Electrochemical behaviour in process of electrodeposition Ni–P alloy coating

Abstract

An Ni-P alloy coating was obtained by electrodeposition on a 45 carbon steel substrate. The surface appearance of the coating was characterised by Hitachi S-4800 scanning electron microscope. The electrodeposition behaviour was investigated using electrochemical methods. The results showed that the Ni-P alloy coating was dense and smooth. The electrodeposition of the Ni-P alloy followed the mechanism of three-dimensional nucleation and subsequent grain growth. The main deposition process changed from heterogeneous nucleation/growth of Ni onto the 45 carbon steel substrate to heterogeneous nucleation/growth of Ni-P onto Ni film. There was low frequency scatter on electrochemical impedance spectroscopy plots, which can be attributed to the production of gas. With increasing negative bias voltage, the low frequency scatter became more obvious, and the charge transfer resistances Rct and Rp increased. K e y w o r d s : Electrodeposition, N i-P alloy, Polarisation © 2014 I n s t it u t e o f M a te ria ls , M in e r a ls a nd M in in g P u b lis h e d b y M a n e y on b e h a lf o f th e I n s titu t e R e ce ive d 22 F e b ru a ry 2014; a c c e p te d 22 A p r il 2014 DOI lo . 1 1 7 9 /174329 441 4Y .0 0 0 0 0 0 0 2 9 1 S u r fa c e E n g in e e r in g S u rfa c e E n g in e e rin g 2 0 1 4 VOL 3 0 n o 8 5 6 1

Structure and properties of Ni–P–graphite (Cg)–TiO2 composite coating

“…6) are obtained at rate of 10 K min 21 . a Ni-P; b Ni-P-TiO 2 ; c Ni-P-C g ; d Ni-P-C g -TiO 2 2 SEM surface micrograph of Ni-P and Ni-P composite coatings a Ni-P; b Ni-P-TiO 2 ; c Ni-P-C g ; d Ni-P-C g -TiO 2 3 EDX spectra of coating Crystallisation temperature decreases with the decrease in heating speed. The peak at approximately 350uC is associated with phase transition.…”

“…45 carbon steel substrate was of good quality: dense and smooth, with good adhesion. 2 The corrosion rate values increased in the following order: Ni-P,Ni-W-P-B 4 C,Ni-P-B 4 C,AZ91D magnesium alloy substrate. 3 At the same time, high phosphorus Ni-P coating heated at 600uC for 1 h has good tribocorrosion resistance in chloride solution and low anodic potential.…”

Heat treatment of electroless Ni-P layers on an austenitic stainless-steel substrate

“…This uniform thickness and composition of a coating results in uniform mechanical and physical properties of the surface layer. 1,2,3 Besides, Ni-P coatings deposited with the electroless process can have good anticorrosive properties, wear resistance and high hardness. [4][5][6] An electroless Ni-P coating has a higher hardness and a better corrosion resistance than the AISI 316 stainless steel.…”

“…1,[9][10][11][12] The application of an appropriate heat treatment of Ni-P coatings deposited with the electroless process can have a significant impact on their hardness. [1][2][3][4][5] The microhardness of Ni-P coatings deposited with the electroless process depends on the heat treatment of the coatings, the content of phosphorus in the coatings and on the contents of other alloying elements in the coatings. 9 Nickel with an amorphous structure has a lower hardness than nickel with a crystalline structure.…”

Electrophoretic Deposition and Characterisation of Chitosan Coatings on Near-Β Titanium Alloy

“…Moreover, it enjoys the advantages of fast deposition rate, high suspension stability and high production efficiency [24]. It is a process in which charged particles dispersed in a colloidal solution or suspension are moved and deposited onto oppositely charged electrodes In this study, chitosan coatings were electrophoretically deposited (EPD) on near-β Ti-13Nb-13Zr alloy.…”