Studying the Structure and Elemental Distribution of Ceramics

Ceramics often have microstructure and grain sizes that affect material performance. It is possible to optimize microstructure and grain boundaries with ceramic processing parameters for specific product requirements.

The grain sizes and distribution are quantified using scanning electron microscope (SEM) images with material contrast. The Phenom (SEM) employs a backscattered electron detector (BSD) which inherently provides compositional information, resulting in rapid automated image analysis.

Elemental identification with EDS is used to correlate microstructure and composition. EDS data can be used in ceramic research and development to analyze agglomerates or contamination, to identify second phases on ceramic surfaces, or to chart nanoparticle diffusion through a porous ceramic.

Advanced ceramic materials are used in several industries, such as aerospace, electronics, healthcare, renewable or alternative energy, and automotive. Ceramic materials are optimized for products that need high melting point, high modulus and hardness, and high corrosion resistance and thermal expansion. Ceramic performance is affected by agglomeration, grain size and volume, microstructure, elemental distribution, porosity, and surface roughness.

Advantages of BSD

Scanning electron microscopy (SEM) can be used to characterize the microstructure of ceramic materials. As shown, a backscattered electron detector (BSD) image denotes material differences with heavier elements brighter in the SEM image than lighter elements. This contrast offers easy thresholding to establish grain sizes and coverage. Using a BSD also enables lower vacuum levels, minimizing sample charging and  beam damage.

Phenom SEM BSD image of an advanced ceramic heating element material

Phenom SEM BSD image courtesy of CoorsTek

Grain Size Distribution

Several ceramic materials are sintered to produce the necessary mechanical properties. BSD images can be used to quantify grain size and coverage. Using Automated Image Mapping with the Phenom SEM, data acquisition can be automated for maximum workflow with statistical analysis. A tiled image comprising of 30 individual SEM image (right) is used to illustrate this. Total acquisition time was less than 3 minutes. The tiled image was subsequently analyzed using a threshold effect, indicating 17% white, 78% gray, and 5% black for this ceramic sample. The grain distribution data can be used to optimize processing conditions to fulfill product requirements. In addition, SEM imaging with material contrast using a backscattered electron detector (BSD) offers a visual understanding of ceramic particulate morphology for insight into the final structure and material properties.

Tiled composite of 30 Phenom SEM images

Threshold image for analysis (right) of an advanced ceramic material

SEM images using backscattered electron detector (BSD) of (left) ceramic powder agglomerates and (right) their effect on the ceramic microstructure. Image/data courtesy of CoorsTek

Elemental Identification

Elemental analysis using EDS with SEM gives material information correlated to structure for ceramic materials. Processes can be evaluated to optimize the most suitable composition for preferred product performance and mechanical properties. EDS can be done over an area, across a line, or at a point. This data can be used in ceramic research and development to chart nanoparticle diffusion through a porous ceramic, to identify second phases on ceramic surfaces, or to examine contamination or agglomerates. Phase morphology can be correlated to composition for ceramic materials using an EDS map.

Backscattered electron detector image (left) and corresponding EDS maps (right) used to identify second phases on ceramic surfaces Image/data courtesy of CoorsTek

Benefits of the Phenom SEM

The Phenom scanning electron microscope was designed to bring high-quality SEM imaging into environments where a conventional SEM was impractical or inconvenient. The Phenom SEM requires no extra infrastructure and no dedicated operator. The Phenom SEM uses a very long life source, offering over a year of continuous uptime.

This information has been sourced, reviewed and adapted from materials provided by Phenom-World BV.

For more information on this source, please visit Phenom-World BV.