A spherical SiC / Al-Si composite powder, a preparation method and application thereof

Abstract

The application relates to a spherical SiC / Al-Si composite powder and a preparation method and application thereof, and belongs to the technical field of nonmetal-containing alloys. The preparation method of the spherical SiC / Al-Si composite powder comprises the following steps: S1, carbonizing reaction of spherical Al-Si pre-alloy powder and a hydrocarbon compound gas (at least one of alkane gas, olefin gas and alkyne gas) at 400-700 DEG C for 1-10 h to obtain carbon-coated spherical Al-Si pre-alloy powder; S2, in-situ reaction of the carbon-coated spherical Al-Si pre-alloy powder in the step S1 in an inert gas atmosphere at 750-1000 DEG C for 0.5-10 h to obtain the spherical SiC / Al-Si composite powder. The spherical SiC / Al-Si composite powder prepared by the preparation method has good fluidity, the SiC content in the spherical SiC / Al-Si composite powder is controllable, and the interface bonding strength between the SiC and the Al matrix is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-metal-containing alloy, in particular to a spherical SiC / Al-Si composite powder and a preparation method and application thereof. BACKGROUND

[0002] SiC reinforced Al matrix composite is widely used in the fields of aviation, aerospace, automobile, military and consumer electronics due to its high thermal conductivity, low thermal expansion coefficient, high strength, high wear resistance, low density and low cost. At present, the preparation methods of SiC / Al matrix composite mainly include liquid-solid forming method and solid-solid forming method. The liquid-solid forming method mainly refers to casting (stirring casting, extrusion casting, etc.) and infiltration (pressureless infiltration, pressure infiltration) process, in which SiC particles are added to molten Al alloy melt or Al alloy melt is infiltrated into the skeleton of SiC preform for solidification forming. The solid-solid forming method mainly refers to powder metallurgy process, including discharge plasma sintering, hot pressing sintering, hot isostatic pressing, powder hot extrusion, injection molding, 3D printing, etc. Al alloy powder and SiC powder are mixed by a mixer or a ball mill and then formed.

[0003] It can be seen that, whether it is liquid-solid forming method or solid-solid forming method, the technical route of external addition is adopted, that is, SiC particles are added to Al alloy melt or Al alloy powder for compounding and then solidification forming. However, since SiC ceramic particles are hard and brittle materials with a hardness close to 30GPa, their morphology is generally irregular with sharp corners, which is difficult to be spheroidized by cold shaping or high temperature plasma. Irregular SiC particles can cause stress concentration in the service process of the composite material, thereby increasing the risk of fracture failure. In addition, SiC ceramic particles have poor wettability with Al melt, and it is difficult to achieve metallurgical bonding. Therefore, surface modification of SiC particles is often needed to improve the interfacial bonding strength, and the surface modification method will inevitably increase the cost and introduce impurities and other unfavorable phases, thereby deteriorating the thermodynamic properties of SiC / Al matrix composite. Moreover, for powder injection molding and 3D printing processes, the morphology and fluidity of the powder are required to be high, and the mixed powder obtained by mixing elemental powder has poor fluidity. Even if the mechanical ball milling can improve the fluidity and uniformity of the mixed powder, the improvement effect is not ideal, and it is difficult to improve the irregular morphology of SiC particles and the poor bonding between Al and SiC. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a spherical SiC / Al-Si composite powder and a preparation method and application thereof.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0006] In a first aspect, the present application provides a method for preparing a spherical SiC / Al-Si composite powder, comprising the following steps:

[0007] S1, carbonizing the spherical Al-Si pre-alloy powder and a hydrocarbon compound gas at 400-700℃ for 1-10h to obtain a carbon-coated spherical Al-Si pre-alloy powder;

[0008] S2, in-situ reacting the carbon-coated spherical Al-Si pre-alloy powder in S1 at 750-1000℃ for 0.5-10h in an inert gas atmosphere to obtain a spherical SiC / Al-Si composite powder;

[0009] The hydrocarbon compound gas in S1 includes at least one of an alkane gas, an alkene gas, and an alkyne gas.

[0010] The present application combines the spherical Al-Si pre-alloy powder and the hydrocarbon compound gas, uses the hydrocarbon compound gas as the carbon source, first forms a carbon coating layer on the surface of the spherical Al-Si pre-alloy powder by in-situ gas deposition, and then obtains a spherical SiC / Al-Si composite powder with good fluidity through in-situ reaction between Al, Si, and C. The SiC content in the spherical SiC / Al-Si composite powder is controllable, the particles are fine and nearly spherical in morphology, and the interface bonding strength with the Al matrix is high. In addition, compared with conventional carbon sources such as graphite powder or phenolic resin, the present application uses the hydrocarbon compound gas as the carbon source and in-situ gas deposition, which not only improves the uniform distribution of carbon, but also effectively prevents powder agglomeration.

[0011] Meanwhile, it is found that when the carbonization reaction temperature in step S1 is too low, the hydrocarbon compound gas cannot be cracked into carbon, and a carbon coating layer cannot be formed on the surface of the spherical Al-Si pre-alloy powder. When the carbonization reaction temperature is too high, the spherical Al-Si pre-alloy powder whose surface has not been coated with a carbon layer will be melted and agglomerated. In addition, the temperature and time of the in-situ reaction in step S2 jointly affect the size of the SiC particles. The higher the temperature and the longer the time of the in-situ reaction, the more conducive to increasing the size of the SiC particles. However, when the temperature exceeds 1000℃, the spherical SiC / Al-Si composite powder will be melted, making it difficult to maintain a spherical shape.

[0012] The above-mentioned spherical Al-Si pre-alloy powder refers to spherical aluminum-silicon alloy particles, which can be obtained by breaking liquid aluminum-silicon alloy into fine droplets and solidifying by the gas mist method. For details, please refer to CN110904368A (Aluminum-silicon electronic packaging material and preparation method thereof).

[0013] Optionally, the temperature of the carbonization reaction in S1 can be any one of 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃ or a range value of any two of them, and the time can be any one of 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h or a range value of any two of them.

[0014] Optionally, the temperature of the in-situ reaction in S2 can be any one of 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃ or a range value of any two of them, and the time can be any one of 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h or a range value of any two of them.

[0015] As a preferred embodiment of the preparation method of the spherical SiC / Al-Si composite powder of the present application, the mass-volume ratio g / mL of the spherical Al-Si pre-alloy powder to the hydrocarbon compound gas is (100-1000):(100-500). Optionally, the mass-volume ratio g / mL of the spherical Al-Si pre-alloy powder to the hydrocarbon compound gas can be 100:100, 200:150, 300:200, 400:250, 500:300, 600:350, 700:400, 800:450, 900:500, 1000:500.

[0016] As a preferred embodiment of the preparation method of the spherical SiC / Al-Si composite powder of the present application, the particle size D 50 of the spherical Al-Si pre-alloy powder is ≤60μm, preferably 1-60μm. Optionally, the particle size D 50 of the spherical Al-Si pre-alloy powder is specifically any one of 1μm, 5μm, 10μm, 15μm, 20μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm or a range value of any two of them. It has been found that the spherical Al-Si pre-alloy powder with the above particle size range can better avoid the aggregation of silicon to form coarse silicon particles during the in-situ reaction, thereby making the in-situ reaction more complete.

[0017] As a preferred embodiment of the preparation method of the spherical SiC / Al-Si composite powder, the spherical Al-Si pre-alloy powder mainly consists of Al and Si, wherein the mass content of Si is 5wt.% to 60wt.%. Optionally, the mass content of Si in the spherical Al-Si pre-alloy powder can be specifically any one of 5wt.%, 10wt.%, 15wt.%, 20wt.%, 25wt.%, 30wt.%, 35wt.%, 40wt.%, 45wt.%, 50wt.%, 55wt.%, 60wt.% or a range value of any two thereof.

[0018] As a preferred embodiment of the preparation method of the spherical SiC / Al-Si composite powder, the mass content of carbon in the carbon-coated spherical Al-Si pre-alloy powder in S1 is 1wt.% to 30wt.%. Optionally, the mass content of carbon in the carbon-coated spherical Al-Si pre-alloy powder can be specifically any one of 1wt.%, 2wt.%, 4wt.%, 6wt.%, 8wt.%, 10wt.%, 12wt.%, 14wt.%, 16wt.%, 18wt.%, 20wt.%, 22wt.%, 24wt.%, 26wt.%, 28wt.%, 30wt.% or a range value of any two thereof. The mass content of carbon in the carbon-coated spherical Al-Si pre-alloy powder can be measured according to the standard GB / T 14265-2017.

[0019] As a preferred embodiment of the preparation method of the spherical SiC / Al-Si composite powder, the mass content of SiC in the spherical SiC / Al-Si composite powder in S2 is 1wt.% to 30wt.%. Optionally, the mass content of SiC in the spherical SiC / Al-Si composite powder can be specifically any one of 1wt.%, 2wt.%, 4wt.%, 6wt.%, 8wt.%, 10wt.%, 12wt.%, 14wt.%, 16wt.%, 18wt.%, 20wt.%, 22wt.%, 24wt.%, 26wt.%, 28wt.%, 30wt.% or a range value of any two thereof. The mass content of SiC in the spherical SiC / Al-Si composite powder can be measured according to the standard GB / T 3045-2017.

[0020] As a preferred embodiment of the preparation method of the spherical SiC / Al-Si composite powder, the alkane gas is at least one of methane, ethane, and propane.

[0021] And / or, the olefin gas is at least one of ethylene, propylene, and butylene.

[0022] And / or, the alkyne gas is at least one of acetylene, propyne.

[0023] As a preferred embodiment of the preparation method of the spherical SiC / Al-Si composite powder, step S1 is specifically: placing the spherical Al-Si pre-alloy powder in an atmosphere rotating tube furnace or a gas fluidized bed, and introducing a hydrocarbon compound gas, and carrying out carbonization reaction at 400-700 DEG C for 1-10 h to obtain carbon-coated spherical Al-Si pre-alloy powder. The atmosphere rotating tube furnace or the gas fluidized bed mainly functions to make the powder flow during the carbonization reaction, so that the uniform coating of carbon is better achieved.

[0024] In a second aspect, the application provides a preparation method of the spherical SiC / Al-Si composite powder prepared by the above preparation method.

[0025] In a third aspect, the application provides an application of the above spherical SiC / Al-Si composite powder in preparing a radio frequency receiver package shell, a radar circuit shell or an engine piston.

[0026] Compared with the prior art, the application has the following beneficial effects:

[0027] The application combines the spherical Al-Si pre-alloy powder and the hydrocarbon compound gas, uses the hydrocarbon compound gas as a carbon source, uses the in-situ gas phase deposition method to form a carbon coating layer on the surface of the spherical Al-Si pre-alloy powder, and then obtains the spherical SiC / Al-Si composite powder with good fluidity through the in-situ reaction among Al, Si and C. The content of SiC in the spherical SiC / Al-Si composite powder is controllable, the particles are small and the morphology is nearly spherical, and the interface bonding strength with the Al matrix is high. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a schematic diagram of the reaction device of the application;

[0029] Figure 2 It is a partial SEM image and an element surface distribution image of the spherical SiC / Al-Si composite powder in Example 1;

[0030] Figure 3 It is an SEM image of the spherical Al-Si pre-alloy powder and the carbon-coated spherical Al-Si pre-alloy powder in Example 1;

[0031] Figure 4 It is a microstructure image of the spherical Al-Si pre-alloy powder and the spherical SiC / Al-Si composite powder in Example 1. DETAILED DESCRIPTION

[0032] In order to better illustrate the purpose, technical scheme and advantages of the application, the application will be further described below in combination with specific embodiments.

[0033] Unless otherwise specified, other materials and reagents used in the examples can be obtained from commercial sources.

[0034] Example 1

[0035] The present invention provides a method for preparing spherical SiC / Al-Si composite powder, comprising the following steps:

[0036] S1. A spherical Al-Si pre-alloyed powder (denoted as Al-12Si, wherein the mass content of Al is 88 wt.%, the mass content of Si is 12 wt.%; the particle size D) is obtained by gas atomization method (refer to CN110904368A for details). 50 =20 μm);

[0037] S2, 500g of the spherical Al-Si pre-alloyed powder in S1 is placed in a rotary tube furnace (such as Figure 1 ), and acetylene gas (gas flow rate of 600 mL / min) was introduced into a rotary tube furnace, and then heated to 600°C at a heating rate of 10°C / min and kept at that temperature for 2 h to obtain a carbon-coated spherical Al-Si pre-alloyed powder (denoted as Al-12Si-5C, i.e., wherein the mass content of carbon is 5 wt.%);

[0038] S3. Heat 500 g of the carbon-coated spherical Al-Si pre-alloyed powder in S2 to 800° C. in an argon atmosphere and keep it for 1 h to obtain spherical SiC / Al-Si composite powder (denoted as Al-7Si-5SiC, where the mass content of SiC is 5 wt.%).

[0039] Figure 2 a is a local SEM image of spherical SiC / Al-Si composite powder, b is the surface distribution map of Al element, c is the surface distribution map of Si element, and d is the surface distribution map of C element; according to Figure 2 It can be seen that the in-situ synthesized SiC particles are small, nearly spherical in shape, and have good interface bonding with the Al matrix without obvious cracks.

[0040] Figure 3 a and c correspond to the SEM images of spherical Al-Si pre-alloyed powder (Al-12Si) and carbon-coated spherical Al-Si pre-alloyed powder (Al-12Si-5C) under low magnification, b and d correspond to the SEM images of spherical Al-Si pre-alloyed powder (Al-12Si) and carbon-coated spherical Al-Si pre-alloyed powder (Al-12Si-5C) under high magnification, respectively; according to Figure 3 It can be seen that by using spherical Al-Si pre-alloyed powder and high-temperature cracking of hydrocarbon compound gas, a layer of carbon can be uniformly coated on the surface of the Al-Si pre-alloyed powder.

[0041] Figure 4 a is a microstructure diagram of the spherical Al-Si pre-alloy powder (Al-12Si), and b is a microstructure diagram of the spherical SiC / Al-Si composite powder (Al-7Si-5SiC); according to Figure 4 It can be found that after the carbonization reaction and in-situ reaction, fine SiC particles are formed in the spherical Al-Si pre-alloy powder and still maintain the spherical morphology.

[0042] Example 2

[0043] The application provides a preparation method of a spherical SiC / Al-Si composite powder, comprising the following steps:

[0044] S1, a spherical Al-Si pre-alloy powder (denoted as Al-40Si, that is, the mass content of Al is 60wt.%, and the mass content of Si is 40wt.%; the particle size D 50 = 20μm) is obtained by using a gas atomization method (for details, refer to CN110904368A);

[0045] S2, 500g of the spherical Al-Si pre-alloy powder in S1 is placed in a rotary tube furnace, and acetylene gas (the gas flow is 600mL / min) is introduced, then the rotary tube furnace is heated to 600℃ at a heating rate of 10℃ / min and kept for 2h, to obtain a carbon-coated spherical Al-Si pre-alloy powder (the mass content of carbon is 5wt.%);

[0046] S3, 500g of the carbon-coated spherical Al-Si pre-alloy powder in S2 is heated to 800℃ in an argon atmosphere and kept for 1h, to obtain a spherical SiC / Al-Si composite powder (the mass content of SiC is 5wt.%).

[0047] Example 3

[0048] The application provides a preparation method of a spherical SiC / Al-Si composite powder, comprising the following steps:

[0049] S1, a spherical Al-Si pre-alloy powder (denoted as Al-12Si, that is, the mass content of Al is 88wt.%, and the mass content of Si is 12wt.%; the particle size D 50 = 20μm) is obtained by using a gas atomization method (for details, refer to CN110904368A);

[0050] S2, 500g of the spherical Al-Si pre-alloy powder in S1 is placed in a gas fluidized bed (such as Figure 1S2, 500g of the spherical Al-Si pre-alloy powder in S1 is placed into a rotary tube furnace, ethylene gas is introduced (gas flow is 600mL / min), and then the rotary tube furnace is heated to 600℃ at a temperature increasing rate of 10℃ / min for 2h, to obtain carbon-coated spherical Al-Si pre-alloy powder (wherein the mass content of carbon is 5wt.%);

[0051] S3, 500g of the carbon-coated spherical Al-Si pre-alloy powder in S2 is heated to 800℃ in an argon atmosphere for 1h, to obtain spherical SiC / Al-Si composite powder (wherein the mass content of SiC is 5wt.%).

[0052] Example 4

[0053] The application provides a preparation method of carbon-coated spherical Al-Si pre-alloy powder, comprising the following steps:

[0054] S1, spherical Al-Si pre-alloy powder (denoted as Al-12Si, that is, the mass content of Al is 88wt.% and the mass content of Si is 12wt.%; particle size D 50 =20μm) is obtained by using a gas atomization method (for a specific reference, CN110904368A);

[0055] S2, 500g of the spherical Al-Si pre-alloy powder in S1 is placed into a rotary tube furnace, ethylene gas is introduced (gas flow is 600mL / min), and then the rotary tube furnace is heated to 600℃ at a temperature increasing rate of 10℃ / min for 2h, to obtain carbon-coated spherical Al-Si pre-alloy powder (wherein the mass content of carbon is 5wt.%);

[0056] S3, 500g of the carbon-coated spherical Al-Si pre-alloy powder in S2 is heated to 800℃ in an argon atmosphere for 1h, to obtain spherical SiC / Al-Si composite powder (wherein the mass content of SiC is 5wt.%).

[0057] Example 5

[0058] The application provides a preparation method of carbon-coated spherical Al-Si pre-alloy powder, comprising the following steps:

[0059] S1, spherical Al-Si pre-alloy powder (denoted as Al-12Si, that is, the mass content of Al is 88wt.% and the mass content of Si is 12wt.%; particle size D 50 =20μm) is obtained by using a gas atomization method (for a specific reference, CN110904368A);

[0060] S2, 500 g of the spherical Al-Si pre-alloy powder in S1 was put into a rotary tube furnace, and acetylene gas was introduced (gas flow rate was 600 mL / min), then the rotary tube furnace was heated to 550℃ at a heating rate of 10℃ / min and kept for 3 h, to obtain carbon-coated spherical Al-Si pre-alloy powder (in which the mass content of carbon was 6 wt.%);

[0061] S3, 500 g of the carbon-coated spherical Al-Si pre-alloy powder in S2 was heated to 800℃ in an argon atmosphere for 1 h, to obtain spherical SiC / Al-Si composite powder (in which the mass content of SiC was 6 wt.%).

[0062] Performance test

[0063] 1) Flowability of the composite powder: Hall flowmeter was used to test the flowability of the powder, a standard funnel with a pore size of 2.5 mm was used, 50 g of powder was taken, and the time was counted from the beginning of the powder leaking from the bottom of the standard funnel to the end of the powder leaking, and the average value was taken by repeating the above process for 3 times.

[0064] 2) Mechanical properties of the composite material: a vertical extruder was used to heat-extrude the spherical SiC / Al-Si composite powder prepared in each example to obtain SiC / Al-Si composite material, and the specific parameters were as follows: extrusion temperature was 450℃, extrusion ratio was 20:1, and extrusion speed was 1 mm / min. Then, a universal testing machine (Instron, 3382, USA) was used to test the tensile strength of the SiC / Al-Si composite material, the tensile rate was 0.5 mm / min, the test standard referred to ASTM, and the tensile test sample was cut along the extrusion direction.

[0065] Table 1: Properties of the spherical SiC / Al-Si composite powder and the corresponding composite material in each example

[0066]

[0067]

[0068] According to the data in Table 1, the flowability of the spherical SiC / Al-Si composite powder in Examples 1-5 was ≤32 s / 50 g, and the tensile strength of the hot-pressed composite material reached 395 MPa or more, indicating that the spherical SiC / Al-Si composite powder prepared by the preparation method of the present application not only has good flowability, but also can make the interface between Al and SiC have high bonding strength, thereby having excellent mechanical properties.

[0069] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for preparing a spherical SiC / Al-Si composite powder, characterized by, The method comprises the following steps: S1, carbonizing the spherical Al-Si pre-alloy powder and a hydrocarbon compound gas at 400-700 DEG C for 1-10 hours to obtain carbon-coated spherical Al-Si pre-alloy powder; S2, in-situ reacting the carbon-coated spherical Al-Si pre-alloy powder in S1 in an inert gas atmosphere at 750-1000 DEG C for 0.5-10 hours to obtain spherical SiC / Al-Si composite powder; The hydrocarbon compound gas in S1 comprises at least one of alkane gas, olefin gas and alkyne gas.

2. The production method according to claim 1, wherein The mass-volume ratio g / mL of the spherical Al-Si pre-alloy powder to the hydrocarbon compound gas is (100-1000):(100-500).

3. The production method according to claim 1, wherein The particle size D of the spherical Al-Si pre-alloyed powder 50 ≤ 60 μm.

4. The production method according to claim 1, wherein The spherical Al-Si pre-alloy powder mainly comprises Al and Si, wherein the mass content of Si is 5wt.%-60wt.%.

5. The production method according to claim 1, wherein The mass content of carbon in the carbon-coated spherical Al-Si pre-alloy powder in S1 is 1wt.%-30wt.%.

6. The production method according to claim 1, wherein The mass content of SiC in the spherical SiC / Al-Si composite powder in S2 is 1wt.%-30wt.%.

7. The production method according to claim 1, wherein The alkane gas is at least one of methane, ethane and propane; The olefin gas is at least one of ethylene, propylene and butylene; The alkyne gas is at least one of acetylene and propyne.

8. The production method according to claim 1, wherein S1 is specifically: placing the spherical Al-Si pre-alloy powder in a gas atmosphere rotary tube furnace or a gas fluidized bed, and introducing the hydrocarbon compound gas, and carbonizing at 400-700 DEG C for 1-10 hours to obtain carbon-coated spherical Al-Si pre-alloy powder.

9. The spherical SiC / Al-Si composite powder prepared by the method in any one of claims 1-8.

10. The application of the spherical SiC / Al-Si composite powder in claim 9 in preparing a radio frequency receiver package shell, a radar circuit shell or an engine piston.

Images