Multilayer Diamond Coatings Applied to Micro-End-Milling of Cemented Carbide
authors Silva, EL; Pratas, S; Neto, MA; Fernandes, CM; Figueiredo, D; Silva, RF
nationality International
author keywords micro-end-milling; CVD diamond; multilayer coating; cemented carbide; transmission electron microscopy
abstract Cobalt-cemented carbide micro-end mills were coated with diamond grown by chemical vapor deposition (CVD), with the purpose of micro-machining cemented carbides. The diamond coatings were designed with a multilayer architecture, alternating between sub-microcrystalline and nanocrystalline diamond layers. The structure of the coatings was studied by transmission electron microscopy. High adhesion to the chemically pre-treated WC-7Co tool substrates was observed by Rockwell C indentation, with the diamond coatings withstanding a critical load of 1250 N. The coated tools were tested for micro-end-milling of WC-15Co under air-cooling conditions, being able to cut more than 6500 m over a period of 120 min, after which a flank wear of 47.8 mu m was attained. The machining performance and wear behavior of the micro-cutters was studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Crystallographic analysis through cross-sectional selected area electron diffraction patterns, along with characterization in dark-field and HRTEM modes, provided a possible correlation between interfacial stress relaxation and wear properties of the coatings. Overall, this work demonstrates that high adhesion of diamond coatings can be achieved by proper combination of chemical attack and coating architecture. By preventing catastrophic delamination, multilayer CVD diamond coatings are central towards the enhancement of the wear properties and mechanical robustness of carbide tools used for micro-machining of ultra-hard materials.
publisher MDPI
isbn 1996-1944
year published 2021
volume 14
issue 12
digital object identifier (doi) 10.3390/ma14123333
web of science category 12
subject category Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter
unique article identifier WOS:000666527100001
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journal impact factor 3.057
5 year journal impact factor 3.424
category normalized journal impact factor percentile 58.121
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