# Effects of Nitrogen Ion Implantation on Wettability and Surface Roughness of WC–Co Tools Used for Wood-Based Panel Machining

## TL;DR

Nitrogen ion implantation improves the wettability of WC–Co tools used in wood machining, with effects depending on ion fluence and time.

## Contribution

Demonstrates dose-dependent and time-dependent wettability changes in WC–Co tools after nitrogen ion implantation.

## Key findings

- Nitrogen ion implantation significantly reduces water contact angles on WC–Co tools.
- Higher ion fluence leads to consistently lower contact angles.
- Wettability partially recovers over time in air exposure.

## Abstract

WC–Co tools implanted with N ions at 50 kV using fluences of 1 × 1017 and 5 × 1017 ions·cm−2

SRIM predicts a modified near-surface layer of ~100 nm for both fluences.

Ra roughness from contact profilometry shows no significant change after implantation.

Water contact angle drops > 70% at 5 h, indicating markedly higher wettability.

Wettability partially recovers: contact-angle reduction achieves ~34% after 30 h in air.

Higher fluence yields consistently lower contact angles, confirming dose dependence.

This work explores the effect of nitrogen ion implantation on the wettability of the cemented tungsten carbide–cobalt (WC–Co) tool surface used for wood-based panel machining. Nitrogen ions with an energy of 50 keV and a fluence of 1 × 1017 and 5 × 1017 cm−2 were implanted into the surface layer of commercially available WC–Co indexable knives using the implanter without a mass-separated ion beam. The wettability was characterized by a contact angle instrument. The implantation of nitrogen ions into WC–Co tools caused a statistically significant and practically useful decrease in the contact angle. This obtained effect was dependent on the fluence of the implanted ions, and it changed over time. This effect may also explain the transfer from the workpiece and the surface capture of carbon atoms in the secondary structure formed during the machining of wood materials on tools with ion implantation. On the other hand, the layer of carbon on the surface of the tool formed during machining explains the reduction in friction coefficient observed in experiments and the increase in tool life during cutting.