Multifunctional Ti based carbonitride coatings for applications in severe environments

Abstract

In this work, the influence of NbZr and ZrSi addition to TiCN coatings are studied, aiming for their use as protective layers for parts subjected to severe corrosion and wear. The coatings with C/N ratios ranging from 0.4 to 2.5 were deposited using the cathodic arc technique in a mixture of N 2 and CH 4 gases, on 316 stainless steel discs and Si (111) wafers. All the coatings exhibited residual compressive stresses, with values ranging from approximately-2.4 GPa to-3.5 GPa. The addition of Si led to an increase in hardness, regardless of the C/N ratio. All coatings with high C/N ratio (~2.5) presented slightly lower stress values and superior performance in 3.5% NaCl corrosive solutions, the best performance being obtained for the TiSiZrCN coating, which exhibited the highest protective efficiency to corrosion (97.8 %), due to its low corrosion current density (1.734 µA/cm 2) and high polarization resistance (31.775 k). The tribological tests, performed at 23 °C and 250 °C, indicated that abrasion and oxidation were the predominant wear mechanism for all

Experimental investigation on chromium-diamond like carbon (Cr-DLC) coating through plasma enhanced chemical vapour deposition (PECVD) on the nozzle needle surface

“…The adhesive strength may have superior bonding, which allows an increase of the tribological characteristics [6][7]. Further, these coated surfaces promote a higher adhesive strength with an increased wear resistance corroborated with superior mechanical properties, corrosion resistance and bioactivity [8][9]. However, to avoid any weakness on DLC adhesiveness during coating of steel substrate, the chromium layer was considered as an intermediate adhesive layer.…”