Study of the role of sodium hypophosphite in electroless nickel bath solution

Cyclic voltametric investigations have been made to understand the electrochemical behaviour of sodium hypophosphite in electroless plating bath solution. The possible reaction steps at the anode and cathode have been identified. An ECE type of mechanism appears to be operative in the overall reaction during electroless plating. Both organic and inorganic species in the bath solution influence the voltammetric pattern of the hypophosphite. Temperature enhances the peak currents and changes the reaction mechanism. The oxidation potentials of the reaction steps vary with temperature and also the presence of organic components in the bath solution

The effect of microstructure on the corrosion behaviour of electroless Ni-P alloys in acidic media

The structure and surface morphology of Ni-P alloys obtained by electroless plating has been analysed by X-ray diffraction and microscopic techniques respectively. The bath composition has been found to affect the microstructure of the alloy. The corrosion behaviour of these alloys in acidic media: 1 N H2SO4, 1 N HCl and 5 NaCl (pH 5) was investigated using electrochemical techniques. The corrosion characteristics varied with the degree of crystallinity, the composition of the alloy and the presence of inclusions in the alloy

Combustion synthesis: An update

Combustion synthesis has emerged as a facile and economically viable technique for the preparation of advanced ceramics, catalysts and nanomaterials. Recent innovations in the combustion and processing parameters have resulted in a better understanding of combustion phenomena and control of microstructure and property of the products. xA9; 2003 Elsevier Science Ltd. All rights reserved

Instant synthesis of nanoscale spinel aluminates

Nanocryslalline metal aluminates MAl2O4, M=Mn, Cu and Zn have been prepared by the combustion of aqueous solutions containing corresponding metal acetate, aluminium nitrate, ammonium nitrate and different fuels, e.g., urea/carbohydrazide/oxalyldihydrazide I/hexamethylenetramine/glycine, The spinels obtained are nanosize (10-80 nm) oxides with surface area varying from 40 to 180 m(2)/g depending upon the fuel used. The products have been characterised by powder XRD and Al-27 MAS NMR spectroscopy. The particulate and morphological properties have been investigated using TEM and SEM techniques. Both ZnAl2O4 and CuAl2O4, prepared with carbohydlazide and glycine furls ale porou

Thermodynamics of adsorption of brighteners on polarized nickel from Watts bath solution

The adsorption of coumarin, nitrocoumarin, and p-toluene sulfonamide on nickel from Watts bath solution has been studied using a polarization technique. The exchange current densities (io) with and without additives were evaluated using a Tafel relation. The addition agents inhibited the deposition process. Surface coverages calculated from the io values were fit into the Langmuir adsorption isotherm. Thermodynamic parameters (ÎG°a, ÎH°a, and ÎS°a) for the adsorption of the addition agents have been evaluated using The Bockris-Swinkles adsorption isotherm. The values of ÎG°a are negative indicating the strong interaction and reactive inhibition of the deposition process by these additives. The electrodeposition interaction is discussed from the viewpoint of the adsorption of the additive molecules on the metal solution interface

Electroless Ni-P alloys from acid bath: Evaluaton of functional properties

Electroless Ni-P alloys have been developed from acid bath solution containing various additives. The functional properties: microhardness, electrical resistivity and coercive force of these alloys are found to depend on the composition, microstructure and occludedinclusions and heat treatment. The observed results indicated the complexity of the system in producing Ni-P alloys with tailor made properties to suit industrial applications

Electroless Ni-​P alloys from acid bath: evaluation of functional properties

Electroless Ni-​P alloys were developed from acid bath soln. contg. various additives. The functional properties: microhardness, elec. resistivity and coercive force of these alloys are found to depend on the compn., microstructure and occluded inclusions and heat treatment. The obsd. results indicated the complexity of the system in producing Ni-​P alloys with tailor made properties to suit industrial applications