# Improvement in Surface Hardness and Wear Resistance of ADI via Arc-Deposited CrAlSiN Multilayer Films

## TL;DR

This study improves the hardness and wear resistance of ductile iron by depositing CrAlSiN films using a specific gas flow ratio.

## Contribution

A novel method of enhancing ADI surface properties via arc-deposited CrAlSiN multilayer films with optimized gas flow ratios.

## Key findings

- CrN/Al(Si)N nano-multilayered films were successfully synthesized using cathodic arc deposition.
- Lower Ar/N2 gas flow ratios increased surface hardness and reduced wear rates in ADI specimens.
- S1 condition achieved the highest hardness (1479 HV0.1) and lowest wear rate (1.6 × 10−⁶ g/m).

## Abstract

In this study, as-cast ductile iron was austempered to produce austempered ductile iron (ADI). A CrAlSiN film was then deposited on the surface of ADI specimens using the cathodic arc deposition (CAD) method. The gas flow ratio of Ar/N2 varied (2, 2.5, and 3) under different processing parameters, designated as S1, S2, and S3, respectively. The composition, structure, hardness, adhesion, and wear resistance of the coated specimens were analyzed to evaluate the effect of the gas flow ratio on surface hardness and abrasion resistance. The experimental results indicated that CrN/Al(Si)N nano-multilayered films were successfully synthesized using oppositely positioned dual targets (Cr and AlSi) reacting with N2 gas during the CAD process. The coatings significantly enhanced the surface hardness and wear resistance of ADI. A comparison of the three coating conditions with varying gas flow ratios revealed that as the Ar/N2 gas flow ratio decreased (i.e., N2 gas flow increased), the surface hardness of the coated ADI specimens increased while the abrasion rate decreased. Among the tested conditions, S1 exhibited the highest hardness (1479 HV0.1) and the lowest wear rate (1.6 × 10−⁶ g/m).