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In order to study the segregation of arsenic impurities at the metal/oxide interface during high temperature exposure, isothermal oxidation behavior of arsenic bearing steels with various Ce content was systematically investigated. The result showed that oxidation mass gain of arsenic bearing steel in the temperature range of 950–1150 °C was decreased as a whole with increasing Ce content from 0 to 0.035 wt.%. At 1100 and 1150 °C, the best results are obtained for 0.027 and 0.035 wt.% Ce. Moreover, Ce addition could prevent grain boundaries oxidation, which reduced or even eliminated the formation of visible oxide particles along grain boundaries at 1000 and 1050 °C. In case of oxidation at 1050 and 1100 °C, the arsenic enrichment amount at the scale/metal interface was firstly decreased with increasing Ce content from 0 to 0.027 wt.% and then slightly increased as Ce content increased from 0.027 to 0.035 wt.%. This variation was attributed to the separation behavior of oxide scale, the formation of a continuous solid Fe2SiO4 layer and the arsenious rare earth particles promoted by Ce addition. [ABSTRACT FROM AUTHOR]

In order to depress the embrittlement induced by grain boundary segregation of arsenic in steel, the effect of Ce addition on the formation of arsenious inclusions and arsenic concentration at grain boundaries were systematically investigated in iron melts. The results showed that different types of arsenious rare earth inclusions were formed with different Ce content. As Ce content increased from 0.037 to 0.095wt%, the dominant inclusion in the melt was changed from the Ce-S-O inclusion fully coated by Ce-S-As inclusion to the Ce-S-As inclusion completely covered by Ce-As inclusion. Simultaneously, the single Ce-S-As and Ce-As inclusions were also detected when Ce content was more than 0.055 wt%. The amount and average size of inclusions increased with increasing Ce content. Transmission electron microscope analysis indicated that the Ce-As inclusion was the CeAs phase, which was formed during solidification process. Furthermore, concentration of arsenic on grain boundaries after adding Ce was decreased to the level of the matrix. [ABSTRACT FROM AUTHOR]