Thermal Expansion Reduction in Alumina-Toughened Zirconia by Incorporation of Zirconium Tungstate and Aluminum Tungstate

2015 ◽  
Vol 98 (9) ◽  
pp. 2858-2865 ◽  
Author(s):  
Carl P. Romao ◽  
Bojan A. Marinkovic ◽  
Ulrike Werner-Zwanziger ◽  
Mary Anne White
Keyword(s):  
Thermal Expansion ◽  
Zirconium Tungstate ◽  
Aluminum Tungstate

Processing of Porous Zirconium Tungstate and Their Thermomechanical Properties

2014 ◽  
Author(s):  
Mingang Wang ◽  
Truong Do ◽  
Patrick Kwon
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Processing Technique ◽  
Thermomechanical Properties ◽  
Processing Route ◽  
Full Density ◽  
Ceramic Powders ◽  
Zirconium Tungstate ◽  
Spherical Graphite ◽  
New Processing

This paper explores a new processing method to fabricate porous zirconium tungstate (ZrW2O8 or ZT) with the porosity content up to 40% in volume. The method uses spherical graphite powders that are mechanically stable, allowing us to compact with ceramic powders in dry condition. Thus, the ceramic powders mixed with spherical graphite powders can be compacted and sintered to a near full density. During sintering, the graphite powders burn out without damaging the powder compact due to their inherent near-zero thermal expansion. The processing route discussed in this paper is applicable to all oxide ceramics where the sintering can take place in air and above 700°C to dissociate the graphite. In this paper, we have applied this processing technique to fabricate porous ZrW2O8. Many porous ZrW2O8 with a range of porosity levels were fabricated and tested for their theromomechanical properties including elastic modulus (E) and coefficient of thermal expansion (CTE). The experimentally determined properties were compared with the predictions based on the micromechanical Mori-Tanaka scheme.

High Temperature Stability of Zirconium Tungstate

2020 ◽  
Vol 993 ◽  
pp. 771-775
Author(s):  
Ping Zhai ◽  
Xiao Feng Duan ◽  
Da Qian Chen
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Solid Phase ◽  
Coefficient Of Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Tungstic Acid ◽  
High Temperature Stability ◽  
Zirconium Tungstate

In this paper, zirconium tungstate ceramic with negative thermal expansion coefficients was prepared from zirconium oxide and tungstic acid by solid phase synthesis and high temperature quenching technique with a sintering temperature of 1200 °C. The phase structure of the material was determined by X ray and the thermal expansion coefficient was measured by dilatometer, while the TG-DTA analysis of the prepared material was also carried out. The results showed that zirconium tungstate with high purity could be obtained by rapid chilled while fired at 1200 °C. The coefficient of thermal expansion at 300 °C was minus 8.5413 × 10-6K-1, which is identical with the theoretical value. The thermal expansion coefficient of the material was negative fired lower than 750 °C, while it was positive fired higher than 750 °C, and this indicates that the decomposition temperature of zirconium tungstate is about 750 °C.

Negative thermal expansion in a zirconium tungstate/epoxy composite at low temperatures

2013 ◽  
Vol 49 (1) ◽  
pp. 392-396 ◽  
Author(s):  
Lauren A. Neely ◽  
Vladimir Kochergin ◽  
Erich M. See ◽  
Hans D. Robinson
Keyword(s):  
Thermal Expansion ◽  
Low Temperatures ◽  
Epoxy Composite ◽  
Negative Thermal Expansion ◽  
Zirconium Tungstate

Zirconium tungstate reinforced cyanate ester composites with enhanced dimensional stability

2009 ◽  
Vol 24 (7) ◽  
pp. 2235-2242 ◽  
Author(s):  
Prashanth Badrinarayanan ◽  
Ben Mac Murray ◽  
Michael R. Kessler
Keyword(s):  
Thermal Expansion ◽  
Dimensional Stability ◽  
Coefficient Of Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Thermomechanical Analysis ◽  
Dynamic Mechanical Properties ◽  
Filler Loading ◽  
Cyanate Ester ◽  
Scanning Calorimetry ◽  
Zirconium Tungstate

Zirconium tungstate (ZrW2O8) is a unique ceramic material characterized by isotropic negative thermal expansion behavior over a wide temperature range. Incorporation of ZrW2O8 is expected to improve the dimensional stability of polymers by reducing the overall coefficient of thermal expansion (CTE). In this work, the thermal and dynamic mechanical properties of a bisphenol E cyanate ester reinforced with various loadings of ZrW2O8 are examined. Thermomechanical analysis indicates that the incorporation of ZrW2O8 results in a decrease in CTE at temperatures above and below the glass transition temperature (Tg) of the neat resin. The dynamic storage moduli of the composites reinforced with ZrW2O8 are found to increase with increasing filler loading. Furthermore, the various phase behaviors exhibited by ZrW2O8 are also examined by differential scanning calorimetry measurements.

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