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A cathode material producer reported premature failure of several silicon carbide roller rods operating in an NCM production kiln.
The rollers had been installed only two months earlier, significantly below the expected service life.
At first glance, the customer suspected a material quality issue.
However, a detailed investigation revealed a different story.
Typical kiln conditions included:
- Temperature: 700–800°C
- Continuous operation
- Lithium-containing atmosphere
- NCM cathode material production
The rollers showed:
- Surface discoloration
- Localized corrosion
- Strength reduction
- Premature fracture
Microscopic examination revealed that the damage was concentrated near the roller surface.
Instead of simple mechanical cracking, the structure showed evidence of chemical degradation.
The most affected areas corresponded to regions exposed to lithium-containing vapors.
The primary failure mechanism was lithium-induced corrosion.
At elevated temperatures, lithium compounds reacted with the protective silica layer on the SiC surface.
The reaction generated lithium silicates, gradually destroying the protective barrier.
Once the surface protection was compromised:
- Corrosion penetrated inward
- Porosity increased
- Mechanical strength decreased
Eventually, the roller fractured under normal operating loads.
Related Reading:
Why Is LiOH More Corrosive to SiC Components in Lithium Battery Kilns?
Layer-by-Layer Corrosion Mechanism of SiC in Lithium Environments
The customer implemented:
- Improved atmosphere control
- Enhanced maintenance inspections
- Higher-density SSiC components
These changes significantly improved roller life.
In lithium battery production, roller failure is not always a mechanical problem.
Chemical degradation may begin long before visible damage appears.