회사 소식 How to Improve SiC Roller Life in NCM Production？

In NCM (Nickel Cobalt Manganese) cathode material production, SiC rollers are exposed to highly aggressive environments involving LiOH, high temperatures, and oxidizing atmospheres.

Under these conditions, roller lifetime can drop significantly, sometimes from ~2 years (LFP conditions) to ~2 months in NCM processes.

Improving SiC roller service life requires a combination of material optimization, process control, and surface engineering.

Why SiC Rollers Fail in NCM Production

Key Operating Conditions

• Lithium source: LiOH
• Temperature-critical zone: 700–800°C
• Atmosphere: Oxidizing + corrosive gases

Main Failure Mechanisms

1. Chemical Corrosion

• SiC reacts with oxygen:
  • Forms SiO₂ layer (temporary protection)
• LiOH decomposition produces reactive lithium species:
  • Reacts with SiO₂ → Li₂SiO₃

At 700–800°C, lithium silicates soften and form molten phases, dissolving protective layers.

2. Molten Salt Attack

• Liquid lithium compounds penetrate the material
• Accelerate corrosion reactions

3. Microstructural Degradation

Typical observations:

• Density drop:
  ≥ 3.05 g/cm³ → ~2.8 g/cm³
• Increased porosity
• Grain boundary weakening

 Leads to structural failure and roller fracture

Key Strategies to Improve SiC Roller Life

1. Surface Coating Protection (Short-Term Solution)

Recommended Coating

• Y₂O₃ / Al₂O₃ (rare-earth coating)
• Applied via plasma spraying

Function

• Prevent molten salt wetting
• Block corrosive gas penetration
• Delay chemical reactions

Technical Impact

• Reduces direct contact between Li-based compounds and SiC
• Slows down corrosion rate

Application Scenario

• Quick improvement in existing production lines
• Cost-sensitive environments

Typical cost: ~1000 RMB per roller

2. CVD SiC Coating (Long-Term Solution)

Process

• Chemical Vapor Deposition (CVD)
• Deposits high-purity SiC layer

Advantages

• Near-zero porosity
• Strong bonding to substrate
• High chemical stability

Engineering Benefit

• Blocks molten phase penetration
• Eliminates weak grain boundary attack
• Maintains structural integrity

Suitable for continuous, high-load production environments

3. Optimize Critical Temperature Zone

Why 700–800°C Matters

• Lithium silicates soften in this range
• Molten phase formation accelerates corrosion

Recommended Actions

• Control heating rate through this zone
• Avoid prolonged residence time
• Stabilize furnace temperature fluctuations

 Reduces molten phase formation and chemical attack

4. Material Selection and Quality Control

Key Parameters

• Density: ≥ 3.05 g/cm³
• Open porosity: ≈ 0
• High purity SiC (≥ 98.5%)

Why It Matters

• Dense structure limits penetration
• High purity reduces reactive phases

 Material quality directly affects corrosion resistance

5. Monitoring and Preventive Maintenance

Recommended Monitoring

• Density measurement
• Surface inspection (spalling, cracks)
• Dimensional stability check

Maintenance Strategy

• Replace rollers before severe degradation
• Track service life vs process conditions

 Prevents unexpected fracture and production downtime

Comparison of Improvement Approaches

Conclusion

Improving SiC roller life in NCM production requires addressing:

• Chemical corrosion (LiOH + SiO₂ reaction)
• Molten phase formation (700–800°C)
• Microstructural degradation

Effective solutions include:

• Surface coatings for quick improvement
• CVD SiC layers for long-term stability
• Process optimization to reduce corrosion conditions

Key Takeaway

For NCM cathode production:

Surface engineering + process control + material quality = extended roller life

Need Technical Support for SiC Rollers?

Providing the following helps optimize performance:

• Furnace temperature profile
• Lithium source (LiOH / Li₂CO₃)
• Roller dimensions and loading conditions
• Target service life

Customized solutions can significantly reduce failure rates and operating costs.