Erosion behavior of aluminide coating modified with yttrium addition underdifferent erosion conditions

Oxygen-active elements have recently been found beneficial to the wear resi stance of (Cr, Al)-containing alloys in corrosive environments. In this wor k, the performance of aluminide coating modified with yttrium, a typical ox ygen-active element, under different erosion conditions was evaluated. Comp ared to yttrium-free coating and the mild steel substrate, the yttrium-cont aining coating showed considerably enhanced erosion resistance under the fo llowing erosion conditions: dry sand erosion at different temperatures; ero sion in tap water containing 30% silica sand; erosion in a dilute NaCl solu tion containing 30% silica sand; and erosion in a dilute H2SO4 solution con taining 30% silica sand. The study demonstrated that yttrium significantly improved the resistance of aluminide coating to both corrosive erosion and dry sand erosion. Yttrium effects on mechanical properties, micro-wear beha vior and corrosion properties were also investigated. It was clarified that the protective role that yttrium played was attributable to its beneficial effect on corrosion behavior rather than the mechanical properties. (C) 20 00 Elsevier Science S.A. All rights reserved.