scholarly journals Mechanical and corrosion performance of multilayer ceramic coatings deposited on an austenitic stainless steel using plasma spray

2019 ◽  
Vol 42 (4) ◽  
Author(s):  
Seyed Rahim Kiahosseini ◽  
Armin Aminian
Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1156 ◽  
Author(s):  
Wei Shi ◽  
Jiaxu Wang ◽  
Ruyi Jiang ◽  
Song Xiang

A low-temperature (400 °C) glow plasma nitriding layer on AISI 904L austenitic stainless steel was obtained at various NH3 pressures and studied using electrochemical method, X-ray diffraction, and scanning Kelvin probe. The pressure of NH3 dominated the microstructure of the nitriding layer. The saturation degree of γN controlled corrosion performance and microhardness. Insufficient NH3 pressure (<100 Pa) resulted in discontinuous nitride caking coverage, whereas excessive NH3 pressure (>100 Pa) facilitated the transformation of the nitriding layer to harmful nitrides (CrN) due to a localized overheating effect caused by the over-sputtering current.


Author(s):  
R.N. Wright ◽  
W.D. Swank

Abstract Cold work and heat treatment influence the mechanical properties, residual stress-state, and corrosion resistance of austenitic stainless steels. In this study we have examined changes in the defect substructure and microstructure of Type 304 stainless steel resulting from surface preparation, and deposition of bond coats and thick ceramic coatings using plasma spray methods. The structure of the stainless steel was examined as a function of depth from the coating surface using optical and transmission electron microscopy, and x-ray diffraction. Grit blasting was found to severely cold work the material to a depth of tens of microns, and the amount of cold work varied with measured abrasive particle velocity. The heat input to the surface as a result of depositing a metallic bond coat or thick ceramic coating resulted in substantial annealing of the cold work imparted into the substrate by surface preparation. There was, however, no evidence of change in grain size near the substrate-coating interface that could be attributed to recrystallization or grain growth in the substrate.


Author(s):  
R. Gonzalez ◽  
L. Bru

The analysis of stacking fault tetrahedra (SFT) in fatigued metals (1,2) is somewhat complicated, due partly to their relatively low density, but principally to the presence of a very high density of dislocations which hides them. In order to overcome this second difficulty, we have used in this work an austenitic stainless steel that deforms in a planar mode and, as expected, examination of the substructure revealed planar arrays of dislocation dipoles rather than the cellular structures which appear both in single and polycrystals of cyclically deformed copper and silver. This more uniform distribution of dislocations allows a better identification of the SFT.The samples were fatigue deformed at the constant total strain amplitude Δε = 0.025 for 5 cycles at three temperatures: 85, 293 and 773 K. One of the samples was tensile strained with a total deformation of 3.5%.


Author(s):  
G. Fourlaris ◽  
T. Gladman

Stainless steels have widespread applications due to their good corrosion resistance, but for certain types of large naval constructions, other requirements are imposed such as high strength and toughness , and modified magnetic characteristics.The magnetic characteristics of a 302 type metastable austenitic stainless steel has been assessed after various cold rolling treatments designed to increase strength by strain inducement of martensite. A grade 817M40 low alloy medium carbon steel was used as a reference material.The metastable austenitic stainless steel after solution treatment possesses a fully austenitic microstructure. However its tensile strength , in the solution treated condition , is low.Cold rolling results in the strain induced transformation to α’- martensite in austenitic matrix and enhances the tensile strength. However , α’-martensite is ferromagnetic , and its introduction to an otherwise fully paramagnetic matrix alters the magnetic response of the material. An example of the mixed martensitic-retained austenitic microstructure obtained after the cold rolling experiment is provided in the SEM micrograph of Figure 1.


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