METHOD OF PRODUCING WORKPIECES OF OPTICAL POLYCRYSTALLINE MATERIALS BASED ON FLUORIDES Russian patent published in 2024 - IPC C30B29/12 C30B33/02 C04B35/553 C04B35/622 B29D11/00 G02B1/02 

FIELD: optics; electronics.

SUBSTANCE: invention relates to the optical and electronic industry and can be used in the manufacture of parts, for example, plates for photomasks, lenses and prisms. Monocrystal made of sodium, potassium and lithium fluoride is placed in a mould of a vacuum moulding furnace equipped with matrix 1, guide holder 2 and punch 3. To prevent diffusion welding of the mould material and the monocrystal and to reduce the friction coefficient between them, a layer of hexagonal boron nitride is pre-applied on the surface of the monocrystal and forming surfaces of the mould. Furnace is evacuated to a residual pressure of not more than 10^-4 mmHg article, and heating selected monocrystal to flow point in range 2/3T_mp≤T<T_mp, where T_mp is melting point in degrees Kelvin. Deformation is carried out by applying pressure to achieve a given value of displacement of punch 3 and free upsetting of the obtained workpiece at a degree of deformation ε, which is 91–95% and calculated by the formula: ε=Δh×100%/h₀, where Δh=h₀-h_f – value of mould punch displacement, h₀ and h_f – initial thickness of monocrystal and final thickness of workpiece. After holding, pressure is smoothly removed and cooling is performed.

EFFECT: increasing strength and heat resistance of ceramic polycrystalline microstructured workpieces made from said materials, while maintaining high optical quality in range of 0,15–11 mcm.

4 cl, 1 dwg, 4 ex