Dot blot immunochemical and infrared analyses of the adhesive layer applied to the painting Imago Pietatis by Domenico Morone

Purpose To investigate the nature of the materials used in the adhesive layer of the Imago Pietatis painting (end of the fifteenth century—beginning of the sixteenth century) by Domenico Morone as a prerequisite for its restoration. Methods Micro-FTIR spectra of the animal glue and a polished cross-section were acquired by a Jasco IRT3000 spectrometer, equipped with a 32× Cassegrain objective. A dot blot immunoassay was used to characterise a minor component of the adhesive layer. Results Micro-FTIR was used as an effective diagnostic tool to detect the major component of the adhesive layer and the binder of the paint. Despite the ageing, the complex matrix and the micro-size of the sample, using a dot blot immunoassay, it was possible to quantify 3.7 ± 2.0 ng of ovalbumin per microgram of sample (corresponding to 0.004 ± 0.002% of the weight). Conclusions The findings were in line with conservation practices described in the old treatises, confirming the correct interpretation of the adhesive layer compounds added to the painting and suggesting for the cleaning the use of an anionic water-soluble surfactant highly effective in the removing of proteinaceous materials.

Study on the Possible Error Due to Matrix Interaction in Automated SEM/EDS Analysis of Nonmetallic Inclusions in Steel by Thermodynamics, Kinetics and Electrolytic Extraction

Up to now, the Fe content of nonmetallic particles has often been neglected in chemical evaluations due to the challenging analysis of matrix elements in nonmetallic inclusions (NMI) in steel by scanning electron microscope and energy dispersive spectroscopy analysis (SEM/EDS). Neglecting matrix elements as possible bonding partners of forming particles may lead to inaccurate results. In the present study, a referencing method for the iron content in nonmetallic inclusions in the submicrometer region is described focusing on the system Fe-Mn-O. Thermodynamic and kinetic calculations are applied to predict the inclusion population for different Fe/Mn ratios. Reference samples containing (Fe,Mn)-oxide inclusions with varying Fe ratios are produced by manganese deoxidation in a high-frequency induction furnace. Subsequent SEM/EDS measurements are performed on metallographic specimens and electrolytically extracted nonmetallic inclusions down to 0.3 µm. The limits of iron detection in these particles, especially for those in the submicrometric regime, as well as the possible influence of electrolytic extraction on Fe-containing oxide particles are examined. The measured inclusion compositions correlate well with the calculated results regarding segregation and kinetics. The examinations performed are reliable proof for the application of SEM/EDS measurements to evaluate the Fe content in nonmetallic inclusions, within the physical limits of polished cross-section samples. Only electrolytic extraction ensures the determination of accurate compositions of dissolved or bonded matrix elements at smallest particles enabling quantitative particle descriptions for submicrometric (particles ≤ 1 µm) steel cleanness evaluations.

Thermal cycle effects on laminated composite plates containing voids

Composite structures are often cured in an autoclave to acquire the required space grade quality. Now the industry is focusing on the out of autoclave manufacturing method which leads to more voids inside laminate with respect to those manufactured in the autoclave. In the present work, the influence of voids on microcrack formation under thermal cycling and environmental conditions was analyzed. Thermal cycle experiments were performed using liquid nitrogen and oven, followed by microscopic observation of the polished cross-section of the 90° layered plies. Cracks were monitored, counted, and measured with respect to void and void free areas. Void content was characterized using microscopic and ImageJ software was used. It was observed that the microcracks will be formed both around the voids and in void free areas. As the number of thermal cycle increases, the number of microcrack around the voids increases much faster than compared to the void free areas. Also it was observed that most of microcracks were propagated in the transverse direction. Interlaminar shear strength was measured. Results indicate that interlaminar shear strength reduces as the number of cycle rises due to the increase in the microcrack density. Finite element method was used to simulate the process. The micro, meso, and macro model were created with respect to original samples voids and positions to calculate the stress distribution and its concentration. Good agreement between experiment and simulation was observed.

Evaluation of oxide ceramics as anodes for SOECs

La2NiO4+δ is characterised as an example for a potential anode material for high-temperature solid oxide electrolyser cells (SOECs). Short-term characterisation is performed from 700 °C to 850 °C between 0.01 and 1 bar oxygen partial pressure (pO2) on asymmetrical cells using Ce0.9Gd0.1O2−δ as the electrolyte. Long-term degradation studies over more than 3000 hours are conducted at 800 °C and 0.2 bar pO2 in dry and humid atmospheres with and without a Cr-source placed in close vicinity to the cell. The SOEC anode performance is investigated by current–voltage curves combined with impedance spectroscopy. Current densities of up to −410 mA cm−2 are applied in current–voltage measurements and during long-term degradation studies. A total increase in anode resistance by 350% is observed over the course of the degradation measurements in an increasingly harsh environment. Post-test analyses by SEM/EDX on a polished cross section of the cell show the presence of several contaminants in the electrode structure. However, chromium has not been identified by EDX even after prolonged exposure to Cr-sources in humid atmospheres, which is attributed to the anodic polarisation of the electrode. Electrode delamination appears to be the main factor for the strong loss in performance.

Application of Different Extraction Methods for Investigation of Nonmetallic Inclusions and Clusters in Steels and Alloys

The characterization of nonmetallic inclusions is of importance for the production of clean steel in order to improve the mechanical properties. In this respect, a three-dimensional (3D) investigation is considered to be useful for an accurate evaluation of size, number, morphology of inclusions, and elementary distribution in each inclusion particle. In this study, the application of various extraction methods (chemical extraction/etching by acid or halogen-alcohol solutions, electrolysis, sputtering with glow discharge, and so on) for 3D estimation of nonmetallic Al2O3inclusions and clusters in high-alloyed steels was examined and discussed using an Fe-10 mass% Ni alloy and an 18/8 stainless steel deoxidized with Al. Advantages and limitations of different extraction methods for 3D investigations of inclusions and clusters were discussed in comparison to conventional two-dimensional (2D) observations on a polished cross section of metal samples.

Intergrowth of several solid phases from the Y–Ni–B–C system in a large YNi2B2C crystal

A YNi2B2C single crystal containing traces of foreign phases was inspected by means of neutron and X-ray diffraction as well as scanning electron microscopy and X-ray spectroscopy methods. The diffraction patterns obtained from the experiments look similar to those expected for a superstructure. Nevertheless, they can be interpreted as crystallographically oriented precipitations of YB2C2and Ni2B within the YNi2B2C crystal, formed during the cooling process. The orientation relation between the lattices was obtained from experimental neutron and X-ray data. Structure refinements of the collected X-ray data were performed by separation of the intensity data of the individual phases. Scanning electron microscopy images of the inclusions found on a polished cross section of the crystal are presented; their chemical composition was determined using wavelength-dispersive X-ray analysis.

Layered Interphases in Ceramic Matrix Composites and Relation with Interfacial Behaviour

Unidirectional SiC/SiC minicomposites were produced by infiltration of a Hi-Nicalon fibre tow by using pulsed chemical vapour deposition (P-CVD). The sequence of precursor gazes inlet steps determines the structure of the Pyrocarbon/TiC layered interphase deposited first on the filaments. The SiC matrix is then deposited with a given thickness. The different interphase structures will be described. The interface behaviour was characterized by indentation method. The load is applied on the fibre-end at a polished cross-section of the composite, and the displacement of that fibre-end is measured. The push-in test on thick specimens shows that the fibre debonds at a given fibre stress and then slides under a certain frictional shear stress. Both parameters increase when the TiC layers become discontinuous, like aligned TiC clusters in a Pyrocarbon matrix. The load-displacement behaviour is in very good agreement with theory when the interfacial shear stress is kept constant, non depending on relative slip displacement. The push-through test on thin composite slices gives directly access to sliding resistance because the fibre is less compressed. The load displacement curves obtained will be described and analysed. For example, sliding velocity jumps revealed a slight increase in sliding resistance with velocity. During push-back, a seating drop was recorded as the fibre returns in its initial position, illustrating a certain effect of roughness.

A Critical Evaluation of the Employment of Microhardness Techniques for Characterizing and Optimizing Thermal Spray Coatings

Frequent reporting of microhardness data for thermal spray coatings testifies to the widespread use of this technique for coatings characterization. However, inadequate reporting of microhardness procedures makes comparisons between published coatings hardness statistics difficult and it appears that both microhardness in general and its significance to characterizing thermal spray coatings in particular, are poorly understood. This paper demonstrates that though microindentation technique is a useful laboratory procedure that can be used for coatings optimization, research and quality control purposes, poor understanding often leads to worthless data and thus to erroneous conclusions. A high quality WC-12%Co coating supplied by Sulzer Metco was hardness tested on both the polished cross-section and plane surface of the coating. Contributions to the variance in results obtained and sources of significant errors are discussed and conclusions are drawn regarding the methodology and suitability of hardness testing for characterizing thermal spray coatings. The limits in repeatability and reproducibility of Vickers microhardness data for hard metal thermal spray coatings are discussed. The necessity for rigorous statistical procedures of data analysis is demonstrated. It is suggested that the technique is inherently unsuitable for characterizing hard thermal spray coatings due to poor intrinsic reproducibility.

Statistical Analysis Of SEM-EDX Spectrum Images Of A Metal-Ceramic Braze

Spectrum imaging, where a complete spectrum is acquired at each pixel in an image, is potentially a very powerful technique for the characterization of materials. The primary challenge to overcome is to extract all of the relevant information from what are typically large data sets that cannot be readily visualized in their entirety. For energy-dispersive X-ray (EDX) spectrum images, simple mapping has typically been done. In this work, the application of multivariate statistical analysis (MSA) to the characterization of a metal/alumina braze by SEM-EDX spectrum images is described.The braze characterized in this work joins polycrystalline alumina and a copper-silver eutectic alloy containing some titanium (an ‘active’ metal). The specimen geometry consisted of a sandwich of two pieces of alumina, two braze layers and a Kovar (primarily Fe, Ni and Co) filler layer in the middle. The entire assembly was heat-treated to bond the interfaces and then a polished cross-section was prepared.

Surface Morphology of Plasma Sprayed Ceramic Coatings

A novel method for characterization of microstructure of coatings is presented. Properties of plasma spray coatings are affected by their microstructure, which depends on the spraying conditions. Therefore, a detailed knowledge of microstructure is very important in order to know the coating formation mechanism and the properties of the coatings. There are many studies to characterize the microstructure of coatings. In most of those studies, the microstructures are characterized from the polished cross-section of the coatings, and the results strongly depend on the preparation methods. In this study, a new method for the characterization of coating microstructures by means of surface morphology is proposed. The distribution of shape and dimensions of splats were examined using quantitative analysis of scanning electron microscope images from the surface of the coatings. The results indicate that the surface morphology strongly depends on the spraying conditions.