Powder X-ray Diffraction

Powder X-ray Diffraction

  • Ravi Ananth added an answer:
    14
    What is the conventional alignment procedure (critical for precision in XRD) for sample surface positioning collinear to the diffractometer axis?

    i. How does one adjust for this type of sample displacement error (see figure in link below) with a conventional diffractometer measurement using the ubiquitous 0D Geiger counter (point counter)?
    https://www.flickr.com/photos/85210325@N04/15511271935/

    ii. What is the typical procedure for this "fine tuning" of the diffractometer?

    iii. How long does something like this take?

    iv. How does one ensure that the "flat" sample surface is collinear (or at least coplanar) with the diffractometer z-axis (rocking axis)?

    I could empathize with those that are real finicky about alignment based on some of our contemporary experiences. I'll share a few :-)

    Really appreciate you folks sharing your experiences in this regard. It will benefit the entire RG community interested in NDE XRD for in situ materials' Nano structure characterization.

     
    Ravi Ananth

    "I stop the sample alignment when the intensity of the intersection point is half of the maximum profile intensity which is measured without the sample"

    This would work if the beam was spatially uniform or at least symmetric about the diffractometer axis. Especially, using the archaic 0D technique of integrating XRD data spatially. It is more of a challenge with high resolution diffractometers & spectrometers equipped with advanced beam conditioners. In these cases, the Nano structure of the beam conditioner is convoluted on the beam as well. All 2D beams we've seen to date are anything but symmetric or uniform. Haven't done so with the Synchrotron yet :-)

    • stats as of today 2/6/16 Views 968, Followers 10, Answers 13
  • Ravi Ananth added an answer:
    8
    Is the X Ray Line Profile Analysis use to Calculate Stacking Fault Energy of Aluminium alloys valid for foil type sample?

    The line profile analysis for SFE calculation, based on calculation of peak shift, extrinsic and intrinsic stacking fault probability has been done for powder samples. 

    Can this be done for bulk sample (in form if thin foil)?

    Ravi Ananth

    You are teasing me :-)

    "Stacking faults have a well know relation to Bragg peaks and can be modeled using structural refinement approaches." I'm looking to learn this better. Got any good references to educate me with?

  • Phil Bailey added an answer:
    6
    Free lime in cement clinkers by powder XRD: peak overlap with C2S?

    I am new to free lime determination, and have been doing a bit of background reading. I have a question for you. I was looking at a brochure from Thermo for equipment to carry out determination of free lime (CaO) in clinkers by combined XRD and XRF. I include the brochure in the link. In their figure 1 it shows the peak for a series of samples with varying CaO. There are problems with this diagram (scale, spelling) which I shall ignore for the moment, but when I looked at my own cement data I noticed that the there is potential problem with the 100% 200 peak from CaO (2.405A) being overlapped by the 18% 221 (2.403A) and 13% 112 (2.410A) lines of C2S. Now the intensities are much lower in C2S, but the proportion of that phase in the mix is vastly greater than CaO. I would have thought that this would create a problem with this type of calibration. They show the peak resolved from C3S - I presume this is the triclinic polymorph - but ignore any mention of C2S. Any comments on this? Does anyone have any XRD data of clinker with a known amount of free lime that I could measure?

    Phil Bailey

    Might be worth posing this question to the ASTM Technical Committee C01 for further insights 

  • Kenneth M Towe added an answer:
    1
    Can any one give the powder xrd details 1. Potassium ferricyanide 2.sodium nitroprusside from jcpds?

    i want result of the above compound from jcpds

  • Bhange D.S. added an answer:
    5
    Can anyone help me out in interpretation of a powder XRD diffractogram? What is a relationship between 2 Theta values and relative intensities?

    I am in a little confusion whether the change in relative intensities at an identified 2 Theta angles from initial to stability (like a change from 100% to 60%) means change in the polymorphic form? Is this applicable always?

    Bhange D.S.

    Dear Dr. Shivkumar,

    In general 2Theta represents the interplanar spacings (more simply interatomic layer distance) in unit cell. While the distribution of the atoms in that particular plane is reflected by the intensity of that reflection. But it is not always true, you have to learn about the prefered orientation effect and so many things,,, Crystal structure solution/refinement can help to get some fruitfull information related to it...

    Best regards,

    Deu Bhange

  • Rumu Halder added an answer:
    2
    How to do Warren Abervach analysis of GIXRD data for irradiated Ni based alloy using MARQX software?

    I have the GIXRD data in raw form taken with a Panalytical instrument using filters. I do not get the tab for WA analysis under the calculations menu in MARQX software. Please suggest what could be source of error. After reading the file I get only two options- calculation of peak areas or least square fit.

    Rumu Halder

    Thanx. I got user manual from them.

  • Yin Li added an answer:
    15
    Can 10 tons pressure destroy the crystal structure of amino acids?

    Hi, folks!

    I wanna measure the FT-IR spectra of some amino acids. I am going to prepare the plates made from the mixtures of amino acids crystals and KBr under 10 tons pressure. But I don't want to destroy the original crystal structure of amino acid. Does anybody know whether the crystal structure of amino acids can survive under such a large pressure?

    Thank you very much in advance!

    Yin

    Yin Li

    Thanks for your calculation and comments, Carlos! I can rest easy without caring for pressure-induced phase transition now.

  • Modeste Tchakoua Tchouaso added an answer:
    5
    How can I determine the atomic compositions of elements in XRD data as well as the phase of the compound?

    Hello All,

    For materials that exist in different phases depending on temperature, how can I determine the phase of the material base on XRD data?

    Can I also determine the atomic composition of different elements in a  compound (for example Ti0.4C0.6) from XRD data? 

    Thanks

    Modeste Tchakoua Tchouaso

    Thanks Professor Smith.

  • Eric Borguet added an answer:
    6
    Do you know the way to find a carboxyl group through the XPS?

    I am studying carbon's surface modification 

    I choose acid treatment among various surface modification and my samples are graphite block 

    After acid treatment, I analyzed functional group using XPS.

    we fitted binding energy spectrum and find carboxylic groups.

    for example, -O=C-OH is carboxylic group. carboxylic group has many binding such as C=O, C-OH.  

    XPS detect binding energy and through this binding energy, we know chemical state. I am wondering how to get a carboxyl group through an XPS

    Eric Borguet

    An alternative method involves chemical derivatization.  This can allow either an atom with a distinct signature to be introduced (e.g. F) or a luminescent chromoophore which can be detected without need for XPS (and UHV) with much higher sensitivity.

    We have used this extensively for the chemical identification and titration of fucntional groups on surfaces and carbon materials

    http://www.temple.edu/borguet/Publication/Publications_FLOSS.html

    For a detailed discussion see 

    Chemical Labeling for Quantitative Characterization of Surface Chemistry
    Yangjun Xing, Nikolay Dementev, and Eric Borguet
    Current Opinion in Solid State & Materials Science, 11, 8691 (2007).
    DOI: 10.1016/j.cossms.2008.07.002

  • Mahmoud Fathy Moubark added an answer:
    15
    I have synthesized Cobalt Oxide nanoparticles but the powder XRD pattern is giving no peaks. What could be the possible reasons?

    I have synthesized Cobalt Oxide nanoparticles but the powder XRD pattern is giving no peaks. What could be the possible reasons? any literature reporting such results?

    Mahmoud Fathy Moubark

    beaks of couplet around 33, 45,60 and 65 degree

    if this not appear or appear with small % its mean the Co present very small in the sample

  • Jose Da Silva Rabelo Neto added an answer:
    22
    How can we determine the crystal structure of a new material with XRD of powders?

    I prepared a hydrated material of CaCO3, but the XRD, FITR and Raman does not correspond to any kind of known CaCO3 polymorphs. It looks like monoclinic according to the SEM images. Does anyone know how to determine the crystal structure of this material with powder XRD pattern? Or any other techniques?

    Jose Da Silva Rabelo Neto

    I have the same problema. And also using the Rietveld it is necessary a pattern, otherwise , like in my case, i am creating until 0 step a lattice with some information and trying to analysing by Rietveld in each case. To long work.

  • Malur Srinivasan added an answer:
    1
    What mixtures of metals (consider mixture of two) could be called an alloy?

    Mixture of metals that are not in single phase, but a mixture of two phases of individual metals themselves are also termed as alloys at many places. This creates confusion regarding definition of alloys. Could anyone please give clarity on this?

    Malur Srinivasan

    When two elements follow Hume-Rothery rules a single phase of the two elements in the solid state and the alloy is termed isomorphous alloy. This is the so-called ideal system. Departures from ideal systems occur in most cases either due to increased liquid clustering or solid clustering. The outcome could be eutectic, monotectic, peritectic and so on. In every case however, it is a (binary) alloy. See the text book by Schaffer, Saxena,et all for full details.   

  • Ravi Ananth added an answer:
    4
    How to carry out Warren–Averbach XRD analysis of irradiated sample?

    I have GIXRD data for Ion irradiated Ni sample. I want to calculate domain size and microstrain using Warren–Averbach method. I donot get the option for WA analysis in the calculation tab using MARQX software after reading the input file. Can someone suggest what could be the reason?

    Ravi Ananth

     It is quite obvious that you are still using the ubiquitous conventional equatorial scan diffractogram at DAE,  Mumbai, India. You are no less than a century behind at least just like the rest of the general XRD world. Fortunately, a state-of-the-art XRD real time 2D quantitative imaging system is available for live demo in Bengaluru, India. This will allow you to monitor the relative dislocation density and relative residual stress in individual grains in your polycrystalline irradiated Ni sample. Using this technique, Weissmann et al at Rutgers, NJ, USA, 1980's were able to track the initiation of fatigue failure to individual grains for aluminum alloys and Ni based alloys. Exciting stuff, to be able to implemented that in real time!

  • Prashant Huilgol added an answer:
    1
    How could I 'cut ' a small piece of ceramic for TEM or XRD?

    As the title.

    I need a small piece of ceramic like 0.1mm or smaller cut from a for TEM, maybe some other for XRD.

    how can I do that?  I am doing some search. But in the same time, please....

    thank u guys .

    Prashant Huilgol

    You can do that with a ultrasonic disc cutter. 

  • Mohammed Adamu added an answer:
    10
    How is XRD analysis of a ceramic membrane sintered at high temperatures carried out?

    How should i prepare the sample for powder X-ray diffraction analysis from the sintered membrane?

    Mohammed Adamu

    Hi Nasir,

    I will encourage you prepare a pellet of any reasonable thickness from your crushed powder and then run XRD on it, you should get your peaks to analyse. The question is how do you crush? You can use laboratory mortar and pestle. I have tried similar stuff by running XRD on both powder and pellet of same sample with same composition, the outcome might be the same or slightly different you wouldn't know until you try. Share your findings.

  • Raji Sudha added an answer:
    7
    How do you choose a JCPDS card for matching HKL values?

    For a particular material we have a JCPDS card. How do we choose it? Is there any condition for choosing a particular card?

    Raji Sudha

    I have calculated strain from XRD by using formula

    strain= (beta*cos theta)/ 4

    I dont know why we are using this 4 in this equation.

    Is it correct sir.

  • Dino Aquilano added an answer:
    9
    Does surface adsorption affect the unit cell volume and XRD peak position?

    Hi all,

    I synthesise crystals in the presence of organic and inorganic additives. Aqueous chemistry analysis shows that there are surface adsorptions and crystal incorporations. Also there are shifts in XRD peak position. Would you please guide me:

    1-  Does surface adsorption affect the unit cell volume and XRD peak position?

    2- If yes, then how can I find out that the XRD peak position shifts relate to the surface adsorption or crystal incorporation?

    Regards,

    Taher

    Dino Aquilano

    Dear Taher,

                                           if , during growth, surface adsorption is not followed by incorporation into the crystal lattice, XRD diagrams will not be affected at all, but only  crystal morphology . However, if absorption follows, this can occur either in a disordered or in ordered way. In these cases both position and shape of the X-ray peaks can be affected.

    I'm sending you three recent papers, in which we showed the double effect of adsorption/absorption.

    All the best

    Dino

    + 2 more attachments

  • Charanjeet Singh added an answer:
    26
    How can I convert an XRD JADE (*.pid or *.raw) file into a file supported by X'Pert HighScore Plus?
    I have data obtained by rigaku rint XRD through JADE software. My data is in *.pid and *.raw format but unfortunately X'Pert HighScore Plus is not supporting both file format, so i I want to change file format of diffraction data. I have used MATCH software, but it done not helped.
    Charanjeet Singh

    Sorry, here is attached RAW file.

  • Ankit Goyal added an answer:
    14
    How do I calculate crystallite size of irregular shaped silicon powder samples?

    I am working on Silicon powders.

    I have added XRD results too in the attached file.

    Thanks and regards

    Ankit

    Ankit Goyal

    Dear Ravi,

                         Your comments are moreover mocking sort of then helpful. Those comments are not helping me. 

    If you understand my problem then please reply in proper manner. I am heartily grateful to you and other experts for giving the precious time to my problem. But I think this is the purpose of ResearchGate, isn't it?

    Anyway I will do it by my own as either i am unable to explain my problem or you are more prone to mock me than help me.]

    Thank you!

    Thanks Dr. Kenn and Dr. Pramod too.

  • M. Kanagasabapathy added an answer:
    6
    How can I calculate peaks of X ray diffraction for any element (metal) having hexagonal lattice?

    even though having values of h,k,l and a,c values; I am unable to calculate exact value of theta for elements having that structure. It would be a great help if anyone can tell how to do calculations for the same manually. (space group : P63/mmc)

    M. Kanagasabapathy

    In my work for Cd, Co and Zn based hcp-ccp binary solid solution, the same can be correlated by simulating the 2 theta based on hkil as well as d-spacing,using self designed crystal hack program.

    Link: http://crystalhack.blogspot.com/

  • Raja Raghavan added an answer:
    10
    What are the important parameters of X-Ray Diffraction (XRD) which are helpful in the absence of single crystal X-ray crystallography?

    I need your precious comments.

    Raja Raghavan

    SIr

    powder xrd gives the details of crystal nature but single crystal xrd gives the full structure. but from your question what u need i cant understand

  • Sandeep Kumar added an answer:
    26
    How to rietveld XRD powder pattern by Fullprof or GSAS?

    I am studying in SrTiO3. However, I do not know how to Rietveld the crystal structure of the sample. Anybody can help me? Thanks.

    + 1 more attachment

    Sandeep Kumar

    https://www.youtube.com/watch?v=u-pNnGIkkFk

  • Ravi Ananth added an answer:
    9
    What is the difference between 2theta scan and 2theta/omega-scan in XRD measurements?
    As we know, there are different scanning modes like 2theta scan (scanning of the diffracted beam) and 2theta/omega (scanning of the incident and diffracted beam). My question is what additional information 2theta scan can provide us which 2theta/omega cannot or vice versa?
    Ravi Ananth

    Views 8433; Followers 14; Answers 8  as of 12/30/2015

  • Valeriy Yatsyshen added an answer:
    3
    Can someone explain the effect of microwave on silicon carbide?

    If is possibile i would like to understand the behavior of silicon carbide with the microwave. Can anyone suggest me paper about this?

    thanks in advancee at all....

    Valeriy Yatsyshen

    The basis for all linear electromagnetic properties  of silicon carbide in the microwave region is the complex dielectric permeability as a function of frequency, which can be calculated by the quantum methods. The imaginary part of this function causes al dissipative processes in media.



  • Sami Mahmood added an answer:
    6
    Will the (107) phase always be the maximum peak in XRD of Barium Hexaferrite that has been aligned in a magnetic field?

    I have been studying the alignment of barium hexaferrite (BaM) in a silicone substrate. The BaM is mixed in the silicone, and as the silicone cures the mixture is placed in a strong magnetic field to align the BaM particles.

    In all but one of my samples the (107) peak has been the largest by far. I am trying to figure out what happened in the sample where this is not the case. (In this sample the (008) is maximum) 

    Any insight and help finding papers on this subject is appreciated. 

    Thanks!

    Sami Mahmood

    Is the (006) reflection in this "odd" sample also strong? If yes, then you have a preferred orientation along the c-axis. If no, notice that the angular position of the (008) reflection is very close to that of the (110) reflection (which is stronger in the powder pattern). Then there might be a confusion between (008) and (110), especially in the absence of the characteristic 3-peak structure just above 2 theta = 30 deg. in the BaM powder pattern. If the mentioned peak corresponds to the (110) reflection rather than (008), then the preferred orientation in this sample is perpendicular to the c-axis.   

  • Francisco J Martínez Casado added an answer:
    3
    Could anyone help in calculating S_L and D_L used in FullProf or GSAS?

    Peak profile: TCH p-v (npr=7 in FullProf).

    (1) For lab source (Beam horizontal size: 12mm and detector type: Lynx eye or scintillation)

    Condition (a) Goniometer radius = 280mm

    Soller slits: 2.3 degree (in both, source & detector arms)

    Is it necessary to have Soller slit width in mm or degree?

    Condition (b) Goniometer radius = 280mm

    Soller slits: 2.5 degree in detector arm only,

    in source arm no soller slits are used. 

    • How to use these numbers to calculate S_L and D_L for Bragg Brentano Geometry?
    • Are these numbers remains same if Parallel beam geometry is used instead of Bragg Brentano?
    • Is calculation of S_L and D_L are affected by choice of detector?
       


    (2) Synchrotron source (with Mar345 image plate detector) Debye-Schrerrer Geometry:

    Sample to detector distance ~ 150 mm. (no slits)

    Mar345 slits: 0.3 mm (Horizontal and vertical directions before capillary).

    Capillary diameter: ~ 0.1 mm.

    Vertical focusing using Pre-Mirror at a distance 12600 mm away from sample (capillary) position.

    Horizontal focusing using second bendable mirror of DCM at a distance 8200 mm away from sample (capillary) position.

    Francisco J Martínez Casado

    Yes, you have to calculate them (with the fit tool in Winplotr) and leave.them fixed in Fullprof.

    In Winplotr, you can start with a value of 0.01, for both values. Refine first one (S_L for example), and then the other. Normally the range of those values is 0-0.03, more or less. In the case that Winplotr doesn't refine the values, change them manually until you have a good fit with your data. And then you'll have S_L and D_L for Fullprof (fixed).

  • Nitai Chandra Maji added an answer:
    8
    Best alternative to PCPDFWIN?
    Till now I was using PCPDFWIN program to view Powder Diffraction Files from ICDD database. But after upgrading my system to Windows 8.1, I'm unable to use PCPDFWIN program. Could anyone kindly suggest me a good alternative that will work on modern platforms?

    Any suggestion would be of help. Thank you!
    Nitai Chandra Maji

    You can also install "virtual Box" software in windows 8 machine and then by flashing windows xp 32 bit, you can use PCPDFWIN software.

  • Muhammad Naveed added an answer:
    4
    Do high peaks mean high texture coefficients?

    Hi, 

    I have performed texture coefficient calculations and found that the highest intensity peaks doesn't represent a higher texture coefficient. Presence of some high intensity peaks with very low intensity values according to JCPDS makes these peaks with higher coefficient. Is there any suitable cross-check for the texture coefficient calculations made through XRD? In case carbides, sulphides are available in an XRD pattern, texture coefficient calculations through a XRD is a preferable method? Please let me know about your views.

    Muhammad Naveed

    Its a thin film

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