Hard and Highly Adhesive AlMgB14 Coatings RF Sputtered on Tungsten Carbide and High-Speed Steel

Alexander M Grishin; Vadim V Putrolaynen

doi:10.3390/ma16216930

Hard and Highly Adhesive AlMgB₁₄ Coatings RF Sputtered on Tungsten Carbide and High-Speed Steel

Materials (Basel). 2023 Oct 28;16(21):6930. doi: 10.3390/ma16216930.

Authors

Alexander M Grishin^{1

2}, Vadim V Putrolaynen³

Affiliations

¹ Division of Electronics and Embedded Systems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Kista, SE-164 40 Stockholm, Sweden.
² INMATECH Intelligent Materials Technology, SE-127 51 Skärholmen, Sweden.
³ Department of Electronics and Electrical Power Engineering, Institute of Physics and Electronics, Petrozavodsk State University, 185000 Petrozavodsk, Russia.

Abstract

We report a new industrial application of aluminum magnesium boride AlMgB₁₄ (BAM) coatings to enhance the hardness of tungsten carbide ceramic (WC-Co) and high-speed steel tools. BAM films were deposited by RF magnetron sputtering of a single dense stoichiometric ceramic target onto commercial WC-Co turning inserts and R6M5 steel drill bits. High target sputtering power and sufficiently short target-to-substrate distance were found to be critical processing conditions. Very smooth (6.6 nm RMS surface roughness onto Si wafers) and hard AlMgB₁₄ coatings enhance the hardness of WC-Co inserts and high-speed R6M5 steel by a factor of two and three, respectively. Complete coating spallation failure occurred at a scratch adhesion strength of 18 N. High work of adhesion and low friction coefficient, estimated for BAM onto drill bits, was as high as 64 J/m² and as low as 0.07, respectively, more than twice the surpass characteristics of N-doped diamond-like carbon (DLC) films deposited onto nitride high-speed W6Mo5Cr4V2 steel.

Keywords: elastic recovery ratio; elastic strain index; friction coefficient; micro and nanohardness; resistance to plastic deformation ratio; work of adhesion.

Grants and funding

The APC was funded by KTH Royal Institute of Technology.