Abstract

TiAlSiN coatings were deposited on YT 15 cemented carbide substrate by reactive direct current magnetron sputtering (DCMS) in a Plasma Immersion Ion Implantation and Deposition (PIII&D) system. The pre-implantation step and the coating deposition were carried out in the same experimental facility. In this article the effects of pre-implantation of several different elements (N, C, and O) were investigated. The adhesion strength, hardness, micro-structure, element concentration, depth profile, and the formation of coatings after the PIII experiments were characterized by a wide variety of techniques such as Rockwell indentation, scratch test, nano-indentation measurement, X-ray diffraction, energy dispersive spectroscopy, and Auger electron spectroscopy. The results showed that the adhesive strength of TiAlSiN coatings was significantly improved on samples pre-implanted with N and O whereas only slightly improved with pre-implantation of C. Additionally, the microstructure and mechanical properties of the TiAlSiN coatings were also altered through pre-implantation. The improved adhesion could be explained by the grain refinement and surface energy enhancement of the substrate by pre-implantation.

Highlights

  • During the past decades, transition-metal nitride coatings, TiN, TiAlN, TiSiN, TiAlSiN, TiAlSiYN, and (TiZrNbTaHf)N in particular, have attracted increasing critical attention and become a research focus in the modern manufacturing industry due to their unique properties including exceeding hardness, resistance against high-temperature oxidation, low friction, and outstanding thermal stability [1,2,3]

  • It can be seen clearly that from each XRD spectrum there are three predominant diffraction peaks (111), (200), (220) corresponding to the B1 (NaCl-type) structure, the same as those observed in TiN or TiAlN. Another discovery claimed our attention in that there was no crystal diffraction peak corresponding to Si element. The reason for this phenomenon may be that Si can substitute Al/Ti at cation lattice sites of the B1-NaCl lattice when the concentration of Si is less than 5 at.%–6 at.% in TiSiN and TiAlSiN coatings, which was verified by other previous studies [18,19]

  • The XRD peak (200) of TiAlSiN coatings pre-implanted with N and O shifted slightly towards a higher angle, implying a decrease in the lattice parameter because of incorporation of other atoms whose radii were smaller than those of the existing atoms [20]; or possibly this shift may be attributed to lattice distortion caused by high energy particle (N+, O+, Ar+ ) bombardment

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Summary

Introduction

Transition-metal nitride coatings, TiN, TiAlN, TiSiN, TiAlSiN, TiAlSiYN, and (TiZrNbTaHf)N in particular, have attracted increasing critical attention and become a research focus in the modern manufacturing industry due to their unique properties including exceeding hardness, resistance against high-temperature oxidation, low friction, and outstanding thermal stability [1,2,3]. TiAlN/TiAlSiN composite multilayer by magnetron sputtering, the experimental results pointed to the conclusion that TiAlN/TiAlSiN composite coating, with its relatively low hardness and columnar structure, could enhance the adhesion strength compared with TiAlSiN single layer. The application of transition layer and multilayer structure to TiAlSiN coating is effective in terms of deposit adhesion improvement, these methods call for further process adjustment or necessitate additional hardware, which raises the manufacturing cost. Immersion Ion Implantation (PIII) is found to be an alternative approach to improve film–substrate cohesion without transferring primary properties (e.g., high hardness, outstanding oxidation, and wear resistance) of the films or involving new equipment and processes. The adhesive strength, microstructure, crystallinity, and the nano-hardness of these coatings were investigated in order to examine the effects of different pre-implanted elements

Pre-Implantation and Deposition
Characterization
Microstructure of As-Deposited Coatings
Adhesion and Mechanical Properties of the Coatings
Auger Electron Spectroscopy Analysis
Conclusions
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