In this study, it is shown that the rate of bond degradation due to ageing in hot & humid conditions can be significantly reduced by the use of a Cu-Zn-Co ternary alloy coating, compared to current compounds and normal brass-coated steel cord. To better understand the adhesion mechanism, X-ray photoelectron spectroscopy is used to investigate the adhesion interface upon hot and humid ageing. In addition, the effect of removal of cobalt salts from compound on static and dynamic rubber compound properties is studied: it is found that this leads to improved heat ageing resistance, slower crack growth rate and less hysteresis. Hence, the new Cu-Zn-Co ternary alloy coating for steel cord allows cobalt salts to be removed from tires, which makes tires more durable and eco-friendly.