Silicon carbide (SiC) rollers, especially pressureless sintered SiC (SSiC) rollers for lithium battery kilns, are widely used in cathode material production due to their high-temperature stability and mechanical strength.

However, under different process conditions, their corrosion behavior can vary significantly.

This case study analyzes the performance of SiC rollers in LFP (LiFePO₄) and NCM (Nickel Cobalt Manganese) production environments, focusing on corrosion mechanisms, failure modes, and optimization strategies.

• Lithium source: Li₂CO₃
• Furnace atmosphere: Low corrosion, mainly water vapor
• Maximum temperature: ~1000°C

Observed performance:

• Uniform gray surface deposition
• No significant density reduction
• No fracture during operation
• Service life: ~2 years

The rollers maintained stable performance under relatively mild conditions.

Under highly corrosive lithium environments, conventional rollers may suffer rapid degradation, while upgraded SSiC roller solutions provide improved structural stability and corrosion resistance.

Observed issues:

• Large-scale surface spalling
• Significant density reduction
• Internal structural degradation
• Service life: ~2 months
• Failure: 2 roller fractures recorded

Corrosion and mechanical failure significantly affected production stability.

XRD and XRF analysis revealed that:

• Original SiC phase significantly decreased
• New compounds formed:
  • Lithium silicates (Li₂SiO₃, Li₂Si₂O₅)
  • Nickel-containing compounds
  • Lithium-manganese oxides

This indicates intense chemical reactions altering the material structure.

SEM analysis showed:

• Increased porosity
• Enlarged pore size
• Loosened internal structure

Measured change:

• Density decreased from ≥3.05 g/cm³ → ~2.8 g/cm³

Corrosion penetrated beyond the surface into the bulk material.

SiC reacts with oxygen:

SiC + O₂ → SiO₂

• Forms a temporary protective layer
• Can fail under aggressive conditions

At high temperature:

• LiOH decomposes → reactive lithium species
• Reacts with SiO₂:

SiO₂ + Li₂O → Li₂SiO₃

At 700–800°C:

• Lithium silicates soften → form molten phase
• Dissolve protective SiO₂ layer

Leads to continuous exposure and accelerated corrosion

SiC reacts with molten lithium compounds:

SiC + Li₂SiO₃ + O₂ → Li₄SiO₄ + Li₂Si₂O₅ + CO/CO₂

Results in rapid material consumption

• Lithium silicates penetrate along grain boundaries
• Grain boundary phases dissolve
• Intergranular bonding weakens

Leads to:

• Structural disintegration
• Reduced mechanical strength
• Roller fracture

Key differences between LFP and NCM:

LiOH + high-temperature molten phase is the main driver of corrosion

• Method: Plasma spraying
• Coating: Y₂O₃ / Al₂O₃

Function:

• Prevent molten salt wetting
• Block gas penetration
• Delay corrosion

Advantages:

• Cost-effective (~1000 RMB per roller)
• Fast implementation

Suitable for short-term improvement

For more aggressive NCM production environments, high-performance pressureless sintered silicon carbide rollers combined with advanced surface engineering can significantly improve long-term corrosion resistance.

Benefits:

• Dense structure
• Strong bonding
• Blocks corrosion pathways

Provides long-term stability and longer service life

When corrosion and thermal stability are both critical, selecting dense SSiC kiln rollers with optimized surface protection can greatly improve service life in lithium battery production systems.

• Implement coating or CVD upgrades
• Start with small-batch trials

• Optimize heating rate in 700–800°C range
• Reduce molten phase formation

• Regular density testing
• Surface inspection
• Replace severely corroded rollers early

This case demonstrates that:

• SiC rollers perform well in mild LFP environments
• But face severe degradation in NCM processes with LiOH

The combination of:

• High temperature
• Reactive lithium compounds
• Molten phase formation

leads to rapid corrosion and structural failure.

For demanding applications such as NCM production:

Material design and surface engineering are critical
Upgraded SiC solutions can significantly improve reliability and service life

Pressureless sintered silicon carbide (SSiC) rollers are widely used in:

• lithium battery cathode material production,
• roller hearth kilns,
• NCM and LFP processing lines,
• and high-temperature corrosive environments.

Key advantages include:

• excellent high-temperature strength,
• stable thermal conductivity,
• improved corrosion resistance,
• and long-term structural reliability.

Explore:

• Pressureless Sintered SiC Rollers
• Pressureless Sintered Silicon Carbide (SSiC) Components