scholarly journals Preparation of Al2TiO5 ceramic fibers and thermal expansion, insulation, and strength of ZrO2-Al2TiO5 fiberboards

2021 ◽  
Author(s):  
Wei Liu ◽  
Yongshuai Xie ◽  
Zhezhe Deng ◽  
Ying Peng ◽  
Jianhong Dong ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Thermal Shock ◽  
Thermal Insulation ◽  
Thermal Shock Resistance ◽  
Single Phase ◽  
Sol Gel ◽  
Ceramic Fibers ◽  
Thermal Expansion Coefficients ◽  
Shock Resistance

Abstract In the field of thermal insulation, Zirconia (ZrO2) fiber and its products have high thermal expansion coefficients and poor thermal shock resistance, which leads to great challenges in the industry. In this work, aluminum titanate (Al2TiO5) single-phase ceramic fibers were prepared by a sol-gel method, using polyacetylacetone titanium-aluminum (PAAT) as the precursors with electrospinning technology. The single-phase Al2TiO5 fibers exhibited excellent high-temperature resistance, and maintained fibers morphology at a high temperature of 1500 ºC. Next, ZrO2-Al2TiO5 (ZAT) fiberboards were prepared by mixing ZrO2 fibers and Al2TiO5 fibers. The mixture was heat-treated to 1500 ºC to prepare the ZAT fiberboards. Characterization results indicated that the contents of Al2TiO5 fibers have obvious effects on the performance of thermal insulation, strength, thermal expansion, and thermal shock resistance. Particularly, the thermal expansion coefficient of ZAT-8 fiberboards was about 20% lower than that of ZAT-0 fiberboards. These attractive characteristics might give ZAT fiberboards enormous potential in the field of high-temperature insulation.

Thermal Expansion Properties of Plasma-Sprayed Thick Coatings

1998 ◽  
Author(s):  
Y.-K. Lee ◽  
H.-J. Kim ◽  
R.-W. Chang
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Powder Size ◽  
Thermal Expansion Coefficients ◽  
Shock Resistance ◽  
Expansion Coefficients ◽  
Plasma Sprayed ◽  
Thick Coatings

Abstract The thermal expansion characteristics of plasmasprayed coatings were investigated. The thermal expansion measurements were carried out up to 1200°C on thick coatings that were substrate free. The effects on the thermal expansion coefficients were studied in terms of composition, powder size, porosity, and the phase transformation. The relationships between the thermal shock resistance and the thermal expansion properties of the coatings are also discussed.

Scaling Behavior of Superheater Tube Alloys in ASME High Temperature Steam Research Tests at 1100–1500 F

1962 ◽  
Vol 84 (3) ◽  
pp. 223-257 ◽  
Author(s):  
F. Eberle ◽  
C. H. Anderson
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Scaling Behavior ◽  
Effect Of Temperature ◽  
Relative Resistance ◽  
Superheater Tube ◽  
Shock Resistance ◽  
High Temperature Steam

The scales formed on seven ferritic and ten austenitic types of commercial tubing presently in use and of potential future use for superheater service were examined after 6, 12, and 18 months’ exposure to air and to flowing steam of 2000 psi at temperatures of 1100, 1200, 1350, and 1500 F. The effect of temperature and time of exposure on the adherence, thermal-shock resistance, thickness, structure, and chemical composition of the scales was investigated and the relative resistance to scaling of the various alloys evaluated.

Utilization of Fly Ash in the Synthesis of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 321 ◽  
pp. 131-140
Author(s):  
Martin Nguyen ◽  
Radomír Sokolař
Keyword(s):  
Thermal Expansion ◽  
Fly Ash ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Power Plants ◽  
Linear Thermal Expansion ◽  
Aluminium Oxide ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Shock Resistance

Forsterite refractory ceramics is utilized in the metallurgical and cement industries as a lining of metallurgical furnaces and rotary kilns for its high refractoriness up to 1850°C and refractoriness under load above 1600°C. Another significant property of forsterite is its coefficient of linear thermal expansion utilized in the electrotechnical industry for ceramic-metal joints. Addition of aluminium oxide into the raw material mixture results in creation of magnesium-alumina spinel (MgO·Al2O3) which improves sintering, thermal shock resistance and mechanical properties in comparison with pure forsterite ceramics. Inexpensive source of aluminium oxide is fly ash. Utilization of fly ash, secondary energetic product of coal-burning power plants, is important for the environment and sustainable development. This paper evaluated properties of fly ash-based forsterite-spinel ceramics in comparison with alumina-based forsterite-spinel ceramics. Forsterite-spinel ceramics was synthesized from olivine, calcined magnesite and fly ash/alumina powders. XRD analysis was used to determine mineralogical composition, thermal analyses were used to determine the behaviour during firing and scanning electron microscopy to determine the morphology of crystal phases. Refractoriness of pyrometric cones, refractoriness under load, thermal shock resistance, coefficient of linear thermal expansion, water absorption, porosity and modulus of rupture were also determined on fired test samples.

scholarly journals High Temperature Bending Strength and Thermal Shock Resistance of Carbon-Ceramics Composites

TANSO ◽  
1985 ◽  
Vol 1985 (120) ◽  
pp. 21-27 ◽  
Author(s):  
Kenji Miyazaki ◽  
Hisayoshi Yoshida ◽  
Kazuo Kobayashi
Keyword(s):  
High Temperature ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Bending Strength ◽  
Shock Resistance

Influence of Zircon Addition on Thermal Shock Resistance of ZTA for Plasma Reactors

2007 ◽  
Vol 544-545 ◽  
pp. 379-382
Author(s):  
Kyung Hun Jang ◽  
Bum Rae Cho
Keyword(s):  
Thermal Expansion ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Sintering Temperature ◽  
Plasma Reactors ◽  
Alumina Ceramics ◽  
Low Thermal Expansion ◽  
Resultant Data ◽  
Shock Resistance ◽  
Zirconia Toughened Alumina

The effect of CaO, MgO and SiO2 as a flux on the sinterability of zirconia toughened alumina(ZTA) used for plasma reactors was investigated and the effect of zircon addition on thermal shock resistance of ZTA with 15wt.% of ZrO2 was also investigated. The resultant data revealed that ZTA shows the best sinterability at the composition of 2wt.% of CaO, 4wt.% of MgO and 2wt.% of SiO2 and at the sintering temperature of 1350°C. Thermal shock resistance of ZTA containing zircon was improved significantly. It is shown that ZTA containing 10wt.% of zircon shows better thermal shock resistance than others. This fact can be explained due to the low thermal expansion coefficient of zircon. It was concluded that zircon is an effective material to improve thermal shock resistance of alumina ceramics.

Improvement on Thermal Shock Resistance of Ceramic Components by Using Self-Healing

2010 ◽  
Author(s):  
Wataru Nakao
Keyword(s):  
Thermal Stress ◽  
High Temperature ◽  
Thermal Shock ◽  
Stress Fracture ◽  
Thermal Shock Resistance ◽  
Self Healing ◽  
Quenching Rate ◽  
Ceramic Components ◽  
Shock Resistance ◽  
Quenching Method

Availability of self-healing on the thermal shock resistance of ceramic components was investigated. Using gas quenching method, the crack-healed alumina-18 vol% SiC composite, which has excellent self-healing ability, was applied to thermal shock of the arbitrary quenching rate. The procedure could give rise to the thermal stress fracture at high temperature. The critical quenching rate at thermal stress fracture of the healed specimen was found to be 6.47 K/s, corresponding to the thermal stress of 452.3 MPa. Alternatively, that of the cracked specimen was found to be 5.02 K/s, corresponding to the thermal stress of 350 MPa. From the obtained results, usage of self-healing was confirmed to improve extremely thermal shock resistance. The present result suggests that usage of self-healing gives a large advantage to design the high temperature ceramic components, because the mechanically reliable design and thermal shock resistance cannot coexist due to low thermal conductivity.

EFFECTS OF THERMAL ENVIRONMENTS ON THE THERMAL SHOCK RESISTANCE OF ULTRA-HIGH TEMPERATURE CERAMICS

2008 ◽  
Vol 22 (14) ◽  
pp. 1375-1380 ◽  
Author(s):  
WEIGUO LI ◽  
DAINING FANG
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Thermal Environment ◽  
Transfer Condition ◽  
Ultra High Temperature Ceramics ◽  
Thermal Environments ◽  
Shock Resistance ◽  
Ultra High Temperature

In the present study, the temperature-dependent thermal shock resistance parameter of Ultra-High Temperature Ceramics (UHTCs) was measured based on the current evaluation theories of thermal shock resistance parameters, since the material parameters of UHTCs are very sensitive to the changes of temperature. The influence of some important thermal environment parameters on the thermal shock resistance and critical temperature difference of rupture of UHTCs were studied. By establishing the relation between the temperature and the thermal or mechanical properties of the UHTCs, we found that thermal shock behavior of UHTCs is strongly affected by the surface heat transfer coefficient, heat transfer condition and initial temperature of the thermal shock.

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