Effects of Polyurethane Substrate Pre-Treatment on Pulsed Cathodic Arc Deposited DLC Films

Abstract

Diamond-like carbon (DLC) films were deposited by means of pulsed cathodic arc deposition on pretreated polyurethane (PU) rubber substrates. Tetrachloroethylene was chosen as a dissolution method to remove the plasticizer added in the PU substrates. Scanning electron microscopy (SEM) and Raman spectroscopy were applied to observe and characterize the surface morphologies and compositions of the deposited films, respectively. The tribological behaviours of uncoated and coated rubbers were investigated with ring-on-disc tribo experiments under dry sliding conditions. The coefficients of friction (COFs) of the coated rubbers were 40% lower than those of uncoated rubber and the COFs of different samples decreased first and then increased slightly with the increase in temperature and the time of ultrasonic treatment under dry friction. Based on the above experiments, ultrasonic treatment with tetrachloroethylene contributes to the increase in the wear resistance of DLC films deposited on PU rubbers. The most suitable temperature and time of ultrasonic treatment with tetrachloroethylene is 50 °C for 15 min.

Effect of Fluorine Incorporation on DLC Films Deposited by Pulsed Cathodic Arc Deposition on Nitrile Butadiene Rubber and Polyurethane Rubber Substrates

“…This phenomenon is discussed later in the next paragraph, where a close observation by SEM is carried out on the wear track morphologies. The improvements of tribological performance of DLC coated NBR and PU rubber substrate are expected and consistent with results reported in the literature [22,23,28]. The mass loss of the samples after the tribo-test were measured and displayed in Figure 3.…”

“…Meanwhile, same thin films show similar cracked segment morphologies with the segment size of less than 1 μm on PU rubber substrates. This unique surface condition is caused by thermal mismatch stress during film growing [22,23]. It is evident that incorporation of 4% F imposes little effect on film surface morphologies compared to the morphologic differences caused by the substrate materials.…”

“…The nitrile butadiene rubber and polyurethane rubber sheets were used as sample substrates with a size of 30 mm × 30 mm × 2 mm. The substrates were pretreated in tetrachloroethylene at 50 • C for 15 min in order to remove the plasticizer in the rubber and enhance adhesion between the film and rubber substrates [22]. After this step, both rubber substrates were dried in an oven at 150 • C for 1 h. Then, the substrates were mounted onto sample holders and placed into vacuum chamber.…”