Epoxy Systems - Cold Mounting by Metallurgical Supplies
Epoxy Systems - Cold Mounting
Epoxy Systems - Cold Mounting - by Metallurgical Supplies a Metallography World Corporation
EPOXY SYSTEMS - COLD MOUNTING SUPPLIES FOR SAMPLE PREPARATION
Epoxy resins are typically two-part systems consisting of a resin and a catalyst (hardener). Mixing ratio's vary from ten parts resin with one part hardener to five parts resin with one part by weight of hardener. The advantages of mounting with epoxy resins include: -Low shrinkage - Relatively clear - Relatively low exotherms - Excellent adhesion - Excellent chemical resistance - Good hardness
Cold Mounting systems are recommended for mounting specimens that are sensitive to high pressures and temperatures. Epoxy products provide good physical adherence, low shrinkage, and excellent infiltration into pores.
Epoxy Systems - Cold Mounting
Epoxy Systems - META-EPOVELOX SERIES
Epoxies have the lowest shrinkage of all cold-mounting resins. The hardened epoxy is duroplastic, and not affected by moderate heat or chemicals. Epoxy resins are suitable for mounting of all types of materials and are especially recommended for vacuum impregnation. The curing time is relatively long, but adhesion to most materials is excellent. They polymerize through a chemical reaction after being mixed in the correct proportions. Metallurgical Supplies' epoxy systems consist of two components: a resin and a curing agent/hardener. Properties such as low vapor pressure, transparency, excellent adhesion, low viscosity, and no shrinkage are all specific to epoxies. As the stoichiometric resin:hardener ratio is critical; both parts should be weighed to obtain the best mounting result. If it is only possible to measure the amount by volume, use syringes to measure the quantities of resin and curing agent/hardener.
Optimized Chemistry for Excellent Results: Epoxy chemistry is a complex balance of many factors including shrinkage, cure time, viscosity and adherence. Each lab application requires a slightly different priority of these factors and our line of epoxies have been specially developed to provide the ideal product for your application.
Mounting specimens in a holding device is necessary when preparing irregular, small, very soft, porous, or fragile specimens, and in those cases where edge retention is required. Embedding is indispensable when multiple specimens are to be included in a single mount or when automatic equipment is to be used in the following preparation. In most cases, mounting follows sectioning, but in the handling of a great number of very small specimens, it may be advantageous to reverse this order. In general, the mounting procedure can be easily adapted to the special problem in question. The shape, size, and numbers, as well as the hardness, brittleness, porosity, and heat and pressure sensitivity of the specimens, have to be considered when mounting. Other considerations are: should a cross or a longitudinal section be prepared, is a controlled material removal required, is good edge retention needed, and should the preparation be carried out manually or with automatic equipment in specific sample holders. A suitable mounting media must meet several criteria: it must have good adhesion to the specimen, sufficient mechanical strength (hardness), and chemical resistance to etchants or solvents that are used during the preparation. For electrolytic polishing, scanning electron microscopy examination, or microprobe analysis, the mounting medium has to be electrically conductive. The mounting material should be easy to handle, economical, if necessary easy to remove, and it should not affect the specimens. For some investigations, a transparent mounting medium is more appropriate than an opaque material, and in cases where the specimens have to be analyzed with x-rays, a mounting material free of any interference reflexes should be selected. Because of these varied requirements, many different techniques were developed for the mounting and embedding of metallographic samples. They are summarized schematically in Fig. 1.2 and can be described as two basic types of mounting: clamping with a sample holder or clamp, and embedding the specimens in organic or inorganic materials.
Embedding or casting of plastic materials around the specimens is the most popular technique and can be divided into “cold” and “hot” mounting, depending on whether or not heat is needed for the polymerization process
Cold mounting (room-temperature curing) requires the mixing of two agents (a crude polymer and a catalyst); this mixture is then cast over the specimen within a mold, in which it reacts to form a solid part. A slightly higher pressure during curing improves the adhesion to the specimen. Special equipment is available to mount several samples simultaneously.
Hot Mounting (compression molding) requires a mounting press where the sample and the mounting compound can be heated and simultaneously compressed. Two essential types of mounting materials are available, thermosetting and thermoplastics. Both types are available as hot and cold mounting compounds, depending on whether the polymer reaction occurs with added heat or with the addition of a catalyst. The curing of thermosetting materials is irreversible, and they cannot be re-softened after curing; cured thermoplastic materials, however, can be re-melted again at elevated temperatures.
Mounting accessories many different clips, cups, pigments, and fillers are available to help simplify, improve, or customize a mounting process.
High-Quality Mounts: Mounting cups are available in multiple shapes and sizes to create high-quality mounts with easy removal.
Consistent Specimen Alignment: Support clips allow for precise placement of the specimen in the mount to ensure the area of interest is properly presented for grinding and polishing.
Unique Mounting Applications: A variety of colored pigments, fillers, and cement offer many options to customize the mounting process to meet any lab's needs.