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 seal rings are made from high-purity alumina through isostatic pressing, high-temperature sintering, and precision grinding. They serve as mating components for rotating and stationary rings in mechanical seals for rotating shafts, valves, pump bodies, and other equipment, providing a sealing end face with high hardness, wear resistance, and corrosion resistance to prevent medium leakage. The seal rings feature high dimensional accuracy, excellent surface finish, and outstanding gas tightness. During long-term use, they do not suffer from wear grooving, thermal cracking, or impurity precipitation, ensuring sealing reliability and extended equipment service life.
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 seal rings have outer diameters ranging from 10 mm to 200 mm, inner diameters from 5 mm to 180 mm, and thicknesses from 2 mm to 30 mm. Large seal rings with a maximum outer diameter of up to 400 mm can be produced. The products are supplied with a flat end face structure as standard, and further processing is available, including double-sided precision lapping, external cylindrical grinding, positioning step machining, and split-type seal rings. Yuko Corporation can also customize non-standard inner/outer diameters, special-shaped cross-sections, and matched rotating and stationary ring assemblies based on customer drawings.
Product Applications:
Alumina ceramic seal rings are widely used in mechanical seals for rotating fluid equipment such as chemical pumps, centrifugal pumps, and magnetic drive pumps. They are also employed in agitator shaft seals for reaction vessels, dry gas seals for compressors, high-temperature valve seals, and sealing parts in ultra-pure fluid transport systems in the semiconductor industry. They are suitable for operating conditions involving water, oil, acid and alkali solutions, and organic solvents.