Toughness enhancement in zirconium-tungsten-nitride nanocrystalline hard coatings

Abstract

An approach is presented to increase the toughness (KIC) while retaining high hardness (H) of Zr-W-N nanocrystalline coatings using energetic ions bombardment. Tuning KIC and H values was made possible by a careful control over the substrate bias, i.e., the kinetic energy (Uk∼9-99 J/cm3) of the bombarding ions, while keeping the deposition temperature relatively low (200 oC). Structural and mechanical characterization revealed a maximum wear resistance (H/Er∼0.23) and fracture toughness (KIC∼2.25 MPam) of ZrWN coatings at Uk∼72 J/cm3. A direct Uk-microstructure-KIC-H relationship suggests that tailoring mechanical properties for a given application is possible by tuning Uk and, hence, ZrWN-coatings’ microstructure.

Low temperature (Ts/Tm < 0.1) epitaxial growth of HfN/MgO(001) via reactive HiPIMS with metal-ion synchronized substrate bias

“…Refractory transition-metal (TM) nitride thin films are employed in a wide variety of applications due to their unique combination of properties including high hardness, [1][2][3][4][5] scratch and abrasion resistance, 6 low coefficient of friction, 7 high-temperature oxidation resistance, [8][9][10] and tunable optical, 11,12 electrical, [12][13][14] and thermal 15 properties. As a result, TM nitrides have gained considerable interest over the past few decades and become technologically important for use as hard wear-resistant coatings, 16,17 decorative coatings, 18 and diffusion barriers; 15,[19][20][21][22][23][24] the latter because of their high thermal stability 8,10 and low electrical resistivity. 13 Epitaxial TM and rare-earth nitride [TiN, 25 CrN, 26 HfN, 27 CeN, 28 ZrN, 14 and VN (Ref.…”

Corrosion Resistant TiTaN and TiTaAlN Thin Films Grown by Hybrid HiPIMS/DCMS Using Synchronized Pulsed Substrate Bias with No External Substrate Heating

“…Refractory transition-metal (TM) nitride thin films are used in a wide variety of applications due to their unique combination of properties, which include high hardness [1][2][3][4][5]; scratch and abrasion resistance [6]; low coefficient of friction [7]; high-temperature oxidation resistance [8][9][10]; and tunable optical [11,12], electrical [11,13,14], and thermal [14], properties. As a result, TM nitrides are widely used as wear-resistant coatings [15,16], decorative coatings [17], and diffusion barriers [18][19][20][21][22][23][24]; the latter because of their high thermal stability [10,25] and low electrical resistivity [13].…”