Investigation of borided layers contribution on the wear resistance and adhesion of TiN coatings

Abstract

The purpose of the investigation was to examine the possibility of improving tool life by reducing the wear effect and improving the adhesion of a thin film through a compound configuration that consists in boriding and PVD deposition. Single layer coatings of TiN were deposited by PVD (cathodic arc) on quenched and tempered and on borided powder metallurgy (P/M) AISI M2 steel. Adhesion test was performed according VDI 3198. Microhardness measurements were performed on Vickers scale and the tribological behavior evaluated through dry sliding wear test, using a ball-on-disk apparatus. The wear tracks were analyzed through scanning electron microscopy (SEM) and confocal microscopy. After the wear test the samples were transversally cut, coating and substrate were investigated using scanning electron microscopy (SEM). The results showed a better adhesion of the coating for the borided sample comparing to the quenched and tempered sample. The wear mechanisms of quenched/tempered-TiN (Q/T-TiN) samples against Al 2 O 3 ball were different from the wear mechanisms of borided-TiN (B-TiN) sample against Al 2 O 3 ball.

Microstructural and tribological characterization of niobium boride coating produced on AISI 1020 steel via multicomponent boriding

“…This could be due to the microstructure heterogeneity of boroniobized samples. While the AISI 52100 steel ball slides over an SiC-coated AISI 1020 surface in the untreated condition leading to an artificial reduction of the wear coefficient for this surface condition [28,[41][42][43], the presence of the porous region in the iron/niobium borides interface in the boroniobized samples may lead to a decrease in the load bearing capacity of the substrate, accelerating the beginning of the wear process through the delamination of the niobium boride layer [44][45][46][47]. Indeed, for a 0.98 N applied load and 0.5 g cm −3 abrasive slurry concentration (lower k according to table 1), the wear crater depth obtained from equation (2) ranged from 22.5 to 87.3 μm for a sliding distance variation of 4-96 m. For the condition that showed the higher wear coefficient, 0.49 N applied load and 0.5 g cm −3 slurry concentration, the wear crater depth ranged from 32.3 to 84.5 μm for the same sliding distance variation.…”