Material Characteristics:
High-purity alumina micro-powder is used as the raw material, with purity ranging from 95% to 99.9%. Through batching, forming, and densification sintering in a high-temperature air atmosphere furnace, high-performance alumina ceramic materials can be obtained, featuring density of 95%–99.9% or higher, uniform microstructure, and no free impurity residues. The material exhibits high hardness, high wear resistance, good electrical insulation, excellent high-temperature strength, and thermal shock resistance.
Product Information:
Alumina ceramic tubes are high-performance hollow tubular ceramic components made from high-purity alumina through isostatic pressing or extrusion forming and high-temperature sintering. As critical parts in high-temperature firing and atmosphere control processes, their primary function is to provide clean, corrosion-resistant gas transport channels, thermocouple protection sheaths, or high-temperature supporting insulation tubes within the furnace, preventing metal impurity volatilization from contaminating the workpieces while ensuring uniform furnace atmosphere and process stability. Ceramic tubes offer excellent thermal shock resistance, high-temperature strength, and electrical insulation properties. During long-term use, the tubes do not easily bend, soften, crack, or precipitate impurities, reliably ensuring firing quality and measurement accuracy under high-temperature clean environments.
Performance Parameters：
| 95% (Al₂O₃≥95%) | 99% (Al₂O₃≥99%) | 99.5% | 99.9% |
Density (g/cm³)： | 3.70–3.75 | 3.85–3.90 | 3.90–3.93 | 3.95–3.98 |
Flexural Strength (MPa)： | 250–350 | 300–400 | 350–450 | 400–550 |
Compressive Strength (MPa)：
| 2000–3000 | 2500–3500 | 2800–3800 | 3000–4000 |
Fracture Toughness (MPa·m¹/²) | 3–4 | 3.5–4.5 | 4–4.5 | 4–5 |
Mohs Hardness： | 8.5–9 | 9
| 9 | 9 |
Elastic Modulus (GPa)： | 300–350 | 350–380 | 370–390 | 380–400 |
Volume Resistivity (Ω·cm) @25°C： | >10¹⁴ | >10¹⁴ | >10¹⁵ | >10¹⁶ |
Maximum Operating Temperature (°C) (long term)： | 1400–1500 | 1550–1650 | 1650–1700 | 1700–1750 |
Dielectric Strength (kV/mm)： | 12–16 | 15–20 | 18–22 | 20–25 |
Thermal Conductivity (W/(m·K)) @25°C： | 20–25 | 28–32 | 30–35 | 35–40
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Product Dimensions:
Standard alumina ceramic tubes have outer diameters ranging from 5 mm to 120 mm, inner diameters from 3 mm to 100 mm, and lengths from 100 mm to 2000 mm, with a maximum producible length of over 2500 mm. Wall thickness can be flexibly adjusted according to operating conditions, with a minimum thickness down to 1 mm. The products can undergo further processing techniques such as internal and external cylindrical grinding, double-end precision grinding, end chamfering, radial drilling, slotting, step machining, and multi-hole through processing. Yuko Corporation can also customize non-standard specifications, variable-diameter tubes, closed-end blind tubes, multi-hole tubes, and complex combined tube assemblies based on specific customer drawings and requirements.
Product Applications:
Alumina ceramic tubes are widely used as protective atmosphere inlet tubes and pusher kiln gas tubes for electronic ceramic sintering, nitrogen or protective atmosphere transport tubes for magnetic material heat treatment, gas distribution tubes and protective sheaths in lithium battery cathode and anode material kilns, high-temperature sintering atmosphere conduits for powder metallurgy products, diffusion furnace and oxidation furnace tubes and thermocouple protection sheaths in the semiconductor industry. Additionally, they serve as core furnace tubes in tube furnaces, providing clean firing and atmosphere isolation channels for materials, and as support insulation tubes for heating elements and ceramic roller rods in high-temperature box furnaces, atmosphere furnaces, and roller kilns, making them core critical components for ensuring clean high-temperature atmospheres and process consistency.