Manufacturing parameters influencing fire resistance of geopolymers: A review

2016 ◽  
Vol 233 (4) ◽  
pp. 721-733
Author(s):  
Ikmal Hakem Aziz ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Heah Cheng Yong ◽  
Liew Yun Ming ◽  
Kamarudin Hussin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
High Temperature ◽  
Thermal Behavior ◽  
High Temperatures ◽  
Fire Resistance ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Technological Parameters ◽  
Manufacturing Parameters

Geopolymers exhibit various unique properties and characteristics, including high compressive strength, high temperature stability, and low thermal conductivity. As a relatively new and perspective material, the behavior of geopolymers subjected to high temperatures is being intensively studied nowadays. This review summarizes the recent achievements in the development of geopolymer-based fire resistance materials. Technological parameters, which influence thermal behavior of geopolymer-based materials, are also discussed. Besides that, recent applications of geopolymers according to their composition are presented.

La2O3 Doped Y2O3 Stabilized ZrO2 TBC Prepared by EB-PVD

2006 ◽  
Vol 317-318 ◽  
pp. 501-504 ◽  
Author(s):  
Mineaki Matsumoto ◽  
Norio Yamaguchi ◽  
Hideaki Matsubara
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
High Resistance ◽  
Thermal Transport ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Microstructural Observation ◽  
Low Thermal Conductivity ◽  
Ysz Coating

Effect of La2O3 addition on thermal conductivity and high temperature stability of YSZ coating produced by EB-PVD was investigated. La2O3 was selected as an additive because it had a significant effect on suppressing densification of YSZ. The developed coating showed extremely low thermal conductivity as well as high resistance to sintering. Microstructural observation revealed that the coating had fine feather-like subcolumns and nanopores, which contributed to limit thermal transport. These nanostructures were thought to be formed by suppressing densification during deposition.

scholarly journals Thermal Conductivity and Sintering Behavior of Sm2Zr2O7 Ceramics with Y3+ Substitution for Different Lattices

2021 ◽  
Author(s):  
Zhaolu Xue ◽  
Xin Wang ◽  
Mengchuan Shi ◽  
Haiyuan Yu ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Solid Phase ◽  
Temperature Stability ◽  
Crystal Phase ◽  
Sintering Behavior ◽  
Thermal Barrier ◽  
High Temperature Stability ◽  
Promising Candidate ◽  
Sintering Method

Abstract Sm2Zr2O7 is one of the most promising candidate materials for ultra-high temperature thermal barrier coatings. In this paper, a series of (Sm1-x1Yx1)2(Zr1-x2Yx2)2O7-x2 ceramics with different lattice sites replaced by Y3+ ions were successfully prepared by the high-temperature solid-phase sintering method. The effect of Y3+ doping on microstructure, phase composition, thermal conductivity and sintering behavior of modified Sm2Zr2O7 ceramics were investigated, respectively. The results showed that (Sm1-x1Yx1)2(Zr1-x2Yx2)2O7-x2 were composed of a single pyrochlore crystal phase within 20% Y3+ ions doping concentration. Compared with pure Sm2Zr2O7, the fracture toughness of each (Sm1-x1Yx1)2(Zr1-x2Yx2)2O7-x2 ceramic was significantly reduced. In terms of reducing the thermal conductivity of Sm2Zr2O7, the substitution of Y3+ ion for Zr4+ was more obvious than the substitution of Y3+ for Sm3+. Thermal conductivity of Sm2(Zr0.9Y0.1)2O6.9 was 1.315 W·m-1·K-1 at 1200 °C, which was the lowest among the studied ceramics.. Sm2(Zr0.9Y0.1)2O6.9 ceramic exhibited a lower grain growth rate at 1400 °C, and still remained a single pyrochlore crystal phase after sintering for 100 h, indicating that Sm2(Zr0.9Y0.1)2O6.9 had good high-temperature stability at 1400 °C.

scholarly journals In Situ Hyperspectral Raman Imaging of Ternesite Formation and Decomposition at High Temperatures

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 287 ◽  
Author(s):  
Nadine Böhme ◽  
Kerstin Hauke ◽  
Manuela Neuroth ◽  
Thorsten Geisler
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Temperature Stability ◽  
Dicalcium Silicate ◽  
Raman Imaging ◽  
Cement Industry ◽  
Solid State Reactions ◽  
High Temperature Stability ◽  
The One

Knowledge of the high-temperature properties of ternesite (Ca5(SiO4)2SO4) is becoming increasingly interesting for industry in different ways. On the one hand, the high-temperature product has recently been observed to have cementitious properties. Therefore, its formation and hydration characteristics have become an important field of research in the cement industry. On the other hand, it forms as sinter deposits in industrial kilns, where it can create serious problems during kiln operation. Here, we present two highlights of in situ Raman spectroscopic experiments that were designed to study the high-temperature stability of ternesite. First, the spectra of a natural ternesite crystal were recorded from 25 to 1230 °C, which revealed a phase transformation of ternesite to the high-temperature polymorph of dicalcium silicate (α’L-Ca2SiO4), while the sulfur is degassed. With a heating rate of 10 °C/h, the transformation started at about 730 °C and was completed at 1120 °C. Using in situ hyperspectral Raman imaging with a micrometer-scale spatial resolution, we were able to monitor the solid-state reactions and, in particular, the formation properties of ternesite in the model system CaO-SiO2-CaSO4. In these multi-phase experiments, ternesite was found to be stable between 930 to 1020–1100 °C. Both ternesite and α’L-Ca2SiO4 were found to co-exist at high temperatures. Furthermore, the results of the experiments indicate that whether or not ternesite or dicalcium silicate crystallizes during quenching to room temperature depends on the reaction progress and possibly on the gas fugacity and composition in the furnace.

Electronic and Ionic Transport Mechanisms of Stoichiometric Lithium Niobate at High-Temperatures

2013 ◽  
Vol 1519 ◽  
Author(s):  
Anke Weidenfelder ◽  
Michal Schulz ◽  
Peter Fielitz ◽  
Jianmin Shi ◽  
Günter Borchardt ◽  
...  
Keyword(s):  
High Temperature ◽  
Lithium Niobate ◽  
High Temperatures ◽  
Temperature Stability ◽  
Ambient Air ◽  
Lithium Content ◽  
High Temperature Stability ◽  
Electromechanical Properties ◽  
Protective Layers ◽  
Total Electrical Conductivity

ABSTRACTThe electrical and electromechanical properties of lithium niobate single crystals are investigated at high-temperatures. The total electrical conductivity is determined as a function of temperature by impedance spectroscopy for Z-cut crystals with different lithium content. For stoichiometric lithium niobate (sLN) the activation energy is found to be (1.49 ± 0.03) eV in the temperature range from 500 to 900 °C.Further, the piezoelectric properties (resonance frequency, Q-factor) of X-cut lithium niobate crystals are determined at high temperatures for samples with compositions ranging from congruent to stoichiometric and, subsequently, compared to the conductivity data in order to identify loss contributions.In this context, the high-temperature stability is examined for X- and Z-cut samples with compositions ranging from congruent to stoichiometric. Series of samples with and without additional alumina protection layers are annealed in air at 900 °C for approximately 50 h. Subsequently, depth profiles are measured by SNMS. In all cases, no lithium loss is observed and, therefore, a high-temperature stability of sLN for at least 50 h at 900 °C can be assumed in ambient air.Further, the influence of protective layers with different thicknesses and compositions is investigated for X- and Z-cut samples. A lithium loss in the first 300 nm is observed for the Z-cut samples, while the X-cut samples show a behavior dependent on the type of protecting layer.

UNS N06455

Alloy Digest ◽  
1989 ◽  
Vol 38 (1) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Stress Corrosion Cracking ◽  
Temperature Stability ◽  
Heat Treating ◽  
High Ductility ◽  
High Temperature Stability ◽  
Nickel Chromium ◽  
Long Time ◽  
Resistance To Stress

Abstract UNS NO6455 is a nickel-chromium-molybdenum alloy with outstanding high-temperature stability as shown by high ductility and corrosion resistance even after long-time aging in the range 1200-1900 F. The alloy also has excellent resistance to stress-corrosion cracking and to oxidizing atmospheres up to 1900 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-367. Producer or source: Nickel and nickel alloy producers.

KENTANIUM K138A

Alloy Digest ◽  
1964 ◽  
Vol 13 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
High Temperature ◽  
Titanium Carbide ◽  
Physical Properties ◽  
Engineering Design ◽  
High Temperatures

Abstract Kentanium K138-A is a high temperature titanium carbide that greatly widens the scope of the engineering design where conditions of intermittent or continuous high temperatures in oxidizing atmospheres are combined with abrasion, and compressive or tensile loads. This datasheet provides information on composition, physical properties, hardness, elasticity, and compressive strength as well as fracture toughness, creep, and fatigue. It also includes information on machining and joining. Filing Code: Ti-40. Producer or source: Kennametal Inc..

UNS R54620

Alloy Digest ◽  
1987 ◽  
Vol 36 (7) ◽  
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Time Use ◽  
Temperature Stability ◽  
High Strength ◽  
Heat Treating ◽  
High Temperature Stability ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Long Time

Abstract UNS No. R54620 is an alpha-beta titanium alloy. It has an excellent combination of tensile strength, creep strength, toughness and high-temperature stability that makes it suitable for service to 1050 F. It is recommended for use where high strength is required. It has outstanding advantages for long-time use at temperatures to 800 F. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ti-86. Producer or source: Titanium alloy mills.

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