Convenient analysis of chemical composition of clay fraction of sediment by electron probe microanalyzer

2017 ◽  
Vol 51 (6) ◽  
pp. 583-588 ◽  
Author(s):  
Youko Miyoshi ◽  
Kazuhiko Shimada ◽  
Hiroshi Sato ◽  
Seiichiro Uehara ◽  
Jun-ichiro Ishibashi
2013 ◽  
Vol 67 (2) ◽  
pp. 331-336
Author(s):  
Aida Mahmutovic

A practice of special interest for metallurgical steelmaking is the relationship between redistribution of solute elements and dendrite microsegregation that occurs during solidification. These phenomena have a significant impact on the final properties of cast and forged products. In this paper, a calculation of the characteristic chemical phases in S355 steel using a software program Thermo-Calc is presented. Also, the paper presents experimental measurements of the dendrites size and non-metallic inclusions using optical and electron probe microanalyzer, as well as the calculation of the local solidification rate on the particular example. These phenomena are of special interest when it comes to thin castings and higher cooling rates. Thin castings require higher quality of casting surface, corresponding distribution, and character than those of non-metallic inclusions. Thermo-calc software was used for calculation of equilibrium phases, temperature ranges of solidification of tested material, and temperature range for developing characteristic equilibrium phase. It was found that during solidification and cooling processes manganese sulphide inclusions were formed. Additionally, accurate values for solidus and liquidus temperatures, which coincide with the values of solidus and liquidus temperatures obtained by the Thermo Calc, were calculated. Using optical and electron probe microanalyzer, the type of inclusions were confirmed, whereas chemical composition and size measurement of dendrites, and formed non-metallic inclusions were determined. Mapping and Linescan methods were used to examine the size and exact chemical composition of sulphides in atomic percents. Using secondary dendrites local solidification rate was calculated (for casting surface area solidification rate was 5 K/s). This paper gives contribution to better understanding the influence of cooling rate on casting microstructure formation and dendrites, which essentially determine the size of non-metallic inclusions and their redistribution.


Author(s):  
Fan Guochuan ◽  
Sun Zhongshi

Under influence of ductile shear deformation, granulite facies mineral paragenesis underwent metamorphism and changes in chemical composition. The present paper discusses some changes in chemical composition of garnet in hypers thene_absent felsic gnesiss and of hypersthene in rock in early and late granulite facies undergone increasing ductile shear deformation .In garnet fetsic geniss, band structures were formed because of partial melting and resulted in zoning from massive⟶transitional⟶melanocrate zones in increasing deformed sequence. The electron-probe analyses for garnet in these zones are listed in table 1 . The Table shows that Mno, Cao contents in garnet decrease swiftly from slightly to intensely deformed zones.In slightly and moderately deformed zones, Mgo contents keep unchanged and Feo is slightly lower. In intensely deformed zone, Mgo contents increase, indicating a higher temperature. This is in accord with the general rule that Mgo contents in garnet increase with rising temperature.


Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers

Among the ultra-light elements B, C, N, and O nitrogen is the most difficult element to deal with in the electron probe microanalyzer. This is mainly caused by the severe absorption that N-Kα radiation suffers in carbon which is abundantly present in the detection system (lead-stearate crystal, carbonaceous counter window). As a result the peak-to-background ratios for N-Kα measured with a conventional lead-stearate crystal can attain values well below unity in many binary nitrides . An additional complication can be caused by the presence of interfering higher-order reflections from the metal partner in the nitride specimen; notorious examples are elements such as Zr and Nb. In nitrides containing these elements is is virtually impossible to carry out an accurate background subtraction which becomes increasingly important with lower and lower peak-to-background ratios. The use of a synthetic multilayer crystal such as W/Si (2d-spacing 59.8 Å) can bring significant improvements in terms of both higher peak count rates as well as a strong suppression of higher-order reflections.


1999 ◽  
Vol 5 (S2) ◽  
pp. 78-79
Author(s):  
C. Merlet ◽  
X. Llovet ◽  
F. Salvat

Studies of x-ray emission from thin films on substrates using an electron probe microanalyzer (EPMA) provide useful information on the characteristics of x-ray generation by electron beams. In this study, EPMA measurements of multilayered samples were performed in order to test and improve analytical and numerical models used for quantitative EPMA. These models provide relatively accurate results for samples consisting of layers with similar average atomic numbers, because of their similar properties regarding electron transport and x-ray generation. On the contrary, these models find difficulties to describe the process when the various layers have very different atomic numbers. In a previous work, we studied the surface ionization of thin copper films of various thicknesses deposited on substrates with very different atomic numbers. In the present communication, the study is extended to the case of multilayered specimens.The studied specimens consisted of thin copper films deposited on a carbon layer which, in turn, was placed on a variety of single-element substrates, ranging from Be to Bi.


2009 ◽  
Vol 24 (8) ◽  
pp. 2638-2643 ◽  
Author(s):  
Kai-Jheng Wang ◽  
Yan-Zuo Tsai ◽  
Jenq-Gong Duh ◽  
Toung-Yi Shih

An Sn-patch formed in Ni(V)-based under bump metallization during reflow and aging. To elucidate the evolution of the Sn-patch, the detailed compositions and microstructure in Sn–Ag–Cu and Ti/Ni(V)/Cu joints were analyzed by a field emission electron probe microanalyzer (EPMA) and transmission electron microscope (TEM), respectively. There existed a concentration redistribution in the Sn-patch, and its microstructure also varied with aging. The Sn-patch consisted of crystalline Ni and an amorphous Sn-rich phase after reflow, whereas V2Sn3 formed with amorphous an Sn-rich phase during aging. A possible formation mechanism of the Sn-patch was proposed.


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