Pure platinum (99.9% or higher purity) with the world’s highest Vickers hardness of 500 HV or higher, strength of 2,000 MPa, and excellent workability for suitability to a wide range of industries

November 14, 2024

TANAKA Kikinzoku Kogyo K.K., which develops industrial precious metal products as one of the core companies of TANAKA Precious Metals, announced that it has succeeded in developing the world’s first bulk² platinum with controlled crystal grain³ size in the nano scale.

The average grain size of a typical bulk metal is about 10 µm at the smallest. In this new technology, the average crystal grain size can be controlled in the nano scale. As a result, the developed pure platinum, with 99.9% or higher purity, has 10 times the hardness and 4 times the strength of typical platinum materials.

It is known that the properties of metals, including precious metals, are enhanced by grain refinement. In recent years, steel and nonferrous metals with nano-sized crystal grains have been produced by deformation processing to apply extreme levels of plastic deformation⁵ and recrystallize their structures. While deformation processing temporarily hardens⁶ metal materials, when highly pure precious metal materials undergo the same process, the arrangement of atoms that form their crystalline structure changes and new crystal grains are nucleated and grown over periods of a few hours to a few days. As a result, the hardness of the material noticeably decreases (softens), and it has been very difficult to refine the crystal grains through deformation processing.

TANAKA Kikinzoku Kogyo has succeeded in manufacturing bulk platinum with controlled crystal grain size in the nano scale by optimizing the manufacturing process. The hardness and strength of the platinum materials manufactured by this technology are much higher than those of typical platinum materials. The developed platinum has a high density of small-angle grain boundaries, large-angle grain boundaries, dislocations, and other lattice defects within the material. Therefore, the developed platinum has properties that are clearly different from the properties of commonly known platinum materials, even without additive elements or alloying. As a new material with high purity and high functionality, it is expected to be applied to a wide field of industries, including the electronics and aerospace industries.

1. World’s first: As of October 30, 2024, and based on internal research (according to a survey of patents and papers on bulk platinum materials)
2. Bulky, bulk: Bulky refers to the state of material where clumps of atoms within the material, not on the surface, are connected three-dimensionally. Solid matter with a bulky structure is called bulk.
3. Crystal grains, crystal grain size: Metals have a structure with a regular arrangement of atoms. Crystal grains refer to individual areas of this structure where the orientation of the atomic arrangement is different from neighboring areas, and crystal grain size refers to the diameter of the grains.
4. Electron backscatter diffraction (EBSD): A method of investigating information on material crystals (crystal system, grain size, orientation, etc.) by analyzing the backscatter diffraction from the surface of a material with a crystalline structure when irradiated with an electron beam
5. Plastic deformation: The amount of deformation that remains in a material, without it returning to its original state, after applying an external force to the material to deform it and then removing that external force
6. Work-hardened: The phenomenon of a metal being hardened by applying stress to the metal to accumulate plastic deformation
7. Royal Pure Platinum: An original material manufactured by TANAKA Kikinzoku Kogyo, with higher hardness and strength than normal platinum materials while maintaining a purity of 99.9%

20241114_TANAKA Successfully Develops the World’s First Manufacturing Technology for Platinum Materials with Nano-Sized Crystal Grains.pdf