scholarly journals Corrosion Resistant TiTaN and TiTaAlN Thin Films Grown by Hybrid HiPIMS/DCMS Using Synchronized Pulsed Substrate Bias with No External Substrate Heating

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 841
Author(s):  
Yuri Chipatecua Godoy ◽  
Olof Tengstrand ◽  
Jairo Olaya Florez ◽  
Ivan Petrov ◽  
Erika Bustos ◽  
...  

Ti0.92Ta0.08N and Ti0.41Al0.51Ta0.08N thin films grown on stainless-steel substrates, with no external heating, by hybrid high-power impulse and dc magnetron sputtering (HiPIMS/DCMS), were investigated for corrosion resistance. The Ta target was operated in HiPIMS mode to supply pulsed Ta-ion fluxes, while two Ti (or Ti and Al) targets were operated in DCSM mode in order to provide a high deposition rate. Corrosion resistance was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy employing a 3.5% NaCl solution at room temperature. The 300-nm-thick transition-metal nitride coatings exhibited good corrosion resistance due to film densification resulting from pulsed heavy Ta-ion irradiation during film growth. Corrosion protective efficiencies were above 99.8% for both Ti0.41Al0.51Ta0.08N and Ti0.92Ta0.08N, and pore resistance was apparently four orders of magnitude higher than for bare 304 stainless-steel substrates.

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 598
Author(s):  
Wenwei Li ◽  
Jun-e Qu ◽  
Zhiyong Cao ◽  
Hairen Wang

The colored films were successfully prepared on the 304 stainless steel surfaces in coloring solutions with different NiSO4 contents. The purpose of this study was to investigate the effects of NiSO4 in the coloring solution on the coloring performance of 304 stainless steel and corrosion resistance of the obtained colored film in NaCl solution. The coloring rate was determined from coloring potential-time curve, and the protection properties of the color films in a 3.5% NaCl solution were characterized by potentiodynamic polarization scan, electrochemical impedance spectroscopy, and wear resistance test. The results showed that adding NiSO4 could accelerate the coloring process but brought about a negative impact on the surface’s corrosion resistance.


CORROSION ◽  
10.5006/2680 ◽  
2018 ◽  
Vol 74 (6) ◽  
pp. 705-714 ◽  
Author(s):  
Yingying Yue ◽  
Chengjun Liu ◽  
Edouard Asselin ◽  
Peiyang Shi ◽  
Maofa Jiang

H2SO4-H2O2 mixtures are a promising and environmentally friendly passivation medium for the stainless-steel pickling process. The corrosion behavior of stainless steel is highly dependent on the kinetics of passive film growth. Long-term electrochemical measurements, including polarization resistance, open circuit potential (OCP), and electrochemical impedance spectroscopy (EIS) measurements were performed to investigate the evolution of the passive state of 304 stainless steel. According to the OCP results, an active-passive transition takes place in 10 ks in 0.5 M H2SO4 solution containing 0.005 M to 0.3 M H2O2. Polarization resistance results indicate that the passive film thickness keeps growing after OCP stabilization in the presence of H2O2. Electrochemical impedance spectroscopy (EIS) results confirmed that the growth of the passive film in H2SO4-H2O2 solutions takes about 9 h. Additionally, according to the Point Defect Model (PDM) and Mott–Schottky analysis, the semiconductor properties of the passive film on 304 stainless steel in H2SO4-H2O2 solution were studied. The results indicate that the passive film is an n-type semiconductor. The donor density is in the range of 1.6 × 10−21 cm−3 to 24 and decreases exponentially with increasing film formation potential (this potential coincides with the final OCP in the corresponding H2SO4-H2O2 solutions). By postulating that most donors are oxygen vacancies, the point defect properties including diffusivity and electrical field strength are obtained.


2019 ◽  
Vol 86 (3) ◽  
pp. 30301 ◽  
Author(s):  
Zouina Amina Ait-Djafer ◽  
Nadia Saoula ◽  
Daniel Wamwangi ◽  
Noureddine Madaoui ◽  
Hamid Aknouche

In this study, a negative substrate bias voltage is used to tune the structural, morphological, mechanical and electrochemical properties of TiAlN coatings fundamental for protective coating applications. TiAlN thin films have been deposited on glass, (001)Si and stainless steel substrates by RF magnetron sputtering at a power density of 4.41 W/cm2. The deposition rate was determined from X-ray reflectivity measurements to 7.00 ± 0.05 nm/min. TiAlN films used in this work were deposited for 60 min to yield a film thickness of 420 nm. Structural analysis has shown that TiAlN coating forms a cubic (fcc) phase with orientations in (111), (200), (220) and (222) planes. The deposited coatings present maximum hardness (H = 37.9 GPa) at −75 V. The dependence of hardness and Young's modulus and corrosion resistance on microstructure has been established. Electrochemical studies by potentiodynamic polarization in aggressive environment (3.5 wt.% NaCl) have revealed that stainless steel substrate with TiAlN coating exhibits excellent corrosion resistance.


Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 838
Author(s):  
Jun Heo ◽  
Sang Yoon Lee ◽  
Jaewoo Lee ◽  
Akram Alfantazi ◽  
Sung Oh Cho

In this study, we fabricated a nanoporous oxide layer by anodization to improve corrosion resistance of type 304 stainless steel (SS) gas tungsten arc weld (GTAW). Subsequent heat treatment was performed to eliminate any existing fluorine in the nanoporous oxide layer. Uniform structures and compositions were analyzed with field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD) measurements. The corrosion resistance of the treated SS was evaluated by applying a potentiodynamic polarization (PDP) technique and electrochemical impedance spectroscopy (EIS). Surface morphologies of welded SS with and without treatment were examined to compare their corrosion behaviors. All results indicate that corrosion resistance was enhanced, making the treatment process highly promising.


2014 ◽  
Vol 40 (8) ◽  
pp. 12359-12366 ◽  
Author(s):  
Paulo R.G. Gonçalves ◽  
José H.G. Rangel ◽  
Marcelo M. Oliveira ◽  
Adeilton P. Maciel ◽  
Elson Longo

Alloy Digest ◽  
2016 ◽  
Vol 65 (2) ◽  

Abstract Outokumpu Type 630 is a martensitic age hardenable alloy of composition 17Cr-4Ni. The alloy has high strength and corrosion resistance similar to that of Type 304 stainless steel. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1238. Producer or source: Outokumpu High Performance Stainless.


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