Tribological properties of silver coatings prepared by low temperature pulsed DC magnetron sputtering and electroplating for aero-engines fasteners

In this work, the causes of failure of electroplating silver coatings on aero-engine nuts were explored. And the microhardness of low temperature pulsed DC magnetron sputtering silver coatings was increased by 25%, and the bonding force was increased by about 1.2 times. At high temperature, the friction coefficients of magnetron sputtering silver coatings was about 20% lower than that of electroplating silver coatings, and the wear volume was about 90% lower than that of it at maximum. The wear mechanism of magnetron sputtering silver coatings was mainly abrasive wear, while that of electroplating silver coatings was mainly adhesive wear. Besides, the results of molecular dynamics showed that silver coatings would move and aggregate in layers during the friction. •Adhesive wear and abrasive wear cause failure of silver coatings on aero-engine nuts.•Low hardness, poor bonding, and thickness uniformity are defect of silver coatings.•Magnetron sputtering silver coatings better perform at high temperature.•Silver coatings transfers and aggregates during friction.