Fabrication and dry cutting performance of Si3N4/TiC ceramic tools reinforced with the PVD WS2/Zr soft-coatings

WS2/Zr soft-coatings were deposited on Si3N4/TiC ceramic cutting tools by medium-frequency magnetron sputtering together with multi-arc ion plating. Microstructural and fundamental properties of the coatings were examined and dry cutting tests on hardened steel were carried out. The cutting performance and wear characteristic of the coated tools were investigated compared with uncoated tool. Results show that the WS2/Zr coated Si3N4/TiC cutting tools significantly improve the lubricity at the tool chip interface; the cutting force, cutting temperature, friction coefficient and tool wear are reduced and the tool life is increased compared with uncoated tool. Crater wear and flank wear occurred both on uncoated and coated tools. Abrasive wear, adhesions and chipping are the predominant wear mechanisms of uncoated tool on crater wear and flank wear; abrasive wear, coating delamination and chipping are the main wear mechanisms of WS2/Zr coated tools. Friction-reduction and increased wear-resistance are attributed to the formation of a transfer lubricant layer at the tool chip interface during the dry cutting process. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.