Damir Kakaš

INFLUENCE OF INTERFACIAL LAYER THICKNESS AND SUBSTRATE ROUGHNESS ON ADHESION OF TiN COATINGS DEPOSITED AT LOW TEMPERATURES BY IBAD

Ion beam assisted deposition (IBAD) was applied to produce TiN coatings on carburized steel substrates. Low deposition temperatures (~50°C) were applied to prevent distortion and softening of previously heat-treated substrates. Mechanical properties of all studied coatings are comparable to those obtained at usually used high temperatures. In order to improve adhesion between TiN coating and substrate, an interfacial layer was prepared by ion beam mixing of Ti atoms and steel substrate. The adhesion strength evaluation revealed significant improvement compared to the coatings produced without the ion beam mixed interfacial layer. Adhesion increased with increase in thickness of the interfacial layer. Substrate roughness was varied systematically in order to determine its influence on adhesion strength. The research was conducted for a rarely studied domain of low roughness (Average roughness Ra below 50 nm). The results of scratch tests revealed improvement of adhesion with increase in substrate roughness. This adhesion trend is different from the one reported by other authors who used rougher substrates. Two groups of opposing mechanisms acting during adhesion testing were identified. It appears that there exists an optimum roughness below which adhesion strength increases, and above which it decreases with the increase in substrate roughness. Accordingly, applying an expensive surface finish does not have to be a guarantee for achieving the appropriate adhesion of TiN coatings deposited at low temperatures.

Duplex Hard Coatings with Aditional Ion Implantation

In this paper, we present the results of a study of TiN thin films which are deposited by a Physical Vapour Deposition (PVD) and Ion Beam Assisted Deposition (IBAD). In the present investigation the subsequent ion implantation was provided with N2+ ions. The ion implantation was applied to enhance the mechanical properties of surface. The thin film deposition process exerts a number of effects such as crystallographic orientation, morphology, topography, densification of the films.. A variety of analytic techniques were used for characterization, such as scratch test, calo test, Scanning electron microscopy (SEM), Atomic Force Microscope (AFM), X-ray diffraction (XRD) and Energy Dispersive X-ray analysis (EDAX).

Characterization of Hard Coatings Modified with Nitrogen Implantation

In this paper, we present results of a study of TiN films which are deposited by Physical Vapor Deposition and Ion Beam Assisted Deposition. In the present investigation the subsequent ion implantation was provided with N2+ ions. The ion implantation was applied to enhance the mechanical properties of the surface. The film deposition process exerts a number of effects such as crystallographic orientation, morphology, topography, densification of the films. The evolution of the microstructure from porous and columnar grains to densely packed grains is accompanied by changes in mechanical and physical properties. A variety of analytic techniques were used for characterization, such as scratch test, calo test, SEM, AFM, XRD and EDAX. The experimental results indicated that the mechanical hardness is elevated by penetration of nitrogen, whereas the Young’s modulus is significantly elevated. Thin hard coatings deposited by physical vapour deposition (PVD), e.g. titanium nitride (TiN) are frequently used to improve tribological performance in many engineering applications. Ion bombardment during vapour deposition of thin films, colled ion beam assisted deposition (IBAD), exerts a number of effects such as densification, changes in grain size, crystallographic orientation, morphology and topography of the films. This paper describes the successful use of the nanoindentation technique for determination of hardness and elastic modulus. In the nanoindentation technique, hardness and Young’s modulus can be determined by the Oliver and Pharr method. Therefore, in recent years, a number of measurements have been made in which nanoindentation and AFM have been combined.

Influence of Ion Implantation on Tribo and Mechanical Behaviour of Duplex Hard Coatings

In this paper, we present the results of a study of TiN films which are deposited by a Physical Vapor Deposition and Ion Beam Assisted Deposition. In the present investigation the subsequent ion implantation was provided with N2+ ions. The ion implantation was applied to enhance the mechanical properties of surface. In the nanoindentation technique, hardness and Young’s modulus can be determined by the Oliver and Pharr method. Indentation was performed with CSM Nanohardness Tester. The results are analyzed in terms of load-displacement curves, hardness, Young’s modulus, unloading stiffness and elastic recovery The analysis of the indents was performed by Atomic Force Microscope. The stress determination follows the conventional sin2 Ψ method, using a X-ray diffractometer. A variety of analytic techniques were used for characterization, such as scratch test, calo test, SEM, AFM, XRD and EDAX. Therefore, by properly selecting the processing parameters, well-adherent TiN films with high hardness can be obtained on engineering steel substrates, and show a potential for engineering applications. The experimental results indicated that the mechanical hardness is elevated by penetration of nitrogen, whereas the Young’s modulus is significantly elevated.© 2010 ASME

S-Type Cultivator Tines Which Comply With ISO Standard: FEM Analysis of Stresses and Manufacturing Issues

ISO Standard is propagating in all aspects of industries worldwide. In order to keep competitiveness, companies are subjected to necessity for their production to be in accordance with ISO. S-type cultivator tines are used in agriculture for the soil preparation. Dimensions and the methods of testing S-tines are proposed by the standards ISO 5678-1993(E) and ISO 8947-1993(E), respectively. The fatigue test defined by ISO-8947(E) proved to be very rigorous. Stresses which develop in the S-type tine during the fatigue test were determined by the finite element method, using MSC Patran/MD Nastran software packages. Results show that tensile stresses during the test are as high as 1100 MPa (around 160 ksi). It is very strict requirement to have the yield strength higher than that value. This requirement is possible to achieve using thermomechanical treatment, a combination of metal working and heat treatment of mainly high-strength low-alloy (HSLA) steels.© 2009 ASME

Some Tribological Aspects of the Duplex Coatings With Additional Ion Bombardment

A duplex surface treatment involves the sequential application of two surface technologies to produce a surface composition with combined properties. A typical duplex process involves plasma nitriding and the coating treatment of steels. In the paper are presented characteristics of hard coatings, type TiN, produced by classic technology PVD (physical vapour deposition) and IBAD (ion beam assisted deposition). The synthesis of the TiN film by IBAD has been performed by irradiation of Ar ions. The evolution of the microstructure from porous and columnar grains to densel packed grains is accompanied by changes in mechanical and physical properties (1). Subsequent ion implantation was provided with N ions. Wear tests were carried out using a pin-on-ring geometry with no lubrication.. Varieties of analytic techniques were used for characterization, such as scratch test, calo test, SEM, XRD and EDAX. X-ray diffraction studies were undertaken in an attempt to determine the phases present, and perhaps an estimate of grain size from line broadening. The results were correlated with properties determined from mechanical and tribological characterisation.Copyright