Sample Preparation Equipment Documents

A new precision argon ion beam cross section polisher simplifies the preparation of samples and makes it possible to prepare truly representative cross sections of samples free of artifacts and distortion. Use of the broad argon ion beam eliminates the problems associated with conventional polishing and allows for larger specimens to be prepared with precision.

A bone tissue of a mouse tail, composed of hard and soft materials, was polished with the Cross-section Polisher (CP) for obtaining wide and smooth cross-section. The prepared specimen was observed with a SEM and analyzed with an EDS.

Traditional mechanical preparation of specimen surfaces suffers from various artifacts, such as scratches and embedded polishing media, that obscure the original microstructure, crystallographic information and precise layer thickness measurements. Broad ion beam polishing using the JEOL cross-section polisher (CP) offers pristine surface preparation with minimal artifacts. CP is a tabletop instrument that is ideally suited for preparation of a variety of environmentally-sensitive and beam-sensitive materials, including metals, polymers, ceramics and composites. The instrument includes both cryo-preparation (down to LN2temperature) and air-isolated transfer and preparation environment.

Modern day Scanning Electron Microscopes (SEMs) are capable of imaging at ultralow voltages or low vacuum modes to handle even the most non-ideal sample types without the need for extensive sample preparation. Low voltage, with its inherent low beam penetration into the sample, allows us to examine fine surface morphology. The added advantage to low voltage imaging is the ability to look at nonconductive samples and minimize charging artifacts. Low vacuum, on the other hand, allows us to look at and analyze non-conductive and outgassing samples at higher voltages required for other analytical techniques such as X-ray Analysis (EDS/WDS), Cathodoluminescence (CL) or Electron Backscatter Diffraction (EBSD). Thus, we have the tools to analyze many sample types with minimal to no sample preparation. A question often asked is with the versatility of today’s SEMs, is there any reason to add a conductive coating when preparing samples for the SEM? And if I add a conductive coating, what do I coat it with? There are a lot of options.

Here we discuss when it is appropriate to add a conductive coating to insulating or beam sensitive materials and how to pick the best coating material for your applications.

Cryomilling involves the ball milling of metal powders in a liquid nitrogen medium. It has been used to produce bulk nanocrystalline materials with high thermal stability [1]. The benefits of milling at cryogenic temperatures include accelerated grain refinement, reduced oxygen contamination from the atmosphere, and minimized heat generated during milling. This mechanical attrition process induces severe repetitive deformation in powders. During milling, the powder particles are repeatedly sheared, fractured and cold-welded, and severe plastic deformation effects the formation of nanostructures [2]. Cryomilled powders exhibit typical grain sizes of 20–60 nm [3].

Scanning electron microscopy backscattered-electron images of paint cross sections show the compositional contrast within the paint system. They not only give valuable information about the pigment composition and layer structure but also about the aging processes in the paint. This article focuses on the reading of backscatter images of lead white-containing samples from traditional oil paintings (17th–19th centuries). In contrast to modern lead white, traditional stack process lead white is characterized by a wide particle size distribution. Changes in particle morphology and distribution are indications of chemical/physical reactivity in the paint. Lead white can be affected by free fatty acids to form lead soaps. The dissolution of lead white can be recognized in the backscatter image by gray ~less scattering! peripheries around particles and gray amorphous areas as opposed to the well-defined, highly scattering intact lead white particles. The small particles react away first, while the larger particles/lumps can still be visible. Formed lead soaps appear to migrate or diffuse through the semipermeable paint system. Lead-rich bands around particles, at layer interfaces and in the paint medium, are indications of transport. The presence of lead-containing crystals at the paint surface or inside aggregates furthermore point to the migration and mineralization of lead soaps.

High-resolution field-emission scanning electron microscopes (FEG-SEMs) have proven to be very powerful tools for energy-related research. Developments in such areas as solar thin films, oil shale, catalysis, and fuel cells require sub-nanometer resolution SEMs with a versatile set of detectors. They also require advanced sample preparation and handling techniques, such as argon ion polishing and FIB (focused ion beam). This article discusses incorporation of both advanced sample preparation and handling techniques, and the newest SEM detectors and imaging capabilities to advance energy research.