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The effect of model compounds on load-carrying capacity of a-C:H:W coated elements. Mihaela Vlad Czesław Kajdas, Remigiusz Michalczewski. TRIBOCHEMIA Warsztaty Tribologiczne Radom, 29-05-2008. Heavy-loaded lubricated machine components. Coated machine components – 2%.
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The effect of model compounds on load-carrying capacity of a-C:H:W coated elements Mihaela Vlad Czesław Kajdas, Remigiusz Michalczewski
TRIBOCHEMIA Warsztaty Tribologiczne Radom, 29-05-2008 Heavy-loaded lubricated machine components Coated machine components – 2% Coated tools - 80% !
PVD coatings exhibit a poor pitting resistance. Introduction PVD coatings exhibit a excellent scuffing resistance. Source: Michalczewski R. et.al. COST 532 Final Report 2007.
AIM Investigation of the effectiveness of various model compounds as potential anti-wear additives for heavy-loaded a-C:H:W coated steel machine parts
Lubricants • Synthetic base oil (PAO-8) • PAO-8 with CHO compounds (0.1 and 1% wt) • CH3 – (CH2)16 –COOH (stearic acid) • CH3 – (CH2)6 – CH2 – CH = CH – (CH2)7 – COOH (oleic acid) • CH3 – (CH2)5 – CH(OH) – (CH2)10 – COOH (12-hydroxyoctadecanoic acid) • CH3 – (CH2)16 – CH2 – OH (stearyl alcohol) • CH3 – (CH2)15 – CH2 – CO-OCH3 (methyl stearate) • PAO-8 with CHNO compounds (0.1 and 1% wt) • 4-(t-butyl)caprolactam • ε-caprolactam
PAO-8 with organic sulphur compounds (0.1 and 1% wt) benzyl disulphide dibenzyl sulphide octyl sulphide 1-adamantanethiol • PAO-8 with organic phosphorus compounds (0.1 and 1% wt) dibenzyl phosphite diethyl 1‑phenylethyl phosphonate
Automatic loading Tribotester used for testingSCUFFING Test conditions • speed of load increase: 409 N s-1 • initial load: 0 N • maximum load: c.a. 7200 N • rotational speed: 500 rpm FOUR-BALL TESTER (T-02) scuffing resistance
Method for testing lubricants underSCUFFINGconditions seizure Applied load, P Friction torque, Mt scuffing initiation Time, s Pt – scuffingload [N]
coated coated Effect of concentration ofCHOcompounds on coated elements
coated coated Effect of concentration ofCHOcompounds on coated elements
AFM results forCHOcompounds for coated balls 1% oleic acid 0.1% oleic acid RMS= 55.9 nm RMS= 64.5 nm 1% methyl stearate 0.1% methyl stearate RMS= 77.0 nm RMS= 121.0 nm
AFM results ofCHNOcompounds for coated balls 0.1 % ε-caprolactam 1 % ε-caprolactam RMS= 314.2 nm RMS= 61.4 nm
Effect of concentration of organicsulphurcompounds on uncoated elements
Effect of concentration of organicsulphurcompounds on coated elements
SEM/EDS results of organic sulphurcompounds for coated balls 0.1% 1‑adamantanethiol 0.1% benzyl disulphide
Effect of concentration of organicphosphoruscompounds on uncoated elements
Effect of concentration of organicphosphorus compounds on coated elements
SEM/EDS results of organic phosphoruscompounds for coated balls 0.1% dibenzyl phosphite 1% dibenzyl phosphite
Conclusions • CHO/CHNOcompounds are not effective for preventing the scuffing initiation of a-C:H:W coated ballsand thus coated machine components, for example: • Comparingoleic acidwithmethyl stearateit is seen that the tested system lubricated with PAO-8 includingoleic acidgenerates more smoother surface than that obtained applyingmethylstearate. The difference might be connected with the polarity of these compounds (oleic acidis more polar thanmethyl stearate).
Only one of organicsulphurcompound (1-adamantanethiol) at 0.1% wt. and 1% wt. concentration, in the base oil, showed an increase in scuffing load value for a-C:H:W- a-C:H:W tribosystem. 1-Adamantanethiol • Benzyl disulphideAW/EP model additive with the treat rate up to 1% wt. increased the scuffing load values for the uncoated steel tribosystem, but the increase in concentration of this compound is harmful for coated balls. Benzyl disulphide
The organicphosphoruscompounds at the treat rate of 0.1% and 1% wt. in the base oil did not show any improvement in scuffing load values for the coated balls. • On the other hand, the increasing concentration of thesephosphorus compounds containing in the base oil, improved the scuffing initiation for the steel‑steel tribosystem.
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The effect of model compounds on load-carrying capacity of a-C:H:W coated elements Mihaela Vlad Czesław Kajdas, Remigiusz Michalczewski