SEM Backscattered-Electron Images of Paint Cross Sections as Information Source for the Presence of the Lead White Pigment and Lead-Related Degradation and Migration Phenomena in Oil Paintings October 20, 2020 Applications, Sample Preparation 0 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. For full details: Attached files often contain the full content of the item you are viewing. Be sure and view any attachments. Cross Sections of Paint.pdf 584.71 KB Related Articles Artifact-free Cross-sections The Cross Section Polisher (CP) is a new cross-section sample preparation device that addresses some of the issues involved with preparing very small and relatively soft specimens for SEM analysis. The CP can easily prepare a cross section that is hundreds of micrometers in width and can preserve nanometer-level fine structures. Pristine Sample Preparation Using Broad Ion Beam 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. Preparation of a High Quality Cross Section of a Bone Tissue for SEM - Application of the Cross-section Polisher to a Biological Specimen 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. Clean Cross Section Preparation with the SM-09010 Cross Section Polisher The cross section polisher (CP), which is supported by the patented technology developed by JEOL, makes a cross section perpendicular to the surface of a specimen. This is suitable for measurement of multi-layered structures. High Quality Cross Sections of Low Melting Point Samples Prepared with Cryo Ion Slicer – Broad Ar Ion Beam Milling Apparatus with a Newly Developed Specimen Cooling Unit Ion Slicer (IS) is an instrument used to prepare TEM lamellas and SEM cross-sections by employing an Ar broad ion beam. The IS has been getting quite popular in TEM and SEM laboratories because of its ease of use and high quality results. However, it is difficult to mill low melting point materials by the Ar broad ion beam because of thermal damage during the milling. Therefore, we have developed a specimen cooling unit for the IS. This cooling unit keeps specimen at low temperature during the ion milling to avoid the thermal damage. We named this system Cryo Ion Slicer(CIS). New Cross-Section Sample Preparation Method Applied to Microstructural and Chemical Investigation of Steel Coatings using FE-SEM Steel strips coated with Al-43.5Zn-1.5Si (Galvalume) alloy exhibit superior corrosion resistance as compared to Zn galvanized steel strips. The continuous hot-dip coating process used to produce such coatings entails a metallurgical reaction between the steel strip and Al-Zn-Si liquid alloy that leads to formation of an intermetallic compound layer at the steel-coating interface. Formability of the coated strip depends strongly on the morphology, dimensions (thickness) and chemical nature of this intermetallic layer. Proper characterization of the intermetallic layer structure and chemistry and the nucleation sites on the steel surface is therefore of paramount importance for the development of formable Galvalume coated steel strips. This requires preparation of artifact free cross-sectional samples. Such samples can be obtained using JEOL Cross-section Polisher (CP). Unlike mechanical sample preparation techniques that introduce significant amount of strain and possible artifacts due to preferential etching of various constituents, the CP uses a broad Ar beam and a rocking stage that minimize possible preferential etching and produces strain free cross-sections. In this paper, SEM images as well as chemical (EDS) data characterizing the interface layer between the steel strip and the Galvalume coating prepared using Cross-sectional Polisher are presented. Showing 0 Comment Comments are closed.