Adherence of oxide scale formed on Ni20Cr1Si alloys with small additions of rare earth elements

摘要: Abstract The isothermal and cyclic oxidation behaviour of Ni20Cr1Si (where the composition is in approximate mass per cent) alloys with small additions rare earth elements has been studied air over temperature range 1273–1523 K. rate was reduced by addition cerium. In most except alloy 0.34 mass% Ce, oxide scales began to spall off at about 1000 K during cooling; this caused difference between thermal contraction that oxides. severely spalled again around 500 oxidized above 1473 these a continuous layer cristobalite formed beneath scales. spalling probably due stress displacive transformation which involves substantial volume change. best improvement scale adherence attained Ce even oxidation. alloy, SiO 2 as spherical shape protective Cr O 3 layer. generated transpormation relaxed deformation adjacent . also improved superficial application CeO powder. suppression observed yttrium, lanthanum or erbium. good prevention void formation alloy-oxide interface keying-on structure