A SEMINAR ON

XRD

K. GANAPATHI RAO(13031D6603)

PresentedBy

Presence ofMr. D. RAKESH

OUT LINE

IntroductionConstructive and DestructiveBasic components Operating ProcedureShut down procedureXRD patternSignificance of PeakApplications of XRDMost important uses of XRDReferences

What is X-Ray Diffraction

The atomic planes of a crystal cause an incident beam of X-rays to interfere with one another as they leave the crystal. The phenomenon is called X-ray diffraction.

Bragg developed a relationship in 1913 to explain why the cleavage faces of crystals appear to reflect X-ray beams at certain angles of incidence.(Roentgenstrahlinterferenzen), commonly known as X-ray diffraction (XRD), and was direct evidence for the periodic atomic structure of crystals postulated for several centuries.

Basic components

D8 machinePC + UPSChiller

Operating Procedure

Switch on systemSwitch on D8 machine and press green button on D8 machineSwitch on chiller

Click on D8 icon on systemClick on “Online status”Click on “Online refresh”

Go to “x-Ray generator” iconThen click “X-Ray software safety capture register”Go to “Utilities”Go to “X-Ray Hardware safety capture register” through X-RayGo to “X-Ray ware safety capture register” through X-RayEnter password as designed “*******”, okGo to positioning Drives Then initialize the theta, 2 theta, spinner step by step, by clicking adjust symbol

Switch on X-Ray generator power supply, by rotating knob in clock wise direction (4 sec, upto x-rays on)Close D8 tools windowOpen x-ray commander symbolThen increase kV & mA gradually, up to 40kV, 30mAClick open door for insert sampleThen insert sampleAnd give 2 theta, scan speed, step sizeStartSave as .raw file

Shut down procedure

Gradually decrease kV and mA up to 20kV, 5mAClick on Init Drives for initializing drives on main menuClose windowX-ray off by rotating anticlock wise directionShut down systemSwithoff D8 power and chiller

Significance of Peak Shape in XRDPeak positionPeak widthPeak intensity

Applications of XRD

XRD is a nondestructive technique To identify crystalline phases and orientationTo determine structural properties: (Lattice parameters (10-4Å), strain, grain size, expitaxy, phase composition, preferred orientation , (Laue) order-disorder transformation, thermal ExpansionTo measure thickness of thin films and multi-layers*To determine atomic arrangementTooth enamel & dentine have been examined.

Most important uses of XRD!!!

Obtain XRD patternMeasure d-spacingsObtain integrated intensitiesCompare data with known standards in the JCPDS file, which are for random orientations (there are more than 50,000 JCPDS cards of inorganic materials)(Joint Committee on Powder Diffraction Standards)

References

http://pubs.rsc.org/en/Content/ArticleLanding/1991/JM/jm9910100511#!divAbstract http://www.iucr.org/publ/50yearsofxraydiffraction http://en.wikipedia.org/wiki/X-ray_crystallography http://webmineral.com/help/XRayDiffraction.shtml#.U7VsJfmSydw http://serc.carleton.edu/research_education/geochemsheets/techniques/XRD.html http://web.pdx.edu/~pmoeck/phy381/Topic5a-XRD.pdf