[B._Beckhoff,_et_al.]_Handbook_of_Practical_X-Ray_(b-ok.org).pdf

Free cutting metals that are among the most widely

Info icon This preview shows pages 46–48. Sign up to view the full content.

View Full Document Right Arrow Icon
Free cutting metals that are among the most widely used industrial ma- terials are typical examples for exhibiting segregation phenomena in metals. Small metal particles like lead in steels and copper alloys influence machine processing of high-speed cutting.
Image of page 46

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
26 References Iwasaki and Hiyoshi studied lead segregation in bronze alloys. Microscopic observations of the surface pictures of a cast bronze showed a mixture of ground metal of copper and lead precipitated particles, and the recast pictures showed the surface with scattering of small lead particles. Comparing surfaces of recast and cast samples, Cu-K α X-rays from cast sample surface exhibited higher intensities and Pb-L α X-rays showed lower intensities. In recast sample surfaces, Cu-K α X-rays showed lower intensities and Pb-L α X-rays higher intensities because of absorption of Cu-K α X-rays and the exciting of bare surfaces of many small particles of lead on analyzing surface [89]. In the analysis of lead free cutting steels (Pb content: 0.1–0.3 wt%), small particles of lead metal (1–15 µ m) are scattered in steel. Arai reported that simple repeatability of Pb-L α X-rays was 0.003 wt% and RMS-difference of lead was 0.018 wt% [90]. The characteristics of segregation or inhomogeneity have been recognized as one of natural phenomena or as discoveries through experimental works. If some studies or works have attained success after long or hard work, possi- bilities of more success or discovery will be increased on the basis of research work and their process. 1.5 Concluding Remarks Elemental analysis of materials is absolute or relative. Gravimetric analysis is a typical example of the former, while X-ray fluorescence and optical emis- sion methods represent the latter. In the case of a relative analysis, standard samples are required, which are attached to reliable or authenticated analyti- cal values supported by absolute analysis. The values guaranteed by absolute analysis are the mean values of volume analysis, while X-ray analytical val- ues represent surface analysis with an information depth of 5–50 µ m. In order to reduce the analytical uncertainty, which orginates from the differences be- tween volume and surface analysis, homogeneous samples samples should be used. For the sake of reducing the effect of inhomogeneity on the sample sur- face, large analyzed surfaces of 3–10 cm 2 are recomended. Since the analytical accuracy is defined by a combination of errors of chem- ical analysis, uncertainty in the measured X-ray intensity, and uncorrected ma- trix effects by the constituent elements,the observed accuracy can be reduced by effective matrix corrections adapted for X-ray analysis, and elimination of other systematic errors may be activated.
Image of page 47
Image of page 48
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern