Highlights • Several Y modified silicide coatings were prepared on the Ti-Al-Nb-Zr alloys. • The Zr contents in the alloys have a significant influence on the coating structure. • Adding 2 at.% Zr can facilitate the formation of a dense SiO 2 layer. • Excessive Zr in the coating will lead to the deterioration of the scale adhesion. Abstract Modified silicide coatings were prepared on Ti-5Al-10Nb- x Zr (x = 0, 2, 5, 10, 15 and 20 at.%) alloys by pack cementation process. The effects of Zr content on the coating structure and oxidation resistance have been investigated. With increasing Zr contents in the substrate, the coating structure shows a significant change. Adding 2 at.% Zr can improve the oxidation resistance of silicide coating due to the formation of a thin and dense SiO 2 layer. But excessive Zr exerts an adverse influence on the oxidation resistance due to the volume expansion caused by the phase transformation of ZrO 2 during the oxidation process. [ABSTRACT FROM AUTHOR]