This paper demonstrates a non-destructive technique to evaluate the internal microstructure in the Sn-Ag-Cu (SAC) solder joint through synchrotron X-ray radiation tomography. Synchrotron X-ray ...tomography is increasingly utilized for characterizing the internal microstructure of materials in 3D images. A 3D model is reconstructed from a set of 2D projection images taken from different angles and angular position during the sample rotation, thus it could provide a more comprehensive description of the microstructure of an alloy compared to 2D images. In this paper, it is successfully observed and evaluated the internal microstructure of a 900 μm solder joint sample. The key principles and methods of synchrotron X-ray tomography are briefly described. Examples of quantitative and qualitative assessments on the grain refinement effect of Mg addition to SAC35 solder joint are also presented in this paper.
Industrial bonding technologies, including soldering and brazing, operate on solid-liquid phase boundaries. Commonly applied in many areas of industry (such as electronics, metallurgy or aviation), ...these bonding processes rely on the wetting of joining surfaces using a liquid bonding material. Understanding the wetting process and quantitative description of its parameters enables the design of new materials and joining technologies, as well as the optimization of existing methods. From the primary interfacial impact parameters, i.e. the contact angle and surface tension, the dynamics of the wetting process can be determined, including adhesive tension. This article investigates two independent measurement systems for wetting parameters in industrial brazing technologies: the sessile drop method and the Wilhelmy plate method. Both methods can be applied effectively in research on wetting processes. The measurement systems are compared in an example study.
Abrasive blasting is one of the methods of surface working before hot-dip zinc-coating. It allows not only to remove products of corrosion from the surface, but it also affects the quality of the ...zinc coating applied later, thereby affecting wettability of surface being zinc-coated. The surface working can be done with different types of abrasive material.
The paper presents an effect of the method of abrasive blasting on wetting the surface of steel sheets by liquid zinc. Steels sheets following blasting with Al
of different granularity and shot peening were examined. The worst wetting was recorded for a sample following shot peening - the results are below those for the reference test conducted for a sample not previously subjected to any treatment. Samples following abrasive blasting have similar parameters, regardless of the size of grain used for the treatment.
The effect of long-term heating on the graphite thermal insulation of a chamber furnace is considered. Mathematical modeling of the process is performed with the help of the ANSYS-FLUENT software. ...The formation of surface layers is analyzed from the standpoint of economy by comparing furnaces with advanced configuration of the thermal insulation and with the traditional thermal insulation of chamber furnaces. The configuration of the graphite thermal insulation of a furnace is optimized in terms of the heat treatment cost.
Mitragyna speciosa, known as kratom, is a tropical tree native to Southeast Asia that has long been used to increase energy and in traditional medicine. Kratom leaves contain several indole alkaloids ...including mitragynine, mitraciliatine, speciogynine, and speciociliatine, which have the same molecular formula and connectivity, but different spatial arrangements (i.e., diastereomers). A routine liquid‐chromatographic–high‐resolution mass‐spectrometric (LC‐HRMS) multi‐analyte method for addictive and herbal drugs in urine did not separate mitragynine from speciogynine and speciociliatine. Separation and individual measurement of the four diastereomers was possible with an improved LC method. All diastereomers were detected in 29 patient urine samples who tested positive for mitragynine with the routine method, albeit at variable absolute amounts and relative proportions. The presence of all diastereomers rather than individual substances indicated that they originated from the intake of kratom (i.e., plant material). Speciociliatine dominated in most samples (66%), whereas mitragynine and mitraciliatine were the highest in 17% each. A kratom product (powdered plant material) marketed in Sweden contained all diastereomers with mitragynine showing the highest level. In Sweden, there are signs of an increasing use of kratom in society, based on the results from drug testing, the number of poisons center consultations on intoxications, and customs seizure statistics. Because there may be health risks associated with kratom use, including dependence, serious adverse reactions, and death, analytical methods should be able to identify and quantify all diastereomers. In Sweden, this is important from a legal perspective, as only mitragynine is classified, whereas the other three diastereomers, and kratom (plant material), are not.
The use of kratom, that is, leaves from the Southeast Asian tree Mitragyna speciosa, has spread to the Western world. Kratom contain several alkaloids including mitragynine and its three diastereomers mitraciliatine, speciogynine and speciociliatine. In Sweden, only mitragynine is classified. Because the laboratory's routine method could not distinguish between the diastereomers, an improved separation method was developed. Of 29 patient urine samples that had tested positive for “mitragynine” by the routine method, all contained all four diastereomers in different proportions.
The article presents results of structural studies of polycrystalline diamond thin films deposited by hot filament CVD on silicon substrates. The films were characterized using Scanning Electron ...Microscopy (SEM), Raman Spectroscopy (RS), Electron Backscattered Diffraction (EBSD), Energy Dispersive Spectroscopy (EDS) and Secondary Ion Mass Spectroscopy (SIMS). Both the EBSD patterns and Raman spectra confirm that the grains visible in the electron micrographs are diamond micro-crystallites. The residual stress in the films is found to be in the range between −4.29 GPa and −0.56 GPa depending on the sample thickness. No evidence of lonsdalite and graphite has been registered in the polycrystalline material of the investigated samples. Evidence of the existence of silicon carbide at the diamond/silicon interface is presented. It is also suggested that an amorphous carbonaceous film covers the silicon surface in the regions of holes in the thin diamond layers.
Three different types of refractory protective coatings deposited by means of reactive and/or non-reactive magnetron sputtering have been developed in the Technical University of Lodz in cooperation ...with the Academy of Mining and Metallurgy in Cracow: metallic AlMo- and AlTi- or covalent-bonded Si-based coatings. The first one consists of the outer AlMo(Si) layer and a particular (TiC/TiN)
×
20 intermediate diffusion barrier multilayer coating protecting the outer layer against the mutual diffusion process at high temperature between the outer layer and the ferrous substrate. The complex nanocrystalline refractory coatings with the diffusion barrier protected the heat- and creep-resistant high chromium AISI 430 ferritic steel substrate against the oxygen and/or sulphur vapours up to the temperatures as high as 1023
K. Another series of amorphous coatings based on Si covalent compounds (Si
x
C
y
, Si
x
C
y
N
z
and Si
x
N
y
) deposited on the same AISI 430 steel protected the substrate against the oxidation up to the temperature 1173
K. At the same time, the coatings protected the steel substrate against electrochemical corrosion as well as against the chemical one even in most aggressive acidic or basic solutions up to the temperature as high as 350
K.
The heat- and creep-resistant intermetallic γ-TiAl substrates have been deposited with nanocrystalline γ-TiAl-based coatings microalloyed with Cr atoms. The deposits have imparted to the γ-TiAl substrate a very good oxidation resistance up to the temperature as high as 1173
K: the oxidation rate of the coated specimens was at least two orders of magnitude smaller than that for the uncoated ones.
The newly developed protective coatings can find a broad range of applications, as, e.g. in power industry, ferrous- and non-ferrous metallurgy, mining, aviation, car and ship industry, chemical processing of carbon, petrochemistry, waste treatment and recycling, microelectronics, MEMS, etc.
Chemical composition and some differences between surface and bulk structure of diamond-like carbon (DLC) thin films studied with Time-of-Flight Secondary Ion Mass Spectrometry (ToF SIMS) are the ...subject of this paper. The DLC films were deposited using radio-frequency plasma-chemical vapor deposition (RF PCVD) method by the decomposition of CH
4 gas in high-frequency plasma. The negative self-bias voltage defining the power used for deposition was in the range of −
100 V to −
400 V.
The results obtained show that the DLC films primarily contain carbon and hydrogen. The collected depth profiles also show that all samples contain considerable amount of Fe, Ni, Cr and some other elements introduced during the deposition process. These elements are mainly placed at the interface region of the substrate and deposited in the DLC film. The mass spectra obtained show that the amount of hydrogen in the surface layer is much greater than in the sample bulk which is consistent with widely accepted models of deposition of hydrogenated DLC films.
The structure of the studied DLC samples was characterized by the analysis of negative carbon cluster ions in the mass spectra obtained. Some significant differences in the surface and bulk energy of fragmentation of carbon clusters are registered. The results suggest that the fragmentation pattern is independent of the self-bias voltage used during film deposition.
Abstract
This papers presents the results of analysis done on a compression-ignition engine supplied with methyl ester of rapeseed oil (Yellow Grease), methyl ester of goose fat (Brown Grease) and ...pure diesel. The analysis included the engine characteristics, emissions and fuel consumption. Results also include chromatographic analysis for all of the three fuels. Additional evaluation was done on a vehicle idling and under load.
PDF
