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Scratch tests were performed on thermal-resistant hard Si–C–N coatings deposited on steel (SS) 304, by radio frequency (RF) magnetron sputtering. The abrasion and wear properties were studied by analyzing the changing failure complexion inside the scratch showing a mixture of ductile and brittle properties. The change in loading rate caused noticeable changes in the failure mode. The plasticity was found to have a peripheral domination initially with an increase in load but was replaced by brittle failure on increasing the loading rate. The work of adhesion and wear rate were determined.

In the present paper, the influences of different double layer on wear and scratch performances of commercially pure Titanium (CP-Ti) were investigated. TiO₂/SiO₂ and SiO₂/TiO₂ double layer coatings were deposited on CP-Ti by sol–gel dip coating process and calcined at 750${}^{\circ }$C. The phase structure, cross-sectional morphology, composition, wear track morphologies, adhesion properties, hardness and roughness of uncoated and coated samples were characterized with X-ray diffraction, scanning electron microscopy (SEM), nano-indentation technique, scratch tester and 3D profilometer. Also, the tribological performances of all samples were investigated by a pin-on-disc tribo-tester against Al₂O₃ ball. Results showed that hardness, elastic modulus and adhesion resistance of double layer coated samples were higher than untreated CP-Ti. It was found that these properties of TiO₂/SiO₂ double layer coatings have higher than SiO₂/TiO₂ double layer coating. Additionally, the lowest friction coefficient and wear rates were obtained from TiO₂/SiO₂ double layer coatings. Therefore, it was seen that phase structure, hardness and film adhesion are important factors on the tribological properties of double layer coatings.