Measurement of Porosity Using a Gallium-Based Infiltrant

Abstract

An apparatus (100) for determining information indicating the porosity of a sample (111) is described, the apparatus comprising the following: i) a measurement chamber (110) configured to accommodate a sample (111) to be measured; ii) an infiltrant reservoir (120) configured to provide an infiltrant (125) to the measurement chamber (110); iii) a pressure device (130) configured to apply a pressure profile to the measurement chamber (110), the pressure device (130) being configured to push the infiltrant (125) into at least a part of the pores of the sample (111); and iv) a determination device (150) configured to determine information indicating the porosity of the sample (111) based on the measured pressure. The infiltrant (125) comprises gallium or a gallium alloy, and the apparatus (100) is configured to provide reducing or inert conditions for the infiltrant (125).

Description

Technical Field

[0001] The present invention relates to an apparatus for determining information indicating the porosity of a sample. Further, the present invention relates to a method for determining information using, for example, the apparatus. Further, the present invention relates to the use of gallium or a gallium alloy as an infiltrant in porosity measurement.

[0002] Therefore, the present invention may relate to the technical field of measurement techniques, particularly porosity measurement techniques.

Background Art

[0003] Multiple materials have pores and, accordingly, have a measurable porosity. Porosity is a measure indicating voids (empty spaces) in a material and can be expressed, for example, as the volume fraction of voids relative to the total volume of the material, for example, as a percentage. The porosity of a material can be important information, or even more important information, in many technical fields such as, for example, pharmacy, ceramics, metallurgy, materials science, mechanical engineering, geology, hydrology, etc.

[0004] To measure the porosity of a sample, several measurement techniques have been developed, for example, optical measurement (using, for example, a microscope), tomography measurement (for example, CT scan), moisture evaporation measurement, gas expansion measurement, mercury intrusion measurement, etc.

[0005] Mercury intrusion can be regarded as the most common and economically important porosity measurement technique. This technique involves infiltrating a non-wetting liquid (i.e., mercury) into a material in a porosimeter at high pressure. The pore diameter can be determined based on the external pressure applied to force the mercury into the pores against the surface tension of the liquid. In particular, the determination of the pore diameter is performed using the Washburn equation. Further, in mercury intrusion (and extrusion) measurement, additional pore-related characteristics such as pore diameter, total pore volume, surface area, etc. can also be determined.

[0006] The main measured quantities are the volume of mercury that has invaded and the applied pressure corresponding thereto. Further, particularly in high-pressure mercury porosimetry, when the pressure is reversed, the volume of mercury extruded can be measured.

[0007] However, there are several drawbacks to the application of mercury. Since mercury is toxic and harmful to the environment, expensive recycling of used mercury is essential. Further, used mercury may not be suitable for recycling within the porosity measuring device due to the toxicity of mercury vapor.

Summary of the Invention

[0008] There may be a need to perform porosity measurements in a cost-effective and environmentally / health-friendly manner.

[0009] An apparatus, method, and use are provided.

[0010] According to a first aspect of the present invention, an apparatus (particularly a liquid (intrusion) porosimeter) for determining information indicating the porosity of a sample is described, the apparatus comprising: i) a measurement chamber (particularly a penetrometer) configured to accommodate a sample to be measured; ii) an intrusion agent reservoir configured to store and provide an intrusion agent to the measurement chamber (the measurement chamber and the intrusion agent reservoir that may be directly connected); iii) a pressure device (e.g., a piston that provides pressure to the measurement chamber) configured to apply a pressure profile to the measurement chamber, the pressure device being configured to push the intrusion agent into at least a part of the pores of the sample comprising. The (above apparatus) particularly comprises a measurement device (e.g., volume measurement, inductive measurement, optical measurement, etc.) configured to measure the volume and / or pressure associated with the provided pressure profile; and iv) a determination device (e.g., a control device) configured to determine information indicating the porosity of the sample based on the measured pressure profile (e.g., using the Washburn equation) and / or the (intrusion / extrusion) volume of the intrusion agent.

[0011] The intrusion agent contains (a gallium-based, i.e.) gallium or a gallium alloy, or consists of a gallium alloy. The device is configured to provide reductive conditions (e.g., using a reducing agent such as an acid) and / or inert conditions (e.g., storage / transport in an inert gas) for the intrusion agent.

[0012] According to a second aspect of the present invention, a method for determining information indicating the porosity of a sample is described, the method comprising: i) providing an intrusion agent to a sample to be measured, the intrusion agent containing gallium or a gallium alloy; ii) applying a pressure profile so as to push the intrusion agent into at least a part of the pores of the sample. (The method particularly comprises measuring the pressure with respect to the pressure profile and / or the (intrusion / extrusion) volume of the intrusion agent) iii) determining the information indicating the porosity of the sample based on the applied pressure profile and / or the volume of the intrusion agent.

[0013] The method further comprises providing reductive conditions or inert conditions for the intrusion agent.

[0014] According to a third aspect of the present invention, the use of gallium or a gallium alloy as an intrusion agent in a porosimeter (method of use) is described, wherein the oxidation of the intrusion agent (particularly with respect to gallium oxide) is prevented by providing reductive conditions and / or inert conditions.

[0015] In the context of this specification, the term "reductive conditions" may in particular refer to conditions in a specific region that are favorable for a chemical reduction reaction (as opposed to an oxidation reaction). A reduction reaction can be a type of chemical reaction in which the oxidation state of an atom changes. In particular, a redox reaction may be characterized by an actual or formal transfer of electrons between chemical species, and in many cases, one species (the reducing agent) undergoes oxidation (loses electrons) while another species (the oxidizing agent) undergoes reduction (gains electrons). An example of reductive conditions in this specification may involve provision of a reducing agent to the surface of the invasive agent (e.g., within the invasive agent reservoir or within the measurement chamber). For example, the reducing agent can be configured as an acid such as hydrochloric acid that prevents the formation of gallium oxide and / or reacts with gallium oxide (Ga2O3) to form the corresponding soluble gallium salt (e.g., gallium chloride (GaCl3) in the case of HCl). Thus, the formation and / or presence of gallium oxide can be prevented by reductive conditions.

[0016] In the context of this specification, the term "inert conditions" may in particular refer to conditions in a specific region that prevent a chemical reaction, particularly an oxidation reaction. An inert substance (particularly a fluid) may not undergo a chemical reaction under a given set of conditions. In one example, an inert gas such as argon is provided as an inert fluid to provide protection against oxidizing the invasive agent (e.g., in the invasive agent reservoir and / or in the measurement chamber). The inert fluid can be a purge gas and / or an operating fluid and can thus be used both to provide inert conditions for the invasive agent and to perform specific tasks for porosity measurement.

[0017] In the context of this specification, the term "pressure profile" may in particular refer to applying a predefined pressure change over time to the measurement chamber. The pressure may force an intrusion agent into the pores (which, due to its surface tension, would not enter the pores under normal conditions). The required pressure may vary depending on the pore size. The pressure may be applied in a continuous or stepwise pressure increase manner during the pressure profile. In one example, the pressure profile is applied in two steps of low-pressure measurement and high-pressure measurement, in particular using different working fluids.

[0018] In the context of this specification, the term "intrusion agent" may in particular refer to a substance (in particular, a fluid) suitable for being introduced into the pores of a sample under the applied pressure. Such an intrusion agent may preferably be a non-wetting liquid that is basically a fluid under the measurement conditions. Furthermore, the intrusion agent should be non-reactive with the sample. A common example of an intrusion agent in porosimetry may be mercury. Nevertheless, gallium-based intrusion agents can be surprisingly effective alternatives.

[0019] According to an exemplary embodiment, the present invention can be based on the idea that when using a gallium-based agent instead of mercury as the intrusion agent and providing inert conditions and / or reducing conditions to protect the gallium-based intrusion agent from oxidation (within the measurement device environment), the porosity measurement can be carried out in a cost-effective and environmentally / health-friendly manner.

[0020] Gallium and gallium alloys have physical / chemical properties comparable to those of mercury and aluminum. Like mercury, gallium (alloys) can be liquid under the measurement conditions and thus are non-wetting liquids. In comparison with mercury, gallium or gallium alloys may have the advantage of being non-toxic and not harmful to the environment. The recycling of gallium (alloys) in the context of porosity measurement can be carried out more efficiently, thereby saving costs on the one hand and not producing waste that can harm the environment / health, which can be a major cost factor. In particular, this is because current laws require the use of specially equipped hazard rooms for operations involving mercury.

[0021] However, gallium (alloys) has had strong drawbacks compared to mercury and has not been considered as a substitute heretofore: gallium may be easily oxidized to gallium oxide (especially Ga2O3), and the latter is not a non-wetting liquid (specifically, it is the solid gallium oxide dispersed on the surface that makes the liquid wetting, and this solid is then dissolved / reduced and remains on top due to aggregation / density surface tension reasons), thereby preventing or even further inhibiting porosity measurement (e.g., by adhering to a measurement chamber, especially a penetrometer column).

[0022] However, it has been surprisingly found by the present inventors here that gallium (and gallium alloys) can be very efficiently applied to intrusion porosity measurement by implementing specific means to prevent the oxidation of gallium in the measurement environment. The above specific means particularly includes the provision of reducing or inert conditions. Specific examples of these conditions will be described for the following exemplary embodiments.

[0023] Gallium (alloys) may further have a larger contact angle compared to mercury so that it can penetrate larger pores at the same pressure. Furthermore, since gallium has a lower density than mercury (the density is approximately half of it), in addition to the contact angle, the hydrostatic pressure is also substantially lower (therefore, the maximum measurable pores are substantially larger). Therefore, more accurate measurement may be possible by using gallium (alloys).

[0024] Furthermore, the described approach can be directly implemented in existing porosity measurement systems, thereby enabling straightforward application. [Exemplary Embodiments]

[0025] According to an embodiment, the gallium alloy contains at least one metal from the group consisting of indium, tin, zinc, potassium, sodium, copper, silver, cesium, bismuth, antimony, lead, gold, thallium, palladium, platinum, selenium, lithium, and cadmium. In particular, the gallium alloy contains at least one of the group consisting of GaIn, GaInSn, GaZn, and GaInZn. This can provide the advantage that established industrially relevant gallium alloys can be directly applied as the penetrant. GaIn, for example, consists of 75.5% Ga and 24.5% In and is liquid at room temperature. GaInSn (brand name Galinstan®) is a eutectic alloy that is liquid at room temperature. GaInSn has low toxicity and low reactivity and may be suitable as an alternative to mercury. In a very specific example, the gallium alloy may contain KNa, rubidium, or francium.

[0026] In one example, any gallium alloy that is liquid under the measurement conditions (in particular, room temperature) may be suitable.

[0027] According to a further embodiment, the inert conditions include at least partially protecting the penetrant with an inert fluid (in particular, an inert gas). The inert fluid can be applied to the penetrant within the device (e.g., placed on top of it). For example, the penetrant reservoir in which the penetrant is stored can be partially filled with the inert fluid. In a further example, the inert fluid can be flowed into the measurement chamber to protect the penetrant therein from oxidation. Further, the penetrant can also be flowed through the supply line of the device together with the inert fluid. In this way, effective protection against oxidation can be provided.

[0028] In one example, the inert fluid is selected from the group consisting of noble gases (in particular, argon), nitrogen, and carbon monoxide (which can also be a reducing agent). In one example, the inert fluid can be used as a cleaning fluid for cleaning the penetrant and / or the device (parts). In a further example, the inert fluid can be used as a working fluid.

[0029] According to a further embodiment, the reducing conditions include the application of a reducing agent (to the invasive agent). While the inert fluid (see above) provides inert conditions to the invasive agent, the reducing agent (or reducing fluid) can provide reducing conditions that prevent oxidation and / or reduce oxidized (invasive agent) substances such as gallium oxide. Additionally or alternatively to the inert fluid, a reducing fluid can be provided to the invasive agent within the device, for example, in an invasive agent reservoir, a measurement chamber, and / or a supply line. In this way, effective protection against oxidation can be provided.

[0030] According to a further embodiment, the reducing agent includes a gallium oxide dissolution solution. This can provide the advantage that oxidized gallium substances (especially gallium oxide) are efficiently reduced (removed) and the invasive agent is recycled. According to a further embodiment, the reducing agent is applied as a fluid to the surface and / or phase boundary of the invasive agent. In this way, the reducing conditions can be provided directly to the invasive agent, especially while the invasive agent is stored (in the reservoir). Further, in the measurement chamber, the reducing agent can cover the surface of the invasive agent. In a particular embodiment (see FIG. 6), in the measurement chamber, the invasive agent is covered with the reducing agent and further covered with an inert (washing) fluid (gas).

[0031] According to a further embodiment, the reducing agent includes a chemically active substance such as an acid or a base. In a specific example, at least one of hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and nitric acid is used. In another example, a base such as sodium hydroxide (NaOH) or potassium hydroxide (KOH) is applied.

[0032] According to a further embodiment, the invasive agent reservoir is configured to store the invasive agent and provide an inert fluid and / or a reducing agent to the stored invasive agent. Thereby, the inert conditions / reducing conditions can be provided directly and effectively to the stored invasive agent.

[0033] According to a further embodiment, the penetrant reservoir is configured to cover the surface of the stored penetrant, in particular such that an inert fluid and / or a reducing fluid floats on the penetrant. In this way, the surface of the penetrant can be effectively protected from oxygen and oxide substances.

[0034] According to a further embodiment, the determination device is further configured to determine information indicating the porosity of the sample using the Washburn equation. This can provide the advantage that the probabilistic evaluation scheme can be directly applied. On the other hand, in other techniques, the evaluation of porosity may be performed using image analysis or magnetic resonance, but the described method can apply the pressure profile evaluated in the context of the measured pressure (and penetrant amount) using the established Washburn equation.

[0035] According to a further embodiment, the apparatus is further configured to provide a cleaning fluid (e.g., an inert fluid) and / or a reducing agent to at least a part of the apparatus and / or the penetrant before and / or after measurement (e.g., within the penetrant reservoir). While the cleaning fluid rather provides an inert condition, the reducing agent is configured to provide a reducing condition. The described apparatus can be designed to protect the penetrant from oxidation in different locations and in different ways. Accordingly, multiple combinations are possible in actual implementations. This increases the degree of freedom in design.

[0036] According to a further embodiment, the apparatus is configured to recover the used penetrant with a reducing agent. In particular, during measurement, the penetrant can be at least partially oxidized and recovered with a reducing agent.

[0037] According to a further embodiment, the measurement chamber is cleaned before measurement. In one example, rinsing (with a reducing fluid) and brushing, rinsing with a cleaning solution (e.g., an alcohol such as isopropyl), and drying with pressurized air are included. In a particular example, it may be advantageous to remove all of the high-pressure working fluid (oil) from the measurement chamber after high-pressure measurement.

[0038] According to a further embodiment, the cleaning step (e.g., with a cleaning fluid) may serve to remove oxygen / oxidant from the measurement chamber / device, especially by further using a vacuum pump.

[0039] According to a further embodiment, the (recovered) penetrant and the recovery agent are separated from each other, for example, using a filter.

[0040] According to a further embodiment, the porosity measurement is carried out under vacuum conditions (e.g., lower than 20 mBar, especially lower than 10 -2 mBar). In a preferred example, the oxygen concentration during measurement in the measurement chamber is lower than 100 ppm, especially lower than 50 ppm, more specifically lower than 20 ppm, and even more specifically lower than 10 ppm.

[0041] According to a further embodiment, the device is further configured to operate in a low-pressure mode. In the low-pressure mode, a gaseous working fluid can be applied as the pressure transmission medium to push the penetrant into the pores of the sample. Pressures in the range of several hundred bar, for example, about 600 bar, can be used.

[0042] According to a further embodiment, a low-pressure working fluid is applied to the penetrant as the pressure transmission medium.

[0043] According to a further embodiment, the low-pressure working fluid contains an inert gas or a reducing gas. This can provide the advantage that at the same time, inert / reducing conditions are provided for the penetrant and the function as a working fluid is fulfilled.

[0044] According to a further embodiment, the low-pressure working fluid contains a gas with an oxygen concentration of less than 100 ppm, especially less than 50 ppm, especially less than 20 ppm, and more specifically less than 10 ppm. Also, the same oxygen conditions can be applied throughout the measurement chamber. This can effectively prevent the oxidation of the penetrant.

[0045] According to a further embodiment, after the low-pressure measurement, the penetrant is recovered using a reducing agent.

[0046] According to a further embodiment, the apparatus is further configured to operate in a high-pressure mode. In the high-pressure mode, a liquid working fluid can be applied as the pressure transmission medium to push the penetrant into the pores of the sample. Pressures in the range of kilobars, for example, about 6000 bars can be used.

[0047] According to a further embodiment, a high-pressure working fluid is applied to the penetrant as a further pressure transmission medium.

[0048] According to a further embodiment, the high-pressure working fluid includes an inert liquid or a reducing liquid. Thereby, at the same time, the advantage that inert / reducing conditions are provided to the penetrant and the function as a working fluid is achieved can be provided.

[0049] In one example, the high-pressure working fluid is silicone oil or mineral oil. Such oils can be substantially inert. Nevertheless, the high-pressure working fluid can contain oxygen that oxidizes gallium (alloys).

[0050] According to a further embodiment, the reducing agent has low or no miscibility with the pressure working fluid, particularly the high-pressure working fluid.

[0051] According to a further embodiment, the reducing agent is arranged, in particular, between the penetrant and the pressure working fluid, particularly the low-pressure working fluid or the high-pressure working fluid, in the measurement chamber (see FIG. 6).

[0052] According to a further embodiment, at least one (inner) side wall of the measurement chamber is coated so as to prevent the adhesion of gallium oxide. This can provide the advantage that the adhesion of gallium oxide to the side wall is prevented and the removal of gallium oxide becomes easier. In particular, the upper part of the penetrometer (stem) can be coated. In one example, this coating is particularly applicable in the context of high-pressure measurements. Thereby, the coating can serve as an alternative to a reducing agent (measurement without a reducing agent) between the penetrant and the high-pressure working fluid (as shown in FIG. 6, for example). In a specific example, the coating can include indium(III) oxide.

[0053] According to a further embodiment, the reducing agent has low or no miscibility with the pressure working fluid (especially a high-pressure working fluid), thereby playing a role in preventing oxidation protection during low-pressure / high-pressure measurements. In particular, an aqueous acid / base is applied as the reducing agent together with a lipophilic pressure medium (working fluid).

[0054] According to a further embodiment, the penetrant is recovered using a reducing agent after high-pressure measurement. Since the high-pressure working fluid (for example, in the case of oil) may form a film on the penetrant, the film can be removed with a film remover, such as an alcohol like isopropyl, before recovery.

[0055] In a specific example, the reducing agent / fluid (or inert fluid) is provided between the penetrant and the (high-pressure) working fluid (see FIG. 6, for example). Thereby, the formation of an undesirable oxygen layer can be efficiently prevented.

[0056] According to a further embodiment, the reducing conditions include the application of an exchange process to remove oxidizing agents and / or oxidized penetrants, in particular gallium oxide, and / or reducing agents and / or reducing gallium substances from the penetrant. This can provide the advantage that undesirable species can be efficiently removed. Under certain conditions, a reducing agent may not be suitable (e.g., due to corrosion), in which case it should be removed. Reducing gallium substances (e.g., gallium chloride) may be undesirable and can therefore be removed.

[0057] According to a further embodiment, the exchange process includes at least one of a membrane, ion exchange, osmosis, density separation, and filtration. This allows probabilistic means to be directly applied to enable efficient separation.

[0058] According to a further embodiment, the apparatus further includes an oxygen sensor configured to monitor the oxygen concentration in at least a part of the apparatus, particularly in an inert fluid. Since oxygen can provide oxidizing conditions that are a major problem in the use of gallium-based penetrants, the oxygen sensor can be applied as a versatile and advantageous monitoring tool and / or alarm function to keep the oxygen content as low as possible.

[0059] According to a further embodiment, the apparatus is further configured to recycle the penetrant after measurement and apply the recycled penetrant in further measurements. This can provide the advantage that the (recovered) penetrant can be applied several times, saving the (significant) cost of purchasing new penetrant and recycling used penetrant. As described above, used penetrant can be treated with a reducing agent to remove oxide substances. Further, separation techniques such as filtration may be applied to remove undesirable substances and / or reaction products. Recycling may be implemented directly in the described apparatus. In another example, recycling may be performed in a separate device.

[0060] According to a further embodiment, the device may be configured as an intrusion porosimeter. Thereby, the described approach may be implemented directly into existing porosimeter designs (see, for example, FIG. 1). The measurement chamber may be configured as an established penetrometer.

[0061] According to a further embodiment, the pressure device is connected around the pressure cell, particularly around the measurement chamber. Again, the described approach may be implemented directly into existing and tested porosimeter designs (see, for example, FIGS. 4 and 5).

Brief Description of the Drawings

[0062] The aspects defined above, and further aspects of the present invention, will be apparent from the examples of embodiments described hereinafter and will be elucidated with reference to the examples of embodiments.

[0063]

Figure 1

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Figure 2

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Figure 3

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Figure 4

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Figure 5

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Figure 6

DETAILED DESCRIPTION OF THE INVENTION

[0069] The illustrations in the drawings are schematic. In different drawings, similar or identical elements are denoted by the same reference numerals.

[0070] FIG. 1 shows an apparatus 100 for measuring porosity according to an exemplary embodiment of the present invention. The apparatus 100 is configured to determine information indicating the porosity of a sample 111 and includes a measurement chamber 110 that houses the sample 111. The measurement chamber 110 is configured like a penetrometer and includes a cavity in which the sample 111 is placed and a column extending in a vertical direction away from the sample 111. The sample 111 is introduced from below and then held in place by a closure 112. The penetrometer 113 is further disposed within a pressure cell 115. A vacuum pump 135 keeps the interior of the measurement chamber 110 under vacuum.

[0071] The apparatus 100 further includes an intrusion agent reservoir 120 that stores an intrusion agent 125 which is gallium or a gallium alloy. If it is only gallium, a further heating step (melting point 29.8 °C) may be required. The intrusion agent reservoir 120 is connected to the measurement chamber 110 (specifically the column), and the intrusion agent 125 can flow directly from the reservoir 120 through a valve into the measurement chamber 110 (the column). In the illustrated example, the intrusion agent 125 has already filled the measurement chamber 110 up to the meniscus 114 of the column. The intrusion agent reservoir 120 is further connected to a supply of the intrusion agent 125. This supply can be fresh intrusion agent 125, recycled intrusion agent 125 (from the same or different measurements), or a mixture of both.

[0072] To provide (chemically) inert conditions within the intrusion agent reservoir 120, an inert fluid 126 (e.g., a cleaning and / or protective fluid) can be supplied to the intrusion agent reservoir 120. Specifically, the inert fluid 126 prevents the intrusion agent 120 from being oxidized within the intrusion agent reservoir 120.

[0073] Additionally or alternatively, a reducing fluid 180 can be supplied to the penetrant reservoir 120 to provide (chemically) reducing conditions within the penetrant reservoir 120. Specifically, the reducing fluid 180 prevents the penetrant 125 from being oxidized and / or reacting with oxidizing species within the penetrant reservoir 120.

[0074] The apparatus 100 further includes a pressure device 130 configured to apply a pressure profile to the measurement chamber 110 so as to push the penetrant 125 into at least a portion of the pores of the sample 111. In this example, the pressure device is configured as a piston connection to a pressure cell. The measurement device 140 of the apparatus 100 is coupled to the pressure device 130 and is configured to measure the pressure with respect to the provided pressure profile (relative to the volume of the corresponding penetrant). In this example, the measurement device 140 includes a capacitance measurement 141 connected to the bottom of the measurement chamber. Since the decrease in the penetrant level within the capillary is recorded capacitively, the exact amount of the infiltrated gallium (alloy) volume with respect to the corresponding applied pressure is also recorded.

[0075] Furthermore, the apparatus 100 includes a determination device 150 coupled to the measurement device 140 configured to determine information indicative of the porosity of the sample 111 based on the pressure measured using the Washburn equation.

[0076] Through additional supply lines 129, an inert fluid 126, a reducing agent 180, a low-pressure working fluid 127, and / or a high-pressure working fluid 128 can be introduced into the measurement chamber 110. Each of these fluids can be configured to provide inert or reducing conditions for the penetrant 125 within the measurement chamber 110. The working fluid and the cleaning fluid can be the same here, but both provide inert / reducing conditions.

[0077] Thus, the apparatus 100 is configured to provide a reducing or inert condition to the penetrating agent 125 as described above by providing the respective fluids 126, 127, 128, 180 within the measurement chamber 110 and / or within the penetrating fluid reservoir 120.

[0078] FIG. 2 shows a penetrating agent reservoir 120 (from the apparatus 100 particularly described in FIG. 1) according to an exemplary embodiment of the present invention. In this example, the penetrating agent reservoir 120 comprises two parts, the upper part being a cleaning unit where the penetrating agent 125 is mixed with an inert cleaning fluid 126 that can be directly supported on top of the penetrating agent 125. The cleaned penetrating agent 125 is then flowed through a valve to the lower second part. The second part includes a non-miscible phase membrane 185 that separates the second part into a penetrating agent 125 compartment and a reducing agent 180 compartment. Each of the penetrating agent 125 and the reducing agent 180 has separate inlets and outlets. Thus, the penetrating agent 125 is flowed from the cleaning part to the penetrating agent 125 compartment and can then be further flowed from the reservoir 120 to the measurement cell 110. The reducing agent 180 is flowed into the reducing agent compartment and can then further flow out of the reservoir 120. In the membrane, the reducing agent 180 provides a reducing condition so that oxidation of the penetrating agent 125 is prevented, and in particular, oxide substances are reduced.

[0079] Figure 3 shows an intrusion agent reservoir 120 (in particular from the apparatus 100 described in Figure 1) according to a further exemplary embodiment of the present invention. The reservoir 120 includes side walls 121 that delimit the volume therebetween and a cover 122 (inert material) as an upper side wall. At the bottom of the reservoir 120, an intrusion agent 125, which is a gallium-based liquid, is disposed. The intrusion agent 125 can be directly supplied to a measurement chamber 110 (not shown here) through a valve. Above the intrusion agent 125, a reducing agent / fluid 180, such as an acid, is disposed. Further, above the reducing agent 180, an inert fluid 126 is disposed and can be provided through an inert fluid 126 supply line. In this example, the inert fluid 126 is an inert gas that is present in the headspace of the reservoir 120 and forms an inert gas blanket for the reducing agent 180 and the intrusion agent 125. In this configuration, the intrusion agent reservoir 120 can be both a reservoir and a cleaning unit at the same time.

[0080] Figure 4 shows an apparatus 100 for porosity measurement in a low-pressure mode according to an exemplary embodiment of the present invention. The apparatus 100 is very similar to that described in Figure 1. The pressure device 130 is configured to push a low-pressure operating fluid 127 into the measurement chamber 110, so that the intrusion agent 125 in the measurement chamber 110 is forced to enter the pores of the sample 111. In one example, a pressure in the range of one hundred bar (e.g., 600 bar) is applied. The low-pressure operating fluid is preferably an inert gas such as argon or nitrogen with a very low oxygen content (e.g., 50 ppm or less).

[0081] Figure 5 shows an apparatus 100 for porosity measurement in a high-pressure mode according to an exemplary embodiment of the present invention. The apparatus 100 is very similar to that described in Figure 1. The pressure device 130 is configured to push a high-pressure operating fluid 128 into the measurement chamber 110, and the intrusion agent 125 in the measurement chamber 110 is forced to enter the pores of the sample 111. In one example, a pressure in the range of one thousand bar (e.g., 6000 bar) is applied. The high-pressure operating fluid 128 is preferably a liquid such as silicone oil.

[0082] Figure 6 shows the measurement chamber 110 (column) according to an exemplary embodiment of the present invention. The measurement chamber 110 is configured as a penetrometer 113, and the column is shown only in FIG. 6 (compared to FIG. 1). The penetrant 125 is present in the column and can penetrate into the lower sample 111 (not shown in the figure). The penetrant 125 fills the column up to the meniscus 114. The penetrant 125 is covered with a reducing agent 180, which is hydrochloric acid in this example. The reducing agent 180 is further covered with a high-pressure working fluid 128, which is oil in this example. Thus, the penetrant 125 can be effectively protected from oxidation during the measurement stage.

[0083] Reference numerals 100 Apparatus, porosimeter 110 Measurement chamber, penetrometer 111 Sample with pores 112 Closure 113 Penetrometer 114 Meniscus 115 Pressure cell 120 Penetrant reservoir 121 Side wall 122 Cover 125 Penetrant, gallium (alloy) 126 Inert fluid, cleaning fluid 127 Low-pressure working fluid 128 High-pressure working fluid 129 Further supply line 130 Pressure device 135 Vacuum pump 140 Measuring device 141 Capacitance measurement 150 Judgment device 180 Reducing agent 185 Membrane

Claims

1. An apparatus, in particular a liquid intrusion porosimetry apparatus for determining information indicating the porosity of a sample, the apparatus comprising: a measurement chamber configured to receive the sample to be measured; an intrusion agent reservoir configured to provide an intrusion agent to the measurement chamber; a pressure device configured to apply a pressure profile to the measurement chamber so as to push the intrusion agent into at least a part of the pores of the sample; and a determination device configured to determine the information indicating the porosity of the sample based on the applied pressure profile and / or the volume of the intrusion agent. The apparatus is provided with; the intrusion agent contains gallium or a gallium alloy, and the apparatus is configured to provide reducing conditions and / or inert conditions for the intrusion agent.

2. The gallium alloy contains at least one metal from the group consisting of indium, tin, zinc, potassium, sodium, copper, silver, cesium, bismuth, antimony, lead, gold, thallium, palladium, platinum, selenium, lithium, cadmium, in particular, the gallium alloy contains at least one of the group consisting of GaIn, GaInSn, GaZn, GaInZn. The apparatus according to claim 1.

3. The inert conditions include at least partially protecting the intrusion agent by an inert fluid, in particular an inert gas. The apparatus according to claim 1 or 2.

4. The reducing conditions include applying a reducing agent, in particular an oxide dissolution solution, to the intrusion agent. In particular, the reducing agent is applied as a fluid to the surface and / or phase boundary of the intrusion agent. More specifically, the reducing agent contains an acid or a base. The apparatus according to claim 3.

5. The intrusion agent reservoir is configured to store the intrusion agent and provide the inert fluid and / or the reducing agent to the stored intrusion agent. In particular, it is configured to cover the surface of the stored intrusion agent. More specifically, the inert fluid and / or the reducing agent are configured to float on the intrusion agent. The apparatus according to claim 4.

6. The determination device is further configured to determine the information indicating the porosity of the sample using the Washburn equation. The apparatus according to claim 1 or 2.

7. Furthermore, before and / or after the measurement, in particular within the penetrant reservoir, the device is configured to provide a cleaning fluid, in particular the inert fluid and / or the reducing agent, to at least a part of the device and / or to the penetrant. The device according to claim 4.

8. Furthermore, it is configured to operate in a low-pressure mode, The low-pressure operating fluid is applied to the penetrant as a pressure transmission medium, In particular, the low-pressure operating fluid contains an inert gas or a reducing gas, More specifically, the gas has an oxygen concentration of less than 100 ppm, in particular less than 50 ppm, more specifically less than 20 ppm, and more specifically less than 10 ppm. The device according to claim 1 or 2.

9. Furthermore, it is configured to operate in a high-pressure mode, The high-pressure operating fluid is applied to the penetrant as a further pressure transmission medium, In particular, the high-pressure operating fluid contains an inert liquid, more specifically silicone oil or mineral oil. The device according to claim 8.

10. The reducing agent has low or no miscibility with the pressure-operating fluid, in particular the high-pressure operating fluid; and / or The reducing agent is arranged between the penetrant and the pressure-operating fluid, in particular the low-pressure operating fluid or the high-pressure operating fluid, especially in the measurement chamber. The device according to claim 9.

11. An oxygen sensor configured to monitor the oxygen concentration in at least a part of the device, in particular in the inert fluid The device according to claim 1 or 2, further comprising.

12. Furthermore, after the measurement, the penetrant is recycled and the recycled penetrant is applied to a further measurement. The device according to claim 1 or 2.

13. The device is configured as an intrusion porosimeter; The measurement chamber has a penetrometer; The side wall of at least one measurement chamber has a coating configured to prevent the adhesion of metal oxides, in particular gallium oxide; The reducing conditions include the application of an exchange process for removing an oxidizing agent and / or an oxidized penetrant, in particular gallium oxide, from the penetrant, In particular, the exchange process includes at least one of a membrane, ion exchange, osmosis, density separation, and filtration The device according to claim 1 or 2, further comprising at least one of the features.

14. A method for determining information indicating the porosity of a sample, the method comprising Providing the penetrant to the sample to be measured, wherein the penetrant contains gallium or a gallium alloy; Applying a pressure profile to push the penetrant into at least a part of the pores of the sample; Determining the information indicating the porosity of the sample based on the applied pressure profile and / or the volume of the penetrant; and Comprising, and the method further Providing reducing conditions and / or inert conditions for the penetrant Comprising, a method. **Claim 15** Use of gallium or a gallium alloy as a penetrant in a porosimeter, wherein oxidation of the penetrant is prevented by providing reducing conditions and / or inert conditions.

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