Microstructure and tribological behavior of TiAlSiN coatings deposited by deep oscillation magnetron sputtering

Abstract

Development of pulsed‐techniques aimed to generate highly ionized target species and high plasma density opens up a new way to tailor composition, structure, and properties of coatings. In this work, TiAlSiN coatings have been deposited at various negative substrate biases (Vs) using deep oscillation magnetron sputtering by sputtering a TiAlSi compound target in Ar/N2 mixtures. The increase in Vs from −30 to −120 V resulted in a decrease in (111)‐preferred orientation and grain size, together with the increase in residual stress and rough morphology. The nc‐TiAlN/a‐Si3N4 nanocomposite structure was obtained in coatings. The highest hardness and Young's modulus reached 42.4 and 495 GPa at −120 V, respectively. However, at −60 V, the coatings with the highest H/E* and H3/E*2 ratios of 0.095 and 0.332 exhibited excellent adhesion with above HF1 level, the lowest coefficient of friction (COF) of 0.35 and specific wear rate of 2.1 × 10−7 mm3 N−1 m−1. Wear mechanism changed from the mixture of severe adhesive, oxidative and abrasive wear to mild oxidative wear to severe oxidative wear. TiAlSiN coatings with high hardness and H/E* and H3/E*2 ratios exhibited the decrease in COF and wear rate due to refined grains in uniform distribution, which well promoted oxide layers formed on sliding contact surface.

Enhanced Tribocorrosion Resistance of Superhard Ti-C-N Ceramics Coatings

“…It is noted that the coatings deposited at 4 kW and -60 V show random orientations of ( 111) and (220). According to our previous researches, the disappearance of the preferred orientation is attributed to the formation of ultra ne grains [40,41].…”

“…The increased HiPIMS target sputtering power and appropriate substarte bias are e cient to generate high ionization rate of target species and the increased metal ion bombardment [40,43]. Thus, a mass of momentum transfer between the growing lm and the incoming metal ions results in the re nement of microstructure with a less coarse columnar.…”

“…At 4 kW, the asymmetric Ti 2p spectrum is composed of two main peaks originated from Ti 2p3/2 and Ti 2p1/2 peaks at Binding energies (BE) of 457.1/463.1 eV, 455.9/461.8 eV and 458.4/464.4 eV (Fig. 2a), indicating 3 possible species for Ti-(C,N), Ti-N and Ti=O bonds, respectively [38, 40,44]. There are no Ti-C bonds detected in the coatings.…”

“…Although hardness and toughness are always considered as the contradiction because they are hard to achieve simultaneously, heterogeneous interfaces are gradually introduced into nanomaterials to enhance them both as interfacial engineering rapidly develops. Hence, hard yet tough and exible hard multilayer or nanocomposite coatings formed by nanocrystalline, amorphous materials and their interfaces exhibit excellent friction and wear properties [5,13,40]. Moreover, superhard yet tough coatings are always expected by the precise control of chemical composition and microstructure to achieve the combined improvement of hardness and toughness 12 .…”

Equipment and Technology for Combined Ion–Plasma Strengthening of Cutting Tools

“…In all cases, the coating is bombarded during the synthesis by ions accelerated from the gas discharge plasma [23][24][25][26] or using broad beam sources of ions or fast gas atoms [27][28][29]. The bombardment improves adhesion and other properties of the coatings [30][31][32][33][34]. For example, when negative 45-kV pulses with 50 µs width and 50 Hz repetition rate are applied to a substrate made of high speed steel (HSS) instead of bias voltage~80 V, the sputtered titanium nitride coating exhibits improved adhesion and nanostructure, a change of yellow color to brown, an increase in microhardness from 2500 HV to 5000 HV, and a decrease in internal stress [35][36][37].…”