????? 10 ?????????????????????????????? Chemical composition analysis

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????? 10 ??????????????????????????????Chemical
composition analysis
1302 423 Industrial Materials Testing Assistant
Professor Dr. Sukangkana Lee
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????????????????

• XRF (X-ray fluorescence)
• XRD (X-ray diffraction) http//www.matter.org.uk/d
  iffraction/x-ray/x_ray_diffraction.htm
• Energy dispersive Spectrometer
• ????????????????? XRF ??? Emission Spectrometer

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?????

• ?????????????? ???????????????
• ????????? ????????
• X-rays ??? ????

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??????????????
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X-rays

• X-radiation (composed of X-rays) is a form of
  electromagnetic radiation.
• X-rays have a wavelength in the range of 10 to
  0.01 nanometers, comparable to spacing between
  atoms/ions/molecules in crystal
• corresponding to frequencies in the range 30
  petahertz to 30 exahertz (30 1015 Hz to 30
  1018 Hz)
• energies in the range 120 eV to 120 keV.
• They are shorter in wavelength than UV rays.

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1. XRF (X-ray fluorescence)

• XRF analysis ?????????????????????????????????????
  ?? (Qualitative) ????????????? (Quantitative)
• ???????????????????????????????????????
• ???????????????????????
• ??????????????????????????????????????????????????
  ???
• ??????????????????????????????????????????????
  5-500 ppm ???

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• ??????????????????????????????????? 10-50 mm
  ????????????? 50 mm ??????????????????????????????
  ????????????????
• ?????????????????????????????? 1 gram
• ???????????????????????????????? 15 ????

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• ??????????? ??????????????????????????? atomic
  number ???????? 11 ??? (H, He, Li, Be, B, C, N,
  O, F, Ne and Na)
• ???????????????????? XRF
• ?????????????????????????????????????????
  ????????? ???? ???????
• ??????????????????????????????????????????????????
  ?????????

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????????????????

• The process in which an x-ray is absorbed by the
  atom by transferring all of its energy to an
  innermost electron is called the "photoelectric
  effect."

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????????????????

• ????????????????????????????? X-rays
  ??????????????????????????????????? electron
  (???? K) ?????????????????? (Ejected core e-)
  ??????????????????????????????????????????????????
  ?? ???????????????????????????????????????????????
  ????????????? secondary X-ray

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• ???????????????????????????? core electron
  ???????????? (Primary x-ray) ???
  ????????????????????????? (Emitted secondary
  x-ray) ???????????????????????????
• XRF Titanium

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• ??????????????????? L shell ???????????? K shell
  ??????????????????????????????????????? ????????
  Ka
• ??????????????????? M shell ???????????? K shell
  ??????????????????????????????????????? ????????
  Kß

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X-ray K-series spectral line wavelengths (nm) for
some common target materials.13
Target Kß1 Kß2 Ka1 Ka2
Fe 0.17566 0.17442 0.193604 0.193998
Ni 0.15001 0.14886 0.165791 0.166175
Cu 0.139222 0.138109 0.154056 0.154439
Zr 0.070173 0.068993 0.078593 0.079015
Mo 0.063229 0.062099 0.070930 0.071359
David R. Lide, ed. CRC Handbook of Chemistry
and Physics 75th edition. CRC Press. pp. 10227.
ISBN 0-8493-0475-X.
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1. ??? x-ray ????????????????????????????????????????
   ?
2. Secondary x-ray ????????????????????????????
   x-ray detector
3. X-ray detector ????? ??? energy wavelength ??? K?
   ??? K? ????????????????????????

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Target
X-ray detector
3
1
2
X-ray filter
Secondary x-ray beam
Primary x-ray beam
Specimen
X-ray source

1. ??? x-ray ???????????????????????????? target
   ???????????????? 10-4 ??? 10-5 m
2. Secondary x-ray ??? Target ????????????? Specimen
   ??? ??????????? X-ray detector
3. X-ray detector ????? ??? energy wavelength ??? K?
   ??? K? ????????????????????????

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2. Optical Emission Spectrometer

• ????????????? ???????????????? ???????????????????
  ??? X-ray ??????????????????????????????????
  X-ray ???????????????????
• ??????????????? 30 ????????????? 1-2 ????

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• ??????????????????????????????????????????????????
  ???? ??????????????? 800-100 V ???????????????????
  ? ?????????????????????????
• ?????????????????????????????????????????????????
  (???????? ground state ) ???????????????????????
  ????????????? (???????? Excited state)
  ?????????????????????????????????
  ??????????????????????
• ?????????????????????????????????????????? (Light
  Emission) ???? ??????????????????
  ?????????????????????????

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Emission of atom
2.Excitation
1.Ground state
3.Emission
Supplied Energy ?E
e-
????????????????????????????????????????
e-
Initial Energy, E1
Energy, E2
Emitting a Photon (E2-E1)
????????????????????????????? (Atomic Phenomenon)
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Plancks equation

• E ??? ??????????????????????????? 2 ????????????
• h ??? ??????????? planck
• ? ??? ???????????????
• C ??? ???????????
• ? ??? ????????????
• ??????? ??????????????????????????
• ???????????? ???????????????????????
• ?????????????????????????????? (Emission)
• ????????

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• ??????????????????????????????????????????????????
  ??? ???????????? Spectrometer ????????????????????
  ???? ??????????????????? (??????? silicon or
  Lithium) ?????????????????????????? ???? Spectrum
  
• ????????????????????????????????????????????????
  Detector ?????????????????????????????????????????
  ?????????????????????????????????????????????????
  ???
• ??????????????????????????????????????????????????
  ???????????????????????? ???????????????????????

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????????????????? Spectrometer
Detector
Computer software
Work Table
Sample
Discharge
Spectrometer
Light Emission
Chamber (with argon flow)
Electrode
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Work Table
Spectrometer