The correlation between tribological properties of nanostructure TiN coatings and deposition process parameters in PACVD system

Abstract

Titanium base coatings are being used extensively for improving wear characteristics at the surface of
different parts. Titanium nitride was deposited by Plasma Assisted Chemical Vapor Deposition (PACVD)
techniques with purpose improve interface with substrate, as this can increase wearing of the entire part in
spite of desirable wear behavior of TiN. Samples from H13 steel were prepared and they experienced plasma
nitriding (PN) prior to TiN deposition. TiN coatings were deposited in different conditions of temperature
(475, 500 and 525°C) and duty cycle (33, 40 and 50%). Topographic studies were preceded by Atomic Force
Microscope (AFM). Surface hardness was evaluated using Vickers's micro-hardness test. In order to study
the wear behavior, pin-on-disc test was chosen which included examining the sample's resistance against
pins from steel and tungsten carbide-cobalt. Based on the results obtained it can be observed that increasing
the deposition temperature from 475 to 525°C will lead to higher values of hardness, thus the obtained
weight loss from samples decreased from 2.1 to 0 mg. In addition to that, with increasing the duty cycle of
system from 33 to 50%, weight loss of the TiN coating has increased from 0 to 2mg due to an increase in the
value of surface roughness.