Influence of Zirconia Content and Grain Size on Physical and Mechanical Properties of Zirconia Toughened Alumina Ceramics

2011 ◽  
Vol 143-144 ◽  
pp. 485-488 ◽  
Author(s):  
Bao Yu Du ◽  
Bo Zhao ◽  
Tie Lin Duan
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Physical And Mechanical Properties ◽  
Composite Ceramic ◽  
Alumina Ceramics ◽  
Alumina Matrix ◽  
Zirconia Toughened Alumina ◽  
Better Than ◽  
Zirconia Content

Physical and mechanical properties as well as microstructure of zirconia toughened alumina ceramics with different zirconia content were tested. The results show that the best physical and mechanical properties are obtained in sub-micron composite ceramic when zirconia content is 25%; while the physical and mechanical properties of nano-zirconia toughened alumina ceramics are far better than those of sub-micron zirconia toughened alumina ceramics. Therefore physical and mechanical properties of ceramics can be improved significantly by adding proper amount of zirconia into alumina matrix and refining zirconia particles.

Effect of TiO2 and MgO on Microstructure of α-Alumina Ceramics and its Sintering Behavior

2015 ◽  
Vol 1112 ◽  
pp. 519-523 ◽  
Author(s):  
Jarot Raharjo ◽  
Sri Rahayu ◽  
Tika Mustika ◽  
Masmui ◽  
Dwi Budiyanto
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Physical And Mechanical Properties ◽  
Basic Material ◽  
Sintering Behavior ◽  
Pressureless Sintering ◽  
Alumina Ceramics ◽  
Density Measurements ◽  
Technical Alumina ◽  
Platelet Structure

Observation on the effect of adding titanium oxide (TiO2) and magnesium oxide (MgO) on the sintering of α-alumina (Al2O3) has been performed. In this study, technical alumina used as basic material in which the sample is formed by the pressureless sintering/cold press and sintered at 1500°C which is lower than alumina sintering temperature at 1700°C. Elemental analysis, observation of microstructure, hardness, fracture toughness and density measurements were carried out to determine the physical and mechanical properties of alumina. The results indicate a change in the microstructure where the content of the platelet structure are much more than the equilateral structure. At sintering temperature of 1500°C, neck growth occurs at ceramics grain, supported by the results of the density test which indicate perfect compaction has occurred in this process.

Controlling Grain Size in Oxide Ceramics for Optimization of Strength and Wear Resistance

2012 ◽  
Vol 715-716 ◽  
pp. 703-710
Author(s):  
W.M. Rainforth ◽  
P. Zeng ◽  
L. Ma
Keyword(s):  
Grain Size ◽  
Sliding Wear ◽  
Second Phase ◽  
Alumina Ceramics ◽  
Size Dependent ◽  
Mild Wear ◽  
Accumulation Mechanism ◽  
Wear Transition ◽  
Magnitude Increase ◽  
Zirconia Toughened Alumina

t is well known that alumina ceramics undergo a time dependent wear transition during sliding wear. The transition, which is associated with 1-2 orders of magnitude increase in specific wear rate, involves a change from mild wear to intergranular fracture. The transition is strongly grain size dependent, with the time to the transition decreasing with grain size. However, there is a minimum grain size that can be achieved in fully dense alumina using commercially viable processing. Alternative strategies for reducing grain size and increasing toughness are through the addition of a fine second phase, with SiC and ZrO2being the most promising. The resultant composite not only has finer grain size, but also exhibits additional toughening mechanisms. This paper reports on the microstructural control in alumina, zirconia toughened alumina and alumina-silicon carbide composites. The grain size and residual stress distribution are related to the damage accumulation mechanism that occur during frictional contact, in particular the surface specific dislocation activity.

Tribological Behaviour of Alumina Ceramics with Nano TiO2 as a sintering aid in Non-Conformal Contact

2021 ◽  
pp. 1-21
Author(s):  
Partha Haldar ◽  
Tapas Kumar Bhattacharya ◽  
Nipu Modak
Keyword(s):  
Mechanical Properties ◽  
Secondary Phase ◽  
Alumina Ceramics ◽  
Alumina Matrix ◽  
Tribological Behaviour ◽  
Nano Tio2 ◽  
Sintering Aid ◽  
Tio2 Addition ◽  
Sintering Behaviour ◽  
Hexagonal Columnar

Abstract The study emphasized the sintering behaviour and tribo-mechanical properties of alumina ceramics by nano TiO2 addition as a sintering aid. With increase in sintering temperature, the bulk density of alumina has increased gradually and optimized at 1600°C. The optimizing effect of densification at 1600°C is 98.25% by the addition of 1 wt.% nano TiO2. The maximum solid solubility of titania in alumina grains was at 1600°C, causes optimisation of densification by 1 wt. % addition. The excess addition of TiO2 formed low dense Al2TiO5, appear as a secondary phase at grain boundaries and does not significantly improved densification. Fracture toughness increases and coefficient of friction decreases with the addition of nano TiO2 in alumina matrix. The 1wt.% nano TiO2 addition improved hardness to 8.82% and reduces specific wear rate to 45.56%. The 1wt.% nano TiO2 addition greatly influenced the microstructure of sintered Al2O3. The morphology was sharply changed from hexagonal columnar shape to order sub round orientation which also directly impact the tribo-mechanical properties of sintered alumina. The 1wt.% addition substantially decreases wear track depth as observed by 3D surface profilometer. Microscopic observation of the worn-out surface showed that wearing is majorly caused by plastic deformation and abrasion.

scholarly journals Comparison of physical and mechanical properties of mining waste with a grain size up to 2 mm reinforced with cement CEM I and CEM III

2019 ◽  
Vol 106 ◽  
pp. 01023
Author(s):  
Justyna Morman-Wątor
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Fine Particles ◽  
Physical And Mechanical Properties ◽  
Mining Waste ◽  
Soil Testing ◽  
Mechanical Parameters ◽  
Freeze Resistance

The article presents the results of tests for mining waste mixtures - cement. The addition of cement was aimed at limiting the leaching of fine particles and improving physical and mechanical parameters. The studies used cement CEM I 42.5 R and CEM III/ A 42.5N - LH / HSR / NA and plasticizing sealant. The paper presents the results of freeze resistance, swelling tests, pH of water leachate and oedometer soil testing.

scholarly journals Effect of Organic Material Type and Proportion on the Physical and Mechanical Properties of Vegetation-Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Daxiang Liu ◽  
Baohua Zhang ◽  
Yueshu Yang ◽  
Wennian Xu ◽  
Yu Ding ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Organic Material ◽  
Physical And Mechanical Properties ◽  
Remarkable Effect ◽  
Material Type ◽  
Distillers Grain ◽  
Main Components ◽  
Corn Distillers ◽  
Protection Engineering

Vegetation-concrete is one of the most widely used substrates in ecological slope protection engineering. The porosity of the vegetation-concrete must be high enough to satisfy the growth needs of the plant roots, while the mechanical properties must be strong enough to satisfy the self-stability requirement of the substrates on the slope. It is necessary to balance these two aspects in the design of vegetation-concrete. As one of the main components in vegetation-concrete, organic material has a remarkable effect on both the porosity and the mechanical properties of the substrate. In this paper, four types of common organic materials (rice husks, sawdust, and corn distillers’ and unhulled rice distillers’ grain) are chosen to research the effect of the organic material type and proportion on the porosity and mechanical properties of the substrate. The experimental results show that the porosity of samples containing corn distillers’ grain is clearly higher than those of the other samples types, while situation of the mechanical properties is the opposite. It can be concluded that organic material with a large grain size is not suitable for use in vegetation-concrete directly and needs to be crushed before use to prevent crack formation. The research results also show that the rates of increase in porosity decrease with more organic material added, while the rates of decrease in the unconfined compressive strength and the elasticity modulus increase. From a comprehensive consideration of the required mechanical properties and plant growth, organic material with a small grain size is most suitable for use in vegetation-concrete, and the suitable proportion is between 7% and 9%.

Study on Characteristics of Outlast Acrylic Fiber

2012 ◽  
Vol 627 ◽  
pp. 85-89 ◽  
Author(s):  
Hai Xia Zhang ◽  
Xi Chang Zhang
Keyword(s):  
Mechanical Properties ◽  
Phase Change ◽  
Physical And Mechanical Properties ◽  
Decomposition Temperature ◽  
X Ray Diffraction ◽  
Acrylic Fiber ◽  
Change Temperature ◽  
And Performance ◽  
Cooling Velocity ◽  
Better Than

To analyze the structure and performance of Outlast acrylic fiber, the fiber structure was observed respectively by FTIR spectra, X-ray diffraction and scanning electron microscope, the normal physical and mechanical properties were measured, and the thermo-regulated performance was investigated by differential scanning calorimeter, thermal gravimeter analysis and step cooling test. The results indicate that the structure and normal physical and mechanical properties of Outlast acrylic fiber are slightly different from that of normal acrylic fiber. Both the melting peak and crystallization peak of Outlast acrylic fiber are single peaks, and the phase change temperature range is applicable and the phase change enthalpy is high. The decomposition temperature of Outlast acrylic fiber is around 311.85°C. The cooling velocity of Outlast acrylic fiber decreases exponentially with the increase in time, and the thermo-regulated ability of Outlast acrylic fiber is better than that of normal acrylic fiber.

Physical and Mechanical Properties of Mo5X3+α (X=Si, B, C) Single Crystals

2002 ◽  
Vol 753 ◽  
Author(s):  
Taisuke Hayashi ◽  
Kazuhiro Ito ◽  
Katsushi Tanaka ◽  
Masaharu Yamaguchi
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Single Crystals ◽  
Plastic Anisotropy ◽  
Physical And Mechanical Properties ◽  
Structure Type ◽  
Advanced Materials ◽  
Anisotropy Ratio ◽  
Higher Temperature ◽  
Better Than

ABSTRACTMo5X3+α (X=Si, B, C) intermetallic compounds such as Mo5SiB2 (D8l), Mo5Si3 (D8m) and Mo5Si3C (D88) have a great potential for ultra-high temperature applications. The present study was undertaken putting greater emphasis on clarifying how their physical and mechanical properties are similar or different in terms of a structure type. Some interesting features are summarized in this paper.The resistivity of Mo5SiB2, Mo5Si3 and Mo5Si3C single crystals exhibited a negative curvature (d2ρ(T)/dT2<0), with a tendency towards saturation. In the Mo5Si3C with large ρ0 due to impurity carbon atoms, resistivity saturation is pronounced. In contrast, a much higher temperature is required to reach saturation in the Mo5SiB2. The anisotropy ratio of CTE (αc/αa) for the Mo5SiB2 is about 1.2–1.6 and is significantly reduced from about 2 of the Mo5Si3 and Mo5Si3C. On the other hand, the Young's modulus of the Mo5SiB2 is more anisotropic than those of the Mo5Si3 and Mo5Si3C. Plastic anisotropy was observed in the Mo5SiB2, because only slip on [001] {100} is operative at 1500°C. On the contrary, plastic deformation was observed at temperatures above 1300°C for the Mo5Si3C and Mo5Si3. Anisotropy of their plastic deformation was much less than that of the Mo5SiB2, presumably because more than two slip systems can be activated. Creep resistance of the Mo5SiB2 is much better than that of the Mo5Si3 as well as the most advanced materials such as MoSi2 and Si3N4 based structural ceramics.

Sintering and Mechanical Properties of Alumina Ceramics Prepared by Nanosize Alumina

2007 ◽  
Vol 544-545 ◽  
pp. 821-824
Author(s):  
Indra ◽  
S.W. Oh ◽  
Hee Joon Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Relative Density ◽  
Mechanical Characteristics ◽  
Indentation Test ◽  
Test System ◽  
Alumina Ceramics ◽  
New Materials ◽  
Size Dependent

This work examined the mechanical properties of alumina that can directly be enhanced by ratio of nano sized alumina powders additives to micro size alumina powders (n/m ratio). These new materials have mechanical properties that are strongly grain size dependent and often significantly different from those of their coarser grained counter parts. The mechanical characteristics of samples were observed by using the indentation test system. This data shows that the relative density for the sample is increased with increasing Meyer hardness.

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