Optimization of the annealing of plaster moulds for the manufacture of metallic foams with an irregular cell structure

Abstract

Metallic foams are the materials, the research of which is still ongoing, with a broad applicability in many different areas (e.g., automotive industry, building industry, medicine, etc.). These materials have interesting potentials due to a combination of properties, which are, on the one hand, related to their metallic character and, on the other hand, to the porous structure. Since the discovery of porous metallic materials numerous methods of production have been developed. This work deals with the optimization of the foundry method for the manufacture of metallic foams using the evaporable polymeric pattern. This technology was used for the manufacture of metallic foams with an irregular cell structure and with fully open pores. Attention, in the experimental part, is devoted particularly to the chosen moulding material -plaster. We checked the suitably of the proposed procedure of manufacturing a plaster mould, the drying process and the subsequent annealing that significantly influence the final properties of the mould and, therefore, the quality of the resulting casting of the metallic foam. Keywords: metallic foams, casting, irregular cell structure, plaster, annealing Kovinske pene so materiali, ki se {e preiskujejo in imajo {iroko podro~je uporabnosti na razli~nih podro~jih (npr. avtomobilska industrija, gradbena industrija, medicina in podobno). Ti materiali so perspektivni zaradi kombinacije lastnosti, ki imajo po eni strani kovinske lastnosti, po drugi pa porozno strukturo. Od odkritja poroznih kovinskih materialov so se razvile {tevilne metode njihove izdelave. Delo obravnava optimizacijo livarske metode izdelave kovinske pene z uporabo izparljivega polimernega modela. Ta tehnologija je bila uporabljena za izdelavo kovinske pene z nepravilno celi~no strukturo in popolnoma odprtimi porami. V eksperimentalnem delu je pozornost usmerjena v izbiro mavca kot materiala za model. Preverjen je bil predlagani postopek izdelave mav~nega modela, postopka su{enja in`arjenja, ki imajo najve~ji vpliv na kon~ne lastnosti modela in na kvaliteto ulivanja kovinske pene.

Manufacturing of cast-metal sponges from copper alloys

“…After the removal of the refractory material, a cast metal foam is obtained, which is an exact copy of the foam pattern. 3 In order to optimize the manufacturing conditions, the castability of the CuSn12 copper alloy was monitored in the conditions of the cast-metal-sponge production. The experiment was carried out on a special Indutherm MC15 casting machine.…”

Use of water-soluble precursors in the production of cast metal foams

“…There are several foundry methods for the production of porous metals, such as the investment-casting technology (using an evaporative pattern), which is considerably expensive. 5 Thanks to the foundry technology we are able to control the porosity (%), pore size and their distribution (regular/irregular). In our case, the production of metal foams with an irregular structure is carried out by pouring filling materials (precursors) into a mould cavity.…”

Use of precursors for the production of cast metallic foams

“…There are several foundry methods for the production of porous metals, such as investment casting technology (using an evaporative pattern), which is considerably expensive. 5 The experimental part of this paper deals with an optimization of the procedure for the production of cast metallic foams, using the infiltration method, which ensures a rapid and economically feasible production of shaped components.…”