JPH063251A - Method for analyzing porosity in porous body - Google Patents

Abstract

PURPOSE:To separate a material other than a target component even when present in a sample, and perform the precise analysis for porosity, pore distribution, the occupying ratio in a porous body pore of the material present in the porous body pore, and the grain size and grain outer circumference in the porous body or a powder forming its starting material. CONSTITUTION:A determined section of a porous body is subjected to two-dimensional matrix processing, component analysis, and binary processing, and one or two or more components are combined to each other, whereby porosity, pore distribution, the occupying ratio in the porous body pore of a material present in the porous body pore, and the grain size and grain outer circumference in the porous body or a powder forming its starting material are analyzed. Thus, the analysis related to a target material in the porous body can be precisely performed, and the measurement error by the contamination of impurities can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analysis method for a porous body, and more particularly to a porosity analysis method for a porous body, a pore distribution analysis method, and a porous body for a substance existing in the pores of the porous body. The present invention relates to a method for analyzing an occupation rate in pores, and a method for analyzing a particle diameter and a particle outer circumference of a porous body or powder as a raw material thereof.

[0002]

2. Description of the Related Art Conventionally, a gas adsorption method or a substitution method has been used to measure the porosity of a porous body. In the gas adsorption method, it is generally considered that all capillaries condense at saturated vapor pressure, so the amount of adsorption at that time is converted into the volume of liquid at that temperature to obtain the pore volume and the apparent volume of the sample. The porosity is obtained by dividing by the volume. The replacement method is water,
The sample is boiled in a liquid such as benzene, cyclohexene, n-hexane, methanol, ethanol, carbon tetrachloride, etc., cooled and dried to measure the weight increase, and the pore volume is obtained and divided by the apparent volume of the sample. To determine the porosity. The occupancy rate in the pores of the substance in the porous body is obtained by measuring the porosity before and after removing the occupying substance by applying this method, and dividing the difference by the porosity after the removal. It was In addition, the capillary condensation method is a method that uses adsorption isotherms and cannot be measured by the mercury injection method.
It was used for measurement in the range of 10 to 300Å.

The measurement of the pore distribution has been carried out by the mercury intrusion method or the capillary condensation method. In the mercury injection method, since mercury does not leak into the pore walls, it does not enter the pores, but when pressure is applied from the outside, mercury begins to enter the pores, and this external pressure and the force that pushes mercury out of the pores are They are in equilibrium with each other.
Utilizing this, the pore distribution was determined from the relationship between the external pressure and the pore diameter.

Regarding the above-mentioned conventional measuring methods,
Keitomi Cho, "Catalyst Chemistry", pp. 461-467, Tokyo Kagaku Dojin (1981).

[0005]

In the gas adsorption method and the substitution method as described above, if the porous base material contains a foreign substance,
Since this cannot be completely separated, it was not possible to accurately determine the porosity of the porous body and the occupation rate of the substance in the porous body in the pores. Further, there is a problem that it is difficult to completely replace the air with the liquid by boiling the sample or boiling the sample.

Further, in the pore distribution analysis method of the porous body using the mercury injection method or the capillary condensation method, if there is a foreign substance in the porous body base material, the porosity and the substance in the porous body are finely divided. As in the case of the occupancy analysis in pores, foreign substances cannot be separated, so that accurate pore distribution analysis cannot be performed. Further, in the mercury intrusion method, if there is a relatively thick pore behind a relatively thin pore, there is a problem that this is analyzed as the diameter of the thin pore.

Next, regarding the analysis of the particle diameter and the particle periphery of the porous body and the powder as the raw material thereof, the liquid phase sedimentation method and the light transmission method were used. If the powder used as the raw material had a foreign substance, it could not be separated and analyzed. The present invention has been made in view of such problems, and an object thereof is a method of analyzing porosity and occupancy by a gas adsorption method or a substitution method,
Or in eliminating the above problems associated with the pore distribution measurement by mercury porosimetry, even if there is a substance other than the target component in the porous body, porosity, pore distribution,
The occupancy rate of the substances present in the pores of the porous body in the pores of the porous body, and the particle diameter and the outer circumference of the powder of the porous body or the raw material thereof can be analyzed without any measurement error. It is to provide an analysis method of porosity and the like in a body.

[0008]

In order to achieve the above object, the method for analyzing the porosity of the porous body of the present invention is a method in which a predetermined cross section of the porous body is two-dimensionally matrixed to form a porous body matrix. Materials and substances other than the porous material base material are subjected to component analysis to be binarized, and the porosity, pore distribution, and porous material pores can be calculated from one component or a combination of two or more components. The present invention is characterized in that the occupancy rate of existing substances in the pores of the porous body and the particle diameter and the outer circumference of the particles in the porous body and the powder used as the raw material thereof are analyzed.

[0009]

With the method for analyzing the porosity of the porous body of the present application having the above-mentioned characteristics, even if there is a substance other than the target component in the porous body, it is excluded from the matrix subjected to the component analysis. By analyzing, the porosity, the pore distribution, the occupancy rate of the substance existing in the pores of the porous body in the pores of the porous body, and the particle size and the particle in the powder as the porous body or the raw material thereof. Peripheral analysis is possible.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

[0011]

[Example 1] A porous nickel body was prepared by embedding a resin into a size (about 2 cm in diameter) that could be observed with a scanning electron microscope (hereinafter referred to as "SEM"), and the cross section of the porous body was polished with polishing paper / wrapping tape. The surface was polished. For surface polishing, a method that facilitates polishing may be used depending on the sample. After that, the sample is carbon-deposited and observed by SEM. At the same time, an energy dispersive X-ray analyzer (hereinafter referred to as EDX
Surface analysis was performed on Ni, which is the main component of the porous body. At this time, the acceleration voltage was 20 keV and the magnification was 200 times. For data acquisition, the SEM and EDX screens were divided into a matrix of 256 × 200, and the data was stored for each matrix. At this time, it is necessary to change the magnification and the number of matrices depending on the pore diameter of the sample, the particle diameter of the matrix, and the like. In this example, the ratio of the length of one side of the matrix to the pore diameter of the sample was set to 1: 5. Then, this Ni-EDX image was binarized to judge the presence or absence of nickel for each matrix, and the porosity was calculated from the ratio of the number of matrices with nickel in the total matrix. FIG. 1 shows a binarized image of this nickel. In the figure,
The spots (red in the actual experiment, the color in the parentheses below represents the color in the actual experiment) are Ni-EDX2.
It is a quantized image 1, and white (black) parts are porous body pores 2.
Is.

Comparative Example 1 With respect to the same sample as in Example 1, a comparative value obtained by the substitution method shown in the prior art was obtained. First, the sample was cut into a rectangle, the vertical, horizontal and thickness were accurately measured, and the apparent volume of the sample was measured, dried at 200 ° C. for 2 hours, cooled in a desiccator, and the weight of the sample was measured later.

This sample was immersed in pure water, degassed with a vacuum desiccator for 10 minutes, returned to the atmosphere, weighed, the pore volume of the sample was determined from the difference between the two weights, and the porosity was determined from the apparent volume. It was The results are compared with those of Example 1 and shown in Table 1. As can be seen from Table 1, Example 1
Has a larger porosity than that of Comparative Example 1. This is because in Comparative Example 1, the impurities existing in the pores of the nickel-based porous body were also measured as the porous body base material, and the pores were accordingly measured to be small. On the other hand, in Example 1, since the nickel-based porous material base material and the other materials can be accurately distinguished by color, there is no measurement error.

[0014]

[Table 1]

[0015]

[Example 2] A nickel-based porous body having a thickness of 0.7 t was 50 mm x 50
After cutting into mm and drying, weigh it, add an arbitrary amount of mixed carbonate containing potassium carbonate to each, 650 ℃,
The mixture was heated in a hydrogen atmosphere for 1 hour to impregnate the porous body with the mixed carbonate. After cooling, each sample was weighed to confirm the impregnated amount. Then, under the same conditions as in Example 1, the component Ni of the porous body and the component K of the mixed carbonate were used.
The surface analysis of EDX was carried out for each of them, and each was binarized. The porosity of the porous body from the ratio of Ni in the matrix: seeking XE, further porous body the pores of the mixed carbonate impregnation from the ratio of Ni and K in the matrix: seeking X _'E, the first equation Occupancy of mixed carbonate in the pores of a more porous body:
I asked for Y _E.

Y _E = (X _E −X ′ _E ) / X _E (Formula 1) Comparative Example 2 Each sample of Example 2 was cut into 50 mm × 20 mm, and the replacement method used in Comparative Example 1 was used. porous body porosity of mixed carbonates during the impregnation of: was determined X _'T. Next, these samples 30 vol% extraction carbonate immersed in aqueous acetic acid was washed away after 20 minutes, washed with pure water, by the same technique and dried, the porosity of the porous bodies: seeking X _T, the Two
The mixed carbonate content in the pores of the porous body: Y _T was determined from the formula.

Y _T = (X _T −X ′ _T ) / X _T .. Second Formula This Y _T and Y _E obtained in the second embodiment are compared and FIG.
Shown in. In FIG. 2, the vertical axis represents the mixed carbonate content in the pores, and the horizontal axis represents the mixed carbonate impregnation amount. In the figure, 3 and 4 are the second embodiment.
3 is a curve obtained from Comparative Example 2. According to this example, it is understood that linearity can be obtained in a wide range when obtaining the occupation ratio of the occupying substance in the pores of the porous body in the pores.

[0018]

Example 3 A nickel-based porous body was impregnated with a mixed carbonate containing potassium carbonate, and at a temperature of 650 ° C., 66% hydrogen gas, 17% carbon dioxide gas, and 17% water were mixed with carbon dioxide gas. The occupancy of the mixed carbonate in the pores of the nickel porous body was determined under the same conditions as in Example 2 for the sample that was supplied alternately at 100% and held for 1600 h. Further, since iron may occupy the inside of the pores as an impurity, Fe was analyzed in addition to Ni and K, and was binarized by the same method, and was not performed when Fe was corrected. The value was calculated about the time. FIG. 3 shows a binarized image of EDX obtained by this. In the figure, the portion indicated by the spots (red) is the Ni-EDX binarized image 1, which is white (black).
Is the porous body pores 2, the black (yellow) portion is the K-EDX binarized image 5, and the shaded portion (blue) is the Fe-EDX binarized image 6.

Comparative Example 3 With respect to the same sample as in Example 3, the occupancy rate of the mixed carbonate in the pores of the porous body was determined by the above equation 2 using the same substitution method as in Comparative Example 2. Table 2 shows a comparison with Example 3. As is clear from Table 2, mixed carbonates between Example 3 and Comparative Example 3 and between both measurement results of Example 3 depend on whether Fe, that is, the hatched portion in FIG. 3 is taken into consideration. It can be seen that the occupancy values of are different.

[0020]

[Table 2]

[0021]

Example 4 The sample used in Example 2 was EDX
Then, surface analysis was performed for Ni and K at an observation magnification of 1000 times, and these images were binarized for each matrix, and each component was set to 1 when it was present and 0 when it was not present. At this time, in a certain matrix, 1) oneself is 2) there is at least one 0 in eight matrices vertically and horizontally and obliquely 1) matrix satisfying both 2) I know the length. FIG. 4 is a model diagram in which this is imaged. The matrix that satisfies both of the conditions mentioned here is the matrix in the shaded area. this,
Corresponding to the image of Ni, the peripheral length of the nickel base material, the base material diameter, etc. were analyzed.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. For example, as a component analysis, a wavelength dispersive X-ray analyzer (WD
It is also possible to employ characteristic X-ray analysis by X), identification analysis by X-ray diffraction, and infrared absorption spectrum analysis (IR).

As the binarization processing method, a standard sample method in which a standard sample is measured in advance and then the background is processed by calculation, a dummy substance is put in the sample pores and measured simultaneously with the sample. It is also possible to use a dummy sample method that is performed by processing the background later, or a dummy peak method that is performed by setting the background peak for the peak of the target component at the time of measurement and then processing the background.

Furthermore, in matrix formation, the smaller of the sample pore size and the base material particle size,
The ratio of the length of one side of one matrix is 1/1 to 1 / 10,000
It is also possible to set within the range.

[0025]

As is apparent from the above description, according to the present invention, a cross section of a porous body is formed into a two-dimensional matrix, and component analysis is performed for each matrix and binarized to obtain one component. Or, from the combination of two or more components, the porosity, the pore distribution, the occupation rate of the substance existing in the pores of the porous body in the pores of the porous body, and the powder of the porous body or the raw material thereof It was possible to analyze the particle diameter and the particle circumference, and it was possible to eliminate those measurement errors due to the inclusion of impurities.

[Brief description of drawings]

FIG. 1 is an EDX binarized image of Ni performed to determine a porosity in Example 1.

FIG. 2 is a diagram showing the relationship between the measured values of mixed carbonate occupancy in pores and the impregnated amount of mixed carbonate obtained in Example 2 and Comparative Example 2.

FIG. 3 is an EDX binarized image of Ni, K and Fe, which was carried out in Example 3 to determine the porosity and the occupation ratio of the substance existing in the pores of the porous body in the pores of the porous body.

FIG. 4 is an image model for analyzing the length of the nickel base material, the diameter of the base material, etc. performed in Example 4.

[Explanation of symbols]

1 ... Ni-EDX binarized image, 2 ... Porous body pores, 3 ... Value obtained from Example 2, 4 ... Value obtained from Comparative Example 2,
5 ... K-EDX binarized image, 6 ... Fi-EDX binarized image

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Yoshida 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory

Claims (11)

[Claims] 1. A predetermined cross section of a porous body is two-dimensionally matrixed, and the porous body base material and a substance other than the porous body base material are subjected to component analysis to be binarized to obtain the porous body. A porosity analysis method for a porous body, comprising: determining a porosity of a porous body from a component of only a base material or from a combination of at least two components including the porous body base material. 2. A predetermined cross section of a porous body is two-dimensionally matrixed, and the porous body base material and a substance other than the porous body base material are subjected to component analysis for binarization to obtain the porous body. The occupancy ratio of the substance existing in the pores of the porous body in the pores is obtained from the components of the matrix alone or a combination of at least two components including the porous body matrix. Occupancy Analysis Method for Porous Substances in Porous Materials. 3. A predetermined cross section of a porous body is formed into a two-dimensional matrix, and the porous body base material and a substance other than the porous body base material are subjected to component analysis to be binarized to obtain the porous body. Porous body pore distribution analysis method, characterized in that the pore distribution of a porous body is obtained from a component of only the base material or a combination of at least two components containing the porous body base material. . 4. A particle size or a particle for each one component or a combination of two or more components obtained by two-dimensionally matrixing a cross section of a porous body or a powder as a raw material thereof and performing component analysis. A particle size and particle circumference analysis method, characterized in that the circumference is determined. 5. The component analysis is performed by a wavelength dispersive X-ray analyzer (WDX) or an energy dispersive X-ray analyzer (E).
The analysis method according to claim 1, 2, 3 or 4, which is elemental analysis utilizing a characteristic X-ray analysis by DX). 6. The analysis method according to claim 1, wherein the component analysis is an identification analysis by X-ray diffraction. 7. The analysis method according to claim 1, 2, 3 or 4, wherein the component analysis is infrared absorption spectrum analysis (IR). 8. The standard sample method according to claim 1, wherein the binarization is a standard sample method in which a standard sample is measured in advance and then the background is processed by calculation. Analytical method. 9. The binarization method is a dummy sample method in which a dummy substance is put in a sample pore and measured simultaneously with the sample, and then the background is processed by calculation. The analysis method according to 2, 3, or 4. 10. The binarization method is a dummy peak method performed by setting a background peak for a peak of a target component at the time of measurement and then processing the background by calculation. The analysis method according to 2, 3, or 4. 11. In the matrix formation, the sample having a smaller pore size or a base material particle size, whichever is smaller, is 1
The analysis method according to claim 1, 2, 3 or 4, wherein the ratio of the length of one side of one matrix is set in the range of 1/1 to 1 / 10,000.