CN113125674A

CN113125674A - Simple method for detecting open area ratio of foam metal with network-shaped through hole structure

Info

Publication number: CN113125674A
Application number: CN202110411626.1A
Authority: CN
Inventors: 宋帅; 刘培生; 顷淮斌
Original assignee: Beijing Normal University
Current assignee: Beijing Normal University
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2021-07-16

Abstract

The invention relates to a method for detecting the open cell content of foam metal with a network-shaped through hole structure, which is a simple detection method without detecting any weight index of a sample and can be also applied to the foam metal with a similar structure as long as the foam metal has an open pore structure. The method directly calculates the open porosity of the sample by measuring the apparent volume of the foam metal sample (the volume of the space occupied by the external contour of the sample) and the volume of the working liquid immersed in the pores of the sample. The measurement operation is simple and convenient because any weight index of the sample does not need to be measured.

Description

Simple method for detecting open area ratio of foam metal with network-shaped through hole structure

The technical field is as follows:

the invention relates to a method for detecting the open cell ratio of foam metal, in particular to a method for detecting the open cell ratio of foam metal with a network-shaped through hole structure.

Background art:

the porous material has the application advantage that other materials are difficult to replace in a plurality of engineering fields^[1-6]. Among various porous materials, the production scale of the foam metal with a network structure is relatively large, and the practical application of the foam metal occupies an important position. The network foam metal is an open-cell porous material with interconnected internal pores, and is suitable for all occasions requiring pore communication and utilizing internal pore surfaces, such as shunting filtration, heat exchange, biological transplantation, catalytic engineering and the like^[5]。

The pores in the foam metal are in the forms of open-connected pores and isolated closed pores, wherein the ratio of the volume occupied by the open-connected pores to the apparent total volume of the foam body is the open-cell ratio of the foam metal^[6]. Many uses of metal foams utilize open porosity^[7]. Grinding machineThe open porosity of the foam metal strongly affects the fluid permeability (permeability) and the effective surface area of the internal pores, thereby greatly affecting the sound absorption, electromagnetic shielding, heat transmission of the whole product and various operational performances of utilizing the surface of the internal pores^[5,7-9]. Therefore, the index of the open cell content is very important for a porous material such as a metal foam.

The detection of the open cell ratio of the foam metal generally adopts mercury pressing method, liquid discharge weighing method and the like, and the balance weighing measurement is required to be carried out for a plurality of times^[6,7]. Wherein the liquid-containing weighing of the sample has higher requirements in the aspects of corresponding auxiliary tools and operation, and brings certain fussy inconvenience for measurement. This is particularly the case where in-liquid weighing is required. The invention provides a novel simple detection method for the open porosity of foam metal, and the open porosity of a sample is obtained by measuring the volume of a sample and the volume of working liquid immersed in the pores of the sample. The weight index of the sample in any link does not need to be measured, so that the measurement operation is simple and convenient.

Reference to the literature

[1] Liu Bei Sheng, Zhe light, Cheng Wei and special review: porous material performance model study 1, mathematical relationship [ J ] material engineering, 2019,47(6):42-62.

[2] Liu Beisheng, Xia Feng jin, Chengwei and special review: porous material performance model study 2. Experimental validation [ J ] material engineering, 2019,47(7):35-49.

[3] Liu Beisheng, Yangchun, Chengwei and special review: porous material performance model study 3. mathematical deduction [ J ] material engineering, 2019,47(8):59-81.

[4]P.S.Liu,K.M.Liang.Functional materials of porous metals made by P/M,electroplating and some other techniques.Journal of Materials Science,2001,36(21):5059-5072.

[5] Liu banking. porous material introduction (2 nd edition) Qinghua Press, 2013.

[6] Liu Bei Sheng, Ma Xiao Ming porous material detection method, Beijing: metallurgical industry publishers, 2006.

[7] Liu Bei Zhen Guang Chen Jing He porous material performance and design [ M ] Beijing, chemical publishing agency, 2019.

[8]Gibson L J and Ashby M F.Cellular Solids:Structure and properties.Cambridge University Press,1999.

[9]Gros E,Panneton R.A missing mass method to measure the open porosity of porous solids.Canadian Acoustics,2004,32(3):20-21.

The invention content is as follows:

the invention aims to provide a method for detecting the open-cell rate of foam metal, in particular to a simple method for detecting the open-cell rate of foam metal with a network-shaped through hole structure. The detection method comprises the steps of measuring the apparent volume (the volume of a space occupied by the external contour of a sample) of a foam metal sample and the volume of working liquid immersed in the pores of the sample, and directly calculating the aperture ratio of the sample by using the ratio of the apparent volume to the volume of the working liquid.

The operation steps and related calculations in the detection method of the present invention are as follows:

the clean foam metal sample is put into a volume measuring tool (such as a proper measuring cup) with volume scale and capacity meeting the measurement precision requirement. Measuring a volume (V) with a measuring cylinder_{Liquid for treating urinary tract infection}) The working liquid (such as deionized water and the like) with good wettability to the sample is poured into the sample containing measuring cup, so that the sample is completely submerged by the using amount of the working liquid. And then placing the sample in an ultrasonic water bath for vibration to remove air bubbles in the pores of the sample, so that the working liquid is fully immersed into the open pore spaces of the sample. After the working liquid immersion irrigation process is finished, the volume corresponding to the liquid level scale of the sample-carrying measuring cup is read to be V_{Measuring sample}I.e. the total volume of the "liquid + sample" system after the liquid has been sufficiently immersed in the sample opening. Taking out the sample, drying, and measuring the apparent volume of the sample as V_{Sample (A)}. The volume of the working liquid immersed in the sample pores, i.e. the volume of the sample opening, is then equal to the difference between the total volume of the "liquid + sample" system when the working liquid is not immersed at all inside the sample and the total volume of the "liquid + sample" system after the liquid has been sufficiently immersed in the sample opening:

V_{opening holes}＝(V_{Liquid for treating urinary tract infection}+V_{Sample (A)})–V_{Measuring sample} (1)

From this, the open porosity of the sample is given:

θ_{opening device}＝(V_{Opening holes}/V_{Sample (A)})×100％

＝{[(V_{Liquid for treating urinary tract infection}+V_{Sample (A)})–V_{Measuring sample}]/V_{Sample (A)}}×100％ (2)

If the working liquid volatilizes in the measuring process, sealing the measuring cup; in addition, it should be noted that the cooling water in the ultrasonic bath is of sufficient quantity to provide sufficient cooling of the heat generated by the ultrasonic vibration of the system. If the measurement accuracy is further improved, a blank comparison experiment can be assisted.

At present, the electrodeposition process is generally adopted at home and abroad to continuously produce the foam metal product with the network-shaped through hole structure on a large scale. During the preparation process, the pores of the electrodeposited metal foam must be accessible to an electroplating solution, which is typically an aqueous solvent, to achieve deposition of the metal within the porous matrix. Therefore, the open-cell rate of all the electrodeposited foam metal products can be detected by the method, and the working liquid only needs to be deionized water.

The method for detecting the open cell ratio is simple in test and convenient to calculate, and can be used for detecting the foam metal sample. As can be seen from the detection process, the method can be applied to the foamed metal product with open pores, and is not limited to the network-like structure (FIG. 1) as long as the product has the open pore structure.

Description of the drawings:

FIG. 1 shows the pore structure of a nickel foam product produced by a certain enterprise.

The specific implementation mode is as follows:

example (b): the sample to be detected is a foamed nickel product produced by a certain enterprise, and the appearance of the pore structure of the sample to be detected is shown in figure 1. The size of the cut large sample is approximately 20cm by 5.5mm, and the pore size of the coarse sample is below 1 mm. To obtain relatively comprehensive statistical data, small samples with dimensions of about 50mm × 40mm × 5.5mm of 4 pieces were cut at 4 different locations of the panel to be examined. Ultrasonic cleaning the sample with acetone, clear water, and alcohol for 10min, oven drying, and placing into a container with a volume scale of 0.5ml (0.5 cm)³) The clean measuring cup. The graduated cylinder was filled with 80ml of deionized water to ensure that there was a sufficient level of liquid above the sample while flooding all of the sample. Then placing the sample in a cold water bath for ultrasonic vibration for 10min, and fully soaking the deionized water into the open pores of the sample. To avoid evaporation of the deionized water, the measuring cup was sealed with a transparent film. After the deionized water immersion filling process is finished, the volume corresponding to the liquid level scale of the measuring cup at the moment is read to be V_{Measuring sample}(ml), the resulting data were rounded to 1 ml. Taking out the sample, drying, then carrying out wax dipping treatment on the sample, and carefully cleaning redundant wax on the surface of the sample; measuring the size of the wax-impregnated sample with vernier caliper with accuracy of 0.02mm, wherein the values of 3 positions such as two sides and the middle of the wax-impregnated sample measured in the length and width directions are averaged, the value of 4 values of 4 angles of the thickness are averaged, the apparent volume of each small sample is calculated, and the total apparent volume V of the 4 small samples is obtained by adding_{Sample (A)}(ml), 0.1ml was obtained by rounding. And then passes through "open area ratio θ" based on the data obtained above_{Opening device}＝[(80+V_{Sample (A)})–V_{Measuring sample}]/V_{Sample (A)}"the open cell content of the sample was calculated, and the results are shown in Table 1.

TABLE 1 open-cell content of a nickel foam product

Claims

1. A method for detecting the open cell content of foam metal is characterized in that: the method does not need to measure any weight index of the sample, which is different from the conventional foam metal open-cell rate detection method; directly calculating the open porosity of the sample by measuring the apparent volume of the foam metal sample (the volume of the space occupied by the external contour of the sample) and the volume of the working liquid immersed in the pores of the sample; the method has the advantages that any weight index of the sample does not need to be measured, so that the measuring operation is simple and convenient.

2. The method for measuring the open cell content of a metal foam according to claim 1, wherein the metal foam has a network structure, and pores are interconnected; however, the detection method may not be limited to this structure, and the present method may be employed as long as the pores can communicate with the outer surface of the article.