SH-Synthesis of Nanostructured Materials Based on SiO2+Al+CaSiO3 with Wollastonite after Ultrasonic Treatment

Abstract

This paper presents the results of a complex study of the structure and properties of wollastonite after ultrasonic treatment (UST) and its effect on the development of the process of technological combustion (SHS) of systems based on quartz, the structure and properties of synthesized composition materials. Ultrasonic treatment of wollastonite of the brand FW100 was carried out in water and 5% aqueous solutions of different alcohols and acids at 40 and 100 kHz as well as at simultaneous UST action of 40 and 100 kHz during 20-60 minutes. In the presence of different organic modifying additives during UST there takes place not only milling of wollastonite particles and erosion of their surface but also different complex structural changes on the surface of particles and their capsulation into colloidal conglomerates. All the structural changes taking place in wollastonite particles under the conditions of UST result also in the change of the chemical activity of the material, which effects the thermal characteristics of the combustion process (SH-synthesis) of the systems containing UST modified wollastonite in the charge mixture. It is stated that, when introducing wollastonite after ultrasonic treatment into SHS-charge, there takes place a more complete conversion of initial components in the combustion process. The greatest amount of corundum and nanocrystalline silicon is formed, when using wollastonite treated in water, aqueous solution of polyvinyl alcohol and acetylsalicylic acid. The synthesized samples are characterized by high stable values of strength (up to 73 MPa) and indices of electric insulation properties.