Characterisation of electrodeposited and heat-treated Ni−Mo−P coatings

Journal of the Brazilian Chemical Society

Régis L. Melo¹  Paulo N. S. Casciano¹  Adriana N. Correia¹  Pedro De Lima-neto¹ 

[1],Universidade Federal do Ceará Departamento de Química Analítica e Físico-Química Fortaleza CE ,Brazil

关键词: Ni−Mo−P;    electrodeposition;    amorphous;    corrosion;    hardness;   

DOI  :  10.1590/S0103-50532012000200020

来源: SciELO

【 摘 要 】

The electrodeposition, hardness and corrosion resistance properties of Ni−Mo−P coatings were investigated. Characterisations of the electrodeposited coatings were carried out using scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis techniques. Corrosion tests were performed at room temperature in 10-1 mol dm-3 NaCl solutions and by potentiodynamic linear polarisation. Amorphous Ni−Mo−P coatings were successfully obtained by electrodeposition using direct current. The coating composition showed to be dependent on the bath composition, current density and bath temperature. Both P and Mo contents contribute for the hardness properties of the Ni−Mo−P coatings and the absence of cracks is a requirement to produce electrodeposited Ni−Mo−P coatings with good hardness properties. The hardness values increase with heat-treatment temperature due to the precipitation of Ni, Ni3P and NiMo phases during the heat treatment. The corrosion resistance of the electrodeposited Ni−Mo−P amorphous coatings increases with P content in the layer. Among the electrodeposited Ni−Mo−P amorphous coatings, Ni78Mo10P12 presented the best hardness and corrosion-resistance properties. The results showed that the addition of P is beneficial for the hardness and corrosion resistance properties of the Ni−Mo-based coatings.

【 授权许可】

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