Search

It is said that plasma electrolytic oxidation (PEO) is considered as an effective technique to boost the surface properties of light materials by means of forming ceramic films on their surfaces. In this study, three different voltage values were applied to the PEO process to AA2024 so that Al2O3 ceramic coatings were directly supplied for AA 2024 substrates by PEO and it is focused on the adhesion of interface between coating and substrate. All of the cases such as microstructure, phase composition, thickness, roughness and hardness of Al2O3 ceramic coatings were assayed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Atomic-force microscopy (AFM), Eddy Current Non-destructive testing and microhardness test, respectively. The results showed that roughness, hardness and thickness of the coatings were increased as we increased the voltage. Therefore, it could be claimed that the voltage parameters have an important role in the unified coating on the metal surface as it is directly connected with the morphologies of the PEO coating. [ABSTRACT FROM AUTHOR] more...

Despite the fact that Titanium and its alloys are materials which have excellent corrosion-resistant properties, they have poor wear and friction performance under tribological conditions. The aim of this study is to find suitable parameters for the surface treatment of Cp-Ti substrates which are used under saline environment. In this study, TiO2coatings were grown on Cp-Ti substrates at different frequencies which are parameters of the coating process. Due to its low cost and ability to achieve high thicknesses, The Plasma Electrolytic Oxidation (PEO) method was applied to grow TiO2coatings. The microstructures, morphology, and crystallographic structure were analyzed using SEM and XRD. Tribocorrosion properties of the coatings were investigated using a combination of the pin-on-disk wear test and potentiodynamic polarization test units. The frequency is known to have a strong impact on the PEO process. The impacts of frequency changes on the PEO coating performance were examined under a constant voltage. As result, the increase of the frequency caused smaller pores and cracks in the surface morphology of the coating and at the same time this  yielded an increment on the tribocorrosion behavior of the coating. [ABSTRACT FROM PUBLISHER] more...

TiBN coatings have high hardness and high adhesion. Due to these excellent properties there has been increasing interest in TiBN coatings. In this study, TiBN coatings were deposited on AISI D2 cold work tool steel and silicon wafers by closed field unbalanced magnetron sputtering (CFUBMS). The structural, mechanical and adhesion properties of these coatings were analysed by X-ray diffraction, scanning electron microscopy, microhardness test, indentation test and scratch tests. TiBN coatings produced by magnetron sputtering exhibited a dense and columnar structure. These results indicate that TiB2, TiN and h-BN exist in crystalline forms at all coatings. The highest hardness was obtained at the lowest nitrogen flow rate. Very few cracks were observed at the edge of the indentation marks at the highest nitrogen flow rate. The highest critical load obtained with scratch test was identified as 102 N. [ABSTRACT FROM PUBLISHER] more...

Composite structured solid thin films were deposited on 52100 tool steel by co-sputtering from BN, TiB2, MoS2 and Ti targets using a closed-field unbalanced magnetron sputtering process (CFUBMS). The structural and mechanical properties of the composite structured coatings were investigated. The composition and morphology of the films were investigated using X-ray diffraction and scanning electron microscopy (SEM). The adhesion properties of the films were characterized by the use of a Revetest-scratch tester. The adhesion test results indicated that bias voltage was the most effective coating parameter related to the critical load. [ABSTRACT FROM AUTHOR] more...