Quality Diagnostics · D03
Color Stain
Color Stain
Symptom: an abnormal color region on the surface after sintering. Color stains are usually a batch-level issue, not a single-part issue.
- Furnace atmosphere deficient or excess oxygen (sintering-atmosphere deviation causes localized discoloration)
- Furnace contamination (residual impurities migrating at high temperature)
- Black/white mixed firing (black zirconia's colorant cross-contaminating white parts at high temperature)
Black and white parts are strictly fired in separate furnace runs - mixed firing is never permitted. Furnace atmosphere and temperature field are calibrated on a regular schedule.