Silver plating goes green: Phosphorus compounds replace toxic cyanide in new process
A research team has developed the world's first eco-friendly silver (Ag) plating technology using a phosphorus (P) compound as a key plating component. This breakthrough technology enables silver plating without the use of highly toxic cyanide, by formulating an acidic plating solution based on phosphorus compounds that successfully produces uniform and stable silver thin films.
The research is in the journal Electrochimica Acta. The team was led by Dr. Ju-Yul Lee and Dr. Seil Kim from the Energy & Environment Materials Research Division at the Korea Institute of Materials Science (KIMS)
Silver plating is an essential process for enhancing electrical signal transmission in semiconductors, electronic components, and circuit boards. Conventional silver plating technologies rely on cyanide, a highly toxic substance, which poses serious environmental and safety concerns.
Moreover, cyanide-based plating solutions cannot be applied to photolithography processes used in semiconductor fabrication, as their alkaline nature dissolves photoresists. Therefore, acidic plating solutions are essential for achieving high-precision manufacturing processes.
There are existing methods for silver plating without cyanide, known as non-cyanide silver plating technologies. However, in acidic environments, these methods face challenges due to hydrogen ion-induced precipitation of silver ions, which results in unstable plating solutions and makes it difficult to achieve uniform silver deposition. Additionally, to improve the stability of the plating solution, various additives must be introduced, making the overall process more complex.
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Due to these challenges, most non-cyanide silver plating technologies have focused exclusively on the development of neutral or alkaline plating solutions, rather than acidic ones.
This research successfully demonstrates a technology that enables uniform and stable silver plating in an acidic environment without the use of cyanide or additional additives. The research team utilized phosphine ligands to stabilize silver ions and prevent their precipitation, and optimized the concentration of phosphorus-based electrolytes to enhance the quality of the plating.
As a result, they achieved a uniform and mechanically robust silver coating. Ultimately, the technology not only meets eco-friendly standards, but also enables high-quality silver thin film fabrication while simplifying the overall plating process.
The global industrial plating market is rapidly expanding, with growing demand for eco-friendly plating technologies in response to increasingly stringent environmental regulations. This research outcome can be applied not only to semiconductor packaging and electronic components, but also to industries that require high-quality silver plating, such as medical devices, optical sensors, and precision parts.
In addition, by reducing reliance on foreign technologies and enabling export expansion through domestically developed solutions, this innovation holds significant industrial value.
Dr. Ju-Yul Lee, the principal researcher at KIMS and lead of the project, stated,"This technology not only addresses the environmental issues associated with conventional silver plating processes, but also enables the production of high-quality coatings required for semiconductor and electronic component manufacturing.
"We expect this advancement to serve as a catalyst for innovation across industrial fields."
More information: Soojin Lee et al, Electroplating behavior of a phosphorous-based cyanide-free silver electrolyte in an acidic environment, Electrochimica Acta (2025).