Owing to its properties, metallic foams can be used as insulation material. Thermal properties of cast metal-ceramic composite foams have applications in transport vehicles and can act as fire resistant and acoustic insulators of bulkheads. This paper presents basic thermal properties of cast and foamed aluminum, the values of thermal conductivity coefficient of selected gases used in foaming composites and thermal capabilities of composite foams (AlSi11/SiC). A certificate of non-combustibility test of cast aluminum-ceramic foam for marine applications was included inside the paper. The composite foam was prepared by the gas injection method, consisting in direct injection of gas into liquid metal. Foams with closed and open cells were examined. The foams were foaming with foaming gas consisting of nitrogen or air. This work is one of elements of researches connected with description of properties of composite foams. In author's other works acoustic properties of these materials will be presented.
The paper presents results of initial research on the possibility of applying microwave radiation in an innovative process of making casting
moulds from silica sand, where gypsum CaSO4∙2H2O was acting as a binding material. In the research were compared strengths and
technological properties of moulding mixture subjected to: natural bonding process at ambient temperature or natural curing with
additional microwave drying or heating with the use of microwaves immediately after samples were formed. Used in the research
moulding sands, in which dry constituents i.e. sand matrix and gypsum were mixed in the ratio: 89/11. On the basis of the results of
strength tests which were obtained by various curing methods, beneficial effect of using microwaves at 2.45 GHz for drying up was
observed after 1, 2 and 5 hours since moisture sandmix was formed. Applying the microwaves for hardening just after forming the samples
guarantees satisfactory results in the obtained mechanical parameters. In addition, it has been noted that, from a technological and
economic point of view, drying the silica sand with gypsum binder in microwave field can be an alternative to traditional molding sand
technologies.