Eforit Oy expert Sari Virta gave an extensive presentation on gold plating, its technology, and why gold remains an irreplaceable material in industry, science, and art at the winter seminar of the Finnish Galvanotechnical Association.
Eforit Oy – A Pioneer in Precious Metal Coating
Eforit Oy has been carrying out electrolytic surface treatment since 1988. The company specializes in precious metal coatings, such as gold, rhodium, silver, indium, black ruthenium, and various nickel coatings.
Sari Virta described the company’s extensive experience as follows:
“Eforit Oy has had the opportunity to take part in many significant gold plating projects, including the Cassini Huygens and BepiColombo satellites, as well as numerous space, quantum, defence industry, and art projects. These have been extremely challenging and rewarding projects.”
Gold – Rare and Unique in Its Properties
Gold is one of the rarest elements found in nature. Its value is based on its rarity, chemical stability, and technological versatility.
Sari Virta summarized the fascinating origin of gold:
“Gold is a rare metal that comes from space – most of it was brought to Earth by meteorites around four billion years ago.”
Some of the world’s largest gold deposits are found in China and Siberia, among other places. The largest source of gold in the world is Witwatersand in South Africa.
The most important properties of gold include:
good electrical conductivity
high density and melting point
chemical inertness
exceptional malleability
Virta described gold’s unique colour as follows:
“There is a gap in the energy state of gold’s electrons that absorbs blue light. As a result, the remaining light is yellow – gold is literally a glowing dawn.”
The Value of Gold and Carats
Carats and millesimal fineness values define the purity of gold. Carats are expressed on a scale from 1 to 24 carats. The gold used by Eforit is nearly 24 K, as its coatings contain 99.8% pure gold.
Virta explained that different alloys produce different properties:
“White gold is created by adding palladium, silver or nickel to gold, while the warm tone of rose gold comes from copper or silver.”
One of today’s challenges is the world market price of gold, which has risen sharply in recent years due to pandemics, inflation, and geopolitical tensions.
Gold Plating Baths – Precision and Technology
Eforit Oy carries out different types of gold plating according to the intended application.
Soft Gold Plating
99.9% pure gold
thick coatings up to 50+ µm
hardness only 50–90 HV
applications: jewellery restoration, solderable coatings, laboratory gold plating
Hard Gold Plating
98–99% gold, typically with cobalt
hardness 120–200 HV
applications: electronics connectors, components, and research equipment
Electroformed Gold, or “Hard Gold Build-Up”
Very thick coating layers, up to 100 microns.
Decorative Gold Baths, or So-Called Colour Baths
gold content varies
coating thickness max. 5 microns
application: jewellery coatings
NanoDAu – Eforit’s Own Innovation
“Our NanoDAu gold electrolyte contains nanodiamonds, which allow us to achieve more than double the wear resistance compared with traditional hard gold plating,” Virta explained.
The innovation is especially suitable for components and connectors that are subject to heavy wear.
The Gold Plating Process Step by Step
In electrochemical gold plating, or electroplating, a metal object is immersed in an electrolyte solution, and gold is deposited onto the surface of the object with the help of an electric current.
The gold plating process consists of the following stages:
Pretreatment
Electrolytic gold plating
Post-treatment and measurements
Virta emphasized the precision and safety of the process:
“High-quality plating is achieved when every stage is carried out carefully – and safety is ensured with appropriate protective equipment and ventilation.”
Environmental Responsibility in Waste Treatment
Eforit follows strict environmental standards. Cyanide handling, heavy metal precipitation, and tertiary water treatment ensure the safety of the process.
Applications of Gold – From Everyday Life to Space
Industry
Gold can be found in smartphones, computers, circuit boards, connectors, and marine industry components, among other things. Gold can also be used in power plants – the turbine at the Keljo power plant is one example of how gold can be utilized.
Science and Space
“The world’s first commercial quantum computer contains parts gold-plated by Eforit – and the gold coatings for the BepiColombo spacecraft were among our most demanding projects,” Virta said.
Art and Design
Gold and gold plating have long traditions in art. Eforit’s gold plating can be found in guitars, furniture, vehicles, jewellery, and works of art.
Sari Virta’s presentation highlighted just how versatile and technically critical gold is as a material – and how Eforit Oy’s expertise makes it possible to utilize it even in the most demanding applications.
“Gold is used everywhere – from the depths of the oceans to the outer reaches of space. Its possibilities are almost limitless.”
