New standard for plug contacts in high-voltage applications

Metal Deposition Solutions

Many requirements for the establishment and expansion of an efficient charging infrastructure have been or are currently being created: an increasing number of charging stations, expanded battery capacities or rising charging power. However, there is still a lack of a sustainable solution for long-lasting charging contacts. Current systems for transferring high charging power from the power source to the battery are still far from satisfactory for manufacturers and suppliers. 

Technical requirements of the industry have not been met so far

Silver is the element in the periodic table with the highest electrical conductivity and thus the prerequisite for connector contacts with the greatest possible power transmission. However, both fine silver (pure silver) and hard silver coatings (silver alloys) still do not meet all the technical properties required by the industry in terms of quality (see adjacent list).

The desire for significant longer durability of high-performance silver coatings for such high-voltage applications is obvious - no wonder, this is the basic prerequisite for longer product life and thus improved cost-effectiveness.

Longevity means competitiveness

The problem is particularly evident in the example of electric cars. Here, the vehicle inlet is permanently installed and a shortened life cycle often means an early, costly and potentially image-damaging replacement of the component.

Increased costs can also arise on the charging infrastructure side due to limited durability of the plug components on the charging station. The charging plugs are plugged in many times in daily use and can show wear of the silver surfaces within a short time. However, since end customers expect reliable charging with the shortest possible charging times, the entire charging pistol must be replaced in the event of wear and thus limited charging function. Besides the additional costs for materials, time and service, this can also result in sales losses due to reduced usage or the downtime of the column. 

High electrical and thermal conductivity


Temperature-stable hardness up to the end-of-life


Extended lifetime of the contacts/connectors


Improved wear resistance and corrosion resistance


High number of mating cycles without performance degradation

Our silver-graphite dispersion electrolyte ARGUNA® C-100 is specially developed for connector contacts used in high-voltage applications (e.g. high-power charging / HPC). A stable layer system with maximum charging performance without restrictions over the entire lifetime of the charging connectors is the result - and thus the new standard for the industry.

ARGUNA® C-100 is based on a simple function

Graphite particles perfectly embedded in the silver layer achieve extraordinary abrasion resistance and thus the high reliability and durability of the plug contact required by the industry. This is made possible by a optimized graphite component which, embedded in the silver matrix, serves as a solid lubricant. In this way, abrasion on the entire contact zone during the mating process can be reduced to a negligible level.

Graphite embedded in perfection

The statistically random distribution and incorporation of the graphite lamellae in the electrodeposited silver matrix is shown by a prepared ARGUNA® C-100 layer under a scanning electron microscope. Here, the silver matrix was selectively etched back and the incorporated graphite lamellae remain in their position. 

A view by element scan (EDX X-ray spectroscopy) of the contact surface shows the uniform and excellent distribution of the graphite over the surface. 

A new surface is created with each friction process and the abraded tips of the graphite lamellae are distributed over the friction surface. The usual abrasion of the silver surface is prevented, the contact resistances are kept small and thus a continuously high charging performance is ensured.

Exceptional abrasion resistance at maximum loading performance

Fine silver is the benchmark in terms of electrical and thermal conductivity. However, the tendency to cold welding in combination with a low hardness causes a high coefficient of friction and leads to wear of the silver layers when mated frequently. 

Hard silver has a higher hardness and shows significantly improved vibration resistance. However, added metals have a negative effect on electrical conductivity and the coefficient of friction is sometimes close to the fine silver level.

ARGUNA® C-100 combines and extends the positive properties of fine and hard silver. On the one hand, the fine silver matrix has excellent electrical conductivity. On the other hand, the solid lubrication of the graphite simultaneously increases abrasion resistance and thus reduces wear even with a high number of mating cycles.

Over 50,000 mating cycles

An end-of-life tribometer test shows the low and stable coefficient of friction of the ARGUNA® C-100 coating system. Even after more than 50,000 mating cycles, an intact silver graphite layer can be detected - and cross-compatibility with other mating contact materials (e.g. fine, hard or dispersion silver layers) completes the extended functionality in the field.

Maximum performance

Fine silver has the highest electrical and thermal conductivity of all metals, making it the functionally preferred charging contact coating to date. ARGUNA® C-100 lasts many times longer in comparison and also has an even lower resistance.

Anytime economical and highly functional charging connectors

The ARGUNA® C-100 layering system is designed for high-power charging with increasing charging powers of 500 kW and more. The robust layering properties maximize performance and durability:

  • Consistent coating performance at elevated temperatures (>150°C)
    even with local temperature rise in the contact point

  • Stable layering properties under humidity and dust
    and other exposed environmental conditions

  • Maintenance-free layer system over the entire service life 
    the otherwise necessary lubrication is not required

  • Cross-compatibility with existing infrastructure
    matching the existing connector types in the field

ARGUNA® C-100 thus offers a contact layer on your connectors that is clearly superior to conventional coatings: more than 50,000 mating cycles without adverse wear and therefore the best possible charging performance at all times without restriction - the new standard in this field.