Influence of the Number of Bilayers on the Mechanical and Tribological Properties in [TiN/TiCrN]n Multilayer Coatings Deposited by Magnetron Sputtering

Abstract

In this work the influence of the number of bilayers was studied on the mechanical, tribological and electrochemical properties of multilayer coatings [TiN / TiCrN]n as a function of the number of bilayers n = 1, 25 and 50, deposited by magnetron sputtering. By Xray diffraction (XRD), a cubic crystal structure centered on the faces (FCC) was determined for all coatings and an increase in the compressive stresses that were generated during the deposition process was found by perfilometry; Atomic force microscopy (AFM) determined that by increasing the number of bilayers, the roughness decreased, due to an increase in the density of the system. By nanoindentation it was found that the hardness (H) and the modulus of elasticity (E) increased as the number of bilayers did. By Pin on disk a decrease in the coefficient of friction was observed as the number of bilayers was increased, which was related to the increase in hardness and the reduction of roughness. The results of EIS and Tafel for the electrochemical properties, determined that the corrosion rate decreased due to the fact that a greater barrier to the passage of the electrolyte towards the substrate is promoted when the number of bilayers increases.

Comparative Study of Tribological and Mechanical Properties Between Single Layers of Al2O3 and Si3N4 Deposited on AISI 316 Stainless Steel

“…This homogeneous surface is attributed to a high ion bombardment of Ar + atoms (Bias voltage) generated during the deposition process, modifying the surface morphology of the layers. This bombardment causes an increase of the energy of the adsorbed atoms on the surface of the substrate, generating an increase of the nucleation sites and thus reducing the grain size, roughness and columnar growth, as well as an increase in the density of the coatings [27,28]. Figures 8a and 8b present the roughness and grain size analysis for all the coatings, where it was determined that the Si3N4 coating presented a roughness reduction of 26.78% and a grain size reduction of 17.48% in relation to the Al2O3 coating.…”

“…This behavior is attributed to the hardness presented by this surface causing a higher resistance to be penetrated. The mechanical properties such as hardness (H) and modulus of elasticity (E) were studied using the Oliver and Pharr method [27]. Figure 10 present the results of hardness (H) and reduced modulus of elasticity (Er) of the coatings deposited on the AISI 316 steel substrates, respectively.…”

“…The friction results in dry environment present two characteristic stages, typical of the Pin-On-Disc test. Stage I, known as the start-up period, is associated with the interferential friction mechanism due to the contact of the asperities and the counterpart (100Cr6 steel pin), in which the asperities are reduced, leading to the formation of wear particles or debris [27], these particles on the surface generate a rapid increase in the friction coefficient followed by a slight decrease until it is stabilized. In stage II, the reduction of such asperities is maintained together with the appearance of new defects in the coating, which leads to a stabilization of such friction coefficient [31].…”

Analysis of the Tribological Evolution of Nitride-Based Coatings

“…A specific type of coatings such as those based on nitrides, which have generated great interest within various and novel coating systems, these coatings were implemented approximately since 1970 [4], being one of the first anti-wear coatings used in the industry. This type of coatings have great hardness, high resistance to wear and high resistance to Tribology corrosion among other interesting properties, such as TiN [4], TiCrN [5], [Al 2 O 3 / Si 3 N 4 ] [6], TiCN [7], BCN [8] among other configurations.…”

Mechanical and Tribological Properties Evolution of [Si3N4/Al2O3]n Multilayer Coatings

“…Continuous industrial demand at a global scale, as well as competitiveness within industries, requires the incorporation of high performance materials to minimize energy loss and to be economically effective [1,2]. Therefore, it is necessary to design tribologically compatible coatings with high wear resistance and low friction, which are able to withstand aggressive environments and provide longer service life to the parts or tools coated with the single layers and multilayers coatings [3][4][5][6][7][8][9][10].…”