Formation and Evaluation of White Jewellery Alloys Based on Gold

The formation of white jewellery alloys based on gold is a complex process that involves careful selection of ligatures and compliance with the conditions of production. Obtaining alloys of white gold with warm and cool tones is theoretically and practically possible either by regulating the ratio of silver and copper in the alloy system Au-Ag-Cu, or by decolouring yellow gold by such metals as Pb, Zn, Mn, Co, In, Cr, Кd or Ga. Colour and tint of the alloy largely determines the aesthetic qualities of jewellery that are made on the basis of precious metals, its conformity to fashion and style, in harmony with the precious stone. Therefore, the evaluation of colour of jewellery alloy is a very important quality characteristics of jewellery that is taken into account at the stage of design development. The aim of this work is the study of factors affecting the white colour and methods of its evaluation for jewellery alloys based on gold. Taking into account the purpose, the following objectives have been set: to carry out a comparative merchandising characteristic of jewellery, including the degree of whiteness of jewellery alloys based on gold of both existing and new jewellery alloys, developed by the authors of the article. While doing the tasks there were used general and specific spectrophotometric research methods. According to the results there have been proposed types of white gold-based alloys, which provide high aesthetic properties and meet the requirements of reliability and safety.