Alumina Powder
Comparable to Buehler MicroPolish / MicroPolish II, Struers alumina suspension, and Allied High Tech alumina suspension for the same final polishing step — at 20 to 40 percent lower cost.
Overview
Alumina Powder
What This Product Is
Alumina powder is dry, high-purity calcined aluminum oxide (Al₂O₃) supplied in graded particle sizes for metallographic polishing and lapping. It is the same abrasive as our alumina suspension, in dry form, so a lab can mix its own slurry to the concentration it prefers and buy in bulk for a lower cost per use.
Graded options include the classic Linde grades — Linde A (0.3 µm, alpha), Linde B (0.05 µm, gamma), and Linde C (1.0 µm) — alongside coarser micron sizes for lapping.
Intended Use in Metallography
Alumina powder is used to prepare polishing or lapping slurries for intermediate and final steps. It is commonly selected when:
- A lab wants to control slurry concentration itself
- Bulk purchasing is more economical than ready-made suspension
- Coarser alumina grades are needed for lapping operations
- A specific water or lubricant carrier is preferred
Typical Applications
Commonly used for:
- Mixing custom alumina polishing slurries
- Final polishing of general metals and alloys
- Lapping with coarser alumina grades
- High-volume labs managing consumable cost
Beyond metallography, alumina powder is also used in:
- Petrography and geological sample lapping and polishing
- Optics and glass polishing
- Ceramics and general lapping
- Custom slurry mixing for any of the above
When This Product Is NOT Ideal
Alumina powder may not be the best choice when:
- A ready-to-use, pre-dispersed suspension is more convenient (use the alumina suspension)
- A deformation-free EBSD finish is required (colloidal silica is usually preferred)
- Mixing and handling dry powder is not practical for the workflow
Where This Fits in the Preparation Process
Alumina powder is typically used:
- After diamond polishing, mixed into a slurry for the oxide polishing step
- Coarser grades can serve earlier lapping operations
Best-Practice Notes
- Mix thoroughly and keep the slurry agitated so particles stay dispersed
- Match grade to step: coarser for lapping, 0.3 µm alpha for polishing, 0.05 µm gamma for the final step
- Rinse the sample and cloth before the slurry dries
- Store the dry powder sealed and dry
Specifications
| Abrasive type | Aluminum oxide (alpha and gamma alumina) |
| Form | Dry powder (mix to slurry) |
| Grades | Linde A 0.3 µm, Linde B 0.05 µm, Linde C 1.0 µm, plus coarser micron sizes — see options |
| Application | Metallographic polishing and lapping |
| Packaging | Bulk sizes for economical, high-volume use |
| Micron Size | Linde A - 0.3 micron, Linde B - 0.05 micron, Linde C - 1 micron, 1 micron, 3 micron, 6 micron, 9 micron, 15 micron, 30 micron, 50 micron |
| Size | 1 lb, 5 lbs, 10 lbs |
| Custom sizing | Custom sizes and concentrations are made to spec if what you need is not listed |
| Compatibility | Buehler, Struers, LECO, Allied, and PACE — and all other major brands. |
Compatibility and Equivalents
Formulated for the same final polishing step as these brand products:
Runs on Buehler, Struers, LECO, Allied, and PACE systems — and all other major brands — with no change to your process. It is a comparable product for the same step — not a branded or drop-in item.
Same grading and micron sizing, typically 20 to 40 percent lower in price.
Request a free sample and test it on your own bench.
Named brand products are referenced only to identify the comparable item and prep step. We do not claim our product is identical to, or a replacement for, any trademarked product, and no affiliation or endorsement is implied.
Frequently Asked Questions
What is the difference between alumina powder and alumina suspension?
They are the same abrasive. The powder is dry so you mix your own slurry and control concentration; the suspension is pre-dispersed and ready to use. Powder is usually more economical in bulk.
What are Linde A, B, and C?
Standard alumina grades: Linde A is 0.3 µm alpha alumina, Linde B is 0.05 µm gamma alumina, and Linde C is 1.0 µm. They correspond to progressively finer polishing steps.
How do I mix alumina powder into a slurry?
Disperse the powder in water (or the preferred carrier) to the concentration your step calls for, and keep it agitated during use so it does not settle or clump.
Can I use alumina powder for lapping?
Yes. Coarser alumina grades are used for lapping; finer grades are used for polishing.
Is alumina powder only for metallography?
No. Because it is a dry abrasive you mix to any concentration, alumina powder is used across petrography, optics and glass polishing, ceramics, and general precision lapping — anywhere a custom alumina slurry is useful. Coarser grades lap; finer grades (0.3 and 0.05 µm) polish.