Sample mounting – when method selection really matters!

Mounting presses are an excellent way to mount many specimens, and can be the most efficient and economical choice for many samples.  However, the heat and pressure can cause significant damage to many samples – especially soft, porous or friable materials and coatings.  In these cases, castable mounting systems must be used. Castable epoxy systems cure at atmospheric pressure. Their peak exotherms are typically lower than the temperatures used to make mounts in a mounting press. Specimens that are especially sensitive to heat should be mounted in epoxies formulated for lower peak exotherm, like EpoThin 2 and EpoxiCure 2.

Epoxies adhere to specimen edges and have low shrinkage. This means that they protect and support edges and preserve features, which allows both faster and higher quality preparation. For porous specimens, their low viscosity allows better infiltration into cracks and pores, especially when vacuum impregna­tion is used.  EpoKwick FC and EpoThin 2 and provide the lowest viscosity available on the market.

Here are a few tips to make the most out of Buehler’s epoxy systems.

Adding ‘Flat Edge Filler’ (hard ceramic filler) can further enhance edge retention and lower shrinkage. Keep in mind this increase the viscosity.

Epoxies are very sensitive to the ratio of resin and hardener. It is usually recommended to mix by mass ratio than by weight.

Warming the epoxy resin to around 30oC prior to mixing will further lower viscosity. This is helpful when vacuum impregna­ting small cracks and pores. This also can accelerate curing.

The cure times for epoxies can be quite long. Some Buehler epoxies can be oven-cured to reduce cure times, although this increases peak exotherm temperature.

Contact us for our recommendations or visit EpoKwick FC Instructions

  1. Figure 2: The specimen is mounted in EpoKwick FC. This specimen is from the same part as the specimen in Figure 1. (100x objective lens)
  2. Figure 1: Aerospace specimen mounted in a hot compression mounting press. The pressure from the press created cracks in the coating. (100x objective lens)
  3. Figure 3: Aerospace specimen mount in a hot compression mounting press. (10x objective lens)
  4. Figure 4: The specimen is mounted in EpoKwick FC using vacuum impregnation. This specimen is from the same part as the specimen in Figure 3. The improved infiltration into cracks and pores gives the coating better support. This allows for better sample preparation. (10x objective lens).

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Optimize Your Sectioning
Buehler an ITW Company
Buehler Products

Applications of Metamaterials

With Prof. Lorenzo Valdevit

An overview of the definitions and classes of metamaterials will be provided with a specific emphasis to the applications as lightweight structural materials. The various features of structural metamaterials will be discussed as well as the role of metal additive manufacturing in enabling the scale of these materials. Future pathways to the implementation of these unique materials will be presented.

Applications of Light Metals

With Dr. Carl Söderhjelm

The lecture will first review the prototypical structures and identifying properties of various industrially relevant light metals. Then, several case studies will be presented to demonstrate the novel use of these materials in light weighting across different fields. The lecture will conclude with emerging materials and tools to design them.

Additive Manufacturing Overview

With Mr. Brandon Fields

The field of metal additive manufacturing will be discussed with a highlight to the variety of technologies currently in use and identify the industry leading techniques. The core principals of each will be presented along with comparisons and use cases for each.

Powder Metallurgy Versus Conventional Processing

With Prof. Diran Apelian or Dr. Ben MacDonald

Powder metallurgy as a class of processing technologies will be covered with an emphasis to the key differentiations with conventional processing. The implication of critical solidification parameters including cooling rate will be reviewed as they affect the refinement of microstructures and the presence of metastable structures. Traditional consolidation approaches to creating bulk parts will be discussed as well as the use of metal powder as a feedstock to additive manufacturing.

The Linkage of Processing Structure Properties

With Dr. Ben MacDonald

This lecture will serve to established and review the core metallurgical principles that are essential to understanding materials as a system. With an overview of the hierarchical structural features of metals, fundamentals of solidification, wrought processing, and heat treatment, the interconnected relationships of processing, structure, and properties will be established.

Current Trends in Light Weighting of Structural Materials

With Prof. Diran Apelian

This lecture will serve as a motivation for the course with emphasis on current trends in light weighting of structural materials. Global context to the need for light weighting will be provided as it is critical to a variety of fields from aerospace to the electrification of transportation. Paths forward will be proposed, specifically the unique potential of metal additive manufacturing to accomplishing these goals. This lecture will conclude by introducing the structure of the lectures that will be presented in the course.