MicroPolish alumina powder

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Identity and purpose

Buehler lists agglomerated MicroPolish alumina powder at 1 µm as 40-10079 (1 lb [0.45 kg]) or 40-10080 (5 lb [2.3 kg]). Code 40-10083 identifies the 0.05 µm liquid suspension in a 6 oz [0.18 L] package. Buehler names pure and alloyed lead and magnesium as applications and gives no numerical removal rate. Buehler, Final polishing suspensions and powders.

The November 2025 US powder SDS lists more than 99% aluminum oxide (Al₂O₃, CAS 1344-28-1) and covers both powder families, including codes 4010075 through 4010080. The common disclosure describes composition, while MicroPolish II undergoes additional processing to break up particle clusters. Buehler powder SDS, reference 1341982, version 2.0, sections 1 and 3.

Nominal sizes and powder codes

The public ordering table lists these MicroPolish powders. Package masses below reproduce Buehler's rounded metric equivalents. Buehler ordering table.

The cited ordering table does not specify a size-distribution method, percentile such as D50, maximum particle size, or agglomerate-size limit. Nominal size alone therefore cannot establish those properties. This is an interpretation of the catalog's stated scope.

Powder, suspension, and MicroPolish II

Buehler’s May 2014 guide describes mixing MicroPolish powder with water. It gives no mixing ratio. Buehler, Quick reference guide to final polishing solutions.

The catalog lists 40-10083 as a 0.05 µm MicroPolish suspension, packaged as 6 oz [0.18 L], rather than a powder sold by mass. It describes MicroPolish II powder separately as deagglomerated alumina and currently lists 40-6322-016 at 1 µm. Buehler product and ordering tables.

The suspension has its own US SDS, reference 1341988, version 2.0, revised July 25, 2023. It covers 4010081, 4010082, and 4010083 as a mixture. Section 9 reports a liquid with pH 8 to 11, and section 15 reports aluminum oxide at 10 to 30%. These are suspension data, not the powder's composition, pH, or a dilution recipe. Section 3's absence of reportable ingredients is a disclosure statement, not evidence that the liquid contains no abrasive. Buehler MicroPolish suspension SDS, sections 1, 3, 9, and 15.

Synthesis. A shared brand, chemical formula, or nominal size is insufficient to establish interchangeability between an agglomerated powder, a deagglomerated powder, and a formulated liquid. The cited sources do not establish that water plus MicroPolish powder reproduces the commercial suspension's formulation or performance.

Crystal phase and agglomeration

Alpha and gamma describe alumina forms, while agglomerated and deagglomerated describe particle grouping and processing. Buehler's general final-polishing discussion names 0.3 µm alpha-alumina and 0.05 µm gamma-alumina suspensions. It also discusses MicroPolish II powders and suspensions, but does not map those phase statements to the six current MicroPolish powder codes above. Buehler, Metallographische Poliermittel, final-polishing section.

The same technical discussion states that calcined alumina retains some agglomeration despite efforts to deagglomerate it. Its comparison with sol-gel alumina is process guidance, not a measured agglomerate distribution for a MicroPolish grade. Buehler technical discussion.

Synthesis and coverage limit. The current powder phase assignments remain unverified here. The general alpha and gamma size examples do not prove that every present 0.3 µm powder is alpha or every 0.05 µm powder is gamma. The powder SDS reports no particle-characteristics data and supplies no grade-specific phase analysis. Powder SDS, sections 3 and 9.

Safety and evidence limits

The 2025 US powder SDS classifies the product as not classified under GHS US. It still specifies ventilation, protective gloves, safety glasses, suitable protective clothing, and suitable respiratory equipment when ventilation is insufficient. It lists strong oxidizing agents as incompatible. The document supplies no pH value for the powder. Safety classification does not establish polishing performance or specimen compatibility. Powder SDS, sections 2 and 7 to 10.

This reference uses the public product page as accessed October 29, 2026 PDT, the dated powder and suspension SDS versions above, the guide marked 05/14, and Buehler's undated German technical article. These documents have different purposes and dates. They do not establish lot certification, phase fractions, working concentration, shelf life, universal cloth choice, polishing time, pressure, speed, achievable roughness, or guaranteed removal rate. Direct shop product links redirected to login during research, so stock and purchase availability are not established.

The documented purpose is laboratory specimen preparation. Application to production finishing or Finishing process references would require separate process evidence. This final distinction is synthesis, not a manufacturer production approval.