X-ray Powder Diffraction Phase Analysis Of The Full Spectrum Fitting

X-Ray diffract ion (XRD) is used to phase analysis, including distinguishing the crystal strcture of sample, the perfact performance of crystal ,crystalline state or amorphous state and so on. From this, we can identify the composition of the sample and the content of each phase. We title this qualitative analysis and quantitative analysis. In the past days,the analysis about atlas of powder diffraction was just using its partial data, such as the position, the integrated intensity , the width , the line shape of one or several diffraction peaks. All these can induce the defective result that the experiment is hard to do and the testing result is not accurate. In the recent ten years,accompanying the increasing distinguishability about diffractometer and the inducing of new data processing method, the application domain of powder diffraction is abtained continuation greatly. The combination between the computer technology and the new idea of data-processing which is about Rietveld whole pattern fitting becomes the new progress of phase analysis.We can extract much message from diffraction atlas successfully. In this paper,we studied fully about the diffractometer and the data acquisition-procession,we also put forword our point of view about qualitative and quantitative analysis.In the first section,we mainly introduce the general develobment situation of phase analysis about powder diffraction and the important significance of this topic research. In the second section, we firstly introduce the theory about crystallology and formulate the Bragg ' s law of XRD, then we discribe the scattering manner about electron, atom, crystal cell, little perfect crystal and real crystal,and discuss theinteract about crystal and X-ray when it passing. We also introduce the theory of Rietveld whole pattern fitting in this section.In order to do whole pattern fitting, the high recgnition and high accuration about diffraction atlas is required. According to the basic structure of BDX90 diffractometer,in the third section,we offer the experiment technology and several matters attention about polycrystal diffractometer,including the preparation of sample and experiment conditions,the adjustment of light path, the election of experiment parameters, the previous proc&ssion of diffraction atlas,etc.The main method about qualitative analysis is PDF card index just now,so in the forth section,we introduce the theory of qualitative analysis firstly. There have letter index and number index in PDF card. The mainly work of PDF card index is comparing large quantity of d value. Its deficiency is that there have so many interferences, and the comparing is too complicated to do. Excluding these two index methods, we also use the complex index software which is offered by BDX90 system. This index uses the result of peak-seeking which arranging d value according to large and small. We can compare the d value pictures and 2theta pictures from experiment atlases and PDF cards. This index is so intuitional and accurate to distinguish the phases of sample. Then we give two examples about uniphase and mixed sample to introduce the complete procedure and flow chart in qualitative analysis.The relevant materials indicate that the traditional methods about quantitative analysis have many hard requirements in material elect ions, experiment and calculateion conditions. These methods include internal standard method, incremental method,external reference method, k value method, thermalinsulation method, and many other methods of improvement and modifiction.Rietveld whole pattern fitting is a new method combining computer technology and data acquisition-procession,which simplify the dada-processing and increase the accuracy of the quantitative analysis. So in the fifth section , we start from the basic theory of Rietveld whole pattern fitting,and get the polynomial fitting about diffraction peaks by using relevant software. To obtain the multiplicity factor and the atom coordinate,we utilize the symmetry of each crystal which w...