Graded epoxy-hard coal composites: Analysis of filler particle distribution in the epoxy matrix

Abstract

The aim of the work was to achieve assumed gradation of hard coal particles distribution in epoxy matrix and thus gradation of properties. It was done by proper selection of compounds composition and conditions of the gradation formation. The graded composites were produced using centrifugal casting. Two types of epoxy resins as a matrix and two types of hard coal of various granulation as a filler were used. Samples in the form of bushings with radial carbon filler gradation were produced by changing filler type, its volumetric content and parameters of centrifugal casting. The first part of the paper presents results of graded materials structure investigations. The microscopic observations of the structure of composites prepared according to elaborated experimental program show that the composites are characterized by continuous change of the filler particles content in radial direction, so they can be classified as graded materials. Results also show that gradation of particles content and thus gradation of properties may be planned and foreseen when mechanisms of gradation formation are known.