Publicação
Characterisation of electrodeposited and heat-treated Ni−Mo−P coatings
| Resumo: | 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. |
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| Autores principais: | Melo,Régis L. |
| Outros Autores: | Casciano,Paulo N. S.; Correia,Adriana N.; Lima-Neto,Pedro de |
| Assunto: | Ni−Mo−P electrodeposition amorphous corrosion hardness |
| Ano: | 2012 |
| País: | Brasil |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | IBICT |
| Idioma: | inglês |
| Origem: | Oasisbr |
| Resumo: | 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. |
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