Mechanism of wear at extreme load and boundary conditions with ashless anti-wear additives: Analysis of wear surfaces and wear debris

Tribological effects of Cu, Fe and Zn nano-particles, suspended in mineral and bio-based oils

“…Performance of 1.8% ZDDP formulations in IMO and IRO was studied in the presence of 1% nanoparticles as well. Effects of nanoFe were interesting because of steel domination over other metals as the main wear debris constituent in most lubricant applications . Influence of nanoCu and nanoZn was also investigated on four‐ball with an expectation that the tribologically effective metal cladding phenomenon could take place in ZDDP presence (Figure ).…”

Role of MoS2morphology on wear and friction under spectrum loading conditions

“…In comparing the bright patches that run across from end to end in the Mo, S, Fe and O maps indicate the formation of compounds like MoSO 4 , Fe 3 O 4 and MoO 3 on the surface. These oxidation products that form in the presence of oxygen are highly abrasive and tend to increase wear on the surface once they are removed from the surface and behave as third body abrasives . Dark regions on the Fe map indicate a thick layer of tribofilm in the region.…”

“…These oxidation products that form in the presence of oxygen are highly abrasive and tend to increase wear on the surface once they are removed from the surface and behave as third body abrasives. 30 Dark regions on the Fe map indicate a thick layer of tribofilm in the region. It may be hypothesised that the frictional heat produced by the collision of opposing asperities causes the oxides formed on the metal surface to be scraped off and the reaction or the deposition products (formed by chemisorption or physisorption of the additives), react with the metal surface to form an 'anti-wear or EP' tribofilm.…”

An analytical study of tribofilms generated by the interaction of ashless antiwear additives with ZDDP using XANES and nano-indentation

“…However, ZDDP has demerits as it is the main source of P, S and metallic residues of Zn in the surface of the catalytic convertor. The presence of these deposits results in the degradation of the efficiency of the catalytic convertor in engines resulting in higher emissions [1,27,28]. It is also one of the main sources of SAPS.…”

“…Commonly recognized ashless chemistries as lubricant additive are phosphorous and sulfur based compounds i.e. phosphate esters [38], thiophosphates and dithiophosphates [27,29,39,42], alkyl/aryl mono and/or di-hydrocarbyl phosphates, amine salts of aryl/alkyl-aryl or aliphatic di-hydrocarbyl thiophosphates [34], dieter polysulfide's [36], dithiocarbamic [33], amidothiophosphates [42], Benzotriazole-thiadiazol [35] and most recently alkylthioperoxydiphosphates and alkylphosphorofluoridothioates [31,32].…”