The mechanical properties of ceramic injection molded (CIM) components are largely
influenced by microstructural inhomogeneities that result from the interaction of rheological
properties of the thermoplastic feedstock with machine parameters and the design of mold and
injection gate. These inhomogeneities (e. g. texture, turbulences, joints, and density gradients) can
form weak spots in the material or lead to anisotropy of the material properties. Additionally, they
can influence the local sinter shrinkage behavior and thereby lead to the formation of residual
stresses in the component. For this reason, it is of great importance to analyze these
inhomogeneities in order to improve CIM processes and CIM components.
A method has been developed for the investigation of preferred crystal orientation and
microstructural defects, applying polarization microscopy of ceramic thin sections and colorimetry.
Polarization microscopy is used in order to visualize the crystal orientation of the single grains.
Different orientations of the optical axes will result in different colors of interference for optically
uniaxial materials. The polarization micrographs themselves are already suitable for the analysis of
the microstructure of CIM components regarding texture, separation planes, etc. Colorimetry is
used in order to measure and describe the colors in a standardized color system. By means of
color/orientation calibration curves that are measured with single crystal references, a quantitative
description of the orientation of single grains as well as texturized areas can be obtained.
Mechanical performance comparison of glass and mono fibers added gypsum composites
