HEAT-RESISTANT SYNTHETIC JEWELLERY MATERIAL

摘要

The invention relates to materials for jewellery industry, in particular, to synthetic materials intended to replace the natural gemstones. The heat-resistant synthetic jewellery material comprises a transparent, translucent or opaque composite nanocrystalline material on the basis of nanosized oxide and silicate crystalline phases. The material comprises at least one of the following crystalline phases: spinel, quartz-like phases, sapphirine, enstatite, petalite-like phase, cordierite, willemite, magnesium aluminotitanates, zircon, rutile, zirconium titanate, zirconium dioxide with a content of ions of transition elements, rare-earth elements and precious metals of from 0.001 to 4 mol%. One of the crystalline phases is additionally quartz-like solid solutions of lithium magnesium zinc aluminosilicates with a virgilite or keatite structure. The composition is selected from the following components, in mol%: SiO 2 - 45-72; Al 2 O 3 - 15-30; MgO - 0.1-23.9; ZnO - 0.1-29; Li 2 O - 1-18; PbO - 0.1-7.0; ZrO 2 - 0.1-10; TiO 2 - 0.1-15; NiO - 0.001-4.0; CoO - 0.001-3.0; CuO - 0.001-4.0; Cr 2 O 3 - 0.001-1.0; Bi 2 O 3 - 0.001-3.0; Fe 2 O 3 - 0.001-3.0; MnO 2 - 0.001-3.0; CeO 2 - 0.001-3.0; Nd 2 O 3 - 0.001-3.0; Er 2 O 3 - 0.001-3.0; Pr 2 O 3 - 0.001-3.0; Au - 0.001-1.0. The invention makes it possible to produce a jewellery material with a low coefficient of thermal expansion and a high degree of heat resistance. Proposed material obtained by this method possesses uniform colour, optical characteristics similar to the characteristics of the main natural coloured minerals and manufacturable. Important advantages of the developed material are low coefficient of thermal expansion, hardness, chemical resistance and colour stability to thermal shock, which allows, in particular, accelerated mode of grinding and polishing as well as permits using the method of "casting with precious stones", as not only faceted samples do not crack in contact with the of silver or gold melt, but they're also able to retain their colour.