Chemical resistance of celsian ceramics in acid and alkaline reagents

Abstract

In the article, the chemical stability of celsian ceramics at different firing temperatures was investigated and the structural-phase features of the obtained samples before and after interaction with alkaline and acid media were studied.
 The technology of obtaining test samples was two-stage. The first stage was the synthesis of the celsian phase in a muffle furnace at a temperature of 1200 °C with a holding time of 2 hours and subsequent cooling together with the furnace. The second stage took place in a silitic furnace at temperatures of 1300, 1350 and 1400 °C with a set rate of 15 deg/min and holding at a maximum temperature of 4 hours. The chemical resistance of celsian ceramics was determined in relation to 20 % solutions of HCl and NaOH. The phase composition of the test samples was determined using the method of X-ray phase analysis (X-ray diffraction) using a DRON-3M diffractometer. The studies of the experimental samples microstructure and the surface morphology of their faults were carried out by the direct method of scanning electron microscopy using a scanning electron microscope PhenomPro.
 It was found that in relation to the 20 % solution of NaOH celsian ceramics was insoluble and has a value of alkali resistance in the range of 99.47—99.67 %. The study of microstructure and phase composition of celsian ceramics samples after treatment with 20 % NaOH solution showed that in all studied samples there was only a crystalline phase of celsian, the corrosion process didn’t occur. In relation to the 20 % HCl solution, the process of celsian ceramics corrosion was observed with the complete chemical interaction of the celsian phase with hydrochloric acid and the subsequent formation of the barium chloride dihydrate phase.