Indium is one of the less commonly used coating metals. It is a light, silvery-colored, highly soft metal with a low melting point, and it belongs to the so-called strategic metals. Its availability and price limit its use, but in the right applications, indium offers properties that no other metal can fully replace.
Eforit Oy is one of the few – and most likely the only company in Finland – that offers electrolytic indium coating. This is a specialty service that is only needed in certain, precisely defined applications.
“Indium is a silver-colored specialty metal, extremely soft and low-melting. It is only used when there is a genuine need for its special properties,” describes expert and chemical engineer Lauri Virta.
What is indium and why is it special?
As a metal, indium is exceptional above all because of its softness and low melting point. It is easily formable and suitable for applications where a dense, flexible, and highly adaptable surface is required.
Indium is more widely known through indium tin oxide (ITO). ITO is used, for example, in LCD displays as a transparent electrical conductor. In these applications, however, the films are produced using vacuum technology – by evaporation or sputtering – not electrolytically.
“When transparent electrically conductive films are made, for example for liquid crystal displays, indium tin oxides are usually used. They are produced with vacuum technology, not electrolytically,” Virta explains.
The indium coating offered by Eforit is therefore a different matter: it is an electrolytically produced metallic indium coating with its own highly specific applications.
Indium coating in vacuum technology applications
One of indium’s key properties is its suitability for ultra-high vacuum technology. Thanks to its softness, indium works excellently as a sealing surface when vacuum chambers are joined together or when the structures of coating equipment are sealed.
“In research equipment, indium can be used as a sealing surface when a vacuum chamber is lowered onto a coating unit. The soft metal conforms to the surfaces and forms a very tight seal,” says Virta.
Indium has also been used as a bearing metal in special applications. For example, in vacuum evaporators and ALD equipment (Atomic Layer Deposition), where coated components are rotated under reduced pressure, materials are needed that function reliably in demanding conditions.
“Indium has been used as a bearing metal, for example in vacuum technology equipment where components are rotated in an evaporator or in ALD systems. It is not a common solution, but in certain special cases it is functional,” Virta says.
Because indium is currently a relatively expensive metal, its use as a large-scale bearing coating is rare. It is only used when its special properties provide a clear technical advantage.
An excellent absorber of X-radiation
Indium also has an exceptional ability to absorb X-radiation. This makes it an interesting material for radiation management applications.
“Indium is a very good absorber of X-radiation. We have made indium coatings, for example, for grids that divide X-rays into smaller units,” Lauri Virta says.
In such applications, material uniformity and controlled coating thickness are crucial. These applications are often related to research and measurement technology, where material choices are made carefully on the basis of physical properties.
A rare service in Finland
Overall, electrolytically produced indium coatings have relatively few applications. This is due both to the price of the metal and to the fact that its properties are only needed in certain special solutions.
At the moment, only one of Eforit’s customers uses indium coating. This reflects both the specificity of the application and the uniqueness of the expertise.
It is precisely such specialty coatings that reflect Eforit’s operating philosophy: a readiness to implement even rare and technically demanding solutions when the customer’s application requires it.
Specialized expertise for demanding needs
Indium coating is not a mass product, but a tailored solution for precisely defined technical requirements. It can be a decisive factor, for example, in:
- sealing surfaces in ultra-high vacuum equipment
- specialty bearings in vacuum technology equipment
- components related to X-radiation management
When something out of the ordinary is needed – such as a silvery, soft, and strategically significant indium coating – the solution can be found in Eforit’s specialized expertise. Indium coating is rare, but in the right application, it is an excellent solution.
