Desenvolvimento de ferramentas de corte auto-lubrificantes utilizando deposição de filmes finos de MoS2/TiN em multicamadas por magnetron sputtering

Abstract

Lubrication in the manufacturing process represents up to 17 % of the total cost of production, therefore a factor of great interest for the industry. In addition to the high cost, in the field of manufacturing and machining, the use of cutting fluids promotes health and environmental risks. Therefore, one of the focuses in the study of lubricants is to replace chemicals products to make the process cleaner. Currently, the most high-speed cutting tools feature coating that replace the use of liquid lubricants or coolants. The use of solid lubricant films, such as MoS2 and graphite, are used in friction control of friction and wear in severe tribological applications. These coatings are usually formed by plasma deposition techniques such as magnetron sputtering. To produce hard and lubricating coating on fast steel and carbide tool In this work, a hybrid process for the formation of multilayer films of titanium nitride (TiN) and molybdenum disulfide (MoS2) was developed using the techniques of deposition by cathode cage and magnetron sputtering. The films were deposited on M2 steel substrates and WC tools. Vickers microhardness test were performed to quantify the surface resistance of the coated samples. Chemical and morphological characterizations were used in this study to relate the structure, phases and number of film layers to friction change and loss of energy in heat in machining process, X-ray Diffraction (XRD) and Dispersive Energy Spectroscopy (EDS) were used to determine the phases and composition, The morphology was observed by the Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM), it also provided the observation of the superficial changes caused by the deposition with cathodic cage and the thickness of the deposited films. The roughness was measured with a portable rugosimeter and after the layer deposition processes on M2 steel discs friction coefficient was evaluated by HFRR test and in WC tools the machining test was performed with conventional lathe. In the test were presented favorable results to the lubricy of the material, showing less energy loss in the form of heat and consequently, reduced friction, which results in increased service life and less possibility of thermal crack formation in tools subjected to the hybrid process (cathode cage deposition and magnetron sputtering) presented in this paper.