Study of nanostructured HfN coatings using layers arrangement
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Study of nanostructured HfN coatings using layers arrangement L. García González1, S.R. Vásquez García2, D.J. Araujo-Pérez1, A. K. García Rueda1, L. Zamora Peredo1, N. Flores Ramírez3, L. Domratcheva Lvova3, T. Hernández Quiroz1 and J. Hernández Torres1 1 Centro de Investigación en Micro y Nanotecnología, Universidad Veracruzana, Veracruz, 94294, Boca del Río, Veracruz, México. 2 Posgrado de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, 58000, Morelia, Michoacán, México. 3 Facultad de Ingeniería en Tecnología de la Madera, Edificio D, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México
ABSTRACT In the present investigation, nanostructured ceramic HfN coatings were deposited onto silicon (100) wafer by magnetron sputtering DC method, from a metallic Hf target. The deposition process followed by a similar pattern as the multilayer film deposition, using cycles with the nitrogen gas turned on for 90 s and turned off for 15 s; four sets of samples were obtained using 5, 10, 15 and 20 cycles. The X ray diffraction (XRD) identified the presence of two different cubic crystalline phases of HfN, corroborated by Rietveld analysis. The Vickers hardness test showed that the hardness values increases with more cycles, due to a higher compressive stress evaluated by Stoney formula. All samples were investigated with no visible fracture until 10 grf for the 5 cycles sample; however, no fractures were visible at all for the 15 and 20 cycle samples for that given load, instead fractures started to appear at 25grf for the 10 and 15 cycles coating. Eventually it is distinguished that, the thickness and morphology of the coatings were measured by field emission scanning electron microscopy FE-SEM. As well as, the thickness increased from 0.4 μm to almost 1.33 μm as the number of cycles also increased, where we can observe the formation of columnar growth, moreover it is possible to distinguish the formation of two different clusters which might be related to different phases. INTRODUCTION In the last years, a lot of research has been conducted for the formation of coatings for mechanical tools, with the objective to provide them higher hardness and wear resistance. Habitually, they were fabricated by chemical vapor deposition (CVD) or physical vapor deposition (PVD), however, from all the techniques used to obtain these coatings, the PVD might have had the heyday in the last twenty years both at academic and industrial level [1,2]. The synthesis of coatings by the sputtering method is one of the most versatile in terms of the amount of materials that can be obtained as a coating, i.e. varying from metals to ceramics. These materials are sputtered from a surface called target to be deposited in the surface of interest, known as substrate. The original material can be maintaining its chemical composition and structure or be modified in a controlled way. This process involves essentially to rip atoms from the target, which then they travel until they collide and condensate in the substrat
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