Free Samples · 48h Dispatch OEM Manufacturer Since 2014 Reply Within 24h
sales@ceramitell.com · +86 151 9017 9780
Alumina Ceramic · 3 Purity Grades
Al2O3

The industrial workhorse —
from wear linings to wafer-grade purity.

Alumina is the most-used technical ceramic in industrial production. We stock 95%, 99%, and 99.7% purity grades — covering everything from cost-sensitive wear-resistant linings to semiconductor-clean components. ISO 9001 certified with lot-specific test certs on every shipment.

99.7%
Max Purity
1700°C
Service Temp
HV 1800
Hardness
3.9
Density g/cm³
Certifications & Standards
ISO 9001IATF 16949CERoHS · REACHUL Recognized
01 · Material Properties

Alumina by the numbers.

Properties below are typical ranges for our standard production grades, measured at room temperature unless noted. Custom compositions and densities available — contact our engineering team with your spec.

PropertyUnit95% Al₂O₃99% Al₂O₃99.7% Al₂O₃
Densityg/cm³3.703.853.92
Hardness (HV)Vickers145017001800
Flexural StrengthMPa300360400
Compressive StrengthMPa200021002200
Fracture ToughnessMPa·m½3.54.24.5
Max Service Temp°C150016501700
Thermal ConductivityW/m·K202730
Thermal Expansion (RT–1000°C)×10⁻⁶/K7.57.88.0
Dielectric StrengthkV/mm101314
Volume Resistivity (20°C)Ω·cm10¹³10¹⁴10¹⁵
Surface Finish (as ground)Ra μm0.40.30.2
Values are typical for standard production grades. Lot certs ship with every production order.
02 · Grade Selection Guide

Pick the right purity grade.

Higher purity costs more but isn't always needed — most industrial wear and insulation jobs run fine on 95% or 99%. Save 99.7% for jobs where particle contamination or chemical inertness actually matters.

🔧
95% — Industrial Wear Grade

The cost-effective choice when bulk wear resistance matters more than chemical purity. Standard for grinding media, wear-resistant pump liners, and low-voltage electrical insulators.

Best for → Wear linings · grinding balls · low-V insulators
⚙️
99% — Engineering Grade

Our default workhorse. Used for heating rod substrates, structural components, lab thermocouple sheaths, and standard industrial electrical insulators. Sweet spot of performance and cost.

Best for → Heating rods · structural · thermocouple sheaths
💎
99.7% — High-Purity Grade

For semiconductor wafer processing, ICP-OES spectral analysis, ultra-pure lab crucibles, and high-voltage isolators. The cleanest standard grade we make — custom 99.9% available on request.

Best for → Semiconductor · spectral · lab crucibles
04 · When to Choose Alumina

Alumina vs. the alternatives.

Alumina is the cost-effective baseline — reach for Si₃N₄, SiC, or ZrO₂ only when your duty cycle specifically exceeds what alumina can handle. Here's when alumina wins and when it doesn't.

Pick Alumina when…

Al₂O₃ wins
  • Cost-sensitive volume — Alumina is the lowest-cost engineering ceramic per kg of finished part
  • Standard service temperature — Up to 1700°C continuous, more than enough for most heating applications
  • Electrical insulation matters — Dielectric strength 14 kV/mm at 99.7% purity
  • Wear resistance vs. metal — HV 1800 outperforms hardened steel by 3–4× in abrasive service
  • Lab-grade purity needed — 99.7% grade is semiconductor-clean and chemically inert
  • Mature supply chain — Decades of industrial use, ample grade variants, predictable lead times

Reach for something else when…

Other materials
  • Thermal shock cycling — Use Si₃N₄: lower thermal expansion (3.2 vs 8.0 × 10⁻⁶/K) handles 100K+ cycles
  • Extreme abrasion + high temp — Use SiC: hardness HV 2800 (vs 1800), plus 1600°C service
  • Maximum fracture toughness — Use ZrO₂: 10 MPa·m½ (vs alumina's 4.5)
  • High thermal conductivity needed — Use AlN: 170 W/m·K (vs alumina's 30) for power electronics heat dissipation
  • Ballistic / armor applications — Use B₄C: lighter than alumina with comparable hardness
★ Engineering Case · German Analytical Equipment Maker

Custom 99.7% alumina crucibles, independent test verified.

A German analytical equipment manufacturer needed custom-geometry alumina crucibles for their ICP-OES instruments — 99.7% purity verified by independent test, lot-specific certs on every shipment. We've supplied them quarterly since 2022.

3-Year Supply Outcome
Why they stayed with us
  • 99.7% Verified purity, independent lab test
  • ±0.1mm Custom geometry tolerance
  • 100% Lot certs on every shipment
  • 4× yr Steady supply since 2022
05 · Engineering FAQ

The questions engineers ask.

Direct answers from our application engineering team. Need a deeper dive? Email engineering@ceramitell.com with your drawing or spec.

What's the real difference between 95% and 99.7% alumina?
The remaining 5% (or 0.3%) is mainly SiO₂, MgO, and CaO sintering aids. As purity rises, hardness and dielectric strength go up, but cost rises faster. Use 95% for wear, 99% for general engineering, 99.7% only when contamination or chemical inertness specifically matters.
Can alumina handle thermal shock?
Moderately. Alumina's thermal expansion (8 × 10⁻⁶/K) is 2.5× higher than Si₃N₄, so it cracks faster under rapid heating/cooling. For 100,000+ thermal cycles (e.g. hot surface igniters), Si₃N₄ outperforms alumina substantially.
What's the minimum order quantity?
Stock geometries (rods, tubes, plates, balls) have no MOQ. For custom-machined alumina parts, MOQ is typically 50 pieces for prototyping, 500+ for production runs. Sample charges credit against your first production order.
Can you match a competitor's drawing?
Yes — send the drawing (PDF, STEP, or DWG) and we reply within 48 hours with DFM feedback, material grade recommendation, and pricing. We routinely produce drop-in replacements for European and US-supplied alumina components.
How fast can I get alumina samples?
Stock-geometry samples (rods 5–50mm diameter, plates 1–10mm thickness) dispatch within 48 hours from our Hangzhou warehouse. Custom prototypes typically ship in 7–14 days from drawing receipt — DFM review included.
Do alumina parts come with material certs?
Every production order ships with lot-specific certs covering density, dimension, surface finish, and (on request) electrical properties. Third-party lab tests by SGS/TÜV/Intertek available for an additional fee on high-value or regulated applications.