Characterization and Wear Response of Magnetron Sputtered W–B and W–Ti–B Coatings on WC–Co Tools

Joanna Radziejewska,Tomasz Mościcki,Rafał Psiuk

doi:10.3390/coatings10121231

Joanna Radziejewska, Tomasz Mościcki + Show 1 more

Open Access

https://doi.org/10.3390/coatings10121231

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Abstract

In this work, α-WB2 and (W,Ti)B2 borides were applied as wear-resistant coatings to commercial WC–Co cutting inserts. Properties of coatings deposited by magnetron sputtering on WC–Co tools were studied. The crystal structure and chemical composition were analyzed. Vickers hardness and surface roughness were determined and wear test in semi-dry conditions was performed. The W–B and W–Ti–B coatings deposited on WC–Co substrate were smooth and very hard. However, titanium alloy W-B films with Vickers hardness of 3630 ± 260 HV0.02 were characterized by lower adhesion to the substrate, influencing the wear mechanism. Turning tests carried out on 304 stainless steel showed that the W–B film caused less wear compared to uncoated insert. Moreover, when W–B coating was applied, flank wear was reduced by 30% compared to uncoated WC–Co insert. Additionally, coating prevented chipping of the edge during cutting under test conditions. The research shows that W–B film deposited by magnetron sputtering has great potential as a coating for cutting tools for difficult-to-cut materials.

Highlights

New tool materials or coatings are needed for special applications, in machining of difficult-to-machine materials [1]
Turning material lossTest of W–Ti–B film compared to other samples and the varying values of the volume loss of material in this case
Very hard delaminated fragments of the films can accelerate wear before they are Cutting test was performed for WC–Co insert and for insert with W–B coating

Summary

Introduction

New tool materials or coatings are needed for special applications, in machining of difficult-to-machine materials [1]. Coatings should be characterized by hardness, strength, and chemical inertness. Such properties are exhibited by boride films [2,3,4,5,6,7]. There are numerous compounds with boron that have good wear resistance, such as ZrB2 , TiB2 , BN, and Ti(B,N) [8]. Tungsten borides and ternary transition (TM) metal-diborides possess very high application potential. The ternary TM-diboride coating films showing exceptionally high phase stability and mechanical properties, even at high temperature or even after exposition to high temperatures [2].

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