MasterMet 2 colloidal silica

Identity and neighboring products

MasterMet 2 is Buehler’s non-crystallizing 0.02 µm amorphous colloidal silica suspension for final polishing. Buehler’s product prose gives about pH 11 and its ordering table gives about pH 10.5. Neither supplies a batch acceptance range. Buehler final polishing suspensions

The product page lists two package volumes with rounded metric equivalents.

The US and UK SDS files also identify code 8175S130, without a package description. That code does not establish a third retail size. Both identify the product as a mixture named MasterMet 2. US SDS, section 1, UK SDS, section 1

Particle size and polishing behavior

The unit conversion 0.02 µm = 20 nm is exact. The product's size remains nominal, not a maximum particle diameter, a measured size distribution, or a guaranteed surface roughness.

Buehler's TECHNotes, volume 8, issue 4, revision 1, updated May 2024, compares MasterMet's 60 nm particles with MasterMet 2's 20 nm particles. Figure 2 shows more remaining scratches with the smaller particles after equal 90-second polishing periods using the same force, speeds, and cloth. The specimen is not fully identified, and no removal-rate ratio is given. This comparison does not establish a universal finish or timing advantage. How to select and use final polishing oxide media, pages 1 to 3

The October 2026 Buehler article describes final polishing as removal of residual surface deformation before demanding microscopy, etching, or electron backscatter diffraction, EBSD. It describes colloidal silica as chemically attacking a surface layer and mechanically removing that layer. It distinguishes alumina's mechanical removal mechanism. Its material examples include aluminum, refractory metals, silicon, and ceramics. These are application categories, not compatibility guarantees for every alloy, coating, phase, or polymer. Colloidal silica vs. alumina for metallographic final polishing

Synthesis. A chemical contribution makes the specimen's response part of the polishing result. Product identity and particle size alone cannot determine selective attack, preservation of a multiphase microstructure, or suitability for a particular analysis. This specimen-preparation evidence does not establish Finishing process references or a production finishing specification.

Non-crystallizing claim and cleanup

Buehler's November 2021 abrasives article says additives in MasterMet 2 greatly retard crystallization. It also describes dried silica residues as a source of scratches and specimen cleaning as a distinct concern. Its language supports reduced crystallization risk, not an unlimited guarantee under every drying or contamination condition. Metallographic polishing abrasives

The May 2024 TECHNotes presents the non-crystallizing formula as useful for automatic dispensing and vibratory polishing. It describes a wider cleaning window than conventional colloidal silica, while retaining a separate discussion of specimen and cloth cleaning. Its general silica-carrier discussion is not a complete MasterMet 2 formulation specification. How to select and use final polishing oxide media, pages 1 to 4

The October 2026 comparison also says non-crystallizing silica makes contamination control easier, but can polish more slowly and give inferior results to MasterMet in demanding applications. It supplies no universal rate penalty. Synthesis. The non-crystallizing property and the achieved specimen finish are separate performance questions. Buehler's comparison

pH and formulation evidence

The sources do not explain the pH discrepancy or establish whether the ingredient-table differences represent reformulation or disclosure differences. Synthesis. These documents cannot be combined into an exact current recipe, and omitted ingredients are not evidence of absence. The reviewed sources do not establish an assured solids concentration, dispersion stability duration, or shelf life for every supplied batch.

Safety and version limits

The 2022 US SDS classifies the mixture for single-exposure respiratory irritation, category 3, H335. Sections 7 and 8 specify ventilation and protective equipment. Section 10 identifies strong oxidizing agents as incompatible. These are product-handling statements, not proof of compatibility with a specimen material or approval of a modified polishing mixture. US SDS, sections 2, 7, 8, and 10

The 2022 UK SDS also gives H335. The historical 2017 US SDS instead says the mixture is not hazardous under the cited OSHA standard. Buehler's SDS index separates MasterMet 2 entries before 31 October 2022 and after 1 November 2022. Those index labels differ from the revision dates printed inside the PDFs. They do not explain the changed classification. UK SDS, section 2, historical US SDS, section 2, Buehler SDS index

Coverage limits

This reference uses the undated US product page, the November 2021 and October 2026 technical articles, the May 2024 TECHNotes, and the dated US and UK SDS files above. The source review date is 29 October 2026 PDT. Public product literature and safety sheets serve different purposes. None establishes customer-approved polishing parameters, specimen acceptance criteria, lot-specific chemistry, or guaranteed roughness.

The US shop's 6 oz product URL redirected to a login page during review. No authenticated shop data, price, availability, or regional formula equivalence is established here. The linked Chinese-hosted TECHNotes was retrieved as a five-page manufacturer PDF. No broader regional catalog completeness is claimed.