Читать книгу X-Ray Fluorescence in Biological Sciences - Группа авторов - Страница 26

X‐ray diffraction (XRD) is a well‐established technique used for the investigation of crystalline materials, which provides information on the structures, phases, texture analysis, average particle size, and crystalline properties of the materials. The combination of XRF and XRD may be uniquely useful because information about the chemical composition of the materials obtained through XRF analysis may be used for their phase analysis with XRD. With that information, phase analysis of the materials is more accurate and faster because many phases with similar structures can be reduced given knowledge of the chemical composition of the materials. A few instrumental concepts combining XRD and XRF are available and an analysis area less than 100 mm has been achieved. This combination can be integrated in one instrument and is useful in cement industries for the analysis and characterization of raw materials [8, 23, 26, 27].

XRD analysis is also position‐sensitive with the use of X‐ray optics in conventional instruments, such as use of capillary optics in combination with a monochromator, or synthetic multi‐layer optics [8]. These instruments can be attached to an EDX detector to measure fluorescence radiation and elemental analysis. The principles of both the techniques are different, however, XRD is also considered a complementary technique to XRF [28]. For example, in a crystalline sample, XRF is used to determine the total concentration of Ca and Fe. On the other hand, XRD provides information on the phases or compounds in crystalline materials such as oxide materials, rocks, and minerals. It also furnishes information about the content of Ca phases such as CaO, CaCO₃, Ca(OH)₂, or the contents of Fe phases such as FeO, Fe₂O₃, Fe₃O₄, or Fe₃C [28]. Therefore, combination of both the techniques will provide better and more complete characterization of crystalline samples. So, the integration of innovative XRD systems allows both techniques to be included in the same instrument, which would bring significant advantages to the users such as:

 cost effectiveness,

 only one sample introduction,

 single user interface for both XRD and XRF,

 both phase and elemental information in single analysis,

 space minimization, and

 reduction of water cooling systems.

Combination of XRF and XRD techniques is useful for numerous applications, which includes the analysis of element in all kinds of materials, free lime in clinker and slags, clinker phase, measurements of Fe²⁺ in sinters, iron phases in direct reduced iron processes, phases related to electrolysis of Al, thin films, etc. [28].