•The effect of alloying on the properties of hard coatings is reviewed.•The influence of coating architecture on the performance of hard coatings is reported.•HiPIMS coatings exhibits superior ...mechanical properties compared to dcMS.
Hard coatings are extensively used in various industries, including automotive, aerospace and tooling industries. Hard coatings are deposited using, typically, chemical vapor deposition (CVD) and physical vapor deposition (PVD) techniques. Among these, magnetron sputtering (MS) is widely used to deposit hard transition metal nitrides and oxides. In the last 20 years, technological development gave birth to a highly ionized magnetron sputtering technique called High Power Impulse Magnetron Sputtering (HiPIMS) that allows application tailored coating development.
The present article reviews studies on the deposition of hard coatings by HiPIMS and direct current MS (dcMS). The effect of alloying and coating architecture design on mechanical properties is highlighted, and comparative studies highlighting the difference between the two techniques are reviewed, while the effect of different HiPIMS deposition parameters on the mechanical properties of the coatings is presented and discussed.
Titanium carbide (TiC) coatings are widely used in several industrial applications, including tooling and tribological applications. These materials are used due to their mechanical, tribological and ...wear resistance properties, and chemical inertness. Hard TiC coatings are conventionally deposited using chemical vapor deposition techniques at temperatures in the range of 1000 °C, which limits its application to temperature sensitive substrate materials. Therefore, plasma enhanced chemical vapor deposition has been utilized as an alternative deposition technique, showing good coating performance at temperatures as low as 500 °C. Recent technology developments have seen the emergence of high-power impulse magnetron sputtering (HiPIMS) as a promising approach to deposit high quality TiC coatings at ambient temperatures, thus making the use of new substrate materials and new applications possible.
The present article introduces magnetron sputtered TiC-based coatings with an emphasis on their structural, mechanical and tribological properties. An overview of the most relevant technological approaches for the development of binary and ternary TiC-based coatings over recent decades is presented. The relationship between the deposition parameters and the final coating properties is highlighted and discussed. Steering towards ternary TiC-based system have shown to improve the coating properties. In this light, several chemical elements have been used resulting in the formation of various coating structures including metastable solid solution, binary and/or ternary phases, or mixtures thereof. The benefit of adding a third element is discussed and its impact on the coating properties is highlighted. Finally, new outlook for potential applications is presented.
•Summary of titanium carbide-based films mechanical and tribological properties.•Properties of ternary Ti-X-C.•Deposition process-to-coating properties relationship.•Impact of high flux-low energy deposition process such as HiPIMS on TiC-based films.•Future research directions and applications are highlighted.
The quality of coatings deposited by magnetron sputtering is known to depend on, among others, the magnetic field strength (Φ) and the magnetic field configuration. Furthermore, high power impulse ...magnetron sputtering (HiPIMS) is known to result in low defect - high density coatings, and is therefore used to deposit barrier coatings against wear and corrosion. The influence of varying the Φ, on deposition rate (R), structure and hardness of titanium nitride coatings prepared by HiPIMS and dc magnetron sputtering (dcMS) was investigated. At 22mT, the ratio between HiPIMS deposition rate and dcMS deposition rate (RHiPIMS/RdcMS) was almost equal to 1. As Φ was increased from 22mT to 35mT, R decreased by 28% for HiPIMS and increased by 15.6% for dcMS, and RHiPIMS/RdcMS was reduced from 1 to 0.63. From 35mT to 44mT, the decrease in R slowed to 6% for HiPIMS and to 12.5% for dcMS. The (111) orientation was dominant over (200) orientation for both HiPIMS and dcMS, and become less dominant with the Φ in the case of dcMS. The residual stresses and surface roughness were determined and their evolution with Φ is highlighted. Mechanical characterization of the deposited coatings was performed, where the hardness tests showed that on average the HiPIMS coatings (29-34GPa) were some 5 GPa harder than dcMS coatings (25-27GPa).
•TiN films were deposited using HiPIMS and dcMS technologies.•The effect of magnetic field strength on structure, hardness and deposition rate of TiN coatings was studied.•TiN coatings obtained using HIPIMS have shown a higher hardness than those obtained using dcMS..•The hardness did not show a noticeable change with the magnetic field strength in the range studied 22-44mT.
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•TiN films were deposited using HiPIMS and dcMS technologies.•The effect of nitrogen content of TixN(1−x), on structure, hardness and corrosion of TiN coatings was studied.•TiN ...coatings obtained using HIPIMS have shown a maximum hardness as a function of the nitrogen content.•The H/E ratio evolution with the nitrogen flow have shown also a maximum.•The corrosion protection efficiency was higher than 90% for all coatings deposited with HiPIMS.
The effect of nitrogen content on the structural, mechanical and corrosion properties of titanium nitride (TixN1−x) coatings deposited by high power impulse magnetron sputtering (HiPIMS) is investigated. The XRD results showed a (111) oriented crystalline structure at low nitrogen flow rate Qv(N2), and a mixed (111) and (200) at high Qv(N2). The average grain size was derived from XRD results and was found to increase with increasing N2 flow. The hardness results showed a maximum with variation of nitrogen content. All coatings exhibited excellent protection efficiency in acidic media compared to the uncoated steel samples, with protection efficiency reaching up to 98.9%. For reference, direct current magnetron sputtered (dcMS) coatings were deposited and investigated, confirming the superior performance of the HiPIMS coatings.
•Recent advances in the application of 2D-BP as ETM and HTM for PCSs are reviewed.•Working mechanisms of 2D-BP as carrier transport material in PSCs are highlighted.•Future research lines for the use ...of 2D-BP in thin film solar cells are proposed.
Perovskite solar cells (PSCs) are the fast-growing branches of thin film photovoltaic technologies in the recent years. This technology offers several advantages; however, efforts are still being made to improve its performance and stability. On the other hand, two-dimensional (2D) black phosphorus (BP) has recently been rediscovered as a very promising 2D layered material for applications in electronic and optoelectronic devices. Thanks to its fundamental properties and structure, this material has opened up new opportunities for use in perovskite solar cells.
In this perspective, this brief review summarizes recent advances in 2D-BP applications as a carrier transporting material in PSCs, tackling subjects on working mechanisms and the positive effect on device performance. Finally, the authors will highlight future research perspectives for the use of 2D-BP in different thin film technologies.
Titanium nitride (TiN) thin films continue to attract unprecedented attention due to their favourable mechanical, thermal, electrical and chemical properties. These properties depend, among others, ...on the morphology and the architecture of the thin film, which can be tuned with different configurations of the deposition parameters. This study presents an experimental investigation to tune the properties of TiN thin film deposited using reactive High-power impulse magnetron sputtering (HiPIMS) at different deposition temperatures (without heating (RT) and 400 °C) and substrate bias potentials (of floating, ground, −20 V, −40 V and −60 V). It is demonstrated that the morphological, structural, and mechanical properties of TiN can be tailored by controlling the deposition temperature and substrate potential bias to deposit dense thin films. A maximum hardness of 30 GPa was achieved for the thin film deposited at RT with a bias voltage of −60 V. The failure mechanism of the fracture toughness exhibited an isotropic behaviour at an applied load of 1 and 2 N respectively, for thin films deposited at RT. In contrast, an anisotropic behaviour was observed in the thin film deposited at a temperature of 400 0C.Overall, the thin film deposited at a temperature of 4000C showed an improved fracture toughness resistance (KIC) than the thin films deposited at RT. The use of bias potential was also observed to be beneficial for improving the KIC of the TiN thin films.
Titanium carbide coatings exhibit a variety of tribological properties depending on their carbon concentration. In the present article, a series of coatings with compositions ranging from pure Ti to ...high carbon nc-TiC/a-C:H nanocomposites are deposited using high-power impulse magnetron sputtering, HiPIMS. The coatings were wear-tested using a ball-on-disk tribometer under different applied loads, and the resulting wear tracks were analysed by Raman spectroscopy. It is observed that the coefficient of friction and wear resistance improve with increasing carbon content. Furthermore, Raman spectroscopy confirms a graphitization at the sliding contact, and shows that the increase of the applied load leads to the enlargement of the sp2 clusters size which explains the self-adaptive behaviour observed during the sliding experiments. Intriguingly, the elasticity index “H/E" does not correlate with the wear rate results. A modified model that takes into consideration the content ratio of the amorphous carbon phase is herewith suggested. The Model better fits the obtained experimental results and predicts the wear behaviour more effectively.
•Increasing the carbon content improves the tribological properties of TiCx coatings.•The sp2-to-sp3 transformation increases with the increase of the applied load.•The nanocomposite nc-TiC/a-C:H coatings exhibit a self-adaptive lubrication behaviour.•Conventional H/E ∼ wear rate relationship is not suitable at high carbon content.•A new model is proposed in predicting the wear behaviour of nc-TiC/a-C:H coatings.
Doped TiAlN thin films are gaining unprecedented attention in recent times due to their functionality and tuneable properties to meet specific demands. The present article focuses on the influence of ...phosphorous-doped TiAlN thin films deposited using high-power impulse magnetron sputtering. Thin films of different elemental compositions of Ti, Al, and P were sputtered on AISI 5206 steel. The thin film cross-sectional morphology and architecture revealed dense and columnar structures. It was indicated that the (111) diffraction peaks in the XRD pattern shifted to higher angles, while the transverse optics (TO)/longitudinal optics (LO) frequency in the optic phonons region of Raman spectra shifted to the right with the modulation wavelength as the Al and P compositions increase. The elementary composition influences the mechanical properties with the maximum hardness of 28 GPa, and adhesion strength of 15 N attained in thin film with the highest Al and P content. The corrosion rate in all the thin films was reduced by at least two orders of magnitude compared with the uncoated samples. The addition of P increases the corrosion resistance of TiAl(P)N thin films.
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