Journal ArticleDOI
A microstructural study of the influence of NaCl vapor on the oxidation of a Ni-Cr-Al alloy at 850°C
M. K. Hossain,S. R. J. Saunders +1 more
TLDR
In this article, a thin protective oxide formed on a Ni-197 Cr-24 Al alloy in air at 850°C was examined and it was shown that the oxide was duplex with an inner chromium-rich layer of NiCr2O4 + Cr2O3 with probably some NiAl2O 4 + Al2O 3 + NiO 3 and an outer nickel rich layer, principally NiO The oxide grew faster in the presence of NaCl and it differed significantly in microstructure and composition from a very early stage.Abstract:
A thin protective oxide formed on a Ni-197 Cr-24 Al alloy in air at 850°C Microstructural examination of stripped films showed that the oxide was duplex with an inner chromium-rich layer of NiCr2O4 + Cr2O3 with probably some NiAl2O4 + Al2O3, and an outer nickel-rich layer, principally NiO The oxide grew faster in the presence of NaCl and it differed significantly in microstructure and composition from a very early stage The thicker regions of the oxide assumed regular polyhedral shapes in air + NaCl, rather than the irregular nodular shape exhibited in clean air, as well as becoming richer in chromium The results suggest that chloride vapor increases cationic mobility in the oxide It is proposed that Cl− ions are incorporated in the oxygen close-packed lattice, thereby increasing ionic mobility in Cr2O3read more
Citations
More filters
Journal ArticleDOI
The implications of chlorine-associated corrosion on the operation of biomass-fired boilers
TL;DR: In this paper, the potential corrosion problems associated with burning biomass fuels either alone or in blends with coal, for electricity production are discussed, and the most severe corrosion problems in biomass-fired systems are expected to occur due to Cl-rich deposits formed on superheater tubes.
Journal ArticleDOI
Corrosion behaviour of various model alloys with NaCl–KCl coating
TL;DR: In this paper, the hot corrosion behavior of various Fe-Cr, Fe-Al and NiAl model alloys was investigated in air with a surface deposit of NaCl-KCl melt.
Journal ArticleDOI
High temperature corrosion behaviour of a gradient NiCoCrAlYSi coating II: Oxidation and hot corrosion
TL;DR: In this article, the high temperature oxidation and hot corrosion behavior of a NiCoCrAlYSi coating and a gradient coating were investigated, and the degradation process of the gradient coating was favorably retarded by the formation of Cr(W)-rich sigma precipitates in the interdiffusion zone.
Journal ArticleDOI
The hot corrosion of 310 stainless steel with pre-coated NaCl/Na2SO4 mixtures at 750°C
TL;DR: In this paper, the high-temperature corrosion behavior of 310 stainless steel has been studied at 750°C in air with 2 1/2 mixtures of various NaCl/Na 2 SO 4 ratios.
Journal ArticleDOI
Effects of wall temperature on slagging and ash deposition of Zhundong coal during circulating fluidized bed gasification
TL;DR: Zhang et al. as discussed by the authors used a 0.4-t/d CFB test rig simulating the real industrial device to evaluate slagging and ash deposition at different wall temperatures.
References
More filters
Journal ArticleDOI
Mechanisms for the hot corrosion of nickel-base alloys
TL;DR: In this article, the authors have shown that the hot corrosion behavior of these alloys can usually be characterized according to one of two types of attack: (1) Na2SO4-induced accelerated oxidation; (2) Na 2SO4induced catastrophic oxidation.
Journal ArticleDOI
High-temperature oxidation of alloys
TL;DR: In this paper, a review of recent developments in the understanding of the oxidation of alloys at elevated temperatures are reviewed, with special reference to binary and ternary alloys upon which many commercial materials are based.
Journal ArticleDOI
Formation and Reactivity Thermodynamics of Sodium Sulfate With Gas Turbine Alloys
M. A DeCRESCENTE,N. S. Bornstein +1 more
TL;DR: Based upon a thermodynamic study of the accelerated oxidation of superalloys exposed in oxidizing environments containing minor quantities of sea salt, it was concluded that NaCl is necessary only to form Na2SO4.
Journal ArticleDOI
The Specific Effects of Chloride and Sulfate Ions on Oxide Covered Aluminum
TL;DR: In this article, the authors measured series capacitance and dielectric loss of oxide covered aluminum as the surface films thin slowly in a slightly alkaline, passivating, sodium chromate solution, and found that chloride ions become included at certain selected locations in the oxide film, creating additional current carriers, and lower the ionic resistance of the film.
Journal ArticleDOI
The relationship between relative oxide ion content of Na 2 SO 4 , the presence of liquid metal oxides and sulfidation attack
TL;DR: In this article, the relationship between accelerated oxidation, oxide ion content of a fused melt and the fluxing of the normally protective oxide scale by liquid metal oxides is discussed, and it is shown that the addition of either MoO3 or V2O5 to nickel imparts sulfidation resistance.