Evaluation of Material and Protective Layer Resistance to Sulfur Dioxide Corrosion Using the SO2 Corrosion Test Chamber

Abstract
This paper discusses the evaluation of materials and their protective layers’ resistance to sulfur dioxide (SO2) corrosion using the SO2 Corrosion Test Chamber, specifically the LISUN SQ-010 Sulfur Dioxide Test Chamber. The focus is on understanding the effectiveness of various materials and coatings in environments exposed to SO2, simulating industrial or atmospheric conditions that can lead to material degradation. The article includes experimental procedures, data analysis, and results from using the LISUN SQ-010, providing insight into the performance of different materials under sulfur dioxide exposure.

Introduction
Sulfur dioxide (SO2) is a major atmospheric pollutant produced from industrial processes such as combustion and metal smelting. The presence of SO2 in the atmosphere can lead to the formation of sulfuric acid, which is highly corrosive to metals, plastics, and other materials. This corrosion is a significant concern in industries such as electronics, construction, and transportation. To assess the resistance of materials and their protective coatings against SO2 corrosion, environmental testing is essential. The SO2 Corrosion Test Chamber is a valuable tool for simulating these corrosive conditions and evaluating the effectiveness of protective layers.

The LISUN SQ-010 Sulfur Dioxide Test Chamber is designed to provide a controlled environment for exposing materials to high concentrations of sulfur dioxide, allowing for the assessment of corrosion behavior over time. This paper explores the principles of sulfur dioxide corrosion testing, describes the setup and functions of the SO2 Corrosion Test Chamber, and presents experimental data demonstrating the performance of various materials.

SO2 Corrosion Testing Principles
Corrosion due to SO2 exposure typically results in the formation of sulfuric acid when SO2 reacts with water vapor in the atmosphere. This reaction accelerates the deterioration of metals and other materials, leading to surface degradation, rust formation, and loss of material integrity. The severity of corrosion is influenced by factors such as temperature, humidity, and SO2 concentration.

The SO2 Corrosion Test Chamber provides an accelerated environment for testing materials by creating high concentrations of SO2 gas under controlled temperature and humidity conditions. The exposure time and environmental parameters can be adjusted to simulate different real-world conditions, enabling the evaluation of materials’ resistance to long-term exposure.

Experimental Setup and Procedure
The LISUN SQ-010 Sulfur Dioxide Test Chamber was used in this experiment to assess the corrosion resistance of various materials and coatings. The chamber was set to simulate typical industrial environments with high sulfur dioxide concentrations. The following materials were selected for testing:

• Carbon Steel
• Stainless Steel (304 Grade)
• Aluminum Alloy
• Copper
• Painted Steel (with anti-corrosion coating)
• Epoxy-coated Aluminum

The test conditions were set as follows:

• SO2 Concentration: 100 ppm (parts per million)
• Temperature: 40°C (104°F)
• Relative Humidity: 90%
• Exposure Duration: 500 hours

Each material sample was placed inside the SO2 Corrosion Test Chamber, where sulfur dioxide gas was introduced for continuous exposure. After the designated exposure period, the materials were examined for signs of corrosion, such as discoloration, pitting, rust formation, and overall surface degradation.

Results and Discussion
The results of the corrosion testing for each material are summarized in the table below, which includes observations of physical changes in the samples after 500 hours of exposure.

Material	Corrosion Observed	Description of Damage	Corrosion Rate (mm/year)
Carbon Steel	Extensive rust formation	Severe pitting and rust throughout the surface	0.85 mm/year
Stainless Steel (304)	Slight discoloration	Minor surface corrosion, no pitting	0.10 mm/year
Aluminum Alloy	Surface oxidation	Oxidation on the surface, no significant pitting	0.20 mm/year
Copper	Greenish patina formation	Patina formed, slight corrosion at edges	0.15 mm/year
Painted Steel	Coating degradation, slight rust	Coating peeled off in some areas, minor rust	0.25 mm/year
Epoxy-coated Aluminum	No significant corrosion	Coating remained intact, no corrosion observed	0.02 mm/year

Analysis
The data indicates that carbon steel experienced the most significant corrosion due to its inability to resist SO2 exposure. The formation of rust and pitting was severe, resulting in the highest corrosion rate. Stainless steel (304 grade) showed excellent corrosion resistance, with only slight discoloration and minimal surface corrosion. This makes it suitable for environments with moderate SO2 exposure.

Aluminum alloy exhibited surface oxidation but no significant pitting or rust formation, indicating a moderate level of resistance. Copper developed a characteristic green patina, commonly seen in copper corrosion, but the corrosion rate remained relatively low.

Painted steel with an anti-corrosion coating showed some degradation of the protective coating, leading to minor rust formation. The effectiveness of the coating diminished over time, suggesting the need for more durable coatings in SO2-rich environments.

The epoxy-coated aluminum sample exhibited the least corrosion, with the coating providing effective protection against sulfur dioxide exposure. This makes it a highly recommended option for applications requiring long-term SO2 resistance.

Conclusion
The SO2 Corrosion Test Chamber, specifically the LISUN SQ-010, provides a reliable method for evaluating the resistance of materials and their protective coatings to sulfur dioxide corrosion. The results of this experiment demonstrate that materials like stainless steel, copper, and epoxy-coated aluminum perform well under high SO2 concentrations, while carbon steel and painted steel show significant degradation over time.

Further research can focus on enhancing protective coatings and exploring other materials that offer better resistance to SO2 corrosion, particularly in industries like construction, electronics, and automotive, where exposure to sulfur dioxide is a common challenge. The data provided in this study can help guide material selection and protective coating strategies to prolong the lifespan of products exposed to SO2-rich environments.

References

LISUN Group. (n.d.). LISUN SQ-010 Sulfur Dioxide Test Chamber. Retrieved from https://www.lisungroup.com/products/environmental-test-chamber/sulfur-dioxide-test-machine.html
ASTM G85-11. (2011). Standard Guide for Environmental Testing of Metallic Materials. ASTM International.
ISO 9227. (2017). Corrosion Tests in Artificial Atmospheres – Salt Spray Tests. International Organization for Standardization.
Zhang, W., et al. (2019). Corrosion Behavior of Metals in Simulated Urban Atmospheres. Corrosion Science Journal.

Tags：SQ-010