Physico-Chemical nanomaterials science

Investigation of the influence of technological parameters on the morphological features of сelsian ceramics
V.V. Voloshchuk1, G.V. Lisachuk1, R.V. Kryvobok1, A.V. Zakharov1, 
A.S. Ryabinina1, A.R. Tymchenko1, R.A. Masalуkin1

1 National Technical University "Kharkiv Polytechnic Institute". 
Kyrpychova str., 2, Kharkiv-61002, Ukraine. 
E-mail: valenty93vol@gmail.com

The creation of radiotransparent materials with a set of high performance characteristics and the development of technological parameters for the manufacture of parts of various shapes and sizes is a common need of the modern aerospace industry. Solving this problem will increase the durability and efficiency of products, improve the controllability of special equipment and reduce the cost of their maintenance.
Technical raw materials: alumina, quartz and barium carbonate were used in the research to obtain celsian ceramics. Samples were obtained by two-stage technology: the first stage - the synthesis of the Celsian phase at a temperature of 1200 °C for 2 hours; the second - casting the slip into gypsum molds, drying blanks and firing products at a temperature of 1350 °C for 2, 4 and 6 hours. For ceramic samples, the microstructure was investigated and the influence of morphological features of the structure on physical and mechanical characteristics was evaluated.
The influence of the holding time at the maximum temperature on the morphological features of ceramics is established. The results of the research showed high values of the flexural strength (up to 292.4 MPa) at a holding time of 4 hours at a temperature of 1350 °C. It is known that the properties of ceramics depend on the ratio of crystalline, amorphous and gas phases. The main contribution to the properties of densely sintered ceramics is made by the crystalline phase. With increasing exposure time to 6 hours, there is an increase in the percentage of glass phase in the melt of the samples due to which the yield strength decreases and the values of dielectric constant deteriorate.
The properties of the studied samples varied depending on the exposure time in the following intervals: water absorption – 4.5-6.2 %, apparent density – 2.57-2.66 g/cm3, porosity – 11.8-15.8 %, flexural strength per bend – 115-292 MPa and dielectric constant - 8.7-12.2.
Further research will focus on the development of optimal technological parameters for the creation of ceramic waveguides used in the rocket industry.