Friction and wear performance of ion-beam-deposited diamond-like carbon films on steel substrates

Abstract

DISCLAIMERThis reportwas preparedas an accountof worksponsoredby an agencyof the United States Government. Neitherthe UnitedStates Government nor any agencythereof,norany of their employees,makesany warranty, expressor implied,or assumesany legal liabilityor responsibility for the accuracy, completeness, or usefulnessof any information, apparatus, product,or processdisclosed,or represents that its use wouldnot infringeprivatelyownedrights.Reference hereinto any specificcommercialproduct,process, or serviceby tradename,trademark, .anufacturer, or otherwisedoes not necessarilyconstituteor imply its endorsement, recom-.,endation,or favoringby the United States Government or any agencythereof.The views and opinionsof authors expressedherein do not necessar'_ L_aL¢or renect those of the United States Governmentor anyagencythereof. ¢',? i-_i_THiBi,iTiOi_Oi: _HhSDOCUMENTIS UNt.IMITI_ ABSTRACT In this study, we investigated the friction and wear performance of ion-beam-deposited diamondlike-carbon (DLC) films (1.5 pm thick) on AISI 440C steel substrates. Furthermore, we ran a series of long-duration wear tests under 5, 10, and 20 N load to assess the load-bearing capacity and durability limits of these films under each load. Tests were performed on a ball-ondisk machine in open air at room temperature =22+1°C, and humidity, =30_+5%.For the test conditions explored, we found that (1) the steady-state friction coefficients of pairs without a DLC film were in the range of 0.7 to 0.9 and the average wear rates of 440C balls (9.55 mm diameter) sliding against uncoated 440C disks were on the order of 10-5mm3/N.m, depending on contact load; (2) DLC films reduced the steady-state friction coefficients of test pairs by factors of 6 to 8, and the wear rates of pins by factors of 500 to 2000; (3) The wear of disks coated with a DLC film was virtually unmeasurable while the wear of uncoated disks was quite substantial, (4) these DLC films were able to endure the range of loads, 5 to 20 N, without any delamination and to last over a million cycles before wearing out. During long-duration wear tests, the friction coefficients were initially on the order of 0.15, but decreased to some low values of 0.05 to 0.07 after sliding for 15 to 25 km, depending on the load, and remained low until wearing out. This low-friction regime was correlated with the formation of a carbon-rich transfer film on the wear scar of 440C balls. Microlaser-Raman spectroscopy and scanning-electron microscopy were used to examine the structure and chemistry of worn surfaces and to elucidate the wear-and friction-reducing mechanisms of the DLC film.

Friction and wear performance of diamond-like carbon films grown in various source gas plasmas

“…The family of DLC coatings is rather large [4,32] and, depending on deposition method and/or condition, more diamondlike or more-graphitelike films may be produced. Furthermore, highly hydrogenated or totally hydrogen-free films can be produced.…”

Tribocamada Formada Em Revestimentos Multifuncionais: Influência Do Ambiente

“…A natureza da contraface pode influenciar significativamente a espessura e a natureza da tribocamada. (24,(35)(36)(37)(38) A literatura mostra, claramente, que o ambiente exerce uma importância fundamental na cinética de formação e na composição da camada triboativa influenciando, portanto, fortemente no atrito e níveis de desgaste. Reações triboquímicas entre o filme transferido e o contra-corpo podem gerar a formação de estruturas complexas.…”

Superlubricity and Wearless Sliding in Diamondlike Carbon Films

“…These particles (sometimes referred to as "third bodies") may be smeared on one or both sliding surfaces as thin films (referred to as "transfer layers"), and the shear rheology of such films may also have strong influence on friction. In the case of diamond and DLC films rubbing against steel or ceramic counterfaces, the debris particles from the wear of carbon films have a disordered graphitic microstructure and are often smeared on the rubbing surfaces of steel and ceramic balls as thin transfer layers [9,10,[31][32][33][34][35]. In most cases, formation of such transfer layers on sliding-ball surfaces is very beneficial and often leads to low friction.…”

“…In fact, the systematic studies on carbon-based materials and coatings in our laboratory since the late 1980s have led to the discovery of amorphous carbon films that provide extremely low friction and wear coefficients 5 [8][9][10][11][12][13][14][15]. One of the films that we optimized over the years provided friction and wear coefficients of 0.001 to 0.005 and 10 -11 to 10 -10 mm 3 /N.m, respectively, when tested in inert gases or high vacuum [14,15,16].…”