Tribological adaptability of TiAlCrN PVD coatings under high performance dry machining conditions

Features of self‐organization in nanostructuring PVD coatings on a base of polyvalent metal nitrides under severe tribological conditions

“…The chromium is oxidized, 28.0% Cr +3 and 39.0% Cr +4 oxides being formed. These films have some lubricious properties as it was shown earlier [9] and could improve wear behavior acting in synergy with protective alumina-based films. The Fig.…”

Self-Organization during Friction in Complex Surface Engineered Tribosystems

“…To study characteristics of the tribofilms, X-ray Photoelectron Spectroscopy (XPS) analysis of the worn tool surface was made (Table 2). A significant amount (around 15.9%) of lubricating [14] chromium oxides were generated (Table 2). A partial chemical transformation of aluminum in the multi-layered coating is taking place: 19.3% of Al retains in the complex nitride, 6.6% of aluminum oxidizes with formation of complex Al-Si-O oxide (mullite), 29.1% aluminum oxides with the formation of Al 2 O 3 (sapphire) [16], which is twice the value compared to mono-layered coating ( Table 2).…”

“…The sapphires and mullites are known as hard oxide crystals that possess high strength, and excellent thermal shock resistance at high temperatures [16,17]. Chromium and silicon oxides have lubricating properties at high temperatures [14,15]. This shifts the friction to a milder mode [5], reducing wear rate.…”

Hierarchical adaptive nanostructured PVD coatings for extreme tribological applications: the quest for nonequilibrium states and emergent behavior

“…Under these, more severe tribological conditions the tribofilms formed during friction consist of protective sapphire-like tribo-oxides [31,96,191,197,[202][203][204][205][206][207] with some nonprotective (at elevated temperatures) rutile-like tribofilms and polyvalent lubricious tribo-oxides of Cr and Nb [87].…”

“…(ii) The elements that form high-temperature stable oxides (such as Al, Si, to a lesser degree Cr and other similar elements) can be used for the coating alloying to enhance formation of protective triboceramic films. (iii) The lubricating action could be performed by the oxygen-containing tribofilms that have enhanced oxidation stability at high temperatures (such as Cr-O tribofilms [203] and amorphous-like Al-O, Si-O tribofilms). This would prevent intensification of chemical and oxidative wear during high-speed cutting [231][232][233][234].…”