ADHESION OF STEEL CORD WITH CU-ZN-FE COATING IN COBALT-FREE COMPOUND

Degui Xia; Baoxing Wang; Zhen Wang; Yiwen Luo; Yohann Hamon

doi:10.5254/rct.24.00024

Article Contents

ABSTRACT
INTRODUCTION
EXPERIMENTAL
RESULTS AND DISCUSSION
CONCLUSION
ACKNOWLEDGEMENTS
REFERENCES

Editorial Type:

Article Category: Research Article

Online Publication Date: 03 Mar 2025

ADHESION OF STEEL CORD WITH CU-ZN-FE COATING IN COBALT-FREE COMPOUND

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Page Range: 31 – 45

DOI: 10.5254/rct.24.00024

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ABSTRACT

The adhesion of steel cord with Cu-Zn-Fe coating in a cobalt-free skim compound in hot and humid conditions was investigated and compared with the current adhesion system consisting of brass-coated steel cord in cobalt-containing skim compound. Standard adhesion tests showed that the adhesion retention of Cu-Zn-Fe–coated cord in a cobalt-free compound was significantly improved with respect to current adhesion system. Advanced characterization of adhesion interphases by field emission scanning electron microscopic examination of cord-compound cross sections and X-ray photoelectron spectroscopy depth profiling revealed that incorporating the Fe element into the coating significantly reduces the dezincification of the metallic coating and prevented excessive growth of adhesion interphase. This results in high adhesion retention of Cu-Zn-Fe–coated steel cord in cobalt-free compound. Furthermore, a hypothesis was proposed to explain how the Fe element decreases the dezincification of the metallic coating in hot and humid conditions. Because Cu-Zn-Fe–coated cord eliminates the need for cobalt salts in the compound, using this cord in cobalt-free compounds generates a completely cobalt-free solution to tackle adhesion degradation and health risks of the current adhesion system.

Fig. 1.

FESEM image of the cross section of a cord-compound composite prepared by cross section polisher.

Fig. 2.

(a) PoF and (b) APR of 3 adhesion systems in RC and CH conditions.

Fig. 3.

Microphotographs showing the surface appearance of cords after 93 °C CH aging and subsequent adhesion test. (a) BC in cobalt-containing compound with 40%APR, (b) BC in cobalt-free compound with 20%APR, (c) FC in cobalt-free compound with 80%APR.

Fig. 4.

FESEM images of the adhesion interphases left on the rubber side of samples after 93 °C CH aging and subsequent adhesion test. (a) BC in cobalt-containing compound with 40%APR, (b) BC in cobalt-free compound with 20%APR, (c) FC in cobalt-free compound with 80%APR.

Fig. 5.

FESEM images of the cross sections of adhesion interphases of three adhesion systems in RC condition. (a) BC in cobalt-containing compound, (b) BC in cobalt-free compound, (c) FC in cobalt-free compound.

Fig. 6.

FESEM images of the cross sections of adhesion interphases of three adhesion systems in CH condition. (a) BC in cobalt-containing compound, (b) BC in cobalt-free compound, (c) FC in cobalt-free compound.

Fig. 7.

XPS depth profiles of three adhesion systems in CH condition.

Fig. 8.

Microphotographs showing the surface color of cords prepared according to the filter paper method in CH condition. (a) BC in cobalt-containing compound, (b) BC in cobalt-free compound, (c) FC in cobalt-free compound.