A tableting device for controlling powder compression porosity and a powder performance detection method

Abstract

The present invention discloses a tableting device for controlling the porosity of powder compression and a powder performance testing method. The tableting device places gaskets of different thicknesses in a mold channel, and powder material is filled above the thinner gasket. The volume of the compacted sample is controlled by the height difference of the gaskets, and a block-shaped test sample with a determined porosity is obtained by compaction and demolding. The powder performance testing method adopts the tableting device, and vacuum impregnation, step-by-step polishing and nanoindentation technology are performed on the block-shaped test sample with a determined porosity. The micromechanical properties under different porosities are fitted by a power exponential model, and the intrinsic micromechanical properties of the powder material under zero porosity are obtained, so that more accurate micromechanical properties of different phases can be measured.

Description

Technical Field

[0001] The present invention relates to a tablet pressing device and method, in particular to a tablet pressing device for controlling the porosity of powder compression and a method for detecting the intrinsic microscopic mechanical properties of powder using the tablet pressing device. Background Art

[0002] At the micro- and nanoscale, the micromechanical properties of materials are typically tested using nanoindentation technology. This technique records the indentation depth-load curve, tests a statistically significant number of points, and performs probability density statistical analysis on the resulting indentation points to determine the micromechanical properties of different phases. Combined with the energy spectrum mode of a scanning electron microscope, nanoindentation technology can analyze the chemical composition and mechanical properties of samples in situ. However, the mechanical properties of these phases are significantly affected by their porosity, making it impossible to determine the micromechanical properties of a phase at zero porosity.

[0003] Existing techniques typically involve pressing powdered materials into sheet specimens for nanoindentation testing. However, without a press equipped with a precise displacement sensor (resolution 0.01mm), quantitative control of the specimen's height and volume during compression is impossible. Some presses equipped with displacement sensors also suffer from significant discrepancies in the results due to the pressure sensing lacking the required sensitivity and precision for specimen height and volume control. For example, the commonly used Jiuwang WDW-100KN microcomputer-controlled electronic universal testing machine has a deformation measurement accuracy within the range of 0.2-10mm. Furthermore, there is an overlap in the elastic modulus values ​​of various materials in their free stacking state. For example, for calcium silicate hydrate and calcium hydroxide, the main components of cement-based materials, the elastic modulus of calcium silicate hydrate ranges from 35.6-63.5 GPa, while that of calcium hydroxide ranges from 35.4-67.8 GPa. This overlap in values ​​makes it difficult to distinguish the micromechanical properties of the actual phases, making it more difficult to determine the relationship between porosity and micromechanical properties. Furthermore, due to the lack of micromechanical property data of zero-porosity phases, the calculation accuracy of the overall mechanical properties of composite materials is greatly reduced, and even seriously inconsistent with reality. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a tableting device for accurately controlling the compressed porosity of pressed powder materials. Another purpose of the present invention is to provide a method for detecting the intrinsic micromechanical properties of powder materials using the above-mentioned device.

[0005] Technical solution: The device for controlling the porosity of powder compression described in the present invention is provided with a pressure transmission part, a mold and a pressure-bearing base from top to bottom. A plurality of cylindrical protrusions are provided at the lower end of the pressure transmission part. The diameter of each cylindrical protrusion is consistent with the diameter of the corresponding channel passing through the mold, and gaskets of different thicknesses are placed in each channel.

[0006] Preferably, a groove is provided at the bottom of the mold, which matches the protrusion provided on the upper surface of the pressure base.

[0007] Preferably, a hollow demoulding base is further included, and the demoulding base is placed at the lower part of the mold.

[0008] The powder performance detection method using the tablet pressing device of the present invention comprises the following steps:

[0009] (1) The pressure base is connected to the mold, and gaskets of different thicknesses are placed in the mold channel. Powder material is filled on the thinner gasket. The volume of the pressed sample is controlled by the height difference of the gasket. The block sample with a certain porosity is obtained by pressing and demolding;

[0010] (2) Take the sample to be tested, perform vacuum impregnation and step-by-step polishing, place it on the nanoindentation loading platform, and calculate the micromechanical properties data of the powder material such as indentation hardness, indentation modulus, creep modulus or characteristic time according to the displacement-load curve;

[0011] (3) The micromechanical properties under different porosities are fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material under zero porosity.

[0012] Preferably, in step (3), the power exponential model is E p =E(1-p) 2 , where E is the intrinsic micromechanical properties of the powder material in the zero-porosity state.

[0013] Preferably, in step (2), the vacuum impregnation is specifically as follows: placing the sample to be tested into a metallographic mold, slowly injecting epoxy resin under vacuum conditions, taking it out and placing it for more than 24 hours to obtain a solidified sample to be tested.

[0014] Preferably, in step (2), the step-by-step polishing is specifically as follows: placing the solidified test sample in a polishing machine, pressing the sample with a load of 20N and a rotation speed of 150r / min, and polishing with 9 micron, 3 micron and 1 micron polishing paste for 1 hour, 3 hours and 3 hours respectively, followed by vacuum drying for more than 24 hours.

[0015] Preferably, in step (2), the nanoindentation test parameters are: maximum indentation load of 1.35 mN, loading and unloading rate of 0.02 mN / s, holding time of 60 s, indentation spacing of 10 μm, and 5×5 dot matrix measurement.

[0016] Preferably, in step (2), the epoxy resin can be further configured with a curing agent:epoxy resin ratio of 1:3 by mass, wherein the elastic modulus of the epoxy resin used is 0.1 GPa, and the working range of the nanoindenter is greater than 3 times the particle size of the test powder material.

[0017] Preferably, step (1) is carried out before pressing according to the volume V and porosity of the molded sample. The functional relationship between To determine the volume corresponding to the required sample porosity.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) the porosity of the bulk test sample can be precisely controlled, the operation is simple and no high-precision instruments are required; (2) based on the bulk test sample obtained by the pressure device, the detection method of the present invention can quickly and accurately obtain the intrinsic micromechanical properties of the powder material at zero porosity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of a tablet pressing device of the present invention;

[0020] Figure 2 Schematic diagram of the mold in the tablet pressing device of the present invention;

[0021] Figure 3 The micro-indentation hardness test results and intrinsic micro-indentation hardness fitting results of calcium silicate hydrate and calcium aluminate hydrate are shown in Figure 2.

[0022] Figure 4 The micro-indentation modulus test results and intrinsic micro-indentation modulus fitting results of calcium silicate hydrate and calcium aluminate hydrate are shown in Figure 2.

[0023] Figure 5 These are the test results of the micro creep modulus of calcium silicate hydrate and calcium aluminate hydrate and the fitting results of the intrinsic micro creep modulus. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0025] Example 1

[0026] like Figure 1 As shown, the tablet pressing device for controlling the porosity of powder compression of the present invention is provided with a pressure transmission member 1, a mold 2 and a pressure-bearing base 3 from top to bottom. The lower end of the pressure transmission member 1 is provided with two cylindrical protrusions. The diameter of each cylindrical protrusion is consistent with the diameter of the corresponding channel 4 passing through the mold 2. A gasket 5 of different thickness is placed in each channel 4.

[0027] like Figure 2As shown, the bottom of the mold 2 is provided with a groove, which matches the protrusion provided on the upper surface of the pressure base 3, and also includes a demoulding base 6 for replacing the pressure base 3.

[0028] Example 2

[0029] (1) Weigh 0.2 g of hydrated calcium silicate powder with a calcium-silicon ratio of 0.8, install a tableting device, fill it with fillers, and press it into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold the corresponding test samples with porosities of 20%, 30%, 50%, and 70% respectively;

[0030] (2) The obtained block sample was impregnated with epoxy resin in a vacuum impregnation device with a curing agent:epoxy resin mass ratio of 1:3, and cured at 20 degrees Celsius for 24 hours. The cured sample was placed in a fully automatic polishing machine with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing paste for 1 hour, 3 hours and 3 hours respectively; after each level of polishing, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0031] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0032] Example 3

[0033] (1) Weigh 0.2 g of hydrated calcium aluminosilicate powder with a calcium-silicon ratio of 0.8 and an aluminum-silicon ratio of 0.1, install a tableting device, fill it with fillers, and press it into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold the corresponding test samples to obtain porosities of 20%, 30%, 50%, and 70% respectively;

[0034] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0035] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0036] Example 4

[0037] (1) Weigh 0.2 g of hydrated calcium aluminosilicate powder with a calcium-silicon ratio of 0.8 and an aluminum-silicon ratio of 0.2, install a tabletting device, fill it with fillers, and press it into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold the corresponding test samples to obtain porosities of 20%, 30%, 50%, and 70% respectively;

[0038] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0039] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0040] Example 5

[0041] (1) Weigh 0.2 g of hydrated calcium aluminosilicate powder with a calcium-silicon ratio of 0.8 and an aluminum-silicon ratio of 0.3, install a tabletting device, fill it with fillers, and press it into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold the corresponding test samples with porosities of 20%, 30%, 50%, and 70% respectively;

[0042] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0043] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0044] Example 6

[0045] (1) Weigh 0.2 g of hydrated calcium silicate powder with a calcium-silicon ratio of 1.2, install a tableting device, fill it with fillers, and press it into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold the corresponding test samples with porosities of 20%, 30%, 50%, and 70% respectively;

[0046] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0047] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0048] Example 7

[0049] (1) Weigh 0.2 g of hydrated calcium aluminosilicate powder with a calcium-silicon ratio of 1.2 and an aluminum-silicon ratio of 0.1, install a tableting device, fill it with fillers, and press it into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold the corresponding test samples with porosities of 20%, 30%, 50%, and 70% respectively;

[0050] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0051] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0052] Example 8

[0053] (1) Weigh 0.2 g of hydrated calcium aluminosilicate powder with a calcium-silicon ratio of 1.2 and an aluminum-silicon ratio of 0.2, install a tabletting device, fill it with fillers, and press it into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold the corresponding test samples with porosities of 20%, 30%, 50%, and 70% respectively;

[0054] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0055] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0056] Example 9

[0057] (1) Weigh 0.2 g of hydrated calcium aluminosilicate powder with a calcium-silicon ratio of 1.2 and an aluminum-silicon ratio of 0.3, install a tableting device, fill it with fillers, and press it into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold the corresponding test samples with porosities of 20%, 30%, 50%, and 70% respectively;

[0058] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0059] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0060] Example 10

[0061] (1) Weigh 0.2 g of calcium hydroxide powder, install a tabletting device, filler, and press into a block test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold to obtain the corresponding test samples with porosities of 20%, 30%, 50%, and 70% respectively;

[0062] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0063] (3) The micromechanical properties of the obtained materials at different porosities were fitted by a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0064] Example 11

[0065] (1) Weigh 0.2 g of aluminum hydroxide powder, install a tabletting device, filler, and press into a block-shaped test sample with a diameter of 20 mm by using the height difference of the gaskets. The height differences of the gaskets are 0.78, 0.91, 0.98, and 1.31 respectively; press and demold to obtain the corresponding test samples with porosities of 20%, 30%, 50%, and 70% respectively;

[0066] (2) The obtained block sample was impregnated with epoxy resin in a ratio of curing agent to epoxy resin = 1:3 in a vacuum impregnation device and cured at 20 degrees Celsius for 24 hours; the cured sample was placed in a fully automatic polishing machine, with a pressing load of 20N and a rotation speed of 150r / min, and polished with 9μm, 3μm and 1μm polishing pastes for 1 hour, 3 hours and 3 hours respectively; after each level of polishing was completed, it was ultrasonically cleaned with alcohol in an ultrasonic cleaning machine for 5 minutes; the polished sample was vacuum dried for at least 24 hours; further, the polished block sample was placed on a nanoindentation loading platform, and the test parameters were set: the maximum indentation load was 1.35mN, the loading and unloading rate was 0.02mN / s, the holding time was 60s, the indentation spacing was 10μm, and a 5×5 dot matrix measurement was performed;

[0067] (3) The micromechanical properties of the obtained materials at different porosities were fitted using a power exponential model to obtain the intrinsic micromechanical properties of the powder material at zero porosity, as shown in Table 1.

[0068] Table 1. Intrinsic micromechanical properties of powder materials at zero porosity in Examples 1-10

[0069] Example Sample name Indentation modulus (GPa) Hardness (GPa) Creep modulus (GPa) Example 2 CSH08 53.37 1.8 115.09 Example 3 CASH0801 47.4 1.24 75.27 Example 4 CASH0802 41.42 1.72 101.56 Example 5 CASH0803 44.54 1.6 108.88 Example 6 CSH12 49.87 1.38 103.9 Example 7 CASH1201 45.3 1.39 96.16 Example 8 CASH1202 45.34 1.51 116.43 Example 9 CASH1203 48.82 1.43 81.58 Example 10 <![CDATA[Ca(OH)2]]> 62.1 2.09 271.81 Example 11 <![CDATA[Al(OH)3]]> 53.17 1.92 157.58

[0070] In Table 1, the differences in intrinsic micromechanical properties of Examples 2-9 due to the different chemical compositions (calcium-silicon ratio and aluminum-silicon ratio) were first tested by the present invention, and the errors of the obtained results were small, such as Figure 2-4 As shown in the error bars in . The smaller error is due to the inevitable thermal drift and partial roughness of the phase surface during the nanoindentation test, but the deviation is not large and is within an acceptable range. In addition, Examples 10 and 11 show that the difference in the intrinsic micromechanical properties of different phases of calcium hydroxide and aluminum hydroxide is not due to pores. Nanoindentation technology is suitable for measuring the micromechanical properties of different phases and cannot detect differences in intrinsic micromechanical properties. When using the test method of the present application, the same preparation process can be used to prepare the sample to be tested, and the same test conditions can be used for testing, and the test results obtained are reliable.

[0071] The model fitting process is as follows Figure 3-5 , the power exponential model is E p =E(1-p) 2 , where E is the intrinsic micromechanical properties of the powder material in the zero-porosity state. Figure 3 The relationship between porosity and indentation hardness of hydrated calcium aluminosilicate with different calcium-silicon ratios and aluminum-silicon ratios is shown by controlling the porosity of powder compression, and the intrinsic indentation hardness in the zero porosity state is further obtained through power exponential fitting. Figure 4 The relationship between porosity and indentation modulus of hydrated calcium aluminosilicate with different calcium-silicon ratios and aluminum-silicon ratios is demonstrated by controlling the porosity of powder compression, and the intrinsic indentation modulus under zero porosity state is further obtained through power exponential fitting. Figure 5 The study demonstrates the relationship between porosity and creep modulus of hydrated calcium aluminosilicates with varying calcium-silicon and aluminum-silicon ratios, by controlling the porosity of the powder during compression. Furthermore, the intrinsic creep modulus at zero porosity is derived through power exponential fitting. Combined with these results, it is clear that this design method perfectly prepares powder materials with the target porosity, accurately derives the relationship between porosity and micromechanical properties, and successfully calculates the intrinsic micromechanical properties of different materials at zero porosity.

Claims

1. A method for testing powder properties using a tabletting device, characterized in that: The tablet pressing device is a tablet pressing device for controlling the porosity of powder compression, and is provided with a pressure transmission member (1), a mold (2) and a pressure-bearing base (3) in order from top to bottom. The lower end of the pressure transmission member (1) is provided with a plurality of cylindrical protrusions, the diameter of each cylindrical protrusion being consistent with the diameter of a corresponding channel (4) passing through the mold (2), and gaskets (5) of different thicknesses are placed in each channel (4). The detection method comprises the following steps: Step 1: Connect the pressure base to the mold, place gaskets of different thicknesses in each channel of the mold, fill the thinner gaskets with powder material, control the volume of the pressed sample by the height difference of the gaskets, and press and demold to obtain a block-shaped sample with a certain porosity. Step 2: Take the sample to be tested, perform vacuum impregnation and step-by-step polishing, place it on the nanoindentation loading platform, and calculate the micromechanical properties data of the powder material such as indentation hardness, indentation modulus, creep modulus or characteristic time according to the displacement-load curve; Step 3: Fit the micromechanical properties under different porosities through a power exponential model to obtain the intrinsic micromechanical properties of the powder material under zero porosity. The power exponential model is E p =E(1-p) 2 , where E is the intrinsic micromechanical properties of the powder material in the zero-porosity state.

2. The detection method according to claim 1, wherein In the tablet pressing device, a groove is provided at the bottom of the mold (2) and matches the protrusion on the upper surface of the pressure-bearing base (3).

3. The detection method according to claim 1, wherein The tablet pressing device further comprises a hollow demoulding base (6), and the demoulding base (6) is placed at the lower part of the mold (2).

4. The detection method according to claim 1, wherein In step 2, the vacuum impregnation method is to place the sample to be tested in a metallographic mold, slowly inject epoxy resin under vacuum conditions, take it out and leave it for more than 24 hours to obtain a cured sample to be tested.

5. The detection method according to claim 1, wherein In step 2, the step-by-step polishing method is to place the solidified test sample in a polishing machine with a pressing load of 15-25N and a rotation speed of 130-170r / min, and polish with 9 micron, 3 micron and 1 micron polishing paste for 1 hour, 3 hours and 3 hours respectively, and then vacuum dry for more than 24 hours.

6. The detection method according to claim 1, characterized in that In step 2, the nanoindentation experimental process conditions are: maximum indentation load of 1.2-2.0 mN, loading and unloading rates of 0.02-0.05 mN / s, holding time of 60-120 s, indentation spacing of 5-15 μm, and 5×5 dot matrix measurement.

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