Zirconium nitrides films were synthesized on Ti6Al4V substrates at a bias voltage of −50 V, −80 V, −110 V and −150 V by the direct current (DC) reactive magnetron sputtering technique. The as-deposited coatings were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The wear and corrosion resistance of the obtained ZrN coatings were evaluated to determine the possibility for their implementation in modern biomedical applications. It was found that the intensity of the diffraction peak of the Zr-N phase corresponding to the (1 1 1) crystallographic plane rose as the bias voltage increased, while the ZrN coatings’ thickness reduced from 1.21 µm to 250 nm. The ZrN films’ surface roughness rose up to 75 nm at −150 V. Wear tests showed an increase in the wear rate and wear intensity as the bias voltage increased. Corrosion studies of the ZrN coatings were carried out by three electrochemical methods: open circuit potential (OCP), cyclic voltammetry (polarization measurements) and electrochemical impedance spectroscopy (EIS). All electrochemical measurements confirmed that the highest protection to corrosion is the ZrN coating, which was deposited on the Ti6Al4V substrate at a bias voltage of −150 V.
28 February 2017 in IOP Conference Series: Materials Science and Engineering
Injection molds used in production of plastic components are subject of heavy abrasion wear. The increase of their wear resistance significantly reduces the production cost. In the current work are presented research results of the wear resistance of injection molds made of steel 1.2343, coated with Ti/TiN/TiCN/nc-TiCN: a-C/nc-TiC:a -C/a-C. The study of the wear rate was done using the volumetric method and the influence of the trace length was investigated. The coating thickness, nanohardness, elastic modulus and adhesion were also tested. The coating was applied on unhardened ground specimens, hardened ground specimens and hardened polished specimens.
1 May 2019 in IOP Conference Series: Materials Science and Engineering
Cutting fluids are used to reduce the negative effects of the heat and friction on both tool and work piece. The cutting fluids produce three positive effects in the process: heat removal elimination, lubrication on the chip–tool interface and chip removal. This paper proposes to study the rheological properties of four different type of cutting fluids, as function of their chemical and physical characteristics. The tests were performed using a cone and plate Brookfield viscometer, by determining the rheological parameters and the variation of the apparent viscosity with the temperature. This approach has been used to quantify the performance of the tested products and to compare products in the marketplace.
1 October 2019 in IOP Conference Series: Materials Science and Engineering
The application of Physical Vapor Deposition (PVD) hard coatings is one time-tested practice in the modern industry. Two of the main tendencies that promise a progress in this area are the combination of more chemical elements in one coating and the creation of nanolaminate structures. Since many combinations are possible in the design of the coatings, it could be expected they would have many different properties which are difficult to predict. In an attempt to work simultaneously in both of these directions, one nanolaminate Ti/TiN/AlTiSiN/(AlTiSiN/TiAlSiN)n/AlTiSiN coating was developed and its mechanical properties were tested. The results obtained give a reason to believe that it could be widely practically applied.
TiCrAlN and CrTiAlN multicomponent coatings have been developed using closed-field unbalanced magnetron sputtering technique (CFUBMS) in a gas mixture of Ar + N2. The nitrogen level was varied by using the feedback control of plasma optical emission monitor (OEM). An investigation into the effect of the CFUBMS process parameters on the properties of the coatings was undertaken. The main coatings parameters such as thickness, surface morphology, nanohardness, strength of adhesion and wear resistance were studied by means of ball-cratering method, atomic force microscopy, scanning electron microscopy, scratch tests and nanoindentation measurements. The study revealed strong dependency of the mechanical properties on the nitrogen flow rate. Analysis of the experimental results showed that Cr-based multicomponent coatings possess better mechanical properties than Ti-based coatings at a nitrogen flow rate of 21 sccm: higher value of hardness (≤ 31GPa) and higher scratch resistance (> 30 N).