Surface modification of ion-implanted AISI 304 stainless steel after oxidation process: X-ray absorption spectroscopy analysis (original) (raw)
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Journal of Electron Spectroscopy and Related Phenomena, 2001
Soft X-ray absorption spectroscopy (XAS) has been used to study the influence of Si ion implantation on the passive layer of AISI 304 stainless steel, as well as on its high-temperature oxidation behaviour. Ion implantation is a usual technique to improve the corrosion and oxidation resistance of steels. To study the effects of ion implantation on the room temperature corrosion behavior of AISI 304 stainless steel, XAS was performed on the passive layer formed spontaneously in contact with air. To analyse the effects of ion implantation at high temperatures, the oxide layer formed after an isothermal oxidation at 9008C for 32 h was also studied. The results show a positive influence of Si ion implantation on the corrosion behaviour of AISI 304 stainless steel. XAS in the soft X-ray excitation mode has proved to be a very suitable technique to perform corrosion science studies.
Corrosion Science, 2003
The chemical modifications introduced in the passive layer of AISI 304 stainless steel after Si, Ce, and Mo ion implantation were investigated and compared with non-implanted steel by soft X-ray absorption spectroscopy. The influence of ion implantation on the passive properties was evaluated by measuring soft X-ray absorption spectra at the Cr, Fe, Ni, Mn and Si 2p in addition to oxygen 1s thresholds. All ion implanted samples show a relative Crenrichment at the surface as compared with non-implanted samples. Fe 2p as well as O 1s spectral changes reveal chemical differences in the passive layer as a function of the element ion-implanted.
Metals
In this work, the corrosion resistance of AISI 321 stainless steel is increased through. the two-stage implantation of oxygen ions and of both aluminum and boron ions together. During ion implantation, a modified layer with a thickness of about 200 nm is formed, which affects the properties of material. The increase in corrosion resistance is confirmed by prolonged acid corrosion tests at pH 3.5 and by accelerated electrochemical tests using a potentiostat. The corrosion rate of the implanted sample is 0.708 μA/cm2, in contrast to the non-implanted sample (1.26 μA/cm2). The modified surface layer is examined using X-ray photoelectron spectroscopy (XPS), secondary-ion mass spectrometry (SIMS), and transmission electron microscopy (TEM). Aluminum and boron are implanted to a depth of more than 250 nm. It is found that the modified surface of the stainless steel substrate contains oxides of implanted ions (Al2O3) and oxides of substrate ions (Cr2O3 and NiCr2O4).
Le Journal de Physique IV, 1993
Stainless steels of type AISI 304 and 316 were heated in air (1-5-15 minutes at 900-1000-1 100 OC) and the oxide layers formed on the surface were analyzed by XRD, CEMS, SIMS and FTIR. At these temperatures the main oxides are CrgOs and a spinel close to MnCr204 for polishing samples (with Fez03 for the chemically cleaned samples). The oxidation induces a Cr and Mn depletion from the metallic substratum and a phase transformation y (f.c.c.) + cu (b.c.c.) in a thin layer of the stee!s near the oxidesmetal interface.
ISIJ International, 1994
The influence of alloy surface preparation as induced by mechanical polishing and electropolishing on the oxidation behaviour of AISI 316 stainless steel in dry air under non-isothermal heating (6 K•min~1) followed by isothermal holding at 1 423 K is reported. Mechanically polished surfaces exhibit a shorter incubation period for initial oxidation but better oxidation resistance during isothermal holding as compared to electropolished surfaces. Such observation is attributed to enhancedoutward diffusion of Cr for easy and early establishment of Cr-rich oxide layer on the mechanically polished surfaces. Themorphologies of the scales and nature of their adherenceto the alloy substrates have beencharacterized by SEM. Distribution of the alloying elements like Ni. Cr, Mn, Mo. Si as well as Fe and oxygen across the oxide layers and the type of compounds formed have been examined by EPMA. EDSand XRD techniques. SEM examinations of the alloy/scale cross section for the mechanically polished and oxidized steel, supplementedby the X-ray imagesof the respective elements, indicate preferential formation of a continuous Cr-rich layer near the oxidelair interface along with two continuous bandsof dopedCr203at the scale/alloy region. Onthe other hand, the scale formed on electropolished surfaces of the steel showsfragmented Ni-rich and Cr-rich oxide areas at the bottom region of the scale with mostly compact Fe303-rich layer at the oxide/air interface.
The oxidation behavior of grade 304L stainless steel (SS) subjected to different surface finishing (machining and grinding) operations was followed in situ by contact electric resistance (CER) and electrochemical impedance spectroscopy (EIS) measurements using controlled distance electrochemistry (CDE) technique in high purity water (conductivity < 0.1 S cm −1 ) at 300 • C and 10 MPa in an autoclave connected to a recirculation loop system. The results highlight the distinct differences in the oxidation behavior of surface worked material as compared to solution annealed material in terms of specific resistivity and low frequency Warburg impedance. The resultant oxide layer was characterized for (a) elemental analyses by glow discharge optical emission spectroscopy (GDOES) and (b) morphology by scanning electron microscopy (SEM). Oxide layers with higher specific resistivity and chromium content were formed in case of machined and ground conditions. Presence of an additional ionic transport process has also been identified for the ground condition at the metal/oxide interface. These differences in electrochemical properties and distinct morphological features of the oxide layer as a result of surface working were attributed to the prevalence of heavily fragmented grain structure and presence of martensite.
Surface and Interface Analysis, 2008
Surface oxidation of Fe-19Cr-17Ni, Fe-19Cr-18Ni-1Al and TiC-enriched Fe-19Cr-18Ni-1Al alloys was investigated by photoelectron spectroscopy (PES). The experiments were conducted at 323 K in pure O 2 (2.7 × 10 −6 mbar). Composition and morphology of the nanoscale surface oxides were determined quantitatively by inelastic electron background analysis. Moreover, use of synchrotron radiation facilities were necessary to obtain improved sensitivity for studying minor alloying elements such as Al and Si. The results indicate oxygen-induced segregation of Al, which significantly hinders the oxidation of the major alloying elements Fe and Cr. Ti remains in its inert carbide form. The relative concentration of Fe within the oxide layer was found to increase with the oxide-layer thickness, indicating greater mobility of Fe relative to other alloying elements.
Comparative study of high temperature oxidation behaviour in AISI 304 and AISI 439 stainless steels
Materials Research, 2003
This work deals with a comparison of high temperature oxidation behaviour in AISI 304 austenitic and AISI 439 ferritic stainless steels. The oxidation experiments were performed between 850 and 950 °C, in oxygen and Ar (100 vpm H 2). In most cases, it was formed a Cr 2 O 3 protective scale, whose growth kinetics follows a parabolic law. The exception was for the the AISI 304 steel, at 950 °C, in oxygen atmosphere, which forms an iron oxide external layer. The oxidation resistance of the AISI 439 does not depend on the atmosphere. The AISI 304 has the same oxidation resistance in both atmospheres, at 850 °C, but at higher temperatures, its oxidation rate strongly increases in oxygen atmosphere. Concerning the performance of these steels under oxidation, our results show that the AISI 439 steel has higher oxidation resistance in oxidizing atmosphere, above 850 °C, while, in low pO 2 atmosphere, the AISI 304 steel has higher oxidation resistance than the AISI 439, in all the temperature range investigated.
Surface and Coatings Technology, 2006
Specimens of AISI 304 and AISI 430 stainless steels (SS) were implanted with nitrogen, argon and silicon up to an ion dose of 1 Â10 15 ion/cm 2 at an accelerating potential of 150 keV. AISI 304 and 430 SS specimens were analysed as-received and after ion implantation using X-ray photoelectron spectroscopy (XPS) in conjunction with Ar + -ion sputtering. Surface chromium enrichment was observed with the argon ion-implanted specimens compared with the non-implanted specimens, enhancing their corrosion resistance. Nitrogen implantation does not seem to have a significant effect on the structure and composition of the passive layer. Finally, silicon-implanted SSs show a very different passive layer, in which SiO 2 is the main component of the outer surface. D
Influence of surface preparation on oxidation of stainless steels at high temperature
Surface and Interface Analysis, 1993
Fourier transform infrared specular reflectance spectra at variable incidence have been recorded in order to characterize the oxide layers formed on both mechanically polished and etched surfaces of stainless steels (AISI 304 and 316). Depending on the surface preparation, the major oxides are either Cr2O3 and MnCr2O4 for polished samples or α-Fe2O3 and Fe3O4 for etched samples in the early stages of the oxidation in air at 900°C. Secondary ion mass spectrometry depth profiles confirm the schematic structure of oxide films (developed on polished surfaces during longer exposures) deduced from infrared reflectance study.