Corrosion resistance of Ni-P\CePO₄coatings obtained from sol solutions

Abstract

Combined sol-gel and electroless plating techniques were used to obtain nickelmatrix composite coatings. Scanning electron microscopy (SEM) was used to examine the surface morphology. Energy dispersive spectroscopy (EDS) was employed to analyze the composition of each coating. Corrosion resistance of the coatings was evaluated by electrochemical impedance spectroscopy (EIS). The composite Ni-P\CePO 4 coating was found to have better protective properties against corrosive environments than simple Ni-P. EIS measurements showed that composite coatings had a higher corrosion resistance during first 4 days of exposure to non-deaerated NaCl solution in comparison to Ni-P. The longer the time of exposure (above 4 days), the protective properties of both types of coatings decreased. Eventually, after 16 days of immersion in a corrosive media, simple Ni-P coating was partially damaged, while Ni-P\CePO 4 was still covering a substrate.

Pressure-Induced Hexagonal to Monoclinic Phase Transition of Partially Hydrated CePO4

“…Cerium orthophosphate CePO 4 is a material with notable physicochemical properties that has received a fair amount of attention because of its multiple potential real-world applications. Due to mixed electrical conduction properties, CePO 4 has been proposed as a promising material for intermediate temperature fuel-cell and oxygen sensors applications. − Photoluminescent terbium-doped CePO 4 is used in the fabrication of sensors for the detection of O 2 , Fe 2+ , Co 2+ , and glucose. − Moreover, being a chemically stable material, CePO 4 is also a promising alternative to ZnO and TiO 2 in sunscreen filters for the protection of human skin from UV rays , and as a better additive for improved corrosion resistance of Ni–P coatings …”

“…4−8 Moreover, being a chemically stable material, CePO 4 is also a promising alternative to ZnO and TiO 2 in sunscreen filters for the protection of human skin from UV rays 9,10 and as a better additive for improved corrosion resistance of Ni−P coatings. 11 CePO 4 is a mineral with a monoclinic crystal structure (space group P2 1 /n), which is the prototype of monazite-type oxides. 12 When hydrated, the material is known as rhabdophane (CePO 4 •0.667H 2 O) and has been described in the literature either with a hexagonal or a trigonal crystal structure.…”

Tuning Interface to Improve Corrosion Resistance of Electroless Ni-P Coating on AZ31B Alloy

“…A uniform coating prepared by surface treatment methods is usually adopted to modify physical and chemical properties of metal materials, in particular to enhance the corrosion resistance. Electroless nickel (EN) coating is one of the common surface treatment methods, which has been widely employed to produce corrosion-resistant Ni-based coatings [6][7][8][9][10][11]. The corrosion resistance depends highly on the quality of EN coatings.…”

Corrosion behavior of tantalum coatings on AISI 316L stainless steel substrate for bipolar plates of PEM fuel cells

“…In the Bode diagram of Fig. 8b), it can be observed that as the polarization time increases the modulus of the impedance decreases in the low frequency region, which is associated with low corrosion resistance [52]. So, it has been demonstrated that for this Ta-based coating the protection against corrosion decreases progressively with time, also affecting both the medium and the high phase angle frequency.…”