YTTRIUM ADDITION EFFECT ON ISOTHERMAL AND CYCLIC HIGH TEMPERATURE OXIDATION BEHAVIOUR OF 304 STAINLESS STEEL

摘要

The aim of the present study is to investigate the beneficial influence of an yttrium sol-gel coating on a chromia forming alloy (304 stainless steel), in air, at 1000 deg C. Thermal cyclic experiments were carried out in order to study the influence of the addition of yttrium on the scale adherence. The yttrium sol-gel coating plays a significant role in enhancing oxidation resistance during isothermal oxidation tests, decreasing specimen weight gain and suppressing the initial transient oxidation stage. Yttrium addition appears to promote silicon segregation at the metal/oxide interface. It is then observed that iron containing oxides are not formed. Under thermal cycling conditions, the addition of yttrium also remarkably improves oxide scale adherence.