crack Resistance ◽  
High Speed ◽  
Thrust Bearing ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
Bearing Materials ◽  
Rotor Bearings

The article presents the issues of replacing leucosapphires in jeweled bearings of the axes of precision instruments with nanostructured crystals of partially stabilized zirconia. The statement is substantiated that doping with rare earth elements provides an improvement in the performance properties of precision instruments by improving the mechanical properties of bearing materials. The efficiency of doping of zirconia crystals with cerium and neodymium oxides is studied. It was found that doped crystals have increased plasticity, which provides an increase in the crack resistance of crystals. Special attention is paid to the issues of increasing the survivability of high-speed rotor bearings by replacing the thrust bearing of leucosapphire with nanostructured crystals of partially stabilized zirconia doped with cerium and neodymium. The efficiency of improving the mechanical properties is confirmed by the X-ray phase analysis of crystals. The phase composition is studied by Raman scattering and the lattice parameters are determined. The increased crack resistance of the thrust bearing is confirmed by tests performed using the kinetic microhardness method.

Phase composition and spectral-luminescent properties of yttrium partially stabilized zirconia crystals doped with Nd2O3 and CeO2

2015 ◽  
Vol 118 (6) ◽  
pp. 918-923 ◽  
Author(s):  
M. A. Borik ◽  
T. V. Volkova ◽  
A. V. Kulebyakin ◽  
E. E. Lomonova ◽  
F. O. Milovich ◽  
...  
Keyword(s):  
Phase Composition ◽  
Luminescent Properties ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
Spectral Luminescent Properties

Thermal Shock Behavior of Calcia Stabilized Zirconia Ceramics with Porosity Gradient Structure

2009 ◽  
Vol 631-632 ◽  
pp. 435-440
Author(s):  
Qiang Shen ◽  
Chang Lian Chen ◽  
Fei Chen ◽  
Qi Wen Liu ◽  
Lian Meng Zhang
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Gradient Structure ◽  
Monoclinic Zirconia ◽  
Stabilized Zirconia ◽  
Zirconia Ceramics ◽  
The Matrix ◽  
Shock Resistance ◽  
Thermal Shock Behavior

Porous calcia stabilized zirconia ceramics (CSZC) with closed pores were presurelessly sintered by adding different contents of zirconia hollow balls. CSZC FGM with porosity gradient structure was then fabricated by laminating five layers with designed contents of zirconia hollow balls. The porosity, microstructure, and bending strength of the obtained CSZC samples were characterized. The results show that the hollow balls distribute uniformly and are well bonded with the matrix, and the porous structure is mainly composed of closed pores. The porosity of the CSZC increases linearly from 5.7 % to 31.6 % when the content of zirconia hollow balls increases from 0 % to 30 %, and the bending strength decreases rapidly from 297 MPa to 30 MPa. The thermal shock behavior of the CSZC and FGM was evaluated using air-quenching technique. It is shown that the residual bending strength of the quenched samples increases after several quenching cycles, and the samples are damaged by thermal shock after eight thermal cycles because of the production of monoclinic zirconia. FGM samples with porosity gradient structure can endure above twelve thermal shock cycles and exhibits better thermal shock resistance.

Microstructure and Phase Composition of Sputter-Deposited Zirconia-Yttria Films

1983 ◽  
Vol 30 ◽  
Author(s):  
R.W. Knoll ◽  
E.R. Bradley
Keyword(s):  
Phase Composition ◽  
Single Phase ◽  
Composition Range ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
Transmission Electron ◽  
Heat Treated ◽  
High Bias ◽  
Sputter Deposited

ABSTRACTThin ZrO2 -Y2 O3 coatings ranging in composition from 3 to 15 mole % Y2 O3 were produced by rf sputter deposition. This composition range spanned the region on the equilibrium ZrO2 -Y2O3 phase diagram corresponding to partially stabilized zirconia (a mixture of tetragonal ZrO2 and cubic solid solution). Microstructural characteristics and crystalline phase composition of as-deposited and heat treated films (1100°C and 1500°C) were determined by transmission electron microscopy (TEM) and by x-ray diffraction (XRD). Effects of substrate bias (0 ∼ 250 volts), which induced ion bombardment of the film during growth, were also studied. The as-deposited ZrO2-Y2O3 films were single phase over the composition range studied, and XRD data indicated considerable local atomic disorder in the lattice. Films produced at low bias contained intergranular voids, pronounced columnar growth, and porosity between columns. At high bias, the microstructure was denser, and films contained high compressive stress. After heat treatment, all deposits remained single phase, therefore a microstructure and precipitate distribution characteristic of toughened, partially stabilized zirconia appears to be difficult to achieve in vapor deposited zirconia coatings.

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