NbC-Ni coatings deposited by DC reactive magnetron sputtering: Effect of Ni content on mechanical properties, thermal stability and oxidation resistance

SURFACE & COATINGS TECHNOLOGY

卷:349

Article; Proceedings Paper

Varela, L. B.¹  Fernandes, F.^2,3,4,5  Cavaleiro, A.^4,5  Tschiptschin, A. P.¹ 

[1] Univ Sao Paulo, Met & Mat Engn Dept, Av Prof Mello Moraes 2463, BR-05508030 Sao Paulo, SP, Brazil

[2] Univ Minho, Phys Dept, CFUM UP, P-4800058 Guimaraes, Portugal

[3] Czech Tech Univ, Fac Elect Engn, Dept Control Engn, Tech 2, Prague 16627 6, Czech Republic

[4] Univ Coimbra, Dept Mech Engn, SEG CEMMPRE, Rua Luis Reis Santos, P-3030788 Coimbra, Portugal

[5] IPN LED&MAT, Inst Pedro Nunes, Lab Ensaios Desgaste & Mat, Rua Pedro Nunes, P-3030199 Coimbra, Portugal

关键词: NbC-Ni coatings;    Magnetron sputtering;    Structure;    Mechanical properties;    Adhesion;    Oxidation resistance;    Thermal stability;   

DOI  :  10.1016/j.surfcoat.2018.06.068

来源: Elsevier

【 摘 要 】

Hard coatings have been widely used in the machine tool industry to increase the wear resistance and hence to improve their service lifetime, as a result of their better mechanical properties. Most of the studies focused more in nitrides and less in carbides. In this study, we evaluated the effect of Ni additions on the properties of NbC films deposited by magnetron sputtering. In particular, we investigated the microstructure, chemical composition, mechanical properties, oxidation resistance and thermal annealing of the films. The properties of Ni rich coatings were compared to a NbC film deposited as reference. All the films displayed a columnar morphology with columns extending from the substrate up to the surface. Increasing the Ni content decreases the NbC columns diameter and their level of compactness. Excluding the substrate contribution, all the diffraction peaks could be generally assigned to the fcc NaCl type structure. A progressive decrease of grain sizes, down to 2.5 non is observed, with Ni additions higher than 17 at.% Ni, leading to a quasi-amorphous structure. Precipitation of a hexagonal NiCx phase led to an antagonistic shift of the (111) emphases and (200) NbC peaks to the right and to the left, respectively. The hardness of the films increased with increasing Ni content in the range of 0 < at.% Ni < 13 and then progressively decreased with further Ni additions. Annealing performed at 600 and 800 degrees C increased the hardness and Young's modulus of the films. Plastic deformation resistance H-3/E-2 parameters also showed a growing trend with Ni additions. TGA measurements showed that Ni additions increased the oxidation performance of the coatings. The onset point of oxidation of the films is higher by 100 degrees C for Ni containing films independently of the Ni amount, when compared to NbC nickel free films.

【 授权许可】

Free