Several factors can erode kiln furniture, reducing its lifespan and performance. Understanding these factors helps in selecting the right materials and maintaining optimal kiln conditions.
1. Choose the Right Material
- Composition: High-quality materials like cordierite-mullite, or silicon carbide generally offer superior thermal shock resistance and strength.
- Thermal Conductivity: Materials with appropriate thermal conductivity can better withstand temperature fluctuations.
- Porosity: Low-porosity kiln furniture is less prone to chemical penetration and wear.
- Design and Thickness: Optimized shapes and sufficient thickness reduce the risk of warping or cracking under load.
2. Working Conditions
- Thermal Shock: Frequent exposure to rapid heating and cooling (thermal shock) can cause cracking or warping. Consistent temperature control is crucial.
- Peak Temperatures: Exceeding the recommended temperature range degrades the material’s strength and structure.
- Atmosphere: Corrosive environments (e.g., those containing alkalis, sulfur, or chlorine) can chemically erode kiln furniture over time.
- Mechanical Load: Heavy or unevenly distributed loads cause stress, leading to sagging or cracking.
3. Contamination
- Residue Build-Up: Accumulated residues from firing processes (e.g., ash or glaze drips) weaken the surface.
- Impurities: Dust or foreign materials can be embedded into the furniture, affecting performance.
4. Design Limitations of Kiln
- Kiln Atmosphere Control: Proper ventilation and atmosphere regulation minimize chemical interactions.
- Load Distribution: Uniform weight distribution prevents localized stress points.
- Alignment: Misaligned or improperly stacked kiln furniture can cause uneven heat distribution and mechanical stress.
5. Frequency of Use
- Firing Cycles: The more cycles the kiln furniture undergoes, the faster wear accumulates, especially under high-temperature or corrosive conditions. Long-term exposure to temperature fluctuations eventually weakens even high-quality materials.
- Downtime: Long periods of inactivity in high-humidity areas can also degrade materials.
6. Protective Measures
- Use kiln furniture made from durable materials like cordierite-mullite or silicon carbide for better resistance.
- Applying protective coatings can shield kiln furniture from chemical and mechanical damage.
- Using kiln separators prevents glaze drips and sticking.
- Follow proper temperature ramp-up and cooling schedules.
- Maintain and clean kiln furniture regularly. Removing residues and contaminants after each cycle prevents build-up and chemical damage.
- Avoid overloading or uneven distribution of weight.
- Periodic checks for cracks, deformation, or wear help prevent sudden failures.
Summary:
Maximizing the working lifetime of kiln furniture requires selecting the right material for the operating conditions, carefully controlling temperature and load, performing regular maintenance, and addressing specific environmental challenges. By optimizing these factors, kiln furniture can achieve its maximum potential lifespan.
