Use case: Corrosion protection using copper-based coatings

Nickel coatings are used in applications where components need to be protected against corrosion, wear, and mechanical stress, and where a high-quality surface finish is desired. They offer high dimensional accuracy and hardness, are characterized by good optical properties, and their electrical conductivity can be tailored.  However, complex deposition processes, the use of cyanide-containing electrolytes, and potential allergic reactions limit their application.

Comparable property profiles that are more environmentally friendly and sustainable can be achieved with copper-based coating systems (copper, tin, zinc). Here, however, it is essential to understand and control the atomic diffusion processes, phase transformations, and corrosion mechanisms in the CuSnZn alloy system. The elimination of cyanide-containing electrolytes also presents a chemical and process engineering challenge.

Our research and development services for identifying and evaluating suitable CuSnZn alloy systems to replace nickel coatings

• Investigation of microstructure and phases using X-ray diffraction, electron backscatter diffraction (EBSD), and energy-dispersive X-ray spectroscopy (EDX) to understand the relationship between chemical composition and phase composition,
• Measurement of local hardness changes using nanoindentation to evaluate the mechanical properties of the coating,
• Ball indentation tests to investigate cracking and spalling under defined loads are necessary to evaluate wear behavior,
• Ageing tests to analyze the thermodynamic stability of the coating-substrate system to test long-term stability,
• Adaptation of thermodynamic-kinetic models and prediction of temperature and time-dependent phase composition and microstructure. Corrosion properties and long-term stability are derived from this,
• Atomistic simulations to describe diffusion processes and mixed-phase formation, as a basis for the targeted optimization of coating properties

These R&D activities are important for identifying and evaluating sustainable alternatives to nickel-based coatings with reduced environmental and health impacts.

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