3D topography of the micro cracks of subsurface damages by etching process

The existence of the subsurface damage of high-precision components is becoming a bottleneck for better performance of high-precision components in the fields of energy, space, national defense equipment, integrated circuit, MEMS and so on. So far there is still no method which is capable of characterizing the 3D topography of subsurface fractures, and this paper presents an idea of investigating the full information of the subsurface damages based on the etching experiments. By micro-indentations some individual subsurface damages with specific geometrical cracks were artificially prepared first, and then dealt with the conventional etching process. The etching process was carried out in the differential mode, namely etching with certain interval time. All 3D topographies of etched cracks during etching were recorded and, dimensions of initial fractures including length, width, depth, etc. were calculated according to the 3D data. Comparison of the calculated results and designed geometrical features indicated that the method used in the paper is a valid method to roughly characterize 3D information of the fractures of the subsurface damage layer and in discussion we proposed a numerical model to accurately characterize the initial 3D holographic information of fractures.