Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Characterization of DLC coating in drilling tools.
Submission Author:
Otávio Pereira , MG
Co-Authors:
Poliana Souza, Marcelo Câmara, William Silva, Jose Rubens Gonçalves Carneiro, Otávio Pereira
Presenter: Otávio Pereira
doi://10.26678/ABCM.COBEM2017.COB17-0631
Abstract
An experimental study on the mechanical properties and adhesion of diamond-like carbon (DLC) coatings was carried out in this work. For this, tools used in machining systems for drilling of high speed steel (HSS) and cemented carbide (WC-Co) were coated by technical PECVD. All analyzes were done in the own tools, being prepared specially by this. In sequence, were made: thickness micrographs and visual analysis of grip of DLC by scanning electron microscopy; topographical images to mark the silicon middle layer in micrometer scales by atomic force microscopy (AFM); wettability tests to identify the type of interaction with water; nanoindentation tests on the coating for hardness and modulus of elasticity measurement; hardness of the substrate and the film adhesion test on a Rockwell hardness test. By topographical analysis (AFM) was confirmed the silicon middle layer with a thickness greater than the DLC itself (1.8 and 1.0 micrometers respectively). The DLC coating presented higher hardness compared both substrates, corresponding to approximately 5 times the hardness of high speed steel (~7.6 GPa) and 2 times the hardness of WC-Co (~13.4 Gpa). The analyzes of the pairs substrate/coating showed that the relationship between their interfaces should be considered, even the WC-Co being harder, its coating obtained lower hardness compared to the HSS. This is associated with the status of substrate before deposition process and its individual properties. It’s important too that the interface has high adhesion by coating, so it can work in the best condition to increase wear resistance, thereby improvement the load capacity of the surface. The properties and therefore the quality of the coating varied with the substrate.
Keywords
characterization, DLC, Drill, HSS, WC-Co
