When evaluating Zirconia Fiber, the most critical factor is its thermal stability. Ensure the fiber can withstand continuous operating temperatures of up to 2200°C (3992°F) without significant shrinkage. You should verify the Zirconia (ZrO2) content, which typically should be 92-95%, stabilized with Yttria (Y2O3) or Magnesia (MgO) to prevent phase transformation and cracking during thermal cycling. Additionally, check the fiber diameter (usually 3-6 microns) and thermal conductivity, as lower conductivity ensures better insulation efficiency in aerospace or industrial furnace linings.