Radom, 29 maja 2008 TRIBOCHEMIA - warsztaty tribologiczne INSTYTUT TECHNOLOGII EKSPLOATACJI - PAŃSTWOWY INSTYTUT BADAWCZY

Monika MAKOWSKA Marian GRĄDKOWSKI Institute for Sustainable Technologies - National Research Institute Pulaskiego 6/ Radom TRANSFORMATIONS OF HYDROCARBONS UNDER MIXED FRICTION CONDITIONS

1. 1.Background of the study 2. 2.Experimental procedure 3. 3.Tribological tests results 4. 4.Rubbing surface analysis 5. 5.Investigation of the boundary layer structure 6. 6.Conclusions Work plan:

lubricant Background of the study Dry friction Mixed friction Boundary friction Boundary layers

Experimental procedure 2. Hydraulic oil HL n-Hexadecane – model lubricant C 16 H 34 Lubricants CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3

Experimental procedure   T-11 ball-on-disk machine  T-11 ball-on-disk machine which allows to run tests at elevated temperatures:  material of the friction pair: bearing steel equivalent to AISI 52100,  ball:  6,35 mm (1/4”), R a = 0,3  m, HRC,  disk:  25,4 mm (1”), R a = 0,25  m, HRC.  Rubbing tests conditions (mixed friction):  radius of ball movement on the disk surface: ~10 mm,  load: 9,81 or 49,05 N,  sliding velocity: 0,25 m/s,  sliding distance: 500 m, 3000 m, m,  temperature: 20  170±5°C. Tribological tests conditions

Experimental procedure SEM/EDS Scanning Electron Microscopy Energy Dispersion Spectroscopy Identification of the elements in external layer of rubbing surface Investigation of the wear scar surface FTIRM Fourier Transform Infrared Microspectrophotometry Identification of the organic products on a rubbing surface XPS X-Ray Photoelectron Spectroscopy Identification of the chemical bonds types in external layer of rubbing surface Secondary Ion Mass Spectrometry Determination of the molecular weight of products present on the rubbing surface SIMS

Friction force and wear scar diameter – CH Friction force and wear scar diameter – C 16 H 34 Tribological tests results Dependence of the friction force and wear scar diameter on the temperature of friction pair lubricated with C 16 H 34 (load of 10 N, sliding distance of 500 m) 80-90°C

Dependence of the wear scar diameter on the temperature of friction pair (load of 10 or 50 N, friction distance of 3000 or m) Wear scar diameter – HL-46 Tribological tests results

Profilograms of the disk surfaces after rubbing at different temperatures (load of 10 N, sliding distance of 3000 m) Profilograms – CH Profilograms – C 16 H 34 Rubbing surface analysis

SEM images of the wear scar formed at different temperatures 20 o C100 o C170 o C SEM images – CH SEM images – C 16 H 34

Rubbing surface analysis Products layered on the steel surface at 100  C (sliding distance of 3000 m) SEM images – CH SEM images – C 16 H 34

Relative content of carbon, iron and oxygen on the disk rubbing surface (load of 10 N, distance of 3000 m) along the marked lines: at 100°C (H-100) and 170°C (H-170) (a and b mark the inner and the outer boundary of the friction track) Rubbing surface analysis SEM/EDS analysis – CH SEM/EDS analysis – C 16 H 34

NoNo Content [% (m/m)] IronCarbonOxygenOxygen/carbon 190,82±2,387,15±1,500, ,24±2,2311,80±1,390, ,52±1,0762,05±1,406,98±1,140,11 498,45±2,530, ,59±2,328,94±1,640,24±1,180,03 642,74±1,3150,99±1,645,10±0,550,10 722,88±0,9668,72±1,357,47±1,110,11 884,25±2,2013,75±1,560,48±1,200, ,34±1,8627,72±2,130,68±1,340, ,86±1,8327,37±1,311,04±1,070, ,11±0,8475,68±1,327,77±1,320,10 126,59±0,3476,58±0,8216,32±0,880,21 138,40±0,4780,50±0,9710,52±0,450,13 Rubbing surface analysis Elemental composition of the products layered on the steel surface at 100 o C (blue cells contain data concerning points within the wear scar) Presence of the elements on rubbing surface – SEM/EDS

IR spectra of the tribochemichal products layered on the steel surface after static and rubbing tests n-hexadecane after static test after rubbing test Investigation of the boundary layer structure Identification of the organic products on rubbing surface - FTIRM

Analysis of the IR spectrum of tribochemical products layered on the steel rubbing surface —C=O, >C=C<, —COO—, [R(COO) m ] n Me C—H, —OH =C—H —OH, —COOH, (RCOO) n Me C—O Investigation of the boundary layer structure Identification of the organic products on rubbing surface - FTIRM

Investigation of the boundary layer structure ESCA/XPS survey profile of the steel disk lubricated by n-hexadecane during rubbing test Fe2p O1sC1s Identification of the chemical bond type - XPS

Investigation of the boundary layer structure Analysis of ESCA/XPS spectrum of tribochemichal products Fe2p O1sC1s Fe2p O1s C1s Fe2p O1sC1s Identification of the chemical bond type - XPS

Investigation of the boundary layer structure Result of the overlapping peak separation in O1s photoelectron spectrum Fe2p O1sC1s Fe2p O1s C1s Fe2p O1sC1s Identification of the chemical bond type - XPS Fe 2 O 3 C=O (org.) C–O (org.) O1s bond eV

Investigation of the boundary layer structure Result of the ovelapping peak separation in O1s photoelectron spectrum (532 eV) Identification of the chemical bond type - XPS Fe2pO1sC1s Fe2p O1s C1s Fe2pO1sC1s Fe 2 O 3 C=O (org.) C–O (org.) O1s bond eV

Chemical structure of the products layered on the rubbing surface R = ~3-12 carbon atoms (C 3-12 ) Investigation of the boundary layer structure Identification of the tribochemical products structure –R– H C H H 284,58 C H 286,40 H Fe 711,50 C O 288,28 O 536,18 531,61

Conclusions Conclusions Aliphatic saturated hydrocarbons undergo conversions under the mixed friction conditions These products are organic salts of carboxylic acids and iron They influence the friction conditions and may decrease the wear These phenomena may be applied in lubrication processes, e.g. in developing ecological lubrication techniques

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