Microstructure and corrosive property of Ni-P/nano-CeO₂ coating electrolessly prepared in acidic condition

Abstract

Electroless Ni-P/nano-CeO₂ composite coating was prepared in acidic condition, and its microstructure and corrosive property were compared with its CeO₂-free counterpart. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and differential scanning calorimeter (DSC) were used to examine surface morphology and microstructure of the coating. Aqueous corrosion was done in 3%NaCl+5%H₂SO₄ solution and high temperature oxidation was done at 750 °C in air. The results showed that Ni-P coating had partial amorphous structure mixed with nano-crystals, while the Ni-P/CeO₂ coating had perfect amorphous structure. At high temperature, Ni3P precipitation and Ni crystallization took place in both coatings at different temperatures. Aqueous corrosion property and high temperature oxidation property of the composite coating were remarkably improved due to the coating’s microstructure change and the rare earth doping effect. During the co-deposition process, some Ce ⁿ⁺(n=3, 4) ions may be adsorbed to metal/solution interface and hinder nickel deposition. Ni-P/CeO₂ coating’s perfect amorphous structure results from the hindered crystal- typed deposition of nickel and the promoted deposition of phosphorous.

Keywords

microstructure / composite coating / electroless plate / ceria / corrosion

References

[1] Paseka I. Influence of Hydrogen Absorption in Amorphous Ni-P Electrodes on Double Layer Capacitance and Charge Transfer Coefficient of Hydrogen Evolution Reaction[J]. Electrochemistry Acta, 1999, 44(2): 4 551-4 559.

[2] Shao G., Qin X., Wang H., . Influence of RE Element on Ni-P Coelectro Deposition Process[J]. Materials Chemistry and Physics, 2003, 80(3): 334-339.

[3] Keong K., Sha W. Crystallization and Phase Transformation Behavior of Electroless Nickel Phosphorous Deposits and Their Engineering Properties[J]. Surface Engineering, 2002, 18(1): 329-334.

[4] Rahmel A., Schutze M. Mechanical Aspects of Rare Earth Effects[J]. Oxidation of Metals, 1992, 38(2): 314-319.

[5] Popczyk M., Budniok A., Lasia A. Electrochemical Property of Ni-P Modified with Nickel Oxide and Metallic Cobalt Powder[J]. International Journal of Hydrogen Energy, 2005, 30(1): 265-270.

[6] Jeong D., Erb U., Aust K., . Relationship between Hardness and Abrasive Wear Resistance of Electrodeposited Nano-crystalline Ni-P Coatings[J]. Scripta Materials, 2003, 48(4): 1 067-1 073.

[7] Hu C., Bai A. Influences of the Phosphorous Content on Physiochemical Properties of Nickel Phosphorous Deposits[J]. Materials Chemistry and Physics, 2003, 80(2): 215-219.

[8] Jin H. M., Felix A., Aroyave M. Influence of Yttrium Ion-implantation on the Growing Kinetics and Microstructure of NiO Oxide Film[J]. Plasma Science and Technology, 2008, 10(1): 43-45.

[9] Jin H. M., Zhang L. N., Liu X. J. Influence of Nanometric CeO₂ Coating on High Temperature Oxidation of Cr[J]. Progress in Natural Science, 2007, 17(5): 601-606.

[10] Shimizu K., Kobayashi K., Skeldon P. Oxidation of an Amorphous Ni₇₇P₃₃ Alloy in Air and Dry Oxygen at 300 °CJ]. Materials Science and Engineering, 1995, A198(1): 35-41.

[11] Palaniappa M., Seshadri S. Structural and Phase Transformation Behavior of Electroless Ni-P and Ni-W-P Deposits[J]. Materials Science and Engineering, 2007, 460(1): 638-644.

[12] Shibli S. M., Dilimon V. S. Effect of Phosphorous Content and TiO₂ Reinforcement on Ni-P Electroless Plates for Hydrogen Evolution Reaction[J]. International Journal of Hydrogen Energy, 2007, 32(3): 1 649-1 655.