The agglomeration and sedimentation tendency of iron fillers with different particle size, shape, and the specific area was investigated by means of microstructural observation. The distribution of filler particles within polymer composite was investigated by the agglomeration and sedimentation tendency. The effect of regular and irregular fillers particles was considered in the silicon based polymer composite for uniform distribution within the volume of the matrix. The role of shape and size of the fillers were emphasized for the distribution and sedimentation behavior within the polymer composite. The extent of aggregation and sedimentation is always determined by the relative magnitude of attractive and separating forces under the sample preparation and testing condition. The effect of density and surface area has a significant effect on the dispersion within the composite. We could condude that composites with sedimentation and aggregates possess lower mechanical properties. (C) 2020 Elsevier B.V. All rights reserved.