Visual Inspection
Surface defects-such as cracks, pores, and inclusions-are observed visually or using a magnifying glass (10x magnification). According to the GB/T 1964-2020 standard, the maximum allowable diameter for a single-point defect is ≤0.5 mm, with a limit of no more than three defects per square centimeter. Industrial-grade ceramic tubes require additional inspection for glaze uniformity, whereas medical-grade tubes (e.g., zirconia tubes) demand zero visible defects.
Dimensional Accuracy Measurement
Tools such as micrometers and Coordinate Measuring Machines (CMMs) are used to measure inner diameter, outer diameter, roundness, and straightness. Taking ISO 6474-2019 as an example, the tolerance range for high-precision ceramic tubes is ±0.05 mm (for inner diameters ≤50 mm); deviations exceeding this limit may result in seal failure or increased fluid resistance.
Mechanical Property Testing
Flexural Strength: Tested using the three-point bending method; standard alumina tubes typically require a strength of ≥300 MPa (refer to ASTM C1161).
Hardness: Measured using a Vickers hardness tester; zirconia tubes typically require a hardness of ≥1200 HV.
Pressure Resistance: Hydraulic testing is conducted to simulate operating pressures; industrial-grade tubes (e.g., for chemical pipelines) must withstand pressures of ≥20 MPa.
Chemical Stability and Thermal Properties
Corrosion resistance is assessed via acid and alkali immersion tests (e.g., immersion in a 5% HCl solution for 24 hours), with a passing criterion of ≤0.1% mass loss. High-temperature performance is evaluated through thermal shock stability testing (e.g., rapid quenching from 800°C to room temperature, with no cracking observed after 5 cycles).