Abstract
In this study, Ni–P/Ni–P–SiC coatings were prepared on pretreated 45 steel substrates by scanning electrodeposition. Prior to the electrodeposition, the substrates were subjected to two types of pretreatments: polishing and sandblasting. The 3D morphology of the pretreated substrates was characterized by laser scanning confocal microscopy. The micromorphology and section morphology of the coating surface were characterized by field emission scanning electron microscopy. The section element composition was characterized using an EDS energy spectrum analyzer. The adhesion and corrosion resistance of 15 coatings were analyzed using an automatic scratch tester and CS350 electrochemical workstation. The results showed the presence of an element penetration region between the coating and the substrate. The sandblasting pretreatment and SiC nanoparticle addition helped widen the penetration region of the elements. The Ni–P–SiC coating prepared by scanning electrodeposition on the sandblasted substrate exhibited the thickest penetration region, up to 28.39 µm. A scratch test conducted on this coating showed that it exhibits the best adhesion force, up to 36.5 N. In electrochemical corrosion experiments, its corrosion potential was found to be the highest, reaching −0.30 V, and the corrosion current density was the lowest, reaching 8.45 × 10−7 A·cm−2. The presence of the element penetration region increased the coating adhesion and improved the corrosion resistance.
Highlights
The 45 steel is used in making equipment and parts that require good comprehensive properties owing to its low price, high strength, and good machinability [1,2,3].the conventional workpiece corrodes during service, limiting its applications [4,5,6].it is important to improve the surface performance of 45 steel substrates to protect against corrosion.Currently, surface modification technologies include chemical heat treatment [7,8], surface coating, thin-film coating, and non-metallic coating [16,17]
To shed new light on the adhesion and corrosion resistance of coatings, in this paper, we propose the concept of an element penetration region, which is formed by the mutual penetration of the elements between the coating and the substrate
The surface of the sandblasted 45 steel substrate had large surface undulations, exhibiting exhibiting an an evident evident mountain mountain peak peak and and gully gully morphology, morphology, as as shown shown in in Figure undulations, These results show that the sandblasting pretreatment could quickly impart a rough appearance on the substrate surface
Summary
The 45 steel is used in making equipment and parts that require good comprehensive properties (corrosion resistance and formability) owing to its low price, high strength, and good machinability [1,2,3]. It is important to improve the surface performance of 45 steel substrates to protect against corrosion. The electrochemical reaction of ions under the action of an electric field is utilized to form a coating at the cathode This technique has advantages, such as low cost, high efficiency, and simple preparation, the limiting current density and deposition efficiency are low [18,19,20]. To shed new light on the adhesion and corrosion resistance of coatings, in this paper, we propose the concept of an element penetration region, which is formed by the mutual penetration of the elements between the coating and the substrate. The effects of the element penetration region on the adhesion and corrosion resistance between the coating and the substrate were investigated. This study lays a foundation for further studying the element penetration mechanism between the coating and the substrate
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
