Correlation between surface-hardness degradation and erosion resistance of carbon steel—Effects of slurry chemistry

• Erosion of steel in acidic slurries was found to be affected by the slurry chemistry but unaffected in neutral or alkaline ones.
• The surface hardness degradation in acidic electrolytes was more significant than that in neutral or alkaline ones.
• The surface mechanical property degradation induced by corrosion is primary mechanism of corrosion-enhanced erosion.

The paper studied the effects of slurry chemistry on erosion of carbon steel. According to experimental measurements, the erosion rate in corroding slurries was a linear function of logarithm of anodic current density. In near-neutral or alkaline slurries, the erosion rates are independent of solution chemistry while the erosion rates in the acidic slurries were sensitive to slurry chemistry. To investigate the underlying mechanism, the in-situ surface hardness in corroding environments was measured with the nano-indentation technique under galvanostatic control. The results indicated that the surface hardness would decrease as anodic current was applied. The surface hardness degradation in near-neutral or alkaline electrolytes were almost unaffected by solution chemistry but that in acidic electrolyte depended heavily on solution chemistry. A linear correlation between the accelerated erosion and surface hardness degradation indicated that corrosion-induced surface-hardness degradation would be the dominant mechanism of corrosion-enhanced erosion.