EFFECT OF SOME OPERATING VARIABLES ON THE CHARACTERISTICS OF ELECTRODEPOSITED CU-ALPHA-AL2O3 AND CU-TIO2 COMPOSITES

Copper-proportional to-Al2O3 and Copper-TiO2 composites were electrodeposited from acidic baths containing 150 CuSO4.5H(2)O, 50 Na2SO4.10H(2)O 25 H3BO3 and either 1-20 gl(-1) proportional to-Al2O3 or TiO2 particles suspended in the bath. The effects were studied of particle size, particle concentration and plating conditions on the cathodic polarization, current efficiency, inert particle content in the composite deposit and on the surface morphology and microhardness of the as-received plate. A mechanism of coelectrodeposition of the inert particles with copper could he suggested from measurements of the cathodic polarization. The efficiency of copper electrodeposition from the selected bath was relatively high (98.5%) and was increased further by increasing the current density and by raising the pH of the the bath. The inert particle content reached 1.7% for proportional to-Al2O3 and 2.3% for TiO2. Ar a current density of 0.66A dm(-2), the microhardness of the copper plate approached 100 kgf mm(-2) and the inclusion of the inert particles in copper composites led to an increase of about 25% in the microhardness. A further increase in the microhardness of copper-proportional to-Al2O3 was achieved by raising of the deposition current density, where it reached 165 kgf mm(-2) at 1.66 A dm(-2). Scanning electron microscopy examination showed a direct correlation between both the inert particles content, their morphological shape and the microhardness of the copper composites.