Ceramic materials have a series of characteristics such as high melting point, high hardness, high wear resistance, and oxidation resistance, and are widely used in various fields of national economy such as the electronics industry, automotive industry, textile, chemical industry, and aerospace. The physical properties of ceramic materials depend largely on their microstructure, which is an important application area of SEM.
What are ceramics?
Ceramic materials are a class of inorganic non-metallic materials made of natural or synthetic compounds through forming and high-temperature sintering and can be divided into general ceramic materials and special ceramic materials.
Special ceramic materials can be classified according to chemical composition: oxide ceramics, nitride ceramics, carbide ceramics, boride ceramics, silicide ceramics, etc.; according to their characteristics and applications can be divided into structural ceramics and functional ceramics.
Figure 1 Microscopic morphology of boron nitride ceramics
SEM helps to study the properties of ceramic materials
With the continuous development of society and science and technology, people's requirements for materials have been increasing, which requires a deeper understanding of the various physical and chemical properties of ceramics. The physical properties of ceramic materials are largely dependent on their microstructure [1], and SEM images are widely used in ceramic materials and other research fields because of their high resolution, wide adjustable magnification range, and stereoscopic imaging. The CIQTEK Field Emission Scanning Electron Microscope SEM5000 can be used to observe the microstructure of ceramic materials and related products easily, and in addition, the X-ray energy spectrometer can be used to determine the elemental composition of materials quickly.
Application of SEM in the Study of Electronic Ceramics
The largest end-use market of the special ceramics industry is the electronics industry, where barium titanate (BaTiO3) is widely used in multilayer ceramic capacitors (MLCC), thermistors (PTC), and other electronic components because of its high dielectric constant, excellent ferroelectric and piezoelectric properties, and voltage resistance and insulation properties [2]. With the rapid development of the electronic information industry, the demand for barium titanate is increasing, and the electronic components are becoming smaller and more miniaturized, which also puts forward higher requirements for barium titanate.
Researchers often regulate the properties by changing the sintering temperature, atmosphere, doping, and other preparation processes. Still, the essence is that the changes in the preparation process cause changes in the microstructure of the material and thus the properties. Studies have shown that the dielectric ferroelectric properties of barium titanate are closely related to the material's microstructure, such as porosity and grain size [3]. The particle morphology, particle size uniformity, and grain size of barium titanate ceramic powders can be characterized by field emission scanning electron microscopy SEM5000 as shown in Figure 2.
The results of microstructure characterization are important guides for the selection of sintering methods as well as process parameters. In addition, the study of the microstructure of materials by SEM helps to understand the relationship between microstructure and properties.
Figure 2 Microscopic morphology of barium titanate ceramic powder
Strontium barium titanate (BaxSr1-xTiO3) is also an important electronic ceramic material, which is a solid solution formed by strontium titanate and barium titanate. Compared with barium titanate, it has a higher dielectric constant, lower dielectric loss, higher breakdown strength, and adjustable phase transition point with composition, and has been widely studied and used in electronic devices by a large number of scholars. [4] Currently, researchers often use methods such as adjusting the Sr/Ba ratio and doping elements to achieve improved performance. However, it is still fundamental to modulate the material properties by changing the microstructure of the material. Figure 3 shows the backscattered electron image of the sintered barium strontium titanate tested by field emission scanning electron microscope SEM5000, which can be used to characterize the compositional homogeneity of the material at low magnification, while the backscattered electron image at high magnification also has a certain morphological lining.
Figure 3 Microscopic morphology of barium strontium titanate sintered products
Ceramic materials, metallic materials, and polymer materials are the three most widely used materials in today's society. With the continuous development of science and technology and the social economy, the future will definitely put forward more demanding requirements on the performance of ceramic materials. The use of SEM to characterize the microstructure of ceramic materials will help to improve the preparation technology of ceramic materials toward higher performance.
CIQTEK Field Emission Scanning Electron Microscope SEM5000
SEM5000 is a high-resolution, feature-rich field emission scanning electron microscope, with advanced barrel design, in-barrel deceleration, and low aberration non-leakage magnetic objective design, to achieve low-voltage high-resolution imaging, that can be applied to magnetic samples. SEM5000 has optical navigation, perfect automatic functions, well-designed human-machine interaction, optimized operation, and use process. Regardless of whether the operator has extensive experience, you can quickly get started with the task of high-resolution photography.
