Study on the Corrosion Resistance Behavior of Multi-Elements Alloy CoCrFeNiTi0.5

2014 ◽  
Vol 541-542 ◽  
pp. 61-68
Author(s):  
Sheng Jiao Pang ◽  
Ping Li ◽  
Ting Ju Li ◽  
Jie Zhao
Keyword(s):  
Corrosion Resistance ◽  
Oxide Scale ◽  
Oxide Layer ◽  
Good Adhesion ◽  
Tube Material ◽  
Protective Oxide ◽  
Good Thermal Stability ◽  
The Matrix ◽  
Internal Sulfidation ◽  
Melting Point Eutectic

Multi-elements alloy with good thermal stability is expected to serve as the superheater tube material of ultra-supercritical boiler and may suffer from hot corrosion under the coal-fired atmosphere. In this study, the corrosion resistance behavior of multi-elements alloy CoCrFeNiTi0.5 coated with alkali metal sulfates at 750°C is investigated systematically. The results showed the corrosion kinetics curves of the alloy followed a parabolic growth rate. The corrosion products, which consisted of volatile Na (CrO4) (SO4), (Fe,Ni) xSy, Cr/Ti oxide as well as compound oxides with spinel structure AB2O4, were found in the oxide scale and internal attack zone of the alloy. The oxide layer had good adhesion with the matrix at the beginning of corrosion. Prolonging corrosion time, the oxide layer in thickness increased and became loose as well as porous. The micro-pores generated in the interface between the oxide scale and matrix with the occurrence of the internal oxidation and internal sulfidation. In a word, the corrosion resistance behavior of multi-elements alloy CoCrFeNiTi0.5 at 750°C can be attributed to the formation of the protective oxide layers and to the basic fluxing in molten Na4SO4 induced by low melting point eutectic.

scholarly journals Electrochemical Anodizing Treatment to Enhance Localized Corrosion Resistance of Pure Titanium

2017 ◽  
Vol 15 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Davide Prando ◽  
Andrea Brenna ◽  
Fabio M. Bolzoni ◽  
Maria V. Diamanti ◽  
Mariapia Pedeferri ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Titanium Alloys ◽  
Oxide Layer ◽  
Corrosion Behavior ◽  
Pure Titanium ◽  
Localized Corrosion ◽  
Anodic Current Density ◽  
Anodic Current ◽  
Protective Oxide ◽  
Pitting Potential

Background Titanium has outstanding corrosion resistance due to the thin protective oxide layer that is formed on its surface. Nevertheless, in harsh and severe environments, pure titanium may suffer localized corrosion. In those conditions, costly titanium alloys containing palladium, nickel and molybdenum are used. This purpose investigated how it is possible to control corrosion, at lower cost, by electrochemical surface treatment on pure titanium, increasing the thickness of the natural oxide layer. Methods Anodic oxidation was performed on titanium by immersion in H2SO4 solution and applying voltages ranging from 10 to 80 V. Different anodic current densities were considered. Potentiodynamic tests in chloride- and fluoride-containing solutions were carried out on anodized titanium to determine the pitting potential. Results All tested anodizing treatments increased corrosion resistance of pure titanium, but never reached the performance of titanium alloys. The best corrosion behavior was obtained on titanium anodized at voltages lower than 40 V at 20 mA/cm2. Conclusions Titanium samples anodized at low cell voltage were seen to give high corrosion resistance in chloride- and fluoride-containing solutions. Electrolyte bath and anodic current density have little effect on the corrosion behavior.

Hot Corrosion Behavior of Sputtered Fe-Y Alloy Coatings with Different Y Contents

2011 ◽  
Vol 391-392 ◽  
pp. 1263-1267
Author(s):  
Guang Yan Fu ◽  
Jing Yu Chen ◽  
Qun Liu ◽  
Yong Su
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Alloy Coating ◽  
Good Adhesion ◽  
Corrosion Scale ◽  
Measurement Results ◽  
The Matrix ◽  
Better Than

Three Fe-Y alloy coatings with differernt kinds of Y contents were prepared on stainless steel by magnetron sputtering. The hot corrosion behavior of sputtered alloy coatings with Na2SO4 deposits at 800 °C was investigated by discontinuous weigh measurement. Results show that the sputtered Fe-Y alloy coatings exhibit good adhesion with the matrix of stainless steel, and the hot corrosion kinetic curves of the specimens approximately follow the parabolic rate law. The Fe oxides are the main substances in the corrosion scale, and the hot corrosion rate of the three Fe-Y alloy coatings increases as the Y content increases. Therefore, the hot corrosion resistance of Fe-15Y alloy coating is better than that of Fe-20Y or Fe-30Y alloy coating.

The Influence of Heat Treatment and Plastic Deformation on the Bio-Degradation of a Mg–Y–RE Alloy

2009 ◽  
Vol 618-619 ◽  
pp. 71-74 ◽  
Author(s):  
Petra Gunde ◽  
Angela Furrer ◽  
Anja C. Hänzi ◽  
Patrik Schmutz ◽  
Peter J. Uggowitzer
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Oxide Layer ◽  
Human Body ◽  
Electrochemical Impedance ◽  
Essential Element ◽  
Heat Treatments ◽  
Protective Oxide ◽  
Degradation Behaviour ◽  
Polarisation Resistance

Magnesium has become an interesting candidate in the field of bioabsorbable implant materials; it is an essential element in the human body, biocompatible and degradable due to its low corrosion resistance in a pH range below 11.5. However, in the human body (pH  7.4) a magnesium implant might degrade too quickly and lose its mechanical strength before the tissue has fully healed. However, the corrosion resistance can be improved for example by the choice of a suitable Mg alloy containing corrosion-inhibiting elements such as yttrium or by the deployment of surface heat treatments at high temperatures causing protective oxide layers to form. We studied the bio-degradation behaviour of a Mg–Y–RE alloy in different heat treatment states by electrochemical impedance spectroscopy and immersion testing in simulated body fluid. The heat treatments caused a change in microstructure and also the formation of a thermal oxide layer on the sample surface, which consisted mainly of Y2O3 and which slowed the degradation and increased the polarisation resistance significantly compared to the polished state. However, in some specimens localised corrosion attacks occurred which drastically weakened the protective effect of the oxide. Because the implant might be deformed during implantation resulting in the oxide cracking, we intentionally strained the samples and investigated the degradation performance. These cracks led to a decrease in polarisation resistance compared to the non-strained oxidised state, but in comparison to the polished state they still perform better. Macroscopically, the degradation process occurred in a homogeneous way without localised corrosion attacks. Microscopically, corrosion attacks started at the cracks and undermined the oxide layer with time.

Effect of RE Elements Addition on Corrosion Behavior of Mg-Zn-Ca Amorphous Alloys for Biomedical Applications

2021 ◽  
Vol 1035 ◽  
pp. 501-510
Author(s):  
Yu Chen Chi ◽  
Bao Ru Guan ◽  
Feng Chen ◽  
Feng Xinag Qin
Keyword(s):  
Thermal Stability ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Oxide Layer ◽  
Corrosion Behavior ◽  
Amorphous Alloys ◽  
Biomedical Applications ◽  
Good Thermal Stability ◽  
Re Elements

The effects of rare earth (RE) elements (La, Y) addition on thermal stability and corrosion behavior of Mg68Zn28Ca4 amorphous alloys were investigated in this paper. The investigated Mg-Zn-Ca-RE amorphous alloys exhibit good thermal stability and enhanced corrosion resistance. The enhanced corrosion resistance of the RE-containing amorphous alloys is owing to the enrichment of the Zn and RE elements in the oxide layer. The corrosion resistance is further improved with the increasing of RE content.

Corrosion Resistance of Vanadis 6 Steel after Conventional Heat Treatment and Sub-Zero Treatment in Cold Nitrogen Gas Followed by Tempering

2019 ◽  
Vol 395 ◽  
pp. 16-29
Author(s):  
Aneta Bartkowska ◽  
Peter Jurči
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Water Solution ◽  
Corrosion Current ◽  
Protective Oxide ◽  
Nitrogen Gas ◽  
Conventional Heat Treatment ◽  
Protective Films ◽  
The Matrix ◽  
Lower Corrosion Rate

The paper presents the results of study of corrosion resistance of Vanadis 6 steel after conventional heat treatment and sub-zero treatment at-140 °C for 17 h. It was found that sub-zero treatment leads generally to decrease in corrosion current, which is in turn reflected in lower corrosion rate of the material subjected to this kind of treatment. The corrosion potential of sub-zero treated specimens was more anodic, suggesting their more noble behavior in 3.5 % NaCl water solution. This behavior was ascribed to the presence of a huge number of small globular carbides in SZT specimens, which seemed to stabilize the protective oxide films on the surfaces. Tempering reduces the corrosion resistance of the steel since this treatment produces fine precipitates of alloyed carbides that deplete the matrix by chromium and thereby destabilizes the protective films on the steel surface.

Improved Corrosion Resistance of Aluminum in 0.5 M HCl Solution using Plasma Electrolytic Oxidation

2019 ◽  
Vol 233 (5) ◽  
pp. 609-625 ◽  
Author(s):  
M. A. Deyab ◽  
S. S. Abd El-Rehim ◽  
A. Abd El Moneim ◽  
H. H. Hassan
Keyword(s):  
Corrosion Resistance ◽  
Surface Morphology ◽  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Aluminum Surface ◽  
Protective Oxide ◽  
High Efficient ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Hcl Solution

Abstract In this paper, the plasma electrolytic oxidation (PEO) was used to improve the corrosion resistance of aluminum in 0.5 M HCl solution. Influence of many factors such as the composition of electrolytes, time and inorganic additives on the performance of PEO process have been investigated. The surface morphology of PEO films was inspected using SEM, EDX and XRD analysis. The electrochemical impedance spectroscopy (EIS) and polarization measurements were carried out to evaluate the corrosion resistance of aluminum. The hardness and reduced modulus of aluminum surface at different PEO process time were determined by nanoindenter measurements. The results showed that the best conditions for formation high efficient oxide layer on the aluminum surface during PEO process were carried out in 0.001 M NaOH electrolyte containing 9 × 10−5 M Na2WO4 for 5 min. The PEO process is able to inhibit uniform and pitting corrosion of aluminum in HCl solution. The surface morphology analysis showed that PEO process produce a highly resistant protective oxide layer, mainly composed of orthorhombic crystalline phase of α-Al2O3. This oxide characterized by its greater hardness.

Structural Imperfections in thin Oxide Films Formed on Some Fe- and Ni-Base Alloys

1970 ◽  
Vol 28 ◽  
pp. 510-511
Author(s):  
L. P. Lemaire ◽  
D. E. Fornwalt ◽  
F. S. Pettit ◽  
B. H. Kear
Keyword(s):  
Oxide Scale ◽  
Oxidation Process ◽  
Short Circuit ◽  
Protective Oxide ◽  
Protective Oxide Scale ◽  
Thin Oxide Films ◽  
Diffusion Paths ◽  
Oxidation Resistant ◽  
Structural Imperfections ◽  
Short Circuit Diffusion

Oxidation resistant alloys depend on the formation of a continuous layer of protective oxide scale during the oxidation process. The initial stages of oxidation of multi-component alloys can be quite complex, since numerous metal oxides can be formed. For oxidation resistance, the composition is adjusted so that selective oxidation occurs of that element whose oxide affords the most protection. Ideally, the protective oxide scale should be i) structurally perfect, so as to avoid short-circuit diffusion paths, and ii) strongly adherent to the alloy substrate, which minimizes spalling in response to thermal cycling. Small concentrations (∼ 0.1%) of certain reactive elements, such as yttrium, markedly improve the adherence of oxide scales in many alloy systems.

COLMONOY 805

Alloy Digest ◽  
1998 ◽  
Vol 47 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Abrasion Resistance ◽  
Coarse Particles ◽  
Powder Metal ◽  
Chromium Boride ◽  
Nickel Chromium ◽  
The Matrix

Abstract Colmonoy 805 is a nickel-chromium-boron alloy with coarse particles of chromium boride added to give it excellent sliding-type abrasion resistance. The alloy contains chromium boride in the matrix as large added particles. It is supplied only as a crushed powder for application with Colmonoy’s Fuseweld process. This datasheet provides information on composition, physical properties, microstructure, and elasticity. It also includes information on corrosion resistance as well as joining and powder metal forms.Filing Code: Ni-233. Producer or source: Wall Colmonoy Corporation. Originally published September 1976, revised December 1998.

scholarly journals Effect of Oxide Scale Microstructure on Atmospheric Corrosion Behavior of Hot Rolled Steel Strip

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 517
Author(s):  
Bin Sun ◽  
Lei Cheng ◽  
Chong-Yang Du ◽  
Jing-Ke Zhang ◽  
Yong-Quan He ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Scale ◽  
Corrosion Product ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Atmospheric Corrosion ◽  
Corrosion Mechanism ◽  
Type I ◽  
Rust Layer ◽  
Hot Rolled

The atmospheric corrosion behavior of a hot-rolled strip with four types (I–IV) of oxide scale was investigated using the accelerated wet–dry cycle corrosion test. Corrosion resistance and porosity of oxide scale were studied by potentiometric polarization measurements. Characterization of samples after 80 cycles of the wet–dry corrosion test showed that scale comprised wüstite and magnetite had strongest corrosion resistance. Oxide scale composed of inner magnetite/iron (>70%) and an outer magnetite layer had the weakest corrosion resistance. The corrosion kinetics (weight gain) of each type of oxide scale followed an initial linear and then parabolic (at middle to late corrosion) relationship. This could be predicted by a simple kinetic model which showed good agreement with the experimental results. Analysis of the potentiometric polarization curves, obtained from oxide coated steel electrodes, revealed that the type I oxide scale had the highest porosity, and the corrosion mechanism resulted from the joint effects of electrochemical behavior and the porosity of the oxide scale. In the initial stage of corrosion, the corrosion product nucleated and an outer rust layer formed. As the thickness of outer rust layer increased, the corrosion product developed on the scale defects. An inner rust layer then formed in the localized pits as crack growth of the scale. This attacked the scale and expanded into the substrate during the later stage of corrosion. At this stage, the protective effect of the oxide scale was lost.

scholarly journals Exploring the Effect of Silicon on the High Temperature Corrosion of Lean FeCrAl Alloys in Humid Air

2021 ◽  
Author(s):  
T. Sand ◽  
A. Edgren ◽  
C. Geers ◽  
V. Asokan ◽  
J. Eklund ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Oxidation Behavior ◽  
High Temperature Corrosion ◽  
The Other ◽  
Oxide Scales ◽  
Protective Oxide ◽  
New Approach ◽  
Fecral Alloys ◽  
Cr Evaporation

AbstractA new approach to reduce the chromium and aluminium concentrations in FeCrAl alloys without significantly impairing corrosion resistance is to alloy with 1–2 wt.% silicon. This paper investigates the “silicon effect” on oxidation by comparing the oxidation behavior and scale microstructure of two FeCrAl alloys, one alloyed with silicon and the other not, in dry and wet air at 600 °C and 800 °C. Both alloys formed thin protective oxide scales and the Cr-evaporation rates were small. In wet air at 800 °C the Si-alloyed FeCrAl formed an oxide scale containing mullite and tridymite together with α- and γ-alumina. It is suggested that the reported improvement of the corrosion resistance of Al- and Cr-lean FeCrAl’s by silicon alloying is caused by the appearance of Si-rich phases in the scale.

Sign in / Sign up

Export Citation Format

Share Document