Corrosion Behaviour Of TiN Coatings Research Articles

Effect of Bias Voltage on Adhesion and Corrosion Resistance of Titanium Nitride Coated Stainless Steel Substrate

In this work, the adhesion and corrosion resistance of TiN coating by magnetron sputtering on stainless steel substrates under different bias voltages conditions (-50 V and-100 V) was investigated. AFM was used for surface roughness and grain size analysis, XRD for phase identification, Rockwell C for adhesion and nanoindentation for hardness and elastic modulus. According to AFM the coating deposited at-100V bias had decreased surface roughness, the value decreased from 2.7 nm (for-50V sample) to 1.8 nm, this was due to an etching like process which occurs when ions with higher energies start hitting the surface. The coated samples came under HF1 adhesion parameter which is the highest class of adhesion in the model on the basis of Rockwell C adhesion test. nanoindentation hardness and elastic modulus results of-50 V and-100V were found to be 224 GPa and 182 GPa, respectively and the value of hardness, 16 GPa and 22 GPa, respectively. The corrosion behavior of TiN coatings were studied in 3.5wt. % NaCl solutions using Tafel Extrapolation, Cyclic Polarization and Open Circuit Potential. It was noted on the basis of these corrosion tests that, as bias voltage is increased, it leads to the formation of more densely packed, fine grained columnar structures with less pores, which decreases the chances of corrosion. .

Morphology, resistivity and corrosion behavior of tin coatings plated from citric acid bath

Pulse electrodeposition of Sn from an electrolyte containing stannous sulfate and citric acid was investigated. The corrosion investigations were done by electrochemical potentiodynamic polarization methods. The phase evolution and coating morphology were studied by x-ray diffraction experiment and scanning electron microscopy. All the deposited films exhibit tetragonal tin β-Sn structure. The coating microstructure consists of big sized grains at lower current density which are refined at higher current density. The electrical resistivity of the coatings was increased continuously with current density. The coatings show the best corrosion resistance at a current density of 30 mA cm−2. This study shows that developed coatings can be a potential candidate for Pb-free soldering technology.

Mechanical and Corrosion Behavior of TiN Coatings Deposited on Nitrided AISI 420 Stainless Steel

TiN coatings are widely used in different applications for extending the lifetime of components due to their high hardness and good wear resistance. However, it is not convenient to deposit them on soft stainless steels. In this work, the wear and corrosion behavior of commercial TiN coatings deposited by Arc-PVD on nitrided and non-nitrided martensitic stainless steel was studied. Two different nitriding conditions were used, one at high temperature (HTN) and the other at low temperature (LTN). Nanohardness and microhardness were measured. The microstructure was characterized by OM, SEM, XRD and XPS. Pin on disk and erosion tests were carried out in order to evaluate their wear resistance. The corrosion behavior was analyzed in salt spray fog and electrochemical tests in NaCl solution and the adhesion was measured in Scratch and Rockwell C Indentation tests.The coating thickness was about 1.5 µm and its hardness of 34 GPa. The nitrided layers were 13 µm and 17 µm thick for LTN and HTN, the hardness was approximately 12 GPa for both nitrided samples. The nitrided layer improved TiN coating adhesion in the Scratch tests. The wear loss volume was similar for both duplex and only coated samples in pin on disk tests. Nevertheless, wear resistance was not good for the LTN or HTN + TiN coating system in the erosion tests. Regarding corrosion behavior, the coatings showed poor corrosion resistance and this could be related to the presence of porous defects, which allow the solution to reach and attack the substrate, thus producing coating detachment around the pits.

The effect of modified epoxy sealing on the electrochemical corrosion behaviour of reactive plasma-sprayed TiN coatings

Reactive plasma sprayed TiN coatings were sealed using epoxy resin which was modified by adding small fraction of TiO2 nanoparticles in this paper. The effect of the sealing treatment on corrosion behaviour of TiN coatings in simulated seawater was investigated using electrochemical methods potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The porosity of the coatings was reduced and the corrosion resistance of the coatings was improved significantly after sealing treatment. The sealing efficiency of modified epoxy resin was two times higher than that of pure epoxy resin.

Corrosion Resistance of TiN Coatings Prepared by Filtered Cathodic Vacuum Arc Process

ABSTRACTFor the purpose of developing the corrosion-resistant and low-cost metallic bipolar plates for direct methanol fuel cell (DMFC), Ti mesh, stainless steel and Si(100) were coated with TiN by using the filtered cathodic vacuum arc system (FCVA). These TiN films have received considerable attention because of its high anti-corrosion behavior and low contact-resistance. In order to improve the corrosion protective ability of TiN films and decrease pinholes of coating, growth modifications such as thickness of the coatings and bias applied to substrates have also been carried out. The microstructures and composition of TiN film were identified by the instrumental analyses such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The corrosion behavior of TiN coatings was studied in 0.5 M H2SO4 solutions by using potentiodynamic polarization method. The DC bias of −150 V was applied to the substrates to achieve a dense structure of approximately 400 nm coating of TiN, so that good corrosion protection of the Ti mesh and stainless steel substrates can be achieved. The TiN coating on stainless steel exhibited excellent corrosion behavior especially in lower corrosion current than 2×10−7 A/cm2.

Corrosion behaviour and protective quality of tin coatings

TiN hard coatings made by different chemical and physical vapour deposition techniques are widely used to increase the wear resistance of steel components. In many applications there are also corrosive stresses combined with different wear mechanisms, but so far very little information is available on the corrosion behaviour of TiN coatings. In this study we determined the corrosion behaviour of various chemically vapour-deposited TiN coatings by electrochemical polarization measurements in an aerated 0.01 N HCl aqueous solution. The effect of some process parameters, e.g. temperature, TiCl 4 concentration and gas flow rate, on the protective quality of the coatings was also studied. The polarization of the TiN coatings was compared with the behaviour of pure TiN and with that of the substrates. The observed polarization behaviour of TiN coatings was correlated to structural details studied by scanning electron microscopy. The results of these tests are presented and discussed. The polarization measurements proved to be very sensitive to different structural defects and this type of measurement can be used to determine the protective quality of thin coatings of the type studied.