In　our　previous　studies　of　Cr-coated　Zr　alloy　cladding,　models　for　the　oxidation　and　degradation　of　Cr　coating　and　for　the　oxidation　and　phase　transformation　of　Zr　alloy　have　been　established.　On　these　foundations,　oxygen　flux　models　for　Cr-Zr　non-eutectic　and　eutectic　conditions　are　developed　in　this　paper,　enabling　a　comprehensive　simulation　of　the　oxidation　processes　of　Cr-coated　Zr　alloy.　The　models　are　validated　through　oxidation　experiments　under　isothermal　and　temperature　ramp　conditions,　showing　good　agreement　with　the　experimental　data.　The　models　can　effectively　simulate　the　processes　where,　under　non-eutectic　conditions,　oxygen　atoms　first　dissolve　into　the　prior　β-Zr　matrix　after　coating　degradation,　followed　by　the　formation　of　α-Zr(O)　and　eventually　ZrO2.　For　conditions　with　eutectic　reaction,　model　assumption　of　immediate　complete　coating　failure　could　lead　to　overestimation　of　substrate　oxidation　extent　at　low　heating　rates.　This　prediction　deviation　decreases　as　heating　rate　increases.　©　2025　Elsevier　B.V.