SCANDIUM - CHROMIUM COLOUR THERMOCHEMICAL REVERSIBLE INDICATOR Russian patent published in 2025 - IPC G01K11/16 C07F5/00 C07F11/00 C07F19/00 

FIELD: chemistry.

SUBSTANCE: invention relates to chemistry, more specifically to a novel colour reversible thermochemical indicator, and can be used for visual monitoring and indication of temperature and measuring temperature fields of surfaces of objects in different technological processes. Proposed is the creation of a novel scandium-chromium colour reversible thermal indicator based on scandium (III) hexa(isothiocyanato)chromate(II)-tris(nicotinato)tris(nicotinic acid), capable of reversibly discolouration when heated to temperature of 170 °C, available in production and easy to use in practice. Starting materials used are potassium hexa(isothiocyanato)chromate (III) and nicotinic acid which is commercially produced as a cheap drug (vitamin PP), which accounts for its low cost and availability.

EFFECT: thermal indicator has a bright colour change, is stable during storage, is thermally stable under operating conditions, is non-toxic, easy to produce, are easily applied on substrates in form of thin thermochromic films and heat-sensitive coatings having durability, which enables to use it as a reversible heat-sensitive colour indicator for visual control of thermal conditions in technological processes.

1 cl