Preventing chloride-induced corrosion in TC25 titanium alloy during long-term performance testing via Cr-coated aluminosilicate fiber ropes

As an effective high-temperature insulating material, aluminosilicate fiber ropes are extensively used for the thermal protection and structural support of titanium alloys in demanding high-temperature applications. This study examines the influence of conventional and Cr-coated aluminosilicate fiber ropes on the high-temperature performance and corrosion resistance of TC25 titanium alloy. Experimental results show that Cl − ions from conventional fiber ropes react with the titanium matrix, forming TiCl 2 and destabilizing the protective oxide layer, leading to surface corrosion and a significant reduction in stress-rupture life. In contrast, Cr-coated fiber ropes effectively block Cl − penetration, preserving the TiO 2 layer and improving corrosion resistance. Density Functional Theory (DFT) calculations further support these findings, revealing that Cr 2 O 3 exhibits greater thermodynamic stability than CrCl 3 , reinforcing the protective role of the Cr coating. As a result, the stress-rupture life of TC25 alloy increased from 61.6 h to 190 h when Cr-coated fiber ropes were employed. These findings demonstrate that Cr-coated aluminosilicate fiber ropes offer a viable and efficient approach to enhancing the high-temperature durability of TC25 titanium alloy, with promising applications in aerospace and other extreme environments.