- •1. Explain electrodeposition technology of tungsten
- •2. Discraibe the electrodeposition technoly of molybdenum.
- •3. Explain electrodeposition technoly of rhenium
- •4. Explain electrodeposition technoly of platinium.
- •6. Explain electrodeposition technoly of rhodium
- •7. Explain electrodeposition technoly of osmium.
- •10. Give a certificate of electrochemical methods of Thallium
- •11. Explain electrochemical deposition methods Iridium
- •12. Give an explanation about Electrochemical methods of obtaining germanium.
- •13. Tell about electrochemical methods of producing niobium
- •14. Give an explanation about Electrochemical obtaning methods of vanadium
- •16. Explain about the technology of electrochemical production of bismuth
- •17.Tell about the technology of electrochemical production of titanium
- •18. Tell about the technology of electrochemical production of gold
- •19.Tell about the technology of electrochemical production of silver.
- •20. How to prepare electrolyte for electrodeposition of niobium from organic solution
- •21. How to prepare alkaline glycerol electolyte for electrodeposition of antimony.
- •22. How to prepare alkaline electolyte for electrodeposition of Gallium
- •24. Explain Kazarov, Loshkarev and chloride electrolyte solution for obtain indium.
- •25. Discribe about Marchenko, Ionychev and cyanide electrolyte solution for obtain indium.
- •26.Discribe about sulforic acid and hbf4 electrolyte solution for obtain indium.
- •27. Iurev and Icakova Elctrolyte for obtain ruthenium.
- •28. How to prepare chloride or Kadaner electrolyte for electrodeposition of ruthenium
- •29. How to prepare electrolyte solution for electrodeposition of ruthenium
- •30.Discribe about electrolyte solution for electrodeposition of platinium.
- •31. How to prepare chloride electrolyte for electroreduction of paladium
- •32. How to prepare chloride electrolyte for electroreduction of paladium
- •33.How to prepare nitrite electrolyte for electroreduction of paladium
- •34. How to prepare sulfamine and monoethanolamine electrolyte for electroreduction of paladium
- •35. How to prepare amino chloride electrolyte for electroreduction of rhodium
- •36. Tell about electrolyte composition for obtain of osmium
- •37. Explain chloride electrolyte for obtain Iridium by electrochemical process.
- •38. Tell about nitrite electrolyte solutions for deposition of platinium.
- •39. How to prepare nitirc electrolyte for electrodeposition of bismuth
- •40. How to prepare organical electrolyte for electrodeposition of bismuth.
- •41. How to prepare electrolyte solution for electrodeposition of arsenium
- •42. Explain cyanide electrolyte solution forelectro deposition of silver.
- •43. Explain cyanide electrolyte solution for electro deposition of gold.
- •44. How to prepare sulfamine and monoethanolamine electrolyte for electroreduction of palladium
- •45. How to prepare amino chloride electrolyte for electroreduction of rhodium
35. How to prepare amino chloride electrolyte for electroreduction of rhodium
The precipitation of rhodium from an amino-chloride electrolyte. Laboratory studies [10] found that the electrolyte contains only one amino-chloride salt of rhodium [Rh(NH3)6Cl]Cl 2 with a concentration of Rh3+ to about 4 g/l Sulfuric acid . . . Temperature, °C ... . The current density DK, A/dm2 current efficiency t], % 40-60 15-25 1,5—2 30-40 64 in terms of metal. For preparation of electrolyte per liter of take 12 g of RhCl3.12H2O and dissolve them in 100 ml of distilled water, the resulting solution is heated to 40--50° C and with vigorous stirring, treated with excess 25% aqueous ammonia. The mixture of mortar with dark-red precipitate is put in a water bath and maintained at 90-95° C until the transition of the precipitate in ammonium complex of a lemon-yellow color and remove excess of ammonia. The reaction of formation of the complex goes according to the equation RhCl3 + 5NH4OH = [Rh(NHs)5Cl]Cl2 + 5H2O Y - the resulting solution add hot distilled water to 1 l, adjust pH in the range 9 to start the operation of the electrolyte at the following mode: Temperature, °C................ 70-80 The current density ?)K, A/dm2...........10 As insoluble anodes are used, or the rhodium sheet with a ratio of anode area to cathode 5:1, or plate spectral pure graphite. For the electrolyte necessary mechanical agitation, filtration and periodic. Adjustment of the electrolyte is to maintain the concentration of Rh+thpH. The obtained coatings have a bright and shiny surface, fine-grained structure and microhardnessof about 850 kgf/mm2. Common to all electrolytes rhodium is a high sensitivity to any impurities and dirt. Therefore, the electrolyte is prepared only from chemically pure preparations, without any additives of organic origin. ^ Is not allowed also the isolation of suspensions and parts g varnishes and plastics. Installation details it is advisable to implement on copper wire. The electrolyte should be systematically subjected to boiling and treatment with activated carbon at least once a week The bath vessel should be made of glass or porcelain, but not made of plastic, and to supply its heating and mixing devices.
36. Tell about electrolyte composition for obtain of osmium
Of all the platinum group of metals osmium has the highest melting point and hardness, and it is chemically very resistant although oxidised in air above 400°C. These properties make it potentially useful in the form of an electrodeposited coating where the atmosphere is not oxidising, as for example in reed relays, and in the last few years efforts have been made to develop a suitable electrolyte for this purpose.
A number of workers have reported unsatisfactory results with hexachloroosmate solutions, while other electrolytes that have been tried include molten cyanides, which gave granular deposits and were unstable, and alkaline electrolytes prepared from OsO4 and sulphuric acid. The latter showed some promise, but now further and more successful results with hexachloroosmate baths have been reported by J. M. Notley of International Nickel in a paper presented to the annual conference of the Institute of Metal Finishing held in May 1972. (Trans. Inst. Metal Finish., 1972, 50, (2), 58).
The advancement described in the paper is the stabilisation of the electrolyte by addition of (i) potassium chloride to suppress hydrolysis of the hexachloroosmate to osmium dioxide, and (ii) of potassium bisulphate to buffer the pH at ∼1.5. Any dioxide that is precipitated is redissolved by chlorine generated at the anode. If the bath is being operated at too low a current density to produce chlorine then a short burst at high current density is usually sufficient to redissolve the dioxide.
The osmium is deposited at 1 to 4 A/dm2 at 70°C with a current efficiency of 20 to 30 per cent, and plating rates up to 4 μm/h. The deposits are bright and although cracked at thicknesses greater than 1.5 μm may be obtained up to 10 μm thick.
Very careful control of the electrolyte at pH 1.0 to 1.5 is necessary to prevent precipitation of OsO2 on to the cathode.
Details are given of the synthesis of the plating salt, K2OsCl6, and of the preparation and analysis of the bath. The kinetics of the decomposition of the electrolyte were investigated and the results were used to adjust the composition to obtain a stable system. The effects of current density and temperature on plating rate and efficiency were determined for a bath using ammonium hexachloroosmate and a sulphamic acid/ammonium sulphamate buffer.