Enhancing Corrosion Resistance in Load Cells and Sensors with Electropolishing and Citric Acid Passivation

Industry Insights

By New England Electropolishing

Stainless steel is the material of choice for many components in the load cell, torque sensor, and strain gauge industry due to its strength, machinability, and corrosion resistance. But even stainless steel isn’t immune to the effects of contamination or harsh environments—especially when components are deployed in marine, industrial, or outdoor applications.

To ensure maximum corrosion resistance and long-term performance, many sensor manufacturers are turning to advanced surface finishing techniques, including electropolishing and citric acid passivation.

Why Surface Finish Matters for Sensors

In precision instruments like load cells, torque sensors, and strain gauges, surface integrity is critical. Any surface contamination or micro-roughness can contribute to:

• Corrosion initiation (especially pitting and crevice corrosion)

• Premature mechanical failure

• Inaccurate or drifting sensor readings

• Seal failure or leakage at mating surfaces

Sensor components are often exposed to aggressive cleaning agents, moisture, salt spray, or temperature fluctuations—all of which can degrade unprotected stainless steel over time.

How Electropolishing Improves Corrosion Resistance

Electropolishing is an electrochemical process that removes a controlled layer of surface material from stainless steel parts. Unlike mechanical polishing, which can smear or embed contaminants, electropolishing cleans the surface on a microscopic level, resulting in:

• A smooth, passive, and chrome-rich surface

• Reduced surface area and fewer trap sites for contaminants

• Enhanced resistance to corrosion, especially in chloride-rich or humid environments

• Improved cleanability for hygienic or high-purity applications

For load cell and sensor housings, this translates to better long-term performance, cleaner welds and joints, and improved surface aesthetics.

Citric Acid Passivation: A Safer, Effective Alternative

After machining or heat treatment, stainless steel parts are susceptible to contamination from free iron and other residues. These contaminants disrupt the passive chromium oxide layer and create points of corrosion.

The passivation of stainless steel with citric acid is a non-toxic, environmentally friendly process that removes these contaminants and promotes the formation of a new, uniform passive layer. Compared to traditional nitric acid passivation, citric acid is safer to handle, easier to dispose of, and just as effective—making it ideal for manufacturers focused on both performance and sustainability.

Applications in Load Cells, Torque Sensors & Strain Gauges

In the sensor industry, surface finishing isn’t just cosmetic—it directly impacts functionality and reliability. At New England Electropolishing, we routinely work with manufacturers of:

• Load cells used in aerospace, marine, and industrial weighing systems

• Torque sensors used in powertrain testing, robotics, and process monitoring

• Strain gauge housings and fixtures requiring precision and long-term exposure to the elements

For all these components, a combination of electropolishing and citric acid passivation ensures the surfaces are clean, passive, and ready for the most demanding environments.

Partnering for Precision

New England Electropolishing specializes in high-performance surface finishing for the sensor industry. With over 35 years of experience, we help manufacturers like Sensing Systems deliver stainless steel parts that not only meet tight tolerances but also outperform in the field.

If your components need the highest level of corrosion resistance and cleanliness, contact us to learn how electropolishing and citric acid passivation can improve your product’s reliability, appearance, and lifespan.

Learn more at neelectropolishing.com