Effect of Graded Bias Voltage on the Microstructure of arc-PVD CrN Films and its Response in Electrochemical & Mechanical Behavior

TL;DR

This study investigates how different bias voltages during arc-PVD deposition influence the microstructure, corrosion resistance, and mechanical properties of CrN films, revealing that higher bias voltages improve hardness but may increase defect-related failure.

Contribution

It provides new insights into how graded bias voltages affect microstructural features and performance of CrN coatings, linking process parameters to functional properties.

Findings

Higher bias voltage (-80 V) increases nano-hardness and elastic modulus.

Bias voltage variations influence corrosion resistance through defect formation.

Microstructural changes affect failure mechanisms and spallation behavior.

Abstract

The effect of graded or constant bias voltages (-40 V, -80 V and -40/60/80 V) on size grain and surface defects of arc PVD deposited CrN films was investigated. Corrosion resistance evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic curves (Tafel) and the mechanical behavior evaluated by means of instrumented nanoindentation and scratch testing was correlated with the microstructural changes. It was found that the bias voltage variation affects corrosion behavior due to the presence of defects (i.e. open voids, droplets) which also affects the failure mechanisms and increasing spallation. High bias voltage (-80 V) increases nano-hardness and the elastic modulus due to the dense microstructure of the CrN coating.