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Hardly any other developer at Heraeus discovered and invented in his life so many different processes for industrial and medical application as Dr. Richard Küch (30.08.1860 to 03.06.1915). On Küch’s 150th birthday in the year 2010, Heraeus remembers this highly gifted inventor. The inventions that Küch made at Heraeus were decisive for the success and growth of the company. His developments can be found in industry and everyday use even today, for example as wonderful precious metal decorations on ceramics and glass.

Heraeus can look back on over 100 years of experience in the development of decoration products for glass and ceramics. In 1896 Heraeus set the foundation for bright gold production with the acquisition of the August Herbst bright gold factory. Bright gold was followed by bright platinum and burnish gold. The „ceramics department“, under the direction of Richard Küch, continued the development of precious metal preparations. This soon came to fruition, for example as high firing gold for the production of gold decorations at temperatures up to 1200°C, screen printing pastes, thermoplastic precious metal preparations and lustre colours. „Today, our department belongs to the leading world-wide producers of decoration products for ceramics and glass, which are now as before based on the basic principles and recipes developed by Richard Küch“, explained Jörn Jahnke, head of the business unit Precious Colours at Heraeus.

Precious metal colours are recipes consisting of several components that are burnt into glass or ceramics. They must be suitable for the relevant application method and after firing achieve an optimal result. The precious metal preparations consist of soluble precious metal compounds or precious metal powders, organometallic bonding agents, as well as resins and solvents. „The products are even today still based on the fundamental bright gold recipe developed by Richard Küch. Decisive for the fulfilment of modern requirements is the addition of other components, which improve the characteristics of the finished preparation“, describes Jahnke. The addition of organometallic compounds to precious metal preparations leads to an optimization of the adhesion and durability of the precious metal alloy. They also affect the appearance of the decoration after firing, for example the brilliance. For this reason there is an optimized formulation for every substrate (glass, porcelain and tiles) that fulfils the high requirements of everyday use. „They must stand up to permanent daily use. They must be resistant to scratching and abrasion, and cope with the harsh conditions in the dishwasher“, says Jörn Jahnke. „In recent years, completely new basic recipes and compounds have been developed by Heraeus, that are based on synthetic raw materials and which present new possibilities.”

Along with the choice from a comprehensive product range, Heraeus also offers made-to-measure solutions. In the development of new precious metal preparations, the developers of today proceed in much the same way as Richard Küch. In intensive development work, a multitude of recipe variations are tested on the customer’s required application, until an optimal product for their process can be made available. There is only one difference: Küch had written all the recipes and experiments neatly into laboratory note books, whereas today the samples and test results are recorded in an electronic data bank.

Heraeus works continually on the improvement and further development of precious metal colours and environmental considerations play an important role. UV technology, for example, presents new possibilities for the processing of the product. „Special products can be cured with uv light. This requires only a few seconds and is environment friendly, when compared to the conventional physical drying, as these products do not normally contain solvents as part of their formulation“, says Jahnke, referring to a current innovation. Richard Küch would have been delighted by this new technology.