FIELD: plastic optical materials. SUBSTANCE: invention relates to a new halide class of photo- and radiation-resistant, non-hygroscopic and plastic optical materials, namely to a method for obtaining highly transparent in the terahertz region from 7.5 to 30.0 THz optical ceramics based on solid solutions of the TlCl0.74Br0.26 - AgCl0.25Br0.75 system. The developed method includes the melting of salts with a purity of 99.9999 wt.% in Pyrex glass ampoules with a conical bottom in an installation that implements the vertical method for directional crystallization, followed by moving the ampule to the lower zone with a lower temperature to form two solid solutions due to the geometric selection cubic and rhombic phases. The melting of salts TlCl0.74Br0.26 and AgCl0.25Br0.75 is carried out at a temperature of 400-460°C, followed by the formation of cubic and rhombic phases at a temperature of 190-240°C by moving the ampoule at a speed of 9-10 mm per hour to the lower zone installation, then the melt is cooled to a temperature of 25°C, pressed under a pressure of 1.2 MPa and a temperature of 180°C. Ceramics includes a Pm3m cubic phase based on a TlCl0.74Br0.26 solid solution, additionally containing a AgCl0.25Br0.75 solid solution, with the following ratio of ingredients in mol%: TlCl0.74Br0.26 93.0-74.0; AgCl0.25Br0.75 7.0-26.0 and an orthorhombic phase of composition Tl0.74Ag0.26Cl0.61Br0.39. In a similar way, ceramics with a cubic phase Fm3m are obtained based on a solid solution of AgCl0.25Br0.75, additionally containing a solid solution of TlCl0.74Br0.26, with the ratio of ingredients in mol.%: AgCl0.25Br0.75 26.0-92.0; TlCl0.74Br0.26 74.0-8.0 and an orthorhombic phase of composition Tl0.08Ag0.92Cl0.29Br0.71. To do this, the melting of salts TlCl0.74Br0.26 and AgCl0.25Br0.75 is carried out at a temperature of 360-400°C, followed by the formation of cubic and rhombic phases at a temperature of 180-190°C by moving the ampoule at a speed of 10-11 mm per hour in lower installation area. EFFECT: ceramics is intended as optical products: windows, lenses, etc., for use in laser systems operating in continuous mode. 2 cl, 2 dwg, 3 ex.
