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This study aims to investigate the corrosion behavior of Cu-containing 3Ni steel in simulated marine environments and to provide basic guidance for improving the corrosion resistance of marine high-strength steels.

The corrosion properties of Cu-containing 3Ni steel were evaluated in five different NaCl concentrations by alternating wet and dry cycling method. The corrosion behavior was investigated by electrochemical impedance spectroscopy, scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The mechanism of the influence of Cl ion concentrations on the corrosion behavior of Cu-containing 3Ni steel in marine environments was analyzed.

The results showed that the corrosion resistance of Cu-containing 3Ni steel decreased with NaCl concentration increasing. With the increase of NaCl concentration, the number of FeOOH particles decreased and their size increased, resulting in an increase in the porosity and a decrease in the density of corrosion products. High NaCl concentration could inhibit the formation of NiFe₂O₄ and disrupt the electronegativity of the inner film of corrosion products, which further weakened the enrichment of Ni and Cu, and enhanced the permeability of Cl ions.

The influence of NaCl concentrations on the corrosion behavior of Cu-containing 3Ni steel was systematically studied and the influence laws of corrosion behavior were obtained in this paper, providing basic data for the optimal design of Cu-containing 3Ni steels.

This paper aims to investigate the lubrication characteristics of siliconized graphite with a wavy-tilt-dam (WTD) pattern applied to the hydrodynamic face seals.

It focuses on two friction pairs, carbon graphite versus tungsten carbide (CG-TC) and siliconized graphite versus siliconized graphite (SG-SG), through a three-dimensional elastic hydrodynamic lubrication numerical model that integrates finite difference method and finite element method. The consequence of axial elastic deformation of sealing pair materials on film thickness, film pressure, cavitation and sealing performance for a WTD mechanical face seal under full working conditions of ΔP = 0.8, 5.3 and 15.8 MPa are analyzed theoretically.

The nuclear hydrodynamic WTD face seal generates a convergent gap and exhibits a dual-characteristic behavior of hydrodynamic and hydrostatic effects under various ΔP. Compared to the CG-TC, the SG-SG shows a lower minimum film thickness, decreasing by 3.9%, 17.3% and 35.1%. The flow leakage rate decreases by 47.8%, 52.1% and 75.4%. In addition, the film stiffness increases by 46.8%, 49.8% and 97.8%. Thus, the SG-SG better deals with the dynamic tracking problem, and the sealing performance is stable. The strength and hardness of siliconized graphite enhance WTD sealing performance and improve cavitation control in high-pressure applications.

The lubrication characteristics of the siliconized graphite with a WTD pattern could inform the future design of hydrodynamic shallow groove wavy seals in boiler feedwater engineering implements under high-pressure conditions for the nuclear power industry.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2024-0382/