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The ceramic used in Radiomir cases is a high-tech zirconium oxide powder (ZrO2) containing 3% binder and colouring pigments.
This high-tech ceramic has many advantages, such as extreme hardness and long-term resistance against wear and corrosion.
The zirconium oxide powder is isostatically pressed (in a liquid at 2,000 to 3,000 bar) to form a cylinder or tube. After the pressing stage, the sintering process starts at a temperature of about 1,500 °C, and the cylinder or tube undergoes a shrinkage of about 20% (this is known as “binder shrinkage”).
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e segue:
"For the Luminor and Luminor 1950 cases, Officine Panerai uses a high-tech ceramic made of zirconium oxide (ZrO2). The material is made from powder which is isostatically pressed while the final shapes of the various components are formed by grinding. This high-tech ceramic has many different qualities: extreme hardness (up to five times greater than that of stainless steel), resistance to scratches and shocks and its surface has a very high aesthetic impact.
Preparation of zirconia powder
The powder consists of about 80% zirconia powder and 20% of a binding powder. To achieve the black colour, a colour pigment highly resistant to heat is added.
Injection of the mixture into the mould
During the injection process, the zirconia powder with the binder is warmed slightly so that it flows as a liquid substance into the injection machine. This liquid substance is forced under extremely high pressure into the mould that forms the shape of the component. This manufacturing step is called the “green stage”.
Machining during the green stage
The case middle, lever and bridge are machined during the green
stage. Since the consistency of the material is still very soft, the components can be shaped by turning, milling and drilling.
Removal of the binder
The binder is removed from the components by a chemical process at a temperature of approximately 100°C. It takes several hours for all the binder to be removed.
Sintering of the ceramic
Over a period of about three days, the components are heated to 1500°C and then allowed to cool down. After this stage, the components consist of 100% zirconia ceramic and have a hardness of 1200HV (5 times greater than stainless steel).
Grinding the ceramic in the hard stage
The grinding phase gives the components their final dimension. In order to achieve the required tolerances, special diamond grinding tools are used. Since the ceramic is extremely hard, the grinding process is very time consuming.
Finishing
The finishing of the ceramic component is carried out by sandblasting."