Formation of a dense layer on corroded interface to suppress corrosion is always desired, but it is controlled by numerous environmental conditions. In this work, corroded microstructures of MgO/Al2O3‐SiC‐C refractories in metal bath area of ladle furnace were investigated after industrial trails. A liquid‐phase isolation layer in which MgO islands and liquid phases was established on the corroded interface of refractories with 6 wt% coarse/fine SiC‐additive. The formed isolation layer against steel/slag attacks led to an approximate 30% improvement in corrosion resistance than that of refractory with 3 wt% fine SiC‐additive. More importantly, the liquid‐phase isolation layer blocked the direct mass transfer between molten steel and refractories while it decreased exogenous pollution from refractories. SiC‐additive affected the formation process of isolation layer by controlling the generation/migration of Mg(g) on refractory' surface. A further formation mechanism of liquid‐phase isolation layer was discussed in detail and role of SiC was elucidated.

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Liquid lead-bismuth eutectic alloy (LBE) is applied in the Accelerator Driven transmutation System (ADS) as the high-power spallation neutron targets and coolant. A 19.2kHz ultrasonic device was deployed in liquid LBE at 550°C to induce short and long period cavitation erosion damage on the surface of weld joint, SEM and Atomic force microscopy (AFM) were used to map out the surface properties, and Energy Dispersive Spectrometer (EDS) was applied to the qualitative and quantitative analysis of elements in the micro region of the surface. The erosion mechanism for how the cavitation erosion evolved by studying the element changes, their morphology evolution, the surface hardness and the roughness evolution, was proposed. The results showed that the pits, caters and cracks appeared gradually on the erode surface after a period of cavitation. The surface roughness increased along with exposure time. Work hardening by the bubbles impact in the incubation stage strengthened the cavitation resistance efficiently. The dissolution and oxidation corrosion and cavitation erosion that simultaneously happened in liquid LBE accelerated corrosion-erosion process, and these two processes combined to cause more serious damage on the material surface. Contrast to the performance of weld metal, base metal exhibited a much better cavitation resistance.

A new type of low‐carbon magnesia carbon refractory (LCMCR) substituting for MgO‐Cr2O3 refractory was successfully used in vacuum oxygen decarburization (VOD) ladle slagline, and the composition and microstructure of the used LCMCR were investigated. The results indicated that the decarburizing reaction (MgO‐C reaction) in the LCMCR under the VOD refining condition (high temperature, low pressure) was inhibited due to the low carbon content in the MgO‐C refractory and the dense layer formed between slag and original layer. The dense layer prevented the penetration of the external O2 into the LCMCR inside because of the lower permeability of this layer, and thus, the direct burnout of the C in the LCMCR was substantially restrained. On the other hand, the large size crystal and the ultra‐low inclusions (SiO2 and Fe2O3) content of the fused magnesia in the LCMCR made the magnesia more slag resistance, because the grain boundary in magnesia had higher slag penetration resistance and the contact area between the slag and the magnesia was reduced. The two aspects of the inhibited decarburizing reaction and the high quality magnesia synthetically contributed to the high slag resistance of the LCMCR.

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