Development of New Cordierite‐Based Refractory Coatings for Casting Applications

Abstract

In this study, new refractory coatings based on synthesized cordierite for the casting applications were developed. The investigation included starting raw materials characterization, synthesis of the cordierite, design of the refractory coating as final product, and its application testing. The obtained results pointed out that coating suspension sediment stability was crucial quality parameter. Design and optimization of the coatings composition, with controlled rheological properties included, were achieved by application of different coating components, namely different suspension agents and by alteration of the coating production procedure. Cordierite, used as filler, was obtained by means of synthesis in the solid‐state reaction on the basis of talc, kaolin, and alumina. The investigation showed that the application of these particular types of water/alcohol‐based coatings has positive influence on surface quality and structural and mechanical properties of the castings of aluminum alloys obtained by casting into sand molds by means of evaporable models method, that is, evaporate pattern casting process.

Influence of mechanical activation of a cordierite -based filler on sedimentation stability of lost foam refractory coatings

“…Refractory coatings and their production processes were designed according to the works [3,8,22], our works [24,26] and domestic norms [43,44]. Based on the analysis of the mechanical activation influence on the filler grain size and shape [27,[28][29][30][31][32][33] as well as of the filler grain size influence on coating suspension sedimentation stability [3,7], cordierite-based, mechanically activated fillers were chosen: first filler C 2 (100% -20 x10 -6 m) and the second combination of fillers C 2 (100% -20x 10 -6 m) and C 3 (100% -12 x10 -6 m). In reference to the filler grain size chosen, two series of the Lost Foam refractory coatings were designed as follows: coating with filler C 2 (marked: A) and coating with combination of fillers C 2 + C 3 (marked: B), which were corrected according to test results for the coating suspensions obtained.…”

“…These products are a frequent cause for castings' defects [1][2][3][4][5]. To obtain quality castings, it is necessary to apply highly permeable Lost Foam refractory coatings [1,[6][7][8].…”