Optimization of structural parameters for the sound absorption performance of a cellular ceramic foam

PurposeThe purpose of this paper is to provide an optimization schedule of structural parameters for the sound absorption performance of a cellular ceramic foam in the sound frequency range of 200–4,000 Hz.Design/methodology/approachThe cellular ceramic foam with porosity of about 60–75% and the pore size of about 1–7 mm was successfully prepared by using natural zeolite powder as the main raw material. For this ceramic foam, the sound absorption performance was measured, and the absorption structure was optimized by some important structural parameters. With orthogonal experiment, optimization of structural parameters was found for absorption performance. By means of the range analysis method, the main factor is known to influence the performance of ceramic foam.FindingsThe present ceramic foam may have good absorption performance although at relatively low frequencies of 400–4,000 Hz while structural parameters of sample are appropriately combined. With orthogonal experiment, optimization of structural parameters for the absorption performance was found to be as follows: sample thickness, 25 mm; porosity, 73.5%; pore size, 4–5 mm and air gap depth, 20 mm. To influence the performance, sample thickness is the main factor, air gap depth is the second and both of pore size and porosity would have a relatively slight effect.Originality/valueThis paper presents a method to optimize the structural parameters of a cellular ceramic foam for sound absorption performance by means of orthogonal experiment.

Firing of Cellular Ceramics from Granulated Foam-Glass

It has been presented the study results of the firing process of cellular ceramics from granulated foam glass. The chemical, mineral and granulometric compositions of the raw materials are given. It has been shown the characteristic of ceramic-technological properties of raw materials. The samples were burned from the granulated mixture in the temperature range of 850-1000 ° C. It has been established the change dependence in the physicomechanical properties of cellular ceramic samples on the temperature and firing duration. The results of the study of the macro-and microstructure of cellular ceramics are given. It has been revealed the effect of intensive formation of the pyroplastic phase and the connection between small pores at a temperature of more than 950 ° C. After the enlargement, the cells leave the three-phase ceramic system and it was the increase in the average density of cellular ceramics is 1.4-1.5 times. The influence of a solid glass-ceramic shell along the inner surface of the pores on the decrease in water absorption of cellular ceramics to 6.5-7% is established.

A Study on Structure and Phase Composition of Cellular Ceramic Materials from Dispersed Silica-Rich Rocks

Studies on structure, phase composition and properties of ceramic wall materials with a glass-crystalline framework from dispersed silica-rich rocks are described. The results of chemical, mineralogical and granulometric compositions of tripolite and granulated foam-glass crystalline material (GFGCM) are presented. The dependence of physical and mechanical properties of cellular ceramic materials on GFGCM content in the composition in the amount from 5 to 75% is determined. Test samples of cellular ceramic materials with dimensions 250 × 120 × 65 mm, having a compressive strength 16.2-20.8 MPa, water absorption 7.1-7.9 % and an average density 0.99-1.32 g/m3 were produced at the factory. At the macroscale level the cellular structure of the ceramic material consists of closed pores with a vitrified inner surface pore, glass-crystalline outer shell of the pores and solid phase of the framework walls. It was established that after firing in the temperature range 850-900 °C the walls of the framework are represented by quartz, feldspar and hematite, a pronounced halo is indicating a significant amount of glass phase.