Enhancing Electrical Conductivity and Corrosion Resistance of CrN Coating by Pt Addition

Transition-metal nitride coating used to protect the electronic connector devices in marine environment is required to have high electrical conductivity and good corrosion resistance. This study synthesized a novel CrN–Pt coating with a dense growth texture. Pt addition induced a pronounced increase in electrical conductivity and corrosion resistance. The resistivity decreased from 0.0149 Ohm·cm in the CrN coating to 0.000472 Ohm·cm in the CrN–Pt coating, while the corrosion current density decreased from 24 nA/cm2 in the CrN coating to 6.3 nA/cm2 in the CrN–Pt coating. The results of the above studies confirm that Pt doping has significant advantages in improving the electrical conductivity and corrosion resistance of nitride coatings for potential applications in the marine environment.

Controlling Friction and Wear with Anisotropic Microstructures in MoN-Coated Surfaces

This study considers anisotropic microstructures with typical dimensions of a few 10 µm which have been created on steel surfaces by laser surface texturing (LST). It is shown that the subsequent deposition of thin molybdenum nitride coatings by high-power impulse magnetron sputtering (HiPIMS) leads to surfaces that conserve the surface microstructures and exhibit a remarkably large resistance against mechanical wear. Tribological experiments with steel counter bodies are substantially influenced by the relative orientation of the structures and the wear track. Both friction and wear are shown to be modified by more than 30%, with the main effect being the removal of abrasion particles from the mechanical contact. Experiments with alumina counter bodies that hardly provide wear particles show that the orientation has no effect on the abrasion of the counter body. The novelty of the article lies in the combination of MoN coatings with surface texturing.

Controlling friction and wear with anisotropic microstructures in MoN coated surfaces

Steel surfaces have been patterned by laser surface texturing (LST) to create anisotropic microstructures with typical dimensions of a few 10 micrometers. The subsequent deposition of thin molybdenum nitride coatings by high power impulse magnetron sputtering (HiPIMS) leads to surfaces that conserve the surface microstructures and exhibit an extraordinarily large resistance against mechanical wear. Tribological experiments with steel counter bodies show a substantial influence of the relative orientation of structures and wear track on friction and wear. It is pointed out that the main effect is the removal of abrasion particles from the mechanical contact. Analogue experiments with alumina counter bodies that hardly provide wear particles show that the orientation effect is absent.

Effect of Bias Voltage on Microstructure and Properties of Tantalum Nitride Coatings Deposited by RF Magnetron Sputtering

TaNx coatings were deposited by RF magnetron sputtering with different bias voltages. The growth morphology, crystalline structure, chemical bond structure, hardness and elastic modulus, adhesion strength and tribological performance of the coatings were studied as a function of the bias voltage. The results showed that an increasing bias voltage refines the coating grains and facilitates structure densification. Simultaneously, the structure of the TaNx coatings transfers from a composite structure consisting of TaN and Ta2N crystals, through a single composite mainly composed of the Ta2N crystal, to an amorphous structure as the bias voltage increases from low to high, indicating that the phase composition of the TaNx coatings can be varied by the bias voltage. The coating composed of Ta2N crystal showed a good overall performance including enhanced hardness, enhanced adhesive strength, and good tribological performance with enhanced wear resistance and a low friction coefficient of 0.18.