Indium Blog

Plating of Indium using an Indium Sulfamate Plating Bath

  • Indium Corporation
  • Indium
  • Indium Wire
  • NanoFoil®

  • The following videos show a live demonstration of the set-up and operation of the indium sulfamate plating bath. The workpiece in this demonstration is a strip of NanoFoil®. (NanoFoil® has traditionally been available with a tin plating as a bonding medium. We are looking at expanding this to using an indium plated coating as the bonding medium.)

    This first video is a shot of the general set-up. You will notice that the workpiece (NanoFoil® strip) is suspended from a copper bar in the center of the container. The workpiece is connected to the negative (-) terminal on the rectifier via the blue colored wire. (The copper rod is just used as a support. It is not connected electrically.) The indium anodes (connected to the positive (+) terminal on the rectifier via the orange colored wires) are taped to the inside of the bucket. There is one on each side of the NanoFoil® strip to insure that both sides of the strip are evenly plated.

    Indium Sulfamate Plating Set Up

    The second video shows the indium sulfamate plating bath solution being poured into the plating container. It is important that the plating solution only touch the indium anodes and workpiece. Allowing the solution level to get high enough to touch other surfaces can contaminate the plating solution.

    Pouring of Indium Sulfamate Plating Solution

    The third video shows the indium plating in process. Notice the evolution (bubbling) of hydrogen gas at the cathode (workpiece).

    Indium Plating in Progress

    The fourth video shows the finished workpiece. It has been rinsed with deionized water. Given the fragility of the NanoFoil® it must be patted dry. The matte area on the strip is the area where the indium has been plated. The shiny portion is the un-plated NanoFoil®. The thickness of the indium plated deposit is a function of the plated area, current, and time.

    Drying of Indium Plated NanoFoil Strips

    This image shows two pieces of indium plated NanoFoil®. The piece on the left exhibits dendritic type growth of the indium plated deposit. This is typical of electro-plated deposits because the current density is highest at edges and corners. Indium is very soft and these dendrites are easily removed.

    Indium Plated NanoFoil Strips (showing dendrites)