METHOD OF PRODUCING REFRACTORY ARTICLES FROM CERAMIC MATERIAL BASED ON POTASSIUM SODIUM NIOBATE

摘要

FIELD: manufacturing technology.;SUBSTANCE: disclosed is a method of producing refractory articles from ceramic material based on potassium sodium niobate in form of different processing equipment: reaction vessels, crucibles, bases, reactors, etc., used in production of technical ceramics, mainly piezoelectric, based on potassium-sodium bismuth titanates (KNBT) or potassium-sodium niobates (KNN), at which during charge preparation initial components N₂CO₃ and K₂CO₃ is used in form of 1 molar aqueous solutions, and Nb₂O₅ in form of powder with average grain size of 10 mcm. During continuous mixing, solutions of potassium and sodium carbonate are mixed with a weight of powder of niobium oxide in molar ratio of 1:1, the obtained aqueous mixture of carbonates and oxide is evaporated to a crumbly mixture, which is further dehydrated in drying cabinet at temperature of 210 °C to consistency of mass and cooled to room temperature in a desiccator. Then, prepared in such way, charge is added with 10 % of temporary process binder in form of 5 % aqueous solution of polyvinyl alcohol by mixing them in a forced action mixer and holding in a closed container during the process time to ensure uniform distribution of polyvinyl alcohol solution and stabilization of moisture content by volume to obtain a homogeneous molding mass, which is then granulated to dimensions facilitating increase in fluidity and layability. Workpieces are formed by double-side uniaxial pressing at pressure of 100 MPa, ensuring identity of the latter according to geometric parameters of finished articles, at that, step for synthesis of sodium potassium niobate material is combined with article sintering step by simultaneously performing one process transition.;EFFECT: reduction of technological process due to simplified preparation of charge and combination of performed operations.;3 cl