CN107974869B

CN107974869B - Preparation method of high-orientation high-filling FeSiAl flexible composite paper

Info

Publication number: CN107974869B
Application number: CN201711292593.3A
Authority: CN
Inventors: 周佩珩; 蒋佳根; 罗小嘉; 陈万里; 李文新; 邓龙江
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2017-12-08
Filing date: 2017-12-08
Publication date: 2020-07-21
Anticipated expiration: 2037-12-08
Also published as: CN107974869A

Abstract

The invention belongs to the field of electromagnetic functional materials, and relates to a preparation method of high-orientation high-filling FeSiAl flexible composite paper. The method adopts a sand core funnel and polypropylene microporous filter membrane suction filtration method, and realizes the consistent orientation of the FeSiAl flaky particles with disordered orientation in a natural state in a compound by means of a fluid dynamics principle; and then the composite material attached to the polypropylene filter membrane is peeled off through the solubility of butyl acetate to the polypropylene filter membrane. The finally obtained high-orientation high-filling FeSiAl flexible composite paper can be directly attached to the curved surface and bent along with the surface, and an electromagnetic shielding effect is provided. The equipment used by the invention is simple, low in cost and pollution-free; the prepared FeSiAl ultrathin flexible composite paper has high filling degree and highly consistent orientation, and has higher magnetic conductivity and lower microwave dielectric constant compared with the existing FeSiAl composite material.

Description

Preparation method of high-orientation high-filling FeSiAl flexible composite paper

Technical Field

The invention belongs to the field of electromagnetic functional materials, and relates to a preparation method of high-orientation high-filling FeSiAl flexible composite paper.

Background

When in use, the alloy powder in the traditional wave-absorbing material is required to be compounded with a base material such as various high polymer materials such as acrylic resin to form a block material with complete mechanical properties for use.

The FeSiAl material has good high-frequency permeability and is a preferred absorbent of a traditional L waveband wave-absorbing material, the FeSiAl composite material has stronger magnetic loss effect, namely stronger wave-absorbing performance, the FeSiAl composite material has higher filling degree of FeSiAl, however, the FeSiAl filling degree is difficult to exceed 35% due to the fact that traditional resin is used as a matrix, the purpose is to guarantee the mechanical strength of the composite and prevent electromagnetic parameter mismatching (worsening wave-absorbing performance) caused by overhigh microwave dielectric parameters of the composite.

However, the currently adopted uniform orientation methods, such as stress rolling, have limited performance and do not solve the problem of mechanical strength reduction caused by filling degree increase and the problem of mismatch caused by microwave dielectric increase. Therefore, an fesai compound capable of realizing high orientation and high filling and maintaining good electromagnetic and mechanical properties and a preparation method thereof are urgently needed.

Disclosure of Invention

Aiming at the problems or the defects, the problems that the strength of the compound is insufficient, the microwave dielectric is increased, the surface roughness of the composite material is high and the consistent orientation degree is insufficient in the process of improving the filling degree by improving the magnetic conductivity in the prior art are solved. The invention provides a preparation method of high-orientation high-filling FeSiAl flexible composite paper, which is based on a consistent-orientation FeSiAl preparation method. The prepared FeSiAl flexible composite paper is ultrathin and has high magnetic conductivity.

The technical scheme of the invention is as follows:

step 1: uniformly dispersing the FeSiAl flaky particles and the nano-cellulose in deionized water according to a ratio to obtain a dispersion liquid A. The mass ratio of the nano-cellulose to the dispersion liquid A is 0.5-5 per mill; the mass ratio of the FeSiAl flaky particles to the nano-cellulose is less than or equal to 20: 1.

Step 2: and (3) carrying out suction filtration on the dispersion liquid A by adopting a sand core funnel and a polypropylene microporous filter membrane in an environment with the pressure less than or equal to 0.1MPa, and keeping the suction filtration state for at least 6 h. The filtration time increased with the increase in the concentration of the dispersion A, i.e., the higher the concentration of the dispersion A, the longer the filtration time.

And step 3: and (3) drying the filter membrane attached with the filter cake obtained in the step (2) at the temperature of 60-80 ℃, and pressurizing at the pressure of 5-10MPa for at least 10 s.

And 4, step 4: and (3) stripping the filter cake and the filter membrane from the filter membrane attached with the filter cake obtained in the step (3) by using a stripping process, and then rinsing the filter membrane in absolute ethyl alcohol to remove polypropylene filter membrane residues attached to the filter cake, so as to obtain the filter cake.

The stripping process comprises the following steps: soaking the polypropylene filter membrane attached with the filter cake in butyl acetate for at least 10s, taking out and spreading the polypropylene filter membrane on a metal flat plate, and finally removing the polypropylene filter membrane which is not completely dissolved.

And 5: and (4) drying the filter cake obtained in the step (4) at the temperature lower than 80 ℃ to obtain the high-orientation high-filling FeSiAl flexible composite paper.

Further, ultrasonic oscillation is required to be carried out after the dispersion liquid A is prepared in the step 1, oscillation is kept until the step 2, and the time of ultrasonic oscillation is not less than 10 min.

The method adopts a sand core funnel and polypropylene microporous filter membrane suction filtration method, and realizes the consistent orientation of the FeSiAl flaky particles with disordered orientation in a natural state in a compound by means of a fluid dynamics principle; and then the composite material attached to the polypropylene filter membrane is peeled off through the solubility of butyl acetate to the polypropylene filter membrane. The finally obtained high-orientation high-filling FeSiAl flexible composite paper can be directly attached to the curved surface and bent along with the surface, and an electromagnetic shielding effect is provided.

The preparation method of the FeSiAl composite paper material provided by the invention comprises the following steps: the equipment is simple, the cost is low, and no pollution is caused; the FeSiAl ultrathin flexible composite paper prepared by the method has high filling degree and highly consistent orientation, and has higher magnetic conductivity and lower microwave dielectric constant compared with the existing FeSiAl composite material.

Drawings

FIG. 1(a) is a scanning electron micrograph of a final real object of example 2; FIG. 1(b) is the final physical map of example 2;

FIG. 2 is a graph comparing the electromagnetic parameters of three examples with those of a comparable non-oriented FeSiAl composite;

FIG. 3 is a comparison graph of the wave-absorbing effectiveness of three examples and a finished product with the thickness of 1mm of the non-oriented FeSiAl composite material in the same proportion under the electromagnetic parameters.

Detailed Description

The technical scheme of the invention is detailed below by combining the accompanying drawings and the embodiment.

Example 1

Step 1: uniformly dispersing 0.02g of FeSiAl flaky particles and 0.01g of nano-cellulose in 15ml of deionized water to obtain a dispersion liquid A; and (3) carrying out ultrasonic oscillation for 20min after the dispersion liquid A is prepared.

Step 2: and (3) clamping a polypropylene filter membrane with the aperture of 0.25 mu m between a sand core layer and a filter cup of the suction filtration device, pouring the dispersion liquid A into the filter cup, pumping a suction filtration cavity to 0.1MPa by using a circulating water type vacuum pump, and then keeping the suction filtration state for 12 hours.

And step 3: and (3) drying the filter membrane attached with the filter cake obtained in the step (2) in an oven at 70 ℃, taking out and pressurizing for 30s at the pressure of 7 MPa.

And 4, step 4: and (3) soaking the polypropylene filter membrane attached with the filter cake obtained in the step (3) in butyl acetate for 30s, taking out, spreading the polypropylene filter membrane on a metal flat plate, scraping the polypropylene filter membrane which is not completely dissolved off by using a scraper, and rinsing the polypropylene filter membrane in absolute ethyl alcohol for 30s to remove residues attached to the filter cake, thereby obtaining the filter cake.

And 5: and (4) drying the filter cake obtained in the step (4) in an oven at 70 ℃ to obtain the high-orientation high-filling FeSiAl flexible composite paper.

The mass ratio of FeSiAl platelet particles to nanocellulose was adjusted without changing other conditions, with 0.03g of FeSiAl platelet particles and 0.01g of nanocellulose and 0.04g of FeSiAl platelet particles and 0.01g of nanocellulose as examples 2 and 3.

When the composite paper obtained in example 2 is analyzed by a scanning electron microscope (as shown in fig. 1 (a)), it can be seen that the consistent orientation degree of the FeSiAl flake particles in the paper is very high; fig. 2 shows graphs comparing electromagnetic parameters of example 1 to example 3 with real parts of permeability of a same-proportion non-oriented fesai composite material, and fig. 2(a) is a graph comparing real parts of permeability of three examples with a same-proportion non-oriented fesai composite material; FIG. 2(b) is a graph comparing the imaginary part of the permeability of three examples with that of a comparable non-oriented FeSiAl composite; FIG. 2(c) is a graph comparing the real dielectric parts of three examples with a comparable ratio of unoriented FeSiAl composite; fig. 2(d) is a graph comparing the imaginary part of the permeability of three examples with that of a comparable non-oriented fesai composite. The electromagnetic performance of the composite paper prepared by the invention is more excellent than that of the traditional FeSiAl composite material.

In conclusion, the invention provides a simple and easy preparation method of the FeSiAl composite paper material, and the method can obtain the ultrathin flexible composite paper with high consistent orientation and high filling degree.

Claims

1. A preparation method of high-orientation high-filling FeSiAl flexible composite paper comprises the following steps:

step 1: dispersing FeSiAl flaky particles and nano-cellulose in deionized water according to a ratio to obtain a dispersion liquid A, wherein the mass ratio of the nano-cellulose to the dispersion liquid A is 0.5-5 per mill, and the mass ratio of the FeSiAl flaky particles to the nano-cellulose is 2: 1-20: 1;

step 2: carrying out suction filtration on the dispersion liquid A in an environment with the pressure less than or equal to 0.1MPa by adopting a sand core funnel and a polypropylene microporous filter membrane, and keeping the suction filtration state for at least 6 h;

and step 3: drying the filter membrane attached with the filter cake obtained in the step 2 at 60-80 ℃, and pressurizing at 5-10MPa for at least 10 s;

and 4, step 4: stripping the filter cake and the filter membrane from the filter membrane attached with the filter cake obtained in the step 3 by using a stripping process, and then rinsing the filter membrane in absolute ethyl alcohol to remove polypropylene filter membrane residues attached to the filter cake, so as to obtain the filter cake;

the stripping process comprises the following steps: soaking the polypropylene filter membrane attached with the filter cake in butyl acetate for at least 10s, taking out and spreading the polypropylene filter membrane on a metal flat plate, and finally removing the polypropylene filter membrane which is not completely dissolved;

2. The method for preparing the high-orientation high-filling FeSiAl flexible composite paper as claimed in claim 1, wherein the method comprises the following steps: and (3) carrying out ultrasonic oscillation after the dispersion liquid A is prepared in the step (1), and keeping oscillation until the step (2), wherein the ultrasonic oscillation time is not less than 10 min.