JPS63145953A - X-rays diffraction apparatus - Google Patents

Abstract

PURPOSE:To achieve a higher analysis efficiency with a higher accuracy of identification, by grouping diffraction lines in diffraction patterns for a sample in terms of half value width. CONSTITUTION:Component substances composing a sample provide diffraction patterns with sharp diffraction lines for those high in the crystallinity on one hand and with mild diffraction lines for those low in the crystallinity on the other depending on mutual relationship of the components and the process of forming sample substances. Therefore, when the diffraction lines in the diffraction patterns of the sample being actually measured are divided into a group A, i.e. wide pointed and a group B, i.e. sharp pointed as grouped according to the size of half value width. Both groups offer diffraction patterns corresponding to the components of respective samples at a high probability. Thus, when a searching work is performed for each combination of diffraction lines thus grouped, this can prevent erroneous identification otherwise caused by searching a diffraction pattern covering several substances and much waste time spent by repeating useless searching work in vain without finding desired substance.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an X-ray diffraction apparatus that performs qualitative analysis of a sample by X-ray diffraction.

Conventional techniques The use of X-ray diffraction for constant analysis is carried out in such a way that a sample is identified as one of the known substances from the X-ray diffraction pattern. For various crystalline materials, the spacing of lattice planes in various directions of the crystal and the intensity of diffraction lines due to the lattice planes have been investigated and published in tables such as JCPDS. Therefore, when actually performing sample identification, the diffraction angle and Xfj intensity of each diffraction line are read from the X-ray diffraction pattern, the lattice spacing is calculated from the diffraction angle, and the lattice spacing is calculated from the above J CPDS table along with the data of the diffraction line intensity. Find the appropriate crystal. However, approximately 40,000 types of substances are registered in the JCPDS, and it is not easy to find the relevant substance among them.

In particular, since the sample substance is generally not a pure substance (or a mixture of multiple types of substances), the X-ray diffraction pattern is a combination of the diffraction patterns of each component substance, and the actually measured diffraction pattern is described above. When comparing with table data such as JCPDS, in reality, several diffraction lines are selected in order of strength from the actually measured diffraction pattern, and the combinations of interplanar spacing and diffraction intensity corresponding to those diffraction lines are selected. Since a substance is searched from a table, the combination of diffraction lines selected often consists of diffraction lines of multiple components. If the corresponding substance is not found, the user will have to change the combination of diffraction lines and try the search again, trying to find the correct combination of diffraction lines. It takes a lot of effort and time to arrive at a combination of diffraction lines and obtain a correct identification result, and even if this process is automated with a computer, the number of operations required is large, making it difficult to determine the sample substance. (It takes time to obtain results, making it difficult to meet the demands for a large amount of analysis. Also, it is difficult to prevent the above-mentioned erroneous identifications, and it is difficult to rely on information obtained from various other analytical methods.) Without it, you won't be able to get reliable results.

C1 Problems to be Solved by the Invention The present invention aims to reduce the amount of calculations in automatic data retrieval, increase the accuracy of identification, and streamline analysis in sample identification using X-ray diffraction. .

21. Means for Solving Problems Conventionally, the 1°n information that can be used for analysis (identification) by X-ray diffraction is data on the lattice spacing and diffraction line intensity of various crystalline substances. In addition to these data, the present invention uses the half-width of the profile of the diffraction line in the diffraction pattern of the sample as a judgment material.The diffraction lines are divided into groups according to the half-width, and each group is identified by the diffraction pattern. I did it like that.

Each component material that makes up a sample has good crystallinity (some materials have good crystallinity, others have poor crystallinity), and sufficient crystal growth depends on the relationship between each component and the formation process of the sample material. There are cases where it is not done, and there are few cases where each component material grows to the same degree.For component materials with good crystallinity, a diffraction pattern with sharp diffraction lines can be obtained, indicating that the crystallinity In a substance with a low component, each diffraction line has a wide width.Therefore, when each diffraction line is divided into globes according to the size of its half-width in the actually measured diffraction pattern of a sample, each group corresponds to each component of the sample. The probability that it is a diffraction pattern is extremely high. Therefore, if you search for each combination of diffraction lines grouped in this way, you may search for diffraction patterns that span multiple substances and make incorrect identifications, or This prevents you from wasting a lot of time by repeating pointless search tasks when you cannot find something.

EXAMPLE FIG. 1 is an example of an actually measured X-ray diffraction pattern, and the horizontal axis represents the diffraction angle. In this example, the diffraction lines are a mixture of sharp lines and wide lines.

Therefore, these many diffraction lines are divided into a wide A group and a sharp B group. In other words, this sample appears to be composed of Substance A, which has low crystallinity, and Substance B, which has good crystallinity. Therefore, for group A, the relevant substance is searched from data files such as JCPDS, and for group B, the relevant substance is searched in the same manner. The search method is to take 3 to 5 diffraction lines from each group in order of strength, calculate the lattice spacing from the diffraction angle, and find materials that show the same data regarding the lattice plane and the diffraction line intensity. is retrieved from the built-in data file.

FIG. 2 shows a flowchart of the search program in the present invention. First, import the measurement data of the X-ray diffraction pattern for the sample (a), then calculate the lattice spacing d for each diffraction line and determine the diffraction line intensity rank I (b),
Furthermore, after calculating the half width of each diffraction line (c),
- Divide each diffraction line into groups according to the rank of the half-width (d), perform search operations starting from the first group (e), and display the search results (g) to complete the − analysis. If information on the element is obtained separately, the search range will be narrowed down considerably, so in such a case, (
After step d) (it goes without saying that this can be done before measuring the diffraction pattern), input the element information (g).
All you have to do is move forward, and then move forward with (e) and (e).

G. Effects According to the present invention, corresponding substances can be searched for combinations of diffraction lines of multiple substances constituting a sample by grouping based on the half-width of each diffraction line in the diffraction pattern of the sample, which has not been done in the past. Pointless search operations are avoided, the possibility of erroneously identifying a sample as a result of such pointless search operations is eliminated, the success rate of identification is improved, and crystallinity is increased in less crystalline substrates. This method is particularly effective in automatically searching for catalysts containing a mixture of components with good crystallinity, alloys containing precipitated components with good crystallinity, etc.

[Brief explanation of the drawing]

FIG. 1 is a graph of an example of an X-ray diffraction pattern, and FIG. 2 is a flowchart of a search operation in an embodiment of the present invention.

Claims (1)

[Claims] The measurement data of the X-ray diffraction pattern of the sample is imported, and the lattice spacing, diffraction line intensity, and half-width of the diffraction line profile are calculated for each diffraction line using the data, and the diffraction lines are divided into groups according to the size of the half-width. , an automatic program that searches for the corresponding substance from the built-in data files of lattice spacing and diffraction ray intensity of various materials based on the data of lattice spacing and diffraction ray intensity for multiple diffraction lines for each group. An X-ray diffraction device characterized by being equipped with a search device.