Ni/TiO&lt;sub&gt;2&lt;/sub&gt; composite electrocoatings

C Kollia,C Patta,P Vassiliou,V Kasselouri

doi:10.3989/revmetalm.2005.v41.iextra.1030

Abstract

Nickel composite coatings have been studied in order to provide increased properties on engineering materials surfaces, such as higher electrical conductivity, wear and corrosion resistance and to decrease the end product manufacturing cost by plating on cheap materials. Adding TiO 2 particles in the bath during the deposition process produced composite coatings. This was tried on electrodeposition from a Watts bath by conventional DC conditions and by pulse plating. The surfaces were studied by SEM, by profilometry and by Vickers microhardness, and its structure by X-ray diffraction. The incorporation percentage of TiO 2 particles in the metallic matrix was estimated by EDS analysis. Corrosion measurements of the deposits were taken by Tafel curves. The results obtained show that particle incorporation percentage is higher for the Ni/TiO 2 electrodeposits produced by pulse current and the microhardness is significantly increased compared to the electrodeposits produced by DC.

Highlights

Composite coatings of a nickel matrix with stable inorganic oxides as fillers may offer the synergistic advantages of the metal matrix which is conductive, corrosion resistant and of the oxide which may enhance the corrosion resistance, optical properties or catalytic properties of the system^
TÍO2 particles are employed for the amelioration of optical, electrical and mechanical properties of engineering materials^ \ Especially, the NÍ/TÍO2 composite electrocoatings have been found that they might be used as photocatalysts for the degradation of organic compounds and as surfaces of high hardness^^^^^^l
From the XRD diagrams the preferred textures of the NÍ/TÍO2 composite electrodeposits were deduced by data treatment (Table I)

Summary

INTRODUCTION

Composite coatings of a nickel matrix with stable inorganic oxides as fillers may offer the synergistic advantages of the metal matrix which is conductive, corrosion resistant and of the oxide which may enhance the corrosion resistance, optical properties or catalytic properties of the system^. TÍO2 particles are employed for the amelioration of optical, electrical and mechanical properties of engineering materials^ \ Especially, the NÍ/TÍO2 composite electrocoatings have been found that they might be used as photocatalysts for the degradation of organic compounds and as surfaces of high hardness^^^^^^l. Both the structure and the properties of composite electrocoatings are influenced by the following parameters: the preparation conditions (composition of the electrolytic bath, pH and temperature of the bath, current density, J etc.), the type of the current applied The work presented in this paper exploits the results obtained from the study of NÍ/TÍO2 composite electro coatings prepared under D.C. and RC. conditions

MATERIALS AND EXPERIMENTAL PROCEDURE

RESULTS AND DISCUSSION

CONCLUSIONS