CN114937874A - A kind of preparation method of FeSiAl/Al2O3/resin composite wave absorbing coating - Google Patents

Abstract

The invention discloses FeSiAl/Al ₂ O ₃ The preparation method of the resin composite wave-absorbing coating comprises the following steps of mixing an organic carrier and a diluent, and mechanically stirring to obtain a carrier diluent; flake FeSiAl powder with the grain diameters of 5-8 mu m and 10-12 mu m respectively and alpha-Al ₂ O ₃ Mixing the powder, mixing the mixed powder with the carrier diluent by a three-roll grinder, and obtaining FeSiAl/Al ₂ O ₃ Printing the mixed slurry on a PET film in a screen printing mode, and then putting the PET film into a drying oven for curing to obtain FeSiAl/Al ₂ O ₃ A resin composite wave-absorbing coating. The resin is used as the matrix of the coating, is green and environment-friendly, and the resin adopts a thermosetting molding process, so that the coating has certain high-temperature resistance. The resin is used as a matrix to improve the adhesive force of the coating, and has better adhesive force in the thermal expansion process of the base material.

Description

A kind of preparation method of FeSiAl/Al2O3/resin composite wave absorbing coating

technical field

The invention belongs to the technical field of coating preparation, in particular to a preparation method of a FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating.

Background technique

In general, absorbing materials can be divided into coating and structural absorbing materials. Structural absorbing materials are not only strong in absorption but also light in weight, high in hardness and good in strength. The coating type can also be called an absorbing coating. By mixing a binder and an absorbent, it is applied to the target surface to form an absorbing coating. It was applied during World War II, and later in the United States, Britain, etc The state has made great progress, and there is still a big gap between my country's absorbing coatings and foreign advanced ones. The specific performance is that the coating density is high, the adhesion is low, and the flexibility is poor. Therefore, it is very important to explore a composite absorbing material coating preparation process with simple process and strong adhesion.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of FeSiAl/Al ₂ O ₃ /resin composite wave absorbing coating, which solves the problem of poor adhesion of the coating prepared by the existing method.

The technical scheme adopted in the present invention is, a preparation method of FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating, which is specifically implemented according to the following steps:

Step 1, the organic carrier and the diluent are mixed, and mechanical stirring is carried out at normal temperature to obtain the carrier dilution;

Step 2, mixing flake FeSiAl powder with particle diameters of 5 μm to 8 μm and 10 μm to 12 μm and α-Al ₂ O ₃ powder to obtain mixed powder;

Step 3, mixing the mixed powder and the carrier diluent using a three-roll mill to obtain FeSiAl/Al ₂ O ₃ mixed slurry;

In step 4, the FeSiAl/Al ₂ O ₃ mixed slurry prepared in step 3 is printed on the PET film by screen printing, and then the film is put into a drying oven with a temperature of 120° C. for curing to obtain FeSiAl /Al ₂ O ₃ /resin composite absorbing coating.

The present invention is also characterized in that,

In step 1, the organic carrier is any one or more of polyester resin, polyurethane, vinyl acetate resin and epoxy resin; the diluent is divalent ester or propylene glycol methyl ether acetate.

In step 1, the mass ratio of the organic carrier to the diluent is 7-10:2-4; the stirring speed is 300r/min; and the stirring time is 10-15min.

In step 2, the mass ratio of flake FeSiAl powder to α-Al ₂ O ₃ powder is 1:0.1-0.3; the mass ratio of FeSiAl powder with small particle size to FeSiAl powder with large particle size is 1:3～ 8; The particle size of the α-Al ₂ O ₃ powder is 0.2 μm, and the purity is 99.999%.

In step 3, the mixing time is 30min-1h, the viscosity of the prepared mixed slurry is controlled between 20-80 Pa·s, and the solid content is between 30%-60%.

In step 4, the thickness of the paste printed on the PET film is controlled at 0.8-3mm; the curing time is 10min-20min.

The beneficial effect of the invention is that the resin is used as the substrate of the coating, which is green and environmentally friendly, and the resin adopts a thermosetting molding process, so that the coating has a certain high temperature resistance performance. Resin as a matrix improves the adhesion of the coating and has better adhesion during the thermal expansion of the substrate.

Description of drawings

Fig. 1 is a graph showing the reflection loss of FeSiAl/Al ₂ O ₃ /resin composite wave absorbing coatings with different thicknesses prepared in Example 1;

Fig. 2 is a graph of reflection loss of FeSiAl/Al ₂ O ₃ /resin composite wave absorbing coatings with different thicknesses prepared in Example 2;

3 is a graph showing the reflection loss of FeSiAl/Al ₂ O ₃ /resin composite wave absorbing coatings with different thicknesses prepared in Example 3;

4 is a graph of reflection loss curves of FeSiAl/Al ₂ O ₃ /resin composite wave absorbing coatings prepared in Example 4 with different thicknesses.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

A preparation method of FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating of the present invention is specifically implemented according to the following steps:

Step 1, the organic carrier and the diluent are mixed, and mechanical stirring is carried out at normal temperature to obtain the carrier dilution;

The organic carrier is any one or more of polyester resin, polyurethane, vinyl acetate resin and epoxy resin;

The diluent is dibasic acid ester (DBE) or propylene glycol methyl ether acetate (PMA);

The mass ratio of organic carrier to diluent is 7-10:2-4;

The stirring speed is 300r/min; the stirring time is 10-15min;

Step 2, mixing flake FeSiAl powder with particle diameters of 5 μm to 8 μm and 10 μm to 12 μm and α-Al ₂ O ₃ powder to obtain mixed powder;

The mass ratio of flake FeSiAl powder to α-Al ₂ O ₃ powder is 1:0.1-0.3;

The mass ratio of FeSiAl powder with small particle size to FeSiAl powder with large particle size is 1:3-8;

The particle size of the α-Al ₂ O ₃ powder is 0.2 μm and the purity is 99.999%;

In step 3, the mixed powder and the carrier diluent are mixed with a three-roll mill, and the mixing time is 30 min to 1 h to obtain FeSiAl/Al ₂ O ₃ mixed slurry;

The viscosity of the prepared mixed slurry is controlled between 20 and 80 Pa·s, and the solid content is between 30% and 60%;

In step 4, the FeSiAl/Al ₂ O ₃ mixed slurry prepared in step 3 is printed on the PET film by screen printing, and then the film is put into a drying oven with a temperature of 120° C. for curing to obtain FeSiAl /Al ₂ O ₃ /resin composite absorbing coating;

The thickness of the paste printed on the PET film is controlled at 0.8-3mm;

The curing time is 10min to 20min.

In the FeSiAl/Al ₂ O ₃ composite wave absorbing coating of the present application, FeSiAl has the advantages of low cost, simple process, large anisotropy, good chemical stability, etc., but the FeSiAl particles themselves have narrow wave absorption and poor impedance matching. The addition of Al ₂ O ₃ improves the impedance matching of FeSiAl, and the composite of FeSiAl and Al ₂ O ₃ can greatly optimize the performance through the mutual complementation of different electromagnetic loss types.

Example 1

A preparation method of FeSiAl/Al ₂ O ₃ /resin composite wave absorbing coating of the present invention is specifically implemented according to the following steps.

Step 1, the organic carrier and the diluent are mixed, and mechanical stirring is carried out at normal temperature to obtain the carrier dilution;

The organic carrier is chloroacetate resin and epoxy resin with a mass ratio of 2:1;

The diluent is dibasic acid ester (DBE);

The mass ratio of organic carrier to diluent is 7:2;

The stirring speed is 300r/min; the stirring time is 10min;

Step 2, mixing flake FeSiAl powder with particle diameters of 5 μm and 10 μm and α-Al ₂ O ₃ powder to obtain mixed powder;

The mass ratio of flake FeSiAl powder to α-Al ₂ O ₃ powder is 1:0.1;

The mass ratio of FeSiAl powder with small particle size and FeSiAl powder with large particle size is 1:3;

The particle size of the α-Al ₂ O ₃ powder is 0.2 μm and the purity is 99.999%;

In step 3, the mixed powder and the carrier diluent are mixed with a three-roll mill, and the mixing time is 30 min to obtain FeSiAl/Al ₂ O ₃ mixed slurry;

The viscosity of the prepared mixed slurry is controlled at 63.2Pa·s, and the solid content is at 46.5%;

In step 4, the FeSiAl/Al ₂ O ₃ mixed slurry prepared in step 3 is printed on the PET film by screen printing, and the thickness of the slurry printed on the PET film is controlled at 0.8 mm; then the film is placed in the PET film. The temperature is 120℃ for curing in a drying oven, and the curing time is 10min, and then the FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating can be obtained;

The adhesion grade of the composite wave absorbing coating is 0. According to the IOS12944-6 standard, the adhesion of grade 1 and above is qualified. Level 0 is completely smooth, without any grid delamination, and maintains its original shape. There is a small piece of peeling at the level 1 intersection with a 5% area of influence. The rest of the grades are unqualified. A rating of 0 indicates that the coating has good adhesion.

The test results of the absorbing performance, that is, the reflection loss curve of the composite absorbing coating is shown in Figure 1. The thickness is 2mm, the reflectivity is -19.4dB at 8.2GHz, and the effective frequency width less than -10dB is 1GHz (8.2-9.2GHz). , the absorption width is moderate. When the thickness of the sample is greater than 2.2mm, the reflection loss is lower than -10dB. Under thinner conditions, the coating has better absorbing performance.

Example 2

A preparation method of FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating of the present invention is specifically implemented according to the following steps:

Step 1, the organic carrier and the diluent are mixed, and mechanical stirring is carried out at normal temperature to obtain the carrier dilution;

The organic carrier is epoxy resin;

The diluent is a dibasic acid ester;

The mass ratio of organic carrier to diluent is 7:4;

The stirring speed is 300r/min; the stirring time is 15min;

Step 2, mixing flake FeSiAl powder with particle diameters of 5 μm and 12 μm and α-Al ₂ O ₃ powder to obtain mixed powder;

The mass ratio of flake FeSiAl powder to α-Al ₂ O ₃ powder is 1:0.3;

The mass ratio of FeSiAl powder with small particle size to FeSiAl powder with large particle size is 1:5;

The particle size of the α-Al ₂ O ₃ powder is 0.2 μm and the purity is 99.999%;

In step 3, the mixed powder and the carrier diluent are mixed with a three-roll mill, and the mixing time is 50h to obtain FeSiAl/Al ₂ O ₃ mixed slurry;

The viscosity of the prepared mixed slurry is controlled at 44.5Pa·s, and the solid content is at 33%;

In step 4, the FeSiAl/Al ₂ O ₃ mixed slurry prepared in step 3 is printed on the PET film by screen printing, and the thickness of the slurry printed on the PET film is controlled at 1 mm; then the film is placed in a temperature The FeSiAl/Al ₂ O ₃ /resin composite wave absorbing coating can be obtained by curing in a drying oven at 120°C, and the curing time is 10 min; the adhesion grade of the composite wave absorbing coating is 0;

The test results of the absorbing performance, that is, the reflection loss curve of the composite absorbing coating is shown in Figure 2. The effective frequency width of the reflectivity less than -10dB is 2.4GHz (8.2-10.6GHz), which is relatively good. The thickness is 2mm, and the frequency is 9.6GHz. The reflectivity is -17.8dB and the peak is shifted towards higher frequencies. When the coating thickness is less than 2.6mm, the absorbing performance is relatively good within the effective frequency width. The absorbing performance is excellent when the thickness of the coating is 2mm.

Example 3

A preparation method of FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating of the present invention is specifically implemented according to the following steps:

Step 1, the organic carrier and the diluent are mixed, and mechanical stirring is carried out at normal temperature to obtain the carrier dilution;

The organic carrier is polyester resin;

The diluent is propylene glycol methyl ether acetate (PMA);

The mass ratio of organic carrier to diluent is 10:3;

The stirring speed is 300r/min; the stirring time is 15min;

Step 2, mixing flake FeSiAl powder with particle diameters of 5 μm and 10 μm and α-Al ₂ O ₃ powder to obtain mixed powder;

The mass ratio of flake FeSiAl powder to α-Al ₂ O ₃ powder is 1:0.1;

The mass ratio of FeSiAl powder with small particle size to FeSiAl powder with large particle size is 1:8;

The particle size of the α-Al ₂ O ₃ powder is 0.2 μm and the purity is 99.999%;

In step 3, the mixed powder and the carrier diluent are mixed with a three-roll mill, and the mixing time is 1 h to obtain FeSiAl/Al ₂ O ₃ mixed slurry;

The viscosity of the prepared mixed slurry is controlled at 26.4Pa·s, and the solid content is at 60%;

In step 4, the FeSiAl/Al ₂ O ₃ mixed slurry prepared in step 3 is printed on the PET film by screen printing, and the thickness of the slurry printed on the PET film is controlled at 1.5 mm; then the film is placed in the PET film. The temperature is 120℃ for curing in a drying oven, and the curing time is 20min, then the FeSiAl/Al ₂ O ₃ /resin composite wave absorbing coating can be obtained; the adhesion level of the composite wave absorbing coating is 1, which means that the coating The layer has good adhesion.

The test results of the absorbing performance, that is, the reflection loss curve of the composite absorbing coating is shown in Figure 3. The effective frequency width less than -10dB is 3GHz (8.2-11.2GHz), the thickness is 2mm, and the reflectivity at 9.7GHz is -16.1dB , the single peak continues to shift to the left with the increase of Al ₂ O ₃ content, and the effective frequency width less than -10dB is 2.8GHz (8.2-11.0GHz), which is excellent. When the thickness of the coating is less than 2.4mm, the wave-absorbing performance of the coating is significantly better than that of the coating with a thickness greater than 2.4mm. The absorbing performance is excellent when the thickness of the coating is 2mm.

Example 4

A preparation method of FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating of the present invention is specifically implemented according to the following steps:

Step 1, the organic carrier and the diluent are mixed, and mechanical stirring is carried out at normal temperature to obtain the carrier dilution;

The organic carrier is chloroacetate resin;

The diluent is divalent ester (DBE); the mass ratio of organic carrier to diluent is 7:4;

The stirring speed is 300r/min; the stirring time is 10min;

Step 2, mixing flake FeSiAl powder with particle diameters of 8 μm and 10 μm and α-Al ₂ O ₃ powder to obtain mixed powder;

The mass ratio of flake FeSiAl powder to α-Al ₂ O ₃ powder is 1:0.3;

The mass ratio of FeSiAl powder with small particle size to FeSiAl powder with large particle size is 1:8;

The particle size of the α-Al ₂ O ₃ powder is 0.2 μm and the purity is 99.999%;

In step 3, the mixed powder and the carrier diluent are mixed with a three-roll mill, and the mixing time is 30 min to 1 h to obtain FeSiAl/Al ₂ O ₃ mixed slurry;

The viscosity of the prepared mixed slurry is controlled at 72.3Pa·s, and the solid content is between 57.9%;

In step 4, the FeSiAl/Al ₂ O ₃ mixed slurry prepared in step 3 is printed on the PET film by screen printing, and the thickness of the slurry printed on the PET film is controlled at 3 mm; then the film is placed in a temperature The FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating can be obtained by curing in a drying oven at 120°C and the curing time is 15min;

The adhesion grade of the composite wave absorbing coating is 1, which means that the coating has good adhesion.

The test results of the absorbing performance, that is, the reflection loss curve of the composite absorbing coating, are shown in Figure 4. When the thickness of the composite coating is 2.0mm, 2.2mm, and 2.4mm, the minimum reflectance values are 9.7GHz, 8.3GHz, and 8.2GHz, respectively. It is -19.1dB, -14.3dB, -14.0dB. When the thickness is greater than 2.4mm, the absorbing performance is poor, and when the thickness is less than 2.4mm, the effective frequency width less than -10dB is 2.8GHz (8.2-11.0GHz), which is excellent. The absorbing performance is excellent when the thickness of the coating is 2mm.

Claims (6)

1. a preparation method of FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating, is characterized in that, is specifically implemented according to the following steps: Step 1, the organic carrier and the diluent are mixed, and mechanical stirring is carried out at normal temperature to obtain the carrier dilution; Step 2, mixing flake FeSiAl powder with particle diameters of 5 μm to 8 μm and 10 μm to 12 μm and α-Al ₂ O ₃ powder to obtain mixed powder; Step 3, mixing the mixed powder and the carrier diluent using a three-roll mill to obtain FeSiAl/Al ₂ O ₃ mixed slurry; In step 4, the FeSiAl/Al ₂ O ₃ mixed slurry prepared in step 3 is printed on the PET film by screen printing, and then the film is put into a drying oven with a temperature of 120° C. for curing to obtain FeSiAl /Al ₂ O ₃ /resin composite absorbing coating. 2. the preparation method of a kind of FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating according to claim 1, is characterized in that, in described step 1, organic carrier is polyester resin, polyurethane, vinyl acetate resin , any one or more of epoxy resins; the diluent is divalent ester or propylene glycol methyl ether acetate. 3. the preparation method of a kind of FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating according to claim 1, is characterized in that, in described step 1, the mass ratio of organic carrier and thinner is 7-10 : 2-4; stirring speed is 300r/min; stirring time is 10-15min. 4. The preparation method of a FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating according to claim 1, wherein in the step 2, flake FeSiAl powder and α-Al ₂ O ₃ The mass ratio of powder is 1:0.1-0.3; the mass ratio of FeSiAl powder with small particle size and FeSiAl powder with large particle size is 1:3-8; the particle size of α-Al ₂ O ₃ powder is 0.2 μm , with a purity of 99.999%. 5 . The preparation method of a FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating according to claim 1 , wherein in the step 3, the mixing time is 30 min to 1 h, and the prepared mixed slurry The viscosity of the material is controlled between 20 and 80 Pa·s, and the solid content is between 30% and 60%. 6. The preparation method of a FeSiAl/Al ₂ O ₃ /resin composite wave-absorbing coating according to claim 1, wherein in the step 4, the thickness of the slurry printed on the PET film is controlled at 0.8-3mm; curing time is 10min～20min.

Images