Powder X-ray diffraction measurement method

Abstract

To provide a technique of conducting an accurate measurement of an X-ray diffraction even when the amount of a powdery sample is small.SOLUTION: A powdery sample holder includes: a tabular holder body unit having a through-hole extending in a thickness direction; a movable mounted unit fitted to be movable in the through-hole in a thickness direction, and recessed from one surface of the holder body unit; and a sample filling unit for filling the powdery sample formed by the recession of the movable mounted unit from the holder body unit. Movement of the movable mounted part can change the capacity of the sample filling unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a powder sample holder and a powder X-ray diffraction measurement method. [Background technology]

[0002] X-ray diffraction measurements of powder samples are sometimes performed to analyze their crystalline structure. When a powder sample is pressed or compacted, it can become oriented, causing the diffraction peaks derived from the powder sample to be detected with different peak intensity ratios than the original peaks. For this reason, powder samples are generally loaded into a powder sample holder to prevent orientation before X-ray diffraction measurements.

[0003] The powder sample holder is a flat plate made of glass or aluminum, with a circular or rectangular groove or hole formed in the center for filling with the powder sample (see, for example, Patent Document 1). This powder sample holder has a reference surface that coincides with the measurement surface, and this surface is machined with higher precision than the other surfaces.

[0004] In X-ray diffraction measurements of powder samples, pseudo-focusing optics is sometimes used to achieve higher measurement accuracy. In pseudo-focusing, a sealed tube or rotating anode X-ray tube is used as the X-ray source, and the X-ray tube, the sample surface of the powder sample filled in a powder sample holder, and a detector that detects X-rays diffracted by the sample surface are arranged on an imaginary circumference called the focusing circle. In this case, it is important to position the sample so that its sample surface is accurately positioned on the focusing circle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-066652 Summary of the Invention [Problem to be solved by the invention]

[0006] Powder sample holders are machined as a single unit, with grooves, holes, and other sample filling sections having a predetermined diameter and depth. There are several types of powder sample holders, each with a different diameter and depth. Therefore, it is necessary to select a powder sample holder large enough to fill the sample filling section with the sample, depending on the amount of sample.

[0007] However, depending on the sample, it may not be possible to secure a sufficient amount of sample to fill the sample packing section, and the sample packing section may not be completely filled with sample. In this case, the diffraction pattern obtained may differ from that obtained when the sample packing section is properly filled with sample, and accurate information on the crystal structure of the sample may not be obtained.

[0008] The present invention has been made in view of the above-mentioned problems, and has an object to provide a technique for performing X-ray diffraction measurement with high accuracy even on a small amount of powder sample. [Means for solving the problem]

[0009] A first aspect of the present invention is a flat plate-shaped holder main body portion having a through hole penetrating in a thickness direction; a movable placement portion that is fitted inside the through hole so as to be movable in the thickness direction and is disposed in a recessed state from one surface of the holder main body portion; a sample filling section for filling a powder sample, the sample filling section being formed by the movable placement section being recessed from the holder body section; The powder sample holder is configured so that the volume of the sample filling section can be changed by moving the movable mounting section.

[0010] A second aspect of the present invention is a method for producing a composition comprising the steps of: an inner peripheral surface of the through hole and an outer peripheral surface of the movable mounting portion both have threads; The holder body and the movable mounting portion are threadedly engaged with each other.

[0011] A third aspect of the present invention is the first or second aspect, Used in X-ray diffraction measurement equipment.

[0012] A fourth aspect of the present invention is A powder X-ray diffraction measurement method for measuring X-ray diffraction of a powder sample, comprising: a step of preparing a powder sample holder comprising: a flat holder body having a through hole penetrating in the thickness direction; a movable mounting part fitted inside the through hole so as to be movable in the thickness direction and disposed in a recessed state from one side of the holder body; and a sample filling part for filling a powder sample, which is formed by the movable mounting part being recessed from the holder body, and wherein the capacity of the sample filling part is changeable by moving the movable mounting part; filling the powder sample into the sample filling portion of the powder sample holder; moving the movable mounting portion so that the powder sample rises from one surface of the holder body; and a step of leveling the powder sample so that the surface of the powder sample is flush with one surface of the holder main body. [Effects of the Invention]

[0013] According to the present invention, X-ray diffraction measurement can be performed with high accuracy even for a small amount of powder sample. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a powder sample holder according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing a schematic configuration of a powder sample holder according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] When performing X-ray diffraction measurements on a small amount of powder sample, the following problems arise.

[0016] First, because the bottom of the sample filling section is exposed, when X-ray diffraction measurements are performed, diffraction peaks originating from the material of the powder sample holder (e.g., glass or aluminum) are detected, which can make it difficult to accurately detect diffraction peaks originating from the sample.

[0017] Furthermore, if a small amount of powder sample is spread across the sample packing section so that the bottom of the section is not exposed, it will be impossible to align the height of the sample surface with the reference surface of the powder sample holder, which will result in an error in the diffraction angle 2θ, which is the position of the detected diffraction peak.

[0018] Another approach to X-ray diffraction measurement of small samples is to collect the powder sample in the center of the sample packing section and align the height of the sample surface with the reference plane of the powder sample holder. However, in this case, the incident X-rays are irradiated not only onto the surface (sample surface) of the collected powder sample, but also onto the side of the collected powder sample, which can cause a discrepancy in the detection angles of the X-rays diffracted from the sample surface and side. This can result in the width of the diffraction peaks broadening, or, for example, a peak that should have been a single peak being detected as multiple diffraction peaks.

[0019] On the other hand, when the sample amount is small, it is possible to avoid using a powder sample holder and use a non-reflective sample plate made of Si or α-SiO2, or to fill the sample into a glass capillary and measure it using the transmission method. However, these methods have the following problems:

[0020] Non-reflective sample plates have the advantage that no diffracted rays are observed even when irradiated with X-rays, because there are no crystal lattice planes parallel to the sample surface. However, non-reflective sample plates have a high background intensity at a diffraction angle 2θ of around 20°. In this case, if a diffraction peak from the sample is detected around that angle, the diffraction peak will be buried in the background and will not be detected, which will affect qualitative analysis.

[0021] Furthermore, measurements using glass capillaries require the transmission method, but the broad diffraction peaks originating from the glass are detected at low angles, making it difficult to detect low-angle diffraction peaks. Also, depending on the type of X-ray source used, the X-rays may be absorbed by the sample, preventing them from penetrating the sample completely, weakening the detected diffraction peaks and affecting qualitative analysis.

[0022] In this way, when the sample amount is small and the sample filling section cannot be filled with powdered sample, measurement errors become large, and qualitative analysis and quantitative analysis, which are evaluated from the position and intensity of diffraction peaks, as well as crystal structure analysis, may not be performed accurately.

[0023] Based on the above, the present inventors investigated a method for performing accurate X-ray diffraction measurements using a powder sample holder, regardless of the sample amount. Commonly used powder sample holders have a sample filling section formed as a groove or hole, making it impossible to adjust the volume of the sample filling section. Based on this, the present inventors came up with the idea of ​​configuring a powder sample holder so that the volume of the sample filling section can be adjusted. Further investigation into this configuration led to the discovery that a powder sample holder can be configured to include a holder main body having a through-hole and a movable mounting section that movably fits into the through-hole and is recessed into the holder main body, with the space formed by the step between the holder main body and the movable mounting section as the sample filling section, and the volume of the sample filling section can be adjusted by moving the movable mounting section. The present invention was made based on the above findings.

[0024] <One embodiment of the present invention> A powder sample holder according to one embodiment of the present invention will now be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing a schematic configuration of a powder sample holder according to one embodiment of the present invention.

[0025] (powder sample holder) As shown in Figure 1, the powder sample holder 1 of this embodiment is a holder for introducing a powder sample into an X-ray diffraction measurement device, and is composed of a holder main body 10, a movable mounting portion 12, and a sample filling portion 13.

[0026] The holder main body 10 constitutes the main body of the powder sample holder 1 and is attached to the X-ray diffraction measurement device. The holder main body 10 is flat and has a through-hole 11 that penetrates in the thickness direction from one surface 10a to the other surface 10b, and is configured so that the movable mounting portion 12 can be inserted and fitted into it. One surface 10a of the holder main body 10 (the upper surface in FIG. 1) is a reference surface that serves as a reference for the measurement surface when the powder sample is filled into the sample filling portion 13.

[0027] The shape and size of the holder body 10 are not particularly limited as long as it can be introduced into an X-ray diffraction measurement device. For example, the shape may be ring-shaped. The size may be an outer diameter of 30 mm to 55 mm and a thickness of 10 mm to 20 mm.

[0028] The material for forming the holder body 10 is not particularly limited as long as it does not interfere with the diffraction pattern of the powder sample during X-ray diffraction measurement. From the viewpoint of workability of the holder body 10, resin or metal is preferred.

[0029] The through hole 11 is formed so as to penetrate through the holder main body 10 in the thickness direction. There are no particular limitations on the type of through hole 11 as long as it can fit the movable mounting part 12, which will be described later. The diameter and shape of the through hole 11 are also determined according to the diameter and shape of the movable mounting part 12. The position of the through hole 11 is not particularly limited, but it is preferable that it be in the center of the holder main body 10.

[0030] The other surface 10b (the lower surface in FIG. 1) of the through hole 11 serves as an insertion opening for inserting the movable mounting part 12. From the viewpoint of facilitating insertion of the movable mounting part 12 into the through hole 11, it is preferable that the edge of the through hole 11 on the other surface 10b side be chamfered.

[0031] The movable mounting portion 12 is inserted into the through-hole 11 of the holder main body 10 and fitted therein so as to be movable within the through-hole 11 in the thickness direction of the holder main body 10. The movable mounting portion 12 is disposed in a recessed state from the holder main body 10. The thickness of the movable mounting portion 12 is not particularly limited as long as it is a thickness that allows the movable mounting portion 12 to be accommodated entirely within the through-hole 11 without protruding from the through-hole 11. For example, it may be 5 mm to 10 mm. The diameter of the movable mounting portion 12 may be appropriately set according to the diameter of the through-hole 11, and may be large enough to be fitted into the through-hole 11 and to be movable within the through-hole 11. For example, it may be 5 mm to 10 mm.

[0032] The material for forming the movable mounting part 12 can be the same as that for the holder main body part 10. The material for forming the movable mounting part 12 can be the same as that for the holder main body part 10, or a different material can be used.

[0033] The sample filling section 13 is a stepped region formed by the movable mounting section 12 being recessed from the holder main body 10. In other words, the sample filling section 13 is a space surrounded by the inner circumferential surface of the through-hole 11 and the upper surface of the movable mounting section 12. The thickness of the sample filling section 13 can be adjusted by raising and lowering the movable mounting section 12.

[0034] For example, if the amount of powder sample is large, it is advisable to position the movable mounting portion 12 relatively deep from one surface 10a of the holder main body 10, form the sample filling portion 13 relatively deep, and increase its capacity. On the other hand, if the amount of powder sample is small, it is advisable to position the movable mounting portion 12 relatively shallow, form the sample filling portion 13 shallow, and reduce its capacity. In other words, it is advisable to change the position of the movable mounting portion 12 and change the depth and capacity of the sample filling portion 13 depending on the amount of powder sample.

[0035] The diameter and depth of the sample filling section 13 are not particularly limited and can be changed appropriately depending on the amount of powder sample filled. The surface of the powder sample filled in the sample filling section 13 becomes the measurement surface irradiated with X-rays, so the diameter of the sample filling section 13 should be larger than the width of the irradiated X-rays. The diameter of the sample filling section 13 should be, for example, 10 mm to 25 mm. Since the width of the irradiated X-rays is 8 mm to 22 mm, by setting the width of the sample filling section 13 within the above range, the X-rays can be irradiated without diverting from the measurement surface. Furthermore, the depth of the sample filling section 13 should be changed appropriately depending on the amount of powder sample and the diameter of the sample filling section 13. When the amount of powder sample is small, it is preferable to position the movable mounting section 12 shallowly from one surface 10a of the holder main body 10 and make the sample filling section 13 thin so that the powder sample can be filled into the sample filling section 13. Specifically, the depth of the sample filling section 13 is preferably at least 0.1 mm or more from the viewpoint of obtaining the diffraction peak derived from the powder sample with high accuracy. The upper limit value may be, for example, 0.5 mm or less. The volume of the sample filling section 13 may be, for example, 8 mm 3 ~240mm 3 It is preferable to set the diameter of the through-hole 11 and the depth of the sample filling portion 13 so that the above formula is satisfied.

[0036] The method for fixing the movable mounting portion 12 to the holder main body 10 is not particularly limited, and any known method can be used. From the viewpoint of easily raising and lowering and fixing the movable mounting portion 12, it is preferable to fix the holder main body 10 and the movable mounting portion 12 by thread engagement. Specifically, it is preferable to form a thread on the inner circumferential surface of the through-hole 11, giving the holder main body 10 a female thread structure, and form a thread on the outer circumferential surface of the movable mounting portion 12, giving the movable mounting portion 12 a male thread structure. With this structure, the movable mounting portion 12 can be raised and lowered within the through-hole 11 by rotating it, and can be fixed by stopping the rotation. Furthermore, the movement of the movable mounting portion 12 can be finely adjusted, allowing fine adjustment of the depth of the sample filling portion 13.

[0037] When the movable mounting section 12 is threadedly fitted to the holder body 10, it is preferable to provide a groove 14 on the surface of the movable mounting section 12 opposite the sample filling section 13. For example, by inserting a tool such as a screwdriver into the groove 14 and rotating it, the movable mounting section 12 can be rotated and moved inside the through-hole 11. In other words, the movable mounting section 12 can be moved more easily. Furthermore, by rotating the tool, the depth of the sample filling section 13 can be finely adjusted, such as by finely adjusting the position of the movable mounting section 12.

[0038] (Powder X-ray diffraction measurement) Next, powder X-ray diffraction measurement using the above-mentioned powder sample holder 1 will be described.

[0039] First, a powder sample and the above-described powder sample holder 1 are prepared.

[0040] Next, the powder sample is filled into the sample filling section 13 of the powder sample holder 1. At this time, the powder sample is filled so that it rises from one surface 10a of the holder main body 10. If the amount of powder sample is small and it is not possible to fill the sample filling section 13 sufficiently, it is advisable to move the movable mounting section 12 toward the one surface 10a to make the sample filling section 13 shallower so that the powder sample rises. Alternatively, the movable mounting section 12 may be moved in advance so that the sample filling section 13 is shallower, and then the powder sample may be filled.

[0041] The powder sample was packed in 8 mm 3 ~240mm 3 In this embodiment, by making the sample filling section 13 shallow, the powder sample can be filled to a depth of 8 mm. 3 Even in the case of a small amount of powder sample, the powder sample can be filled into the sample filling section 13.

[0042] Next, the powder sample that has risen from the sample filling section 13 is scraped off. For example, a glass plate is prepared as a flat jig, and the flat surface of the glass plate is brought into surface contact with one surface 10a of the powder sample holder 1. Then, while maintaining both flat surfaces parallel to each other, the glass plate is moved to scrape off the raised portion of the loaded powder sample. This results in a measurement sample. In the measurement sample, the surface of the powder sample is at the same height as one surface 10a of the holder main body 10 (the reference surface for measurement), which becomes the measurement surface.

[0043] Next, the measurement sample is attached to the sample attachment section of the X-ray diffraction measurement device. Then, appropriate X-ray diffraction measurement conditions are selected according to the components contained in the powder sample, and X-ray diffraction measurement is performed. The scanning conditions can be a continuous mode, in which measurements are taken while the axis is driven at a constant speed, or a step mode, in which measurements are taken while the axis is moved at a constant angle and kept stationary.

[0044] In this way, a diffraction pattern derived from the powder sample is obtained.

[0045] <Effects of this embodiment> According to this embodiment, one or more of the following effects are achieved.

[0046] In the powder sample holder 1 of this embodiment, the movable mounting portion 12 is movably fitted into the through-hole 11 of the holder body 10 and is recessed from the holder body 10, thereby forming a sample filling portion 13 in the area defined by the step between the holder body 10 and the movable mounting portion 12. The powder sample holder 1 allows the depth and volume of the sample filling portion 13 to be adjusted by raising and lowering the movable mounting portion 12. Therefore, even when the amount of powder sample is small, for example, the measurement surface of the powder sample can be adjusted to the same height as the reference surface by moving the movable mounting portion 12 so that the sample filling portion 13 is shallower. Thus, the powder sample holder 1 adjusts the depth and volume of the sample filling portion 13 according to the amount of powder sample, thereby aligning the measurement surface of the powder sample with the reference surface of the powder sample holder 1. This allows the powder sample to be filled regardless of its amount, enabling X-ray analysis.

[0047] In addition, it is preferable that the powder sample holder 1 has a screw thread on the inner peripheral surface of the through-hole 11 and the outer peripheral surface of the movable mounting portion 12, and these are threadedly engaged. This threaded engagement allows the movable mounting portion 12 to be moved inside the through-hole 11 by rotating it, and can be fixed by stopping the rotation. This makes it easy to adjust the depth of the sample filling portion 13.

[0048] <Other embodiments> Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the present invention.

[0049] In the above-described embodiment, when the movable mounting portion 12 is raised and lowered after being filled with a powder sample, the powder sample may get in between the holder main body portion 10 and the movable mounting portion 12, causing the powder sample to leak from the powder sample holder 1 and contaminating the X-ray diffraction measurement device.

[0050] In this regard, as shown in FIG. 2, a sample leakage prevention plate 15 may be provided on the surface of the holder main body 10 opposite to the surface on which the sample loading section 13 is formed. The sample leakage prevention plate 15 is attached to a hole serving as an attachment section that communicates with the through-hole 11, and is provided so as to seal the lower side of the movable mounting section 12. The sample leakage prevention plate 15 can be attached to the holder main body 10, for example, by providing threads on the outer peripheral surface of the sample leakage prevention plate 15 and the inner peripheral surface of the attachment section, and then fastening them by screwing them together. In this case, a groove 14 may be provided on the bottom surface of the sample leakage prevention plate 15 so that it can be rotated and fastened with a tool such as a screwdriver.

[0051] From the viewpoint of sealing the through-holes 11, the size of the sample leakage prevention plate 15 is preferably larger than that of the through-holes 11. For example, if the diameter of the holder main body 10 is 30 mm to 55 mm and the diameter of the through-holes 11 is 10 mm to 25 mm, the size of the sample leakage prevention plate 15 should be 20 mm to 35 mm. The thickness of the sample leakage prevention plate 15 is not particularly limited, but should be, for example, 3 mm to 4 mm. The mounting portion should be shaped and sized so that the sample leakage prevention plate 15 can be fitted into it.

[0052] When preparing a measurement sample using the powder sample holder 1 having the structure shown in Figure 2, first, the movable mounting portion 12 is fitted into the holder main body 10, and the powder sample is filled into the sample filling portion 13. Next, the movable mounting portion 12 is moved and fixed so that the powder sample protrudes from the holder main body 10, and then leveled off with a glass plate or the like. After that, a sample leakage prevention plate 15 is attached to the mounting portion, and the bottom side of the movable mounting portion 12 is sealed. This prevents the powder sample from leaking from the sample filling portion 13 and contaminating the X-ray diffraction measurement device.

[0053] In the above embodiment, the movable mounting portion 12 is fitted into the holder main body 10, the powder sample is filled into the sample filling portion 13, and then the movable mounting portion 12 is moved. However, the present invention is not limited to this. For example, a plate-like member is prepared, and the holder main body 10 is placed so that one surface 10a, which serves as the reference surface, contacts the plate-like member and closes the through-hole 11. Next, the powder sample is filled into the through-hole 11 from the other surface 10b. Next, the movable mounting portion 12 is fitted into the through-hole 11 and moved so that it comes into contact with the filled powder sample. Then, the powder sample holder 1 is inverted, the plate-like member is removed, and the powder sample is scraped off. This allows the sample to be used for X-ray diffraction measurement.

[0054] Furthermore, in the above-described embodiment, the movable mounting portion 12 is fixed to the holder main body 10 by screw-fitting. However, the present invention is not limited to this. For example, the movable mounting portion 12 may be fixed by providing a threaded hole extending to the through-hole 11 on the outer circumferential surface of the holder main body 10 and inserting a screw into the threaded hole and pressing it against the movable mounting portion 12. For example, the inner circumferential surface of the through-hole 11 may be provided with a protrusion made of an elastic material, and the protrusion may be pressed against the movable mounting portion 12 inserted into the through-hole 11 to fix the movable mounting portion 12. Alternatively, the movable mounting portion 12 may be provided with a protrusion made of an elastic material on the outer circumferential surface of the movable mounting portion 12, and the protrusion may be pressed against the inner circumferential surface of the through-hole 11 to fix the movable mounting portion 12. For example, the movable mounting portion 12 may be made of an elastic material, and the movable mounting portion 12 may be fixed by fitting into the through-hole 11. [Explanation of symbols]

[0055] 1 Powder sample holder 10 Holder body 10a One side (reference surface) 10b The other side 11 Through hole 12 Movable mounting section 13 Sample filling section 14 groove 15. Plate for preventing sample leakage

Claims

1. A powder X-ray diffraction measurement method for measuring X-ray diffraction of a powder sample, comprising: a step of preparing a powder sample holder comprising: a flat holder body having a through hole penetrating in the thickness direction; a movable mounting part fitted inside the through hole so as to be movable in the thickness direction and disposed in a recessed state from one side of the holder body; and a sample filling part for filling a powder sample, which is formed by the movable mounting part being recessed from the holder body, and wherein the capacity of the sample filling part can be changed by moving the movable mounting part; filling the powder sample into the sample filling portion of the powder sample holder; moving the movable mounting portion so that the powder sample rises from one surface of the holder body; and a step of leveling the powder sample so that the surface of the powder sample is flush with one surface of the holder main body.

2. The inner peripheral surface of the through hole and the outer peripheral surface of the movable mounting portion both have threads, The holder body and the movable mounting portion are threadedly engaged with each other. The powder X-ray diffraction measurement method according to claim 1 .

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