Electron microscopy tools like transmission electron microscope (TEM) and scanning electron microscope (SEM) are popular in various industries for their analytical capabilities.1
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They can image a wide range of materials and biological samples with high magnification, resolution, and depth of field, thereby revealing surface structure and chemical composition.
Industries like materials science, electronics, pharmaceuticals, aerospace, energy, forensics, geology, agriculture, and healthcare employ these tools in nanoscale analysis for quality control, failure analysis, and research and development.1,2
Role of Electron Microscopy in Quality Control
Electron microscopes can be coupled with several spectroscopic techniques, such as energy-dispersive X-Ray spectroscopy (EDS), to analyze the chemical composition of materials during the processing stage.
Their high analytical and non-destructive capabilities, paired with nanoscale resolution, facilitate easy visualization of the sample topography and microstructure. This helps identify quality control issues, sometimes using a single image.1
Quality control in materials science is crucial for applications like forensic examinations, additive manufacturing, and automotive/aerospace cleanliness.
The increasing complexity of materials has driven the demand for rapid, reliable, and scalable quality control methods.
As artificial materials evolve from macro- to micro-, nano-, and now pico-scales, efficient visualization and chemical characterization at these levels have become crucial for the production and quality control using high-resolution microscopy techniques. Electron microscopes provide valuable insights during material characterization with minimal time and resource utilization.1
In pharmaceutical research and development, the ongoing battle against evolving pathogens and increasing drug resistance underscores the importance of quality control for advancing new drugs and enhancing existing ones.
All solid drugs contain excipients (bulking agents, stabilizers, and coatings) and an active pharmaceutical ingredient (API). These compounds must be chemically and morphologically characterized at the nanoscale to assess shelf life, dosage, and efficacy. Electron microscopy assists in controlling particle sizes and excipients during manufacture and evaluates efficacy after product formulation.1
Global environmental concerns have increased the search for sustainable energy sources such as solar, wind, geothermal, and tidal.
Batteries are crucial for portable storage of any form of energy. The quality, safety, and lifespan of the interfacial region—which includes the cathode, insulator, and anode—of batteries determine their performance.
Electron microscopy helps in the analysis of the interfacial regions through visualization of the surface, particle size, and voids. It helps ensure the battery’s quality through efficient electrode and electrolyte configurations.1
Applications of Electron Microscopy in Failure Analysis
Electron microscopy has gained popularity as a critical tool for failure analysts. It can be used for quality control during device manufacturing and failure analysis post-manufacturing.
The structure and functionality of the components in an electronic chip are commonly analyzed using SEM.1 It helps identify surface failures and internal nonconformities and investigate solder joints to detect possible leakage or porosity in the event of a chip/device failure.2
The steel industry relies heavily on alloys and coatings. In the event of a structure failure, a thorough analysis becomes crucial to avoid future accidents. Thus, electron microscopy is commonly used to identify cracks, imperfections, or contaminants in steel coatings.
Failure analysis of coatings is also vital in the medical field, particularly for devices and implants.2 The failure of a medical device/implant can be life-threatening for a person, and precise analysis of such occurrences can save many lives.
In the oil and gas industry, electron microscopy is the preferred method for analyzing failed parts. Morphological studies of the fracture surfaces using SEM facilitate the easy identification of failure modes, such as the formation of dimples in highly ductile alloys of low-carbon steel, aluminum, or copper.
Electron microscopy can also reveal failures due to material fatigue or brittleness. It is also used to examine flow-accelerated corrosion, a common issue in the industry, by analyzing the flow regime in steel pipes and the resultant formation of scallops or tiger bands.3
Case Studies: Examples of Electron Microscopy in Industry
Over the past few years, electron microscopy has found novel industrial and commercial applications.
For instance, the book Evaluation Technologies for Food Quality describes the extensive use of SEM in food technology, where it is used to investigate the impact of various pre- and post-treatments on the microstructure and morphology of different foods.
SEM-EDS combination helps to map food contamination. It can identify organic and inorganic contaminants in foods during quality analysis at production sites or when they undergo product recall. Additionally, microbial presence in complex food samples can be analyzed using SEM, including food-microbe and microbe-microbe interactions.4
A recent article in Frontiers in Molecular Biosciences demonstrated the use of TEM for the quality assessment of virus-like particles (VLPs). VLPs are self-assembled higher-order nanostructures that imitate viruses in terms of morphology and size but lack their infectious genetic material. They are used as delivery vehicles, antigen presentation, and vaccine platforms.
Assessment of their bioactivity, potency, and stability is vital to certify the efficacy and safety of vaccines. The researchers proposed the use of a low-voltage TEM called MiniTEM integrated with convolutional neural networks-based software for chemical and structural analysis of VLPs. The analysis method and workflow apply to the development of vaccines for Dengue and other endemic diseases.5
Electron Microscopy: Future Trends and Innovations
The large-scale installation and maintenance costs of electron microscopy equipment may impede its entry into smaller industries. Thus, efforts are underway to enhance the compactness and cost-effectiveness of microscopy instruments while ensuring they retain the capability to deliver essential details.1
For example, benchtop SEM and low-voltage TEM with assisted image capture and analysis have been introduced in various industrial applications. Such systems do not require any specialized facilities or time-consuming training and have low start-up and running costs.1,5
Recent advances in machine learning and deep learning have expanded the scope of innovation and industrial application of electron microscopy. Defect detection and classification through microscopy images can be enhanced with minimal cost by the application of machine learning and deep learning algorithms.6
Artificial intelligence and machine learning can alleviate performance and simplify the analysis process by enabling automation and eliminating subjectivity, which is an increasing requirement for quality checks by regulatory authorities.5
Electron microscopy is thus an indispensable tool for several key industries, and the current trend of research and innovation will further push the boundaries of its analytical capabilities.
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References and Further Reading
1. Harvey, K., Edwards, G. (2022). Using Benchtop Scanning Electron Microscopy as a Valuable Imaging Tool in Various Applications. Microscopy Today. doi.org/10.1017/s1551929522001109
2. University of the West Indies (n.d.). Electron Microscopy Unit. University of the West Indies. Available at: https://sta.uwi.edu/fst/physics/electronmicroscope
3. Nasrazadani, S., Hassani, S. (2016). Modern analytical techniques in failure analysis of aerospace, chemical, and oil and gas industries. Handbook of Materials Failure Analysis with Case Studies from the Oil and Gas Industry. doi.org/10.1016/B978-0-08-100117-2.00010-8
4. Sharma, V., Bhardwaj, A. (2019). Scanning electron microscopy (SEM) in food quality evaluation. Evaluation technologies for food quality. doi.org/10.1016/B978-0-12-814217-2.00029-9
5. De Sá Magalhães, S., et al. (2022). Quality assessment of virus-like particle: A new transmission electron microscopy approach. Frontiers in Molecular Biosciences. doi.org/10.3389/fmolb.2022.975054
6. López de la Rosa, F., et al. (2021). A Review on Machine and Deep Learning for Semiconductor Defect Classification in Scanning Electron Microscope Images. Applied Sciences. doi.org/10.3390/app11209508
