Coatings are integral to a wide array of industries, from the sleek, durable finishes on automobiles to the protective layers that shield industrial machinery from wear and corrosion. Given their critical roles, ensuring coatings meet high-performance standards is paramount. Coating quality control is essential to guarantee that coatings serve their purpose effectively. Here, Britta Siefer, Senior Sales Account Manager at Thermo Fisher Scientific, explores how automated tools, integrated with scanning electron microscopes (SEMs), are transforming quality control in coating applications.
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Coatings in Various Sectors
Coatings contribute significantly to the performance and longevity of products across multiple sectors. In automotive and aerospace manufacturing, coatings protect parts from harsh environmental conditions and wear, while in the energy sector, they prevent corrosion in oil and gas pipelines. Similarly, in the field of battery technology, coatings improve efficiency by optimising charge/discharge cycles. In medical device applications, they can provide wear resistance, enhance biocompatibility and maintain functionality under extreme conditions.
Challenges in Coating Design and Application
Designing and applying coatings that perform reliably over time involves addressing complex material challenges. For instance, achieving optimal adhesion to diverse substrates — whether metals, plastics or composites — requires careful surface preparation and precise application techniques. Coatings must also be engineered to resist environmental factors such as UV degradation, corrosion and extreme temperatures. Furthermore, coatings need to endure mechanical stresses like abrasion and impact, while maintaining uniform coverage without defects such as pinholes or bubbles. Achieving these goals requires balancing performance, cost-effectiveness and compliance with environmental and safety standards.
Case Study: Automotive Steel Coatings
To illustrate the integral role coatings, play in product performance, let’s take a look at an example. Sheet steel has been the dominant structural material in the automotive industry since the 1920s, with its strength and stiffness making it an ideal choice for durable chassis and welded parts. The metal has found its place in many other applications across various industries, such as construction, food packaging and wear-resistant tools like springs and high-strength wires, with an unbeatable value for mass production.
Despite its strength, steel has a weakness. The material’s primary disadvantage is its low corrosion resistance, a critical challenge in automotive manufacturing. Rust on vehicles not only compromises their appearance but also undermines mechanical integrity and safety. In response, the industry has worked to enhance corrosion resistance through galvanisation techniques. Electro galvanised coatings, featuring layers of zinc, zinc phosphate and paint primers, play a crucial role in prolonging the lifespan of vehicles. Ensuring the uniformity and adhesion of these coatings is vital to their performance, emphasising the importance of advanced coating quality control methods.
The Role of SEM in Coating Quality Control
The electro galvanisation process is highly sensitive to variations in production conditions. Small imperfections or inconsistencies in the coating can undermine the effectiveness of the zinc layer, leading to areas where rust may form more quickly, compromising the vehicle’s durability and safety. This is why advanced microscopy, such as SEM, plays a vital role in ensuring the success of the electro galvanisation process.
An SEM allows for high-resolution imaging of the coated surface, enabling the detection of defects at the microscopic level, such as uneven coating thickness, surface contamination or poor adhesion between the zinc and steel layers. The ability to observe these defects in fine detail helps identify potential issues early in the production process, ensuring that corrective actions can be taken before the components reach the final stages of manufacturing.
Additionally, SEM’s ability to perform elemental analysis through energy-dispersive X-ray spectroscopy (EDS) further enhances its value in quality control. EDS provides precise compositional data, allowing for the assessment of the zinc layer’s purity and its adherence to the steel substrate. By using SEM to monitor the electrogalvanisation process, manufacturers can ensure that each coated steel component meets the rigorous standards required for long-lasting corrosion protection and performance.
Optimising Coating Quality Control with SEM Technology
Characterising coatings with standard SEMs often involves a fragmented and time-consuming workflow. Lab workers must switch between imaging and elemental analysis modes, using separate software to process data, which increases the complexity of the task. This disjointed process can lead to inconsistencies in correlating visual and compositional data, making it harder to accurately identify defects. Additionally, the steep learning curve for operating multiple systems adds to the inefficiency, posing challenges for routine quality control in industries like automotive manufacturing.
The Axia ChemiSEM from Thermo Fisher Scientific overcomes these challenges with an integrated and streamlined approach. It’s always-on EDS provides real-time compositional data directly linked to SEM images, enabling immediate and accurate analysis to eliminate the need for separate software and repeated data acquisition, saving time and improving consistency. With an intuitive interface and automated corrections, the Axia reduces the complexity of coating characterisation, making advanced analysis accessible even to less experienced users. By enhancing workflow efficiency and providing actionable insights, the Axia ChemiSEM ensures more reliable failure analysis and coating quality control for applications requiring durable, corrosion-resistant coatings.
Conclusion: The Future of Coating Quality Control
Coating quality control is vital for improving product durability and functionality across industries, with their performance dependent on precise design, application and quality control to ensure uniformity and resistance to stress. Advances in material science and streamlined analytical tools have enhanced failure analysis precision and ensured coatings meet strict safety and performance standards.
You can learn more about solutions for coating quality control, and for more materials science updates and insights, you can sign up receive the latest news and resources at Thermo Fisher.
