Preparation of indium sulfamate plating solution
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How is indium sulfamate solution prepared? 105 g/L; I used an ammonium sulfonate solution plus indium hydroxide. When indium hydroxide was added to the ammonium sulfonate solution, a turbid solution was obtained, with a pH of 0.67. The acidity level seems to be sufficient as well. How can it be dissolved? Thank you all!
This post was last edited by Yang Qing on 2020-11-13 08:01. Is it from the indium plating tank or from a solution prepared in the laboratory? What is the purity of the two substances and of the water used for preparation? If turbidity is caused by purity issues, it can be resolved using filtration equipment. Check again to see if the mixing ratio is accurate There are also the amounts of other additives added.
It is a solution prepared in the laboratory. The water used for preparation is high-purity water (18 MΩ). Indium hydroxide and sulfamic acid are mixed in a molar ratio of 1:3; no other additives have been added at present.
Indium is in the form of 4N grade indium ingots, which are dissolved in analytically pure hydrochloric acid, followed by the addition of ammonia to precipitate the substance at a pH of 7.4. After washing three times, indium hydroxide is obtained. Aminosulfonic acid is of analytical purity.
Some solutions may require stirring for a longer period of time to achieve stability and clarity; it is worth trying to use a magnetic stirrer for an extended period to obtain a clear solution. I encountered a similar situation once as well; I suspected it was due to the water quality or the purity of the reagents, but after shaking it the next day, it became clear. Of course, it’s not for preparing indium sulfamate; it’s for preparing other solutions.
This post was last edited by Yang Qing on 2020-11-13 08:44. There is no problem with 4N indium ingots; in fact, the dosage is determined based on the molar ratio of indium to sulfamic acid. If the ratio follows the theoretical value of 1:3, then the purity and moisture content of sulfamic acid need to be taken into account. However, judging from the pH of the resulting solution, the amount of sulfamic acid used is sufficient. Also, perhaps because the solubility of sulfamic acid is relatively low, sufficient reaction time may be required to fully form indium sulfamate. Is the solute indium sulfamate at 105 g/L or one containing 105 g/L of indium? I have worked with electrolytic copper, and *I assumed by default that the electrolyte concentration was based on the metal element. If calculated on an indium sulfamate basis, the solubility is fine.
The concentration of indium sulfamate is 105 g/L, while the concentration of indium is 30 g/L; actually, these concentrations are not very high