Microbiologically influenced corrosion (MIC) is a major challenge for extending the service life of X65 pipeline steel, especially in environments with high concentrations of Pseudomonas aeruginosa. This study prepared a Ni-P/PDMS-SiO₂ hierarchical composite coating to extend protection by creating a dual-barrier defense system. Systematic electrochemical tests over 45 days showed that both bare X65 steel and the single Ni-P intermediate layer deteriorated rapidly. However, the composite coating maintained a relatively high level of low-frequency impedance modulus (|Z|_0.01 Hz), approximately 10¹⁰ Ω∙cm². It was six orders of magnitude greater than that of bare steel and did not show any significant change after being immersed in the P. aeruginosa-containing medium. Based on these results, it could be assumed that a stable Cassie-Baxter air plastron and a dense amorphous Ni-P interlayer have a combined effect of physically blocking bacterial attachment and metabolite infiltration, thereby providing a support structure. This paper offers a feasible approach to designing extended-life anti-MIC coatings in bacterial-laden environments.

Transporting massive quantities of carbon dioxide through a pipeline in its supercritical state is extremely convenient. Because of the unique properties of supercritical carbon dioxide, however, leakage occurring in such conditions can be extremely intricate, resulting in the dispersion area following leakage being influenced by numerous factors. In this study, this problem is addressed in the frame of the so-called Unified Dispersion Model (UDM), and various influential parameters are considered, namely, leakage pressure, leakage temperature, leakage aperture, leakage angle, atmospheric stability, wind speed, and surface roughness. The results show that the supercritical carbon dioxide dispersion is primarily influenced by high air temperatures, low wind speeds, reduced surface roughness, and release temperatures slightly below the critical temperature. Additionally, leak apertures also contribute to the dispersion. The dispersion is maximized under atmospheric stable D conditions, and when the leakage angle is 0°, the farthest downwind distance is 10 times greater than that at a leakage angle of 90° under the same conditions.

To improve the accuracy of erosion prediction, the effect of subsequent particles impacting the same area while the first single particle rebounds from the substrate must be considered. This issue has rarely been considered in studies pertaining to erosion damage. In the present study, the ABAQUS software is used to investigate the erosion crater morphology and stress distribution on a target material subjected to overlapping impacts of spherical particles. Subsequently, the validated model is applied to investigate the effect of the overlapping impacts of particles on the target. Accordingly, the correlation between erosion severity and the impact locations of the two incident particles is quantified. The results show that the horizontal distance between two solid particle impact locations can significantly affect the erosion magnitude and pattern. The interactions of the resulting craters diminish when the horizontal distance exceeds 0.6 times the particle diameter. When the horizontal distance is approximately 0.06 times the particle diameter, the energy loss originating from collisions reaches the maximum, which modifies the crater morphology. The present study is expected to provide in-depth insights into erosion mechanisms and erosion modeling.