23 research outputs found
Electrodeposition of Zinc from Low Temperature Molten Salt Electrolyte: Part II - Imidazole – Alcl3/Zinc Chloride LTMS
Low Temperature Molten salts (LTMS) have a
number of applications in metal finishing including electrolytic deposition and anodic processes like polishing and colouring. Imidazolium, pyridinium and choline based cations are normally used in LTMS [1-5]. Zinc deposition was carried out from imidazole - AlCl3 / ZnCl2 LTMS electrolyte at temperature < 100º C and the mole ratio was optimized in our research. Surface morphology of electrodeposited coatings was characterized by SEM and XRD. Cathodic and anodic current efficiencies of Imidazole – AlCl3 / ZnCl2 LTMS were evaluated
Electrodeposition of Zinc From Low Temperature Molten Salt Electrolyte:Part I-Imidazole And Zinc-Chloride Electrolyte
Abstract: Our R & D work was focused on the electro
deposition of Zinc from imidazole as low temperature molten
salt (LTMS) electrolyte with zinc chloride as a supporting
salt at <100º C., without required controls from the previous
existing non aqueous baths as well additive free system for
the zinc deposition. Surface morphological studies and
crystallographic orientation results were evaluated
Bright zinc-cobalt alloy deposits from an alkaline non-cyanide bath
Cobalt ions were added to a non-cyanide alkaline zinc bath to produce an alloy of zinc containing
0.6-0,8%Co. Bright deposits were produced using organic additives. The effect of different
parameters such as cobalt concentration, current density, complexant concentration, additive
concentration, temperature, agitation, etc. on the composition of the alloy and current efficiency
was studied. Structural characterisation using scanning electron microscopy showed that the
deposits are nanocrystalline
Bright zinc–nickel alloy deposition from alkaline non-cyanide bath
Zinc–nickel alloy deposition with polyvinyl alcohol and piperonal as bath additives has been
investigated. The effects of additive concentration, triethanolamine concentration and other
parametric variables on the deposit and solution properties have been studied. Polarisation
studies were carried out under different conditions to understand the effect of triethanolamine and
the brighteners on the co-deposition. Results indicated that the additives lead to bright alloy
deposition containing ,10% nickel. The deposit produced at the optimum conditions with the
additives has a nanograined structure with a c phase
Information retrieval in electrochemistry using microcomputer
experiences gained in the intial stages of computerised handling and processing of electrochemical
information using DATAWEALTH, a microcomputer of PSI Data Systems are presente
Role of additives in bright zinc deposition from cyanide free alkaline baths
A new additive formulation for non-cyanide alkaline zinc baths was identified after experiments with various
additives. Polyvinyl alcohol addition was found to be the best primary additive of those tested. The secondary
additives selected belonged to the aldehyde group. The selection of the additives was made based on Hull cell,
cathode current efficiency and throwing power studies. Thickness measurements at various points on a cathode
indicated uniform thickness distribution. XRF showed uniform deposition. SEM examination indicated a finegrained
deposit structure. Finally, the influence of each additive was studied using cyclic voltammetry
A noncyanide alkaline bath for Zinc-Nickel alloy deposition
Zinc-nickel alloy has been proven as a highly corrosion resistant coating meant especially for automotive applications. The acid baths have the drawback of poor throwing power and high composition dispersion. On complicated structures, this property not only results in variation in appearance but also, ends up with setting up of local cells within the deposit itself due to variation in composition leading to lower service life than expected. So, these baths are mainly preferred for plating uncomplicated structures. The alkaline baths on the other hand, obviate the above problems, yielding deposits with uniform appearance and composition throughout the component. Due to the environmental and operational hazards posed by the conventional cyanide baths, non-cyanide baths are highly recommended and are in commercial practice abroad.
This paper deals with our experience with a non-cyanide alkaline bath for depositing smooth deposits. Special addition agent has also been identified to function as a brightener. The effect of parametric variables on the composition, current efficiency and throWing power of the deposits are dealt with
Surface Morphology and Microstructure of Zinc Deposit From Imidazole with Zinc Chloride Low Temperature Molten Salt Electrolyte in The Presence of Aluminium Chloride
Low temperature molten salts have variety of applications in organic synthesis, catalytic processing, batteries and electrode position due to their air and water stability. They have wide potential window for their applications in voltage and temperature and hence there is a possibility to deposit metals which could not be deposited from aqueous electrolytes. Our aim and scope of our research was to deposit zinc from low temperature molten salt electrolyte (LTMS) containing zinc salt in the presence of aluminium chloride at different current densities and to qualify the nature of deposits. We could identify the effect of current density on the deposit at low temperature molten salt electrolyte by analysing the nature of deposits using different instrumental techniques. Compact, adherent, dense fine grained deposits of zinc with average grain size of 40-150 nm could be obtained from low temperature molten salt electrolyte. (LTMS
Synergetic effects of pulse constraints and additives in electrodeposition of nano-crystalline zinc:Corrosion,structural and textural characterization
Pulse electrodeposition was to produce nanocrystalline(nc) zinc from alkaline non-cyanide electrolyte with primary and secondary additives. The combined effect of pulse parameters(ON-time(TON), OFF-time (TOFF), pulse peak current density(IP)) and additives on the corrosion properties (evaluated using electrochemical techniques) of zinc electrodeposits are elucidated in terms of surface morphology(using scanning electron microscope),topography and rootmeansquare(RMS)roughness(using atomic force
microscope), crystallitesize,its orientations and relative texture co-efficient(RTC,%)were evaluated
using X-ray diffraction.The corrosion resistance of zinc electrodeposits obtained at constant TON and IP
enhanced (i.e.,low Icorr and high Rct values) with increased TOFF. Atconstant TOFF and IP, the Icorr values
increased and Rct values decreased with TON while the former decreases and latter increases with
IP at constant TON and TOFF. The inclusion of primary and secondary additives in to the electrolyte pro-
duced nc zinc electrodeposits at 5Adm−2, showed enhanced protective properties(Icorr—16-Acm−2 and
Rct—481.8-cm−2). inegrained due to high negative over potential,reduced roughness and higher per-centage of basal plane[00.2] orientation have major impact for the enhanced corrosion resistances