Microstructure and corrosion resistance of ERNiCrMo-13 and NiCrBSi coatings in simulated coal-fired boiler conditions: The effect of fly-ash composition

2020 ◽  
Vol 399 ◽  
pp. 126134
Author(s):  
C. Fu ◽  
Y. Li ◽  
Y.F. Wang
Keyword(s):  
Corrosion Resistance ◽  
Fly Ash ◽  
Ash Composition ◽  
Nicrbsi Coatings

Influence of Fly Ash on Corrosion Resistance of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 325 ◽  
pp. 181-187
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Fly Ash ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Zones ◽  
Refractory Ceramics ◽  
Scanning Electron

This article examines the influence of fly ash on corrosion resistance of refractory forsterite-spinel ceramics by molten iron as a corrosive medium. Fly ash in comparison with alumina were used as raw materials and sources of aluminium oxide for synthesis of forsterite-spinel refractory ceramics. Raw materials were milled, mixed in different ratios into two sets of mixtures and sintered at 1550°C for 2 hours. Samples were characterized by X-ray diffraction analysis and thermal dilatometric analysis. Crucibles were then made from the fired ceramic mixtures and fired together with iron at its melting point of 1535°C for 5 hours. The corrosion resistance was evaluated by scanning electron microscopy on the transition zones between iron and ceramics. Mixtures with increased amount of spinel had higher corrosion resistance and mixtures with fly ash were comparable to mixtures with alumina in terms of corrosion resistance and refractory properties.

Sulfate Resistance of Concrete under Restrained Condition

2011 ◽  
Vol 280 ◽  
pp. 67-70
Author(s):  
Zhong Hua Li ◽  
Shu Rong Feng ◽  
Chao Su
Keyword(s):  
Corrosion Resistance ◽  
Fly Ash ◽  
Concrete Cracking ◽  
Surface Cracking ◽  
Sulfate Resistance ◽  
Restrained Condition ◽  
Drying And Wetting Cycles

Cracking due to shrinkage and restraint can accelerate corrosion of concrete resulted from harmful environment. Sulfate resistance of concrete under restrained condition was researched during drying and wetting cycles. The results showed that restraint can lead to controlled concrete cracking as result of shrinkage. It decreased sulfate corrosion resistance of concrete compared with free concrete. Due to 30% slag and 20% fly ash was added, surface cracking was avoided but scaling mass still higher than free concrete after drying and wetting cycles.

scholarly journals Resistance to Sulfuric Acid Corrosion of Geopolymer Concrete Based on Different Binding Materials and Alkali Concentrations

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7109
Author(s):  
Wei Yang ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang ◽  
Wei Ge ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Fly Ash ◽  
Acid Corrosion ◽  
Geopolymer Concrete ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Naoh Solution ◽  
Sulfuric Acid Corrosion

Geopolymer binder is expected to be an optimum alternative to Portland cement due to its excellent engineering properties of high strength, acid corrosion resistance, low permeability, good chemical resistance, and excellent fire resistance. To study the sulfuric acid corrosion resistance of geopolymer concrete (GPC) with different binding materials and concentrations of sodium hydroxide solution (NaOH), metakaolin, high-calcium fly ash, and low-calcium fly ash were chosen as binding materials of GPC for the geopolymerization process. A mixture of sodium silicate solution (Na2SiO3) and NaOH solution with different concentrations (8 M and 12 M) was selected as the alkaline activator with a ratio (Na2SiO3/NaOH) of 1.5. GPC specimens were immersed in the sulfuric acid solution with the pH value of 1 for 6 days and then naturally dried for 1 day until 98 days. The macroscopic properties of GPC were characterized by visual appearance, compressive strength, mass loss, and neutralization depth. The materials were characterized by SEM, XRD, and FTIR. The results indicated that at the immersion time of 28 d, the compressive strength of two types of fly ash-based GPC increased to some extent due to the presence of gypsum, but this phenomenon was not observed in metakaolin-based GPC. After 98 d of immersion, the residual strength of fly ash based GPC was still higher, which reached more than 25 MPa, while the metakaolin-based GPC failed. Furthermore, due to the rigid 3D networks of aluminosilicate in fly ash-based GPC, the mass of all GPC decreased slightly during the immersion period, and then tended to be stable in the later period. On the contrary, in metakaolin-based GPC, the incomplete geopolymerization led to the compressive strength being too low to meet the application of practical engineering. In addition, the compressive strength of GPC activated by 12 M NaOH was higher than the GPC activated by 8 M NaOH, which is owing to the formation of gel depended on the concentration of alkali OH ion, low NaOH concentration weakened chemical reaction, and reduced compressive strength. Additionally, according to the testing results of neutralization depth, the neutralization depth of high-calcium fly ash-based GPC activated by 12 M NaOH suffered acid attack for 98 d was only 6.9 mm, which is the minimum value. Therefore, the best performance was observed in GPC prepared with high-calcium fly ash and 12 M NaOH solution, which is attributed to gypsum crystals that block the pores of the specimen and improve the microstructure of GPC, inhibiting further corrosion of sulfuric acid.

Effect of fly ash composition on the retention of mercury in coal-combustion flue gas

2016 ◽  
Vol 142 ◽  
pp. 6-12 ◽  
Author(s):  
Ping He ◽  
Xianbing Zhang ◽  
Xiaolong Peng ◽  
Jiang Wu ◽  
Xiuming Jiang
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Coal Combustion ◽  
Ash Composition

scholarly journals Improving Sustainability through Corrosion Resistance of Reinforced Concrete by Using a Manufactured Blended Cement and Fly Ash

2018 ◽  
Vol 10 (6) ◽  
pp. 2004 ◽  
Author(s):  
Hector Campos Silva ◽  
Pedro Garces Terradillos ◽  
Emilio Zornoza ◽  
Jose Mendoza-Rangel ◽  
Pedro Castro-Borges ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Reinforced Concrete ◽  
Fly Ash ◽  
Blended Cement

Corrosion Resistance Performance of Ethylamines in Fly Ash Blended Cement Concrete

2014 ◽  
Vol 507 ◽  
pp. 286-290
Author(s):  
V. Rajkumar
Keyword(s):  
Corrosion Resistance ◽  
Fly Ash ◽  
Blended Cement ◽  
Impedance Measurement ◽  
Chloride Ions ◽  
Experimental Investigations ◽  
Optimal Dosage ◽  
Cement Concrete ◽  
Chloride Permeability ◽  
Resistance Performance

The main aim of this investigation is to study the influence of monoethylamine, diethylamine and triethylamine inhibitors on the corrosion resistance performance of 25% fly ash blended cement concrete. These inhibitors were added in dosages of 1%, 2%, 3% and 4% by weight of cement and experimental investigations have been carried out to compare the effectiveness of these three inhibitors with regard to strength and corrosion resistance. The mechanical strength properties studied were compressive, split tensile, flexural and bond strengths. The resistance to corrosion was evaluated based on the performance of the concrete for the penetration of chloride ions by means of impressed voltage technique, Rapid chloride permeability test (RCPT), AC impedance measurement, and weight loss measurement and ultimately the most effective of the three inhibitors and its optimal dosage has been determined.

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