Performance Of TiN Coatings Research Articles

Improvement of anti‐erosion performance of TiN coatings through using a filtration cathode vacuum arc deposition method

AbstractSand erosion is a major factor that shortens the service life of aircraft in desert regions. The anti‐erosion performance of titanium alloys may be improved using TiN coatings. However, few studies have employed Ti sputtering on Ti transition layers to improve the erosion resistance of the coatings. Herein, TiN coatings with a sputtering layer between the Ti transition layer and the TiN layer were deposited on a Ti–6Al–4V alloy by filtered cathodic vacuum arc deposition. For comparison, another group of TiN coatings without a Ti sputtering layer but processed using the same deposition parameters were prepared. The effects of the nanoscale sputtering layer on the microstructure, mechanical properties, and anti‐erosion performance of the coatings were investigated using scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, and nanoindentation. The results show that the introduction of a Ti sputtering layer promoted the growth of TiN grains, leading to the formation of finer and denser TiN columnar grains. The preferred orientation of the coatings with the sputtering layer is (111) plane, whereas that of the coatings without the sputtering layer is (200) plane. The TiN coatings containing a sputtering layer exhibit higher hardness, elastic modulus, and H3/E2 ratio, which enhances the anti‐erosion performance of the coatings. The coatings with a sputtering layer exhibited better erosion resistance (erosion rate reduced by 75%) than the coatings without a sputtering layer. The underlying mechanism to understand the effect of the sputtering layer on the erosion resistance was discussed based on variations in the microstructure and mechanical properties of the coatings with and without the Ti sputtering layer. Ti sputtering layer was finally proved to be an effective method to improve the erosion resistance of TiN coatings.

Surface hardening of VT-22 alloy by inductively coupled plasma nitriding and magnetron deposition of TiN films

The surface of VT-22 Russian grade titanium alloy samples was modified by inductively coupled plasma (ICP) nitriding followed by magnetron deposition of TiN coatings. Different operating conditions of ICP nitriding and magnetron deposition were considered. The microhardness depth profiles were measured for samples after nitriding. The performance of TiN coatings was examined with a scratch tester.

Studies on the surface modification of TiN coatings using MEVVA ion implantation with selected metallic species

Improvement in the performance of TiN coatings can be achieved using surface modification techniques such as ion implantation. In the present study, physical vapor deposited (PVD) TiN coatings were implanted with Cr, Zr, Nb, Mo and W using the metal evaporation vacuum arc (MEVVA) technique at a constant nominal dose of 4×1016ionscm−2 for all species. The samples were characterized before and after implantation, using Rutherford backscattering (RBS), glancing incident angle X-ray diffraction (GIXRD), atomic force microscopy (AFM) and optical microscopy. Friction and wear studies were performed under dry sliding conditions using a pin-on-disc CSEM Tribometer at 1N load and 450m sliding distance.A reduction in the grain size and surface roughness was observed after implantation with all five species. Little variation was observed in the residual stress values for all implanted TiN coatings, except for W implanted TiN which showed a pronounced increase in compressive residual stress. Mo-implanted samples showed a lower coefficient of friction and higher resistance to breakdown during the initial stages of testing than as-received samples. Significant reduction in wear rate was observed after implanting with Zr and Mo ions compared with unimplanted TiN. The presence of the Ti2N phase was observed with Cr implantation.

Effects of the Deposition Temperature on the Structure and Solar Control Performance of TiN Coatings Prepared by APCVD

Titanium nitride coatings were prepared on common glass slides using TiCl4 and NH3 by atmospheric pressure chemical vapor deposition. The deposition temperature range from 450-650 °C was applied. X-ray diffraction, scanning electron microscope, energy dispersive X-ray Spectrometer, four-point probe sheet resistance instrument and UV-Vis spectrometer were employed to characterize the obtained coatings. The crystallization and electrical conductivity of the coatings was improved with increasing deposition temperature. The reflectance and transmittance spectra showed all the coatings exhibited solar control performance. The coating prepared at 650 °C presented the optimum solar control performance in the present study.

Titanium Nitride - Silicon Nitride Composite Coatings Deposited by Reactive Magnetron Sputtering

The performance of TiN coatings can be improved by the addition of elements promoting the growth of passive layers. Silicon has been incorporated into TiN during deposition in order to form passivating SiO2 at the surface of the coating. Thin films of Ti-Si-N at thicknesses up to 8 microns have been deposited in a reactive unbalanced magnetron sputter system using a titanium and a silicon target. In contrast to the established coatings containing aluminum or chromium the addition of silicon during the deposition of TiN leads to a multiphase composite deposit with sub-micron sized crystalline TiN embedded in an amorphous SiNx matrix. The addition of small amounts of Si to TiN transforms the (111) oriented columnar structure which develops under typical growth conditions into a dense fine grained structure. The microhardness HV 0.1 of the Ti- Si-N films of about 3500 is significantly higher than the one of Si-free TiN films deposited under the same conditions. The stress states of these films are markedlly enhanced with respect to TiN providing a better wear resistance.

Development and characterization of TiN coatings by ion beam assisted deposition process for improved wear resistance

TiN thin layers have been deposited on mould and die steel STD11 by ion beam assisted deposition (IBAD) process and the wear behaviour of the TiN-coated steel has been evaluated. The synthesis of the TiN film has been performed by irradiation of nitrogen or Xe ions under various nitrogen partial pressures with in situ Ti evaporation at an accelerating voltage range from 25 to 40 keV below 200 °C. TiN coating by Xe irradiation was more effective in enhancing the surface hardness and wear resistance. The formation behaviour and mechanical properties of TiN films synthesized by the IBAD process are discussed with Auger electron spectroscopy, X-ray diffraction and other analysis data. In addition, the performance of TiN coatings on precision moulds and dies in semiconductor manufacturing lines is also discussed.

Substrate rotation in PVD processes and effects on the performance of coated tools

TiN and (Ti,Cr)N coatings were deposited on hard metal inserts in a semi-industrial deposition device equipped with two hollow cathode arc evaporators and a substrate holder system with two superimposed basic rotations. The growth conditions on the rotating substrate holder were modelled and the appearance of a beating frequency as well as its absence depending on the position on the substrate holder was shown. The cutting tool inserts were mounted at two positions determined in this way, and coated in one charge. The performance of the coatings was investigated by metal cutting (turning) experiments on 50CrV4 steel. The appearance of the beating frequency in the coating conditions dramatically improved the performance of the (Ti,Cr)N coated samples. The effect is discussed in connection with the performance of TiN coatings deposited in the same deposition device.