Effect of the Cooling Ways on the Properties and Microstructure of ZrO2/ZrW2O8 Ceramic Composites

2016 ◽  
Vol 697 ◽  
pp. 381-385 ◽  
Author(s):  
Jin Ping Li ◽  
Cheng Yang ◽  
Song He Meng ◽  
Fa Jun Yi ◽  
Yu Han Li
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Chemical Properties ◽  
Ceramic Composites ◽  
Cold Isostatic Pressing ◽  
Thermal Expansion Coefficients ◽  
Lower Thermal Expansion ◽  
Physical And Chemical

ZrO2 has been widely used due to its good physical and chemical properties and the ZrO2/ZrW2O8 ceramic composites with adjustable thermal expansion coefficient can be prepared by mixing and sintering the ZrO2 and ZrW2O8 powders. In this paper, the ZrO2/ZrW2O8 ceramic composites have been prepared by mixing, cold isostatic pressing and atmospheric sintering, and then being cooled in air or in water. We focus on the effect of the cooling ways on the properties and microstructure of the ZrO2/ZrW2O8 ceramic composites. The results show that the relative density of all samples is more than 98%. For the in-situ method, the density and flexural strength of the samples cooled in air and in water are 98.1% and 98.4%, 112.96MPa and 45.23MPa, respectively. The ZrW2O8 content and thermal expansion coefficient of the samples cooled in the air are less and higher than those in the water, respectively. For the direct mixture method, the density and flexural strength of the samples cooled in air and in water are 98.9% and 99.3%, 195.99MPa and 58.71MPa, respectively. For the four groups of the composite samples, they behave better mechanical properties after cooled in air, and lower thermal expansion coefficients after cooled in water.

scholarly journals Alternative of bone china and porcelain as ceramic hand molds for rubber latex glove films formation via dipping process

2020 ◽  
Vol 59 (1) ◽  
pp. 523-537
Author(s):  
Chaturaphat Tharasana ◽  
Aniruj Wongaunjai ◽  
Puwitoo Sornsanee ◽  
Vichasharn Jitprarop ◽  
Nuchnapa Tangboriboon
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Mold Surface ◽  
Rubber Latex ◽  
Latex Glove ◽  
Bone China ◽  
Synthetic Rubber ◽  
Natural And Synthetic

AbstractIn general, the main compositions of porcelain and bone china composed of 54-65%wt silica (SiO2), 23-34% wt alumina (Al2O3) and 0.2-0.7%wt calcium oxide (CaO) suitable for preparation high quality ceramic products such as soft-hard porcelain products for teeth and bones, bioceramics, IC substrate and magneto-optoelectroceramics. The quality of ceramic hand mold is depended on raw material and its properties (pH, ionic strength, solid-liquid surface tension, particle size distribution, specific surface area, porosity, density, microstructure, weight ratio between solid and water, drying time, and firing temperatures). The suitable firing conditions for porcelain and bone china hand-mold preparation were firing at 1270°C for 10 h which resulted in superior working molds for making latex films from natural and synthetic rubber. The obtained fired porcelain hand molds at 1270°C for 10 h provided good chemical durability (10%NaOH, 5%HCl and 10%wtNaCl), low thermal expansion coefficient (5.8570 × 10−6 (°C−1)), good compressive (179.40 MPa) and good flexural strength (86 MPa). While thermal expansion coefficient, compressive and flexural strength of obtained fired bone china hand molds are equal to 6.9230 × 10−6 (°C−1), 128.40 and 73.70 MPa, respectively, good acid-base-salt resistance, a smooth mold surface, and easy hand mold fabrication. Both obtained porcelain and bone china hand molds are a low production cost, making them suitable for natural and synthetic rubber latex glove formation.

Reduction in Wear Rate of α-Alumina and Silicon Nitride by Diffusional Surface Modification

1988 ◽  
Vol 140 ◽  
Author(s):  
A.K. Gangopadhyay ◽  
M.E. Fine ◽  
H.S. Cheng
Keyword(s):  
Wear Resistance ◽  
Thermal Expansion ◽  
Surface Modification ◽  
Silicon Nitride ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Surface Region ◽  
Lattice Parameter ◽  
Lower Thermal Expansion ◽  
Wear Modes

AbstractThe surface regions of α-alumina and hot pressed silicon nitride were modified by suitable alloying in order to improve their wear resistance. The surface modification in polycrystalline α-alumina was done by diffusing chromia into the surface region which resulted in the formation of a thin layer of A12O3 - Cr9O3 solid solution which has a lower thermal expansion coefficient than pure α-alumina. Also Cr2O3 has a larger lattice parameter than α-alumina thus during cooling the surface was put into compression. The surface region of hot pressed silicon nitride was modified by diffusing α-alumina into the surface which resulted in the formation of a thin sialon layer. A surface compressive stress was again introduced due to the lower thermal expansion coefficient and larger latticeparameter of sialon compared to silicon nitride.Wear tests were conducted against 52100 steel under both lubricated and unlubricated sliding contact using a block on ring apparatus. The wear resistance of chromia surface alloyed α-alumina was improved considerably over unalloyed α-alumina under both lubricated and unlubricated conditions. The wear resistance of alumina surface alloyed silicon nitride was also improved over unalloyed silicon nitride under both lubricated and unlubricated conditions.Different wear modes were identified by examining the worn surfaces under the scanning electron microscope.

Crystallization Behavior and Performance of MgO-Al2O3-SiO2 Glass-Ceramics by Sintering

2010 ◽  
Vol 92 ◽  
pp. 65-71 ◽  
Author(s):  
Pei Xin Zhang ◽  
Li Gao ◽  
Qiu Hua Yuan ◽  
Hai Lin Peng ◽  
Xiang Zhong Ren ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Crystallization Process ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Low Thermal Expansion ◽  
Main Crystalline Phase ◽  
And Performance

The glass-ceramics of MgO-Al2O3-SiO2 system were prepared by sintering technology. The crystallization process of MgO-Al2O3-SiO2 glass-ceramics was investigated with X-ray diffraction (XRD), scanning electron microscopy (SEM), and other techniques; the discussion of breaking strength, thermal expansion coefficient and relevant properties at different sintering temperatures was also presented. The results show that: (1) The main crystalline phase isα-cordierite at different sintering temperatures, and the samples show high flexural strength and low thermal expansion coefficient; (2) with the increase of sintering temperature, the content of crystal phase increases, while the thermal expansion coefficient decreases evidently, the flexural strength and tightness density rise up first, then go down.

Low-Melting Glass-Ceramic Composites with Low Linear Thermal Expansion Coefficient for Radio-Electronics

2015 ◽  
Vol 756 ◽  
pp. 313-318 ◽  
Author(s):  
Valeriy M. Pogrebenkov ◽  
Kirill S. Kostikov ◽  
E.A. Sudarev ◽  
A.V. Elistratova ◽  
Ksenia S. Kamyshnaya ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Glass Ceramic ◽  
Ceramic Composite ◽  
Linear Thermal Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
Ceramic Composites ◽  
Radio Electronics ◽  
Glass Ceramic Composite

Glass-ceramic composite materials based on lead-borate glass and eucryptite – a compound with a negative coefficient of linear thermal expansion (CTE), along with the conditions for their production are studied in this paper. Effects of the amount and granulometric composition of the eucryptite as well as time/temperature processing conditions on the change of the linear thermal expansion coefficient of the sintered samples are also examined.

Measurement of thermal expansion coefficient of substrate GGG and its epitaxial layer YIG

1999 ◽  
Vol 14 (1) ◽  
pp. 2-4 ◽  
Author(s):  
Rui-sheng Liang ◽  
Feng-chao Liu
Keyword(s):  
Thin Film ◽  
Thermal Expansion ◽  
Single Crystal ◽  
Thermal Expansion Coefficient ◽  
Epitaxial Layer ◽  
Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
New Method ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

A new method is used in measuring the linear thermal expansion coefficients in composite consisting of a substrate Gd3Ga2Ga3O12 (GGG) and its epitaxial layer Y3Fe2Fe3O12 (YIG) within the temperature range 13.88 °C–32.50 °C. The results show that the thermal expansion coefficient of GGG in composite is larger than that of the GGG in single crystal; the thermal expansion coefficient of thick film YIG is also larger than that of thin film. The results also show that the thermal expansion coefficient of a composite consisting of film and its substrate can be measured by using a new method.

scholarly journals Twisted Fibers Can Have an Adjustable Thermal Expansion

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 456
Author(s):  
Donghua Yue ◽  
Liming Wei
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Carbon Fibers ◽  
Expansion Coefficient ◽  
Twist Angle ◽  
Capacitive Sensor ◽  
Model Calculations ◽  
Thermal Expansion Coefficients ◽  
Geometrical Features ◽  
Expansion Coefficients

In this paper, a device with high accuracy capacitive sensor (with the error of 0.1 micrometer) is constructed to measure the axial thermal expansion coefficent of the twisted carbon fibers and yarns of Kevlar. A theoretical model based on the thermal elasticity and the geometrical features of the twisted structure is also presented to predict the axial expansion coefficient. It is found that the twist angle, diameter and pitch have remarkable influences on the axial thermal expansion coefficients of the twisted carbon fibers and Kevlar strands, and the calculated results are in good agreement with experimental data. We found that, with the increase of the twist angle, the absolute value of the axial thermal expansion coefficient increases. For the Kevlar samples, the expansion coefficient will grow by about 46% when the twist angle increases from 0 to 25 degrees, while the carbon fiber samples will grow by about 72% when the twist angle increases from 0 to 35 degrees. The experimental measurements and the model calculations reveal important properties of the thermal expansion in the twisted structures. Most notably, the expansion of the strand during heating or cooling can be zero when the twist angle is around β = arcsin(αL/αT)^1/2, where β denotes twist angle of the strand and αL, αT are the longitute and the transverse thermal expansion coefficient of the strand, respectively. According to the present experiments and analyses, a method to control the axial thermal expansion coefficient of this new kind of twisted structure is proposed. Moreover, the mechanism of this tunable thermal expansion is discussed. Based on the model, a method that can be used to rectify the thermal expansion properties of the twist structures is established. This may be a new way of fabricating zero expansion composite materials in the future.

Properties of ZrO2/Glass-Ceramics Composite

2007 ◽  
Vol 280-283 ◽  
pp. 995-998
Author(s):  
Y.M. Zhu ◽  
Xia Wan Wu ◽  
Zhi Hong Li
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Glass Powder ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Glass Ceramics ◽  
Glass Content ◽  
Thermal Expansion Coefficients ◽  
Lower Thermal Expansion ◽  
Expansion Coefficients

In order to reduce the raw materials cost, lower the sintering temperature of 3Y-TZP optical fiber ferrules, the 3Y-TZP/ LAS glass ceramics composites were prepared and their properties were investigated in this paper. The results showed that the sintering temperatures and thermal expansion coefficients of the 3Y-TZP/LAS glass ceramics composites were lowered with the increase of glass content. The flexural strength of the composites were decreased with the increase of glass content, but the flexural strength of the composite with 15% weight glass was higher than 400MPa. The LAS glass powder added into the composites was crystallized and b-spodumene s.s was precipitated. during sintering. The b-spodumene s.s. having lower thermal expansion coefficient and higher strength was beneficial to reduce thermal expansion coefficients and keep higher strengths of the composites .

Thermal expansion coefficients of a binary alloy Ni80Zr20 at elevated temperatures

1984 ◽  
Vol 17 (5) ◽  
pp. 359-360
Author(s):  
S. K. Shadangi ◽  
U. K. Shadangi ◽  
S. C. Panda
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Elevated Temperatures ◽  
Intermetallic Phase ◽  
Lattice Parameter ◽  
Solid Solution Phase ◽  
Linear Variation ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The Debye–Scherrer pattern of the alloy Ni80Zr20 clearly shows the presence of a nickel solid-solution phase along with a new intermetallic phase Ni23Zr6, which seems to be isostructural with the Co23Zr6 phase. The thermal expansion coefficient of the Ni23Zr6 phase has been investigated in the temperature range 1003–1493 K. Linear variation of lattice parameter with temperature has been observed. The thermal expansion coefficient remains almost constant throughout this temperature interval.

Fabrication and Characterization of Low Thermal Expansion Cordierite/Spodumene/Mullite Composite Ceramic for Cookware

2018 ◽  
Vol 766 ◽  
pp. 276-281
Author(s):  
Pranee Junlar ◽  
Thanakorn Wasanapiarnpong ◽  
Lada Punsukmtana ◽  
Noppasint Jiraborvornpongsa
Keyword(s):  
Thermal Expansion ◽  
Water Absorption ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
Slip Casting ◽  
Ceramic Composites ◽  
Modulus Of Rupture ◽  
Mullite Phase ◽  
Low Thermal Expansion

Ceramic cookware can be taken a direct flame or stove top for the duration without damage. The selected materials must have low thermal expansion coefficient, high strength, low water absorption and high thermal shock resistance, reasonable in cost and easy to be produced. Cordierite and spodumene composite has been interested for ceramic cookware due to their fitted properties. In previous work, study in the cordierite-spodumene composite with low thermal expansion coefficient of 2.60 x 10-6 /°C when sintered at 1250 oC with a ratio of spodumene 60 wt% and cordierite 40 wt% can withstand the pot shape samples. However, the sample showed relatively high water absorption and low strength which was not appropriate for using in this application. In this research, mullite is added in the formula to improve strength and densification of ceramic composites. Spodumene, ball clay, calcined talc and calcined alumina are used as starting raw materials and formed by slip casting. All samples are sintered in a temperature range from 1250-1275 °C in an electric furnace. Water absorption and bulk density were tested by Archimedes method, modulus of rupture was tested by the three-point bending method, microstructure were investigated by SEM and the coefficient of thermal expansion was measured by dilatometer. It was found that the mullite phase was investigated when adding mullite more than 30 wt% in cordierite-spodumene composite.

The Influence of Nanosized Leucite on Dental Porcelain Properties

2007 ◽  
Vol 280-283 ◽  
pp. 1605-1608 ◽  
Author(s):  
Jin Ping Yang ◽  
Jian Qing Wu ◽  
Ping Gen Rao ◽  
Chong Fei Xin ◽  
Dong Dan Chen
Keyword(s):  
Thermal Expansion ◽  
Flexural Strength ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Sol Gel ◽  
Micro Structure ◽  
Dental Porcelain ◽  
Gel Method ◽  
Sol Gel Method

The influence of leucite on dental porcelain properties is investigated in this paper. The nanosized leucite powder prepared by sol-gel method was added into a low-fusing temperature frit to fabricate dental porcelain fused to metal. The porcelains with different leucite contents were sintered at the temperatures ranging from 780° to 900°C. The flexural strength and the thermal expansion coefficient (TEC) of the dental porcelain containing leucite particles are evaluated. The micro- structure and phases of the porcelain are characterized and the mechanism that nanosized leucite particles strengthening the porcelain is discussed.

Sign in / Sign up

Export Citation Format

Share Document