Effect of Flow Velocity and Impact Angle on Erosion–Corrosion Behavior of Chromium Carbide Coating

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
A. R. Hemmati ◽  
M. Soltanieh ◽  
S. M. Masoudpanah
Keyword(s):  
Mass Loss ◽  
Flow Velocity ◽  
Corrosion Behavior ◽  
Chromium Carbide ◽  
Impact Angle ◽  
Coated Sample ◽  
High Mass ◽  
Carbide Coating ◽  
Chromium Carbide Coating ◽  
Erosion Corrosion

In this study, the effect of flow velocity (4–7.5 m s−1) and impact angle (30–90 deg) on erosion–corrosion behavior of chromium carbide coating was investigated under impingement by silica containing NaCl solution. Chromium carbide coating was deposited on low carbon steel by thermal reactive deposition/diffusion method at 1050 °C for 12 h in a molten salt bath. Mass loss measurement and potentiodynamic polarization tests were employed in order to determine coating performance under impingement. Polarization curves showed that the coated samples had less corrosion current density and high chemical stability. High mass loss at low impact angle indicated ductile behavior for the uncoated sample, while the mass loss for the coated sample changes less than 30% with impact angle up to 60 deg. Furthermore, the erosion–corrosion behavior of the coated sample was slightly dependent on flow velocity. Scanning electron micrographs showed that at lower impact angle, the Cr7C3 coating eroded with flake fragmentation mechanism, while at high impact angle, fatigue fracture is the main degradation mechanism.

Oxidation Kinetics of Chromium Carbide Coating Produced on AISI 1040 Steel by Thermo-Reactive Deposition Method during High Temperature in Air

2012 ◽  
Vol 445 ◽  
pp. 649-654 ◽  
Author(s):  
Şaduman Şen ◽  
Ozkan Ozdemir ◽  
A. Sukran Demirkıran ◽  
Uğur Şen
Keyword(s):  
Chromium Carbide ◽  
Oxidation Kinetics ◽  
Coating Layer ◽  
Initial Period ◽  
Coated Steel ◽  
Deposition Method ◽  
Carbide Coating ◽  
Reactive Deposition ◽  
Chromium Carbide Coating ◽  
Second Period

Oxidation of chromium carbide coating formed on AISI 1040 steel deposited by thermo-reactive deposition method (TRD) has been realized by two stepped reactions. In the initial part of the reactions in the oxidation process, carbon atoms combined with chromium on the outer part of the coating layer react with the oxygen in air, effectively up to 120 min. After that, the chromium atoms react with oxygen in the air and produce Cr2O3phase on the coating layer. The higher the temperature and the longer the treatment time, the more the Cr2O3phases became. The kinetic study was realized for the reactions of carbon and chromium with oxygen, individually. The kinetic study of oxidation was calculated by weight changing of the coated samples at the temperatures of 973 K, 1073 K and 1273 K up to 720 min. We established that the chromium carbide coated steel are characterized by an insignificant increase in the mass in the oxidation period up to 3.5 h, after which the degree of oxidation increases somewhat. The nature of oxidation kinetics for chromium carbide coated steel varies from some mass degrease in the initial period ( 2 h) in connection with the formation of CO and CO2to later mass increase with in connection with the formation of Cr2O3layer. The oxidation resistance of chromium carbide coated steel decrease with an increase in oxidation temperature. The growth rate constant of oxidation of chromium carbide coated steel ranged from 5.13x10-13to-9.617x10-11g4.cm-2s-1in the initial period of oxidation (up to 120 min), while it ranged from 3,163x10-13to 2.188 x10-10g4.cm-2s-1in the second period of oxidation test (over 120 min). The activation energies of oxidation of the chromium carbide coated steel are 185 kJ/mol for the initial period and 215 kJ/mol for the second period.

scholarly journals Slurry Erosion–Corrosion Characteristics of As-Built Ti-6Al-4V Manufactured by Selective Laser Melting

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3967 ◽  
Author(s):  
Saleh Ahmed Aldahash ◽  
Osama Abdelaal ◽  
Yasser Abdelrhman
Keyword(s):  
Selective Laser Melting ◽  
Tap Water ◽  
Pure Water ◽  
Impact Angle ◽  
High Mass ◽  
Slurry Erosion ◽  
Laser Melting ◽  
Erosion Corrosion ◽  
Impact Angles ◽  
The Impact

Erosion and erosion–corrosion tests of as-built Ti-6Al-4V manufactured by Selective Laser Melting were investigated using slurries composed of SiO2 sand particles and either tap water (pure water) or 3.5% NaCl solution (artificial seawater). The microhardness value of selective laser melting (SLM)ed Ti-6Al-4V alloy increased as the impact angle increased. The synergistic effect of corrosion and erosion in seawater is always higher than erosion in pure water at all impact angles. The seawater environment caused the dissolution of vanadium oxide V2O5 on the surface of SLMed Ti-6Al-4V alloy due to the presence of Cl− ions in the seawater. These findings show lower microhardness values and high mass losses under the erosion–corrosion test compared to those under the erosion test at all impact angles.

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