Application of Taguchi Method to the Optimization of a-C:H Coatings Deposited Using Ion Beam Assisted Physical Vapor Deposition

W H Kao,J H Horng,S H Yao,H C Huang,Y L Su

doi:10.1155/2014/582653

Abstract

The Taguchi design method is used to optimize the adhesion, hardness, and wear resistance properties of a-C:H coatings deposited on AISI M2 steel substrates using the ion beam assisted physical vapor deposition method. The adhesion strength of the coatings is evaluated by means of scratch tests, while the hardness is measured using a nanoindentation tester. Finally, the wear resistance is evaluated by performing cyclic ball-on-disc wear tests. The Taguchi experimental results show that the optimal deposition parameters are as follows: a substrate bias voltage of 90 V, an ion beam voltage of 1 kV, an acetylene flow rate of 21 sccm, and a working distance of 7 cm. Given these optimal processing conditions, the a-C:H coating has a critical load of 99.8 N, a hardness of 25.5 GPa, and a wear rate of 0.4 × 10−6 mm3/Nm.

Highlights

Diamond-like carbon (DLC) coatings were first prepared by Aisenberg and Chabot in 1971 [1] and have an amorphous rather than crystalline structure
The results confirm the effectiveness of the ion beam assisted physical vapor deposition (PVD) method in producing a-C:H coatings with good bonding properties without an intermediate layer given an appropriate specification of the deposition parameters
This study has utilized the Taguchi robust design method to optimize the adhesion, hardness, and wear properties of a-C:H coatings deposited on AISI M2 steel substrates using the ion beam assisted physical vapor deposition (PVD) method

Summary

Introduction

Diamond-like carbon (DLC) coatings were first prepared by Aisenberg and Chabot in 1971 [1] and have an amorphous rather than crystalline structure. The tribological properties of the two different types of coating vary depending on the environment. Generally speaking, both coatings are characterized by high hardness, good corrosion resistance, high thermal conductivity, good electrical resistance, high optical penetration in the infrared range, excellent biological compatibility, a low friction coefficient, and high wear resistance [4,5,6,7,8]. It has been shown that this problem can be mitigated by depositing an intermediate metallic layer between the DLC coating and the substrate [10,11,12,13,14]. In the present study, the Taguchi design method is used to optimize the adhesion, hardness, and wear resistance properties of DLC coatings deposited directly on a steel substrate using the ion beam assisted physical vapor deposition (PVD) method

Methods

Results

Conclusion