Electronic structure and mechanical properties of hard coatings from the chromium–tungsten nitride system

Abstract

Synthesis and mechanical properties of boron suboxide thin filmsCr 1Ϫx W x N y films were deposited on silicon by rf reactive magnetron sputtering. The phase and texture were determined by x-ray diffraction analysis. All the films crystallize in the fcc phase. Scanning tunneling microscopy revealed a finely grained surface morphology. The grain size decreases with increasing tungsten content in the films. Quantitative values can be assigned to morphology differences through the measurement of the optical reflectivity. Hardness values obtained by nanoindentation, and the packing density significantly increase upon addition of a small percentage of W to CrN. The electronic structure was analyzed using x-ray photoelectron spectroscopy. As deduced from core level binding energy values ͑chemical shifts͒, the W 2 N and Cr 1Ϫx W x N films are more covalent than binary CrN. The higher hardness values in W 2 N and Cr 1Ϫx W x N compounds compared to that of CrN are related to their prominent covalent bonding character between the metal and nitrogen ions.

Tungsten doped chromium nitride coatings

“…3. The (111), (200), (220), (311), and (222) textures were found and assigned to the face-centered-cubic (fcc) B1 NaCl phase [11,12,14,15]. In addition, the diffraction peaks of the films with W content shifted toward lower diffraction angles.…”

“…A binary nitride with a third element is often adopted to adjust parameters such as the lattice constant, grain size, orientation, hardness, elasticity, thermal expansion, or corrosion stability in order to optimize the overall performance of the coatings. Chromium nitride films with a scope of tungsten have also been reported to have excellent hardness, adhesion, and wear properties at elevated temperatures [5,11,12].…”

“…Due to excellent mechanical properties and thermal stability, chromium nitride based coatings are used as protective films in glass molding. For Cr-based ternary nitrides, the structural, mechanical, and oxidation properties of Cr-Me-N (Me = Ti, Mo, Al, Ta, Si, and W) thin films have been extensively studied [5][6][7][8][9][10][11][12]. A binary nitride with a third element is often adopted to adjust parameters such as the lattice constant, grain size, orientation, hardness, elasticity, thermal expansion, or corrosion stability in order to optimize the overall performance of the coatings.…”

Study of Electrical, Mechanical, and Tribological Properties of CrN x Thin Films as a Function of Sputtering Conditions

“…In fact, new advanced metallization materials should combine good electrical properties, comparable to those currently used, with high hardness and elasticity, fine adhesion on Si and low interface stresses. Hitherto, most of the research done on chromium nitride thin films is concentrated either entirely on the electrical properties (Ref [13][14][15] or entirely on the mechanical and tribological properties (Ref [16][17][18][19].…”

Design of Transition-Metal Nitride Thin Films for Thermoelectrics

“…[154][155][156] At Néel temperature (TN) above 270 − 286 K i.e., CrN possesses a paramagnetic B1 (NaCl) crystal structure with a lattice parameter reported to range from 4.135 to 4.185 Å. 143,[157][158][159][160] When temperature below Néel temperature, it changes its phase to antiferromagnetic orthorhombic structure. Rivadulla et al, found that the pressure can induce phase transformation between paramagnetic CrN or antiferromagnetic CrN resulting the TN is pressure dependent parameter.…”