Rubber Bonded Brass-Coated Steel Tire Cords: An Adhesion Mechanism Study

Adhesion between brass-coated steel tire cords and rubber has been studied using surface sensitive characterization techniques such as Time-Of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Grazing Incidence Angle X-ray Diffraction (GIXRD). Normally drawn samples were first laminated in order to obtain a flat surface conducive to the GIXRD technique and then cured to a standard belt rubber compound. Cord samples extracted from such cured specimens were used to observe the effects of changing the copper (Cu) content in the brass coating on the interfacial sulfide layer. ToF-SIMS analysis of samples obtained from cured samples clearly showed the presence of a sulfide layer on the sample surface. Exposing the cured samples to different steam, heat and humidity conditions before extracting the cords from them allowed the study of the effects of aging on the sulfide layer. Different aging conditions clearly have different effects on the sulfide layer. The CuxS layer is almost completely destroyed on steam aging, Heat aging led to a growth in the overall thickness of the sulfide layer while humidity aging caused the oxide layers to grow more quickly.