Paper Number 3.7
GIXRD and SIMS Analysis
of the Rubber-Steel Tire Cord Interface
Prasan Harakuni[1]
Akshay Ashirgade
William Vanooij
Department of Chemical and Materials Engineering
Adhesion of steel tire cords to rubber
plays an important role in the overall performance of tires. Brass-coated steel wires are extensively used
in the belts of radial tires because this not only leads to better handling but
also improves the mechanical properties of the tire. Past research done on the
tire cord-rubber interface has shown the adhesion is a result of the formation
of a CuxS layer at the interface which leads to chemical bonding and mechanical
interlocking. Grazing incidence angle Xray diffraction (GIXRD) analyses of
flat-rolled brass-coated steel wires containing two different Cu loadings were
conducted in order to study the effects of different brass loadings on the
adhesion interface. The GIXRD data shows
that a change in the copper loadings does affect the crystallization behavior
of the sulfide, these differences are, however, fairly subtle and based on just
these one would not really expect the Cu loadings in brass to have an impact on
the rubber-tire cord adhesion. Time-Of-Flight
Secondary Ion Mass Spectroscopy (ToF-SIMS) analyses however show that the
change in copper loading leads to significant differences in the thickness and
chemical make-up the interfacial sulfide layer. ToF-SIMS analyses of samples
aged in different conditions including steam, heat and humidity once also
showed that the different conditions affect the adhesion layer differently. While steam aging leads to an almost complete
destruction of the interface, heat and humidity aging lead to extensive growth
of the sulfide layer.