Glassy carbon manufacture using rapid photonic curing

Photonic curing was explored as a rapid method for producing glassy carbon coatings, reducing processing time from ~ 20 h for conventional thermal processing down to ~ 1 min. A resole-type thermoset polymer resin coated on steel foil was used as a precursor, placed in a nitrogen purged container and exposed to high energy light (~ 27 J/cm2 per pulse for up to 20 pulses). Comparison samples were produced at 800 °C using a conventional nitrogen purged thermal route. For both photonic and conventionally produced coatings, Raman spectroscopy and primary peak XPS data showed sp2 bonded carbon, indicative of bulk glassy carbon. This transformation evolved with increasing number of pulses, and therefore amount of energy transferred to the coating. The produced coatings were resilient, highly smooth, with no evidence of surface defects. XPS analysis indicated greater sp3 content at the immediate surface (5–10 nm) for photonic cured carbon compared with thermally cured carbon, likely due to the local environment (temperature, atmosphere) around the surface during conversion. The ability to rapidly manufacture glassy carbon coatings provides new opportunities to expand the window of applications of glassy carbons in coatings towards large-scale high volume applications.

Laser-patterned carbon coatings on flexible and optically transparent plastic substrates for advanced biomedical sensing and implant applications

Plasma and laser-based processing for tailoring DLC thin film properties for state-of-the-art wearable sensing applications.

Thermohydrodynamic behavior of partially coated plain journal bearings with/without considering wall slip

A thermohydrodynamic model was used to study the influence of partial composite coatings on the behavior of plain journal bearings, considering solid elastic deformations and wall slip occurring at the oil film–polytetrafluoroethylene coating interface, and heat conduction between film, coating, interlayer and basement. The purpose is to design partial polytetrafluoroethylene coating to obtain improved bearing behavior based on analyzing the maximum temperature and minimum film thickness in different coating positions (or slip zones). The influences of coating thickness and coating materials (polytetrafluoroethylene, graphite and diamond-like carbon coatings) at different coating positions are also presented. Results show that polytetrafluoroethylene coatings that are completely located in the film convergent region have a small influence on thermal behavior in both nonslip and slip cases. Without slip, a full polytetrafluoroethylene coating can increase the maximum temperature; however, wall slip occurring on a full polytetrafluoroethylene coating surface is helpful in decreasing the maximum temperature when accompanied by a lower minimum film thickness. A thicker polytetrafluoroethylene coating causes bearing seizures more readily. Unlike polytetrafluoroethylene, graphite and diamond-like carbon coatings improve the thermal behavior.