CN116275026A - A kind of preparation method of aluminum silicon carbide material based on plasma deposition - Google Patents

Abstract

The invention discloses a method for preparing an aluminum silicon carbide material based on plasma deposition, comprising the following steps: 1) particle gradation; 2) preliminary coating; 3) thermal spray coating; 4) plasma deposition 5) hot isostatic Pressing the rough billet finally yields aluminum silicon carbide. The invention discloses a method for preparing an aluminum silicon carbide material based on plasma deposition, and obtains an aluminum silicon carbide material with a high volume fraction of silicon carbide, low porosity, high thermal conductivity and adjustable coefficient of thermal expansion.

Description

A kind of preparation method of aluminum silicon carbide material based on plasma deposition

technical field

The disclosure of the present invention relates to the technical field of preparation of aluminum silicon carbide materials, in particular to a preparation method of aluminum silicon carbide materials based on plasma deposition.

Background technique

Aluminum silicon carbide material is an inorganic non-metallic particle reinforced metal-based material that uses aluminum alloy as the matrix, and silicon carbide in a certain form, proportion and distribution state as the reinforcement according to the design requirements. Due to its light weight, high specific strength, high thermal conductivity, adjustable thermal expansion coefficient and other excellent mechanical and thermophysical properties, it is widely used in electronic packaging, precision instruments, automotive parts, aerospace and other fields.

There are many methods for preparing aluminum silicon carbide materials, and the common ones are stirring casting method, powder metallurgy method, infiltration casting method, and spray deposition method. Among them, the spray deposition method is a forming process that combines the metal liquid atomization and deposition process to prepare metal composite materials under the action of inert gas. The process includes matrix metal melting, liquid metal atomization, particle addition and metal atomization. Mixing, deposition and solidification of streams, etc. The spray deposition method utilizes the characteristics of rapid solidification, the temperature required for production is relatively low, and the contact time between particles is very short, which can significantly refine the grains, avoid macro segregation, reduce interface reactions, reduce the degree of oxidation, and strengthen the body. The volume fraction and size of the product can be unlimited, and the comprehensive performance of the product has been greatly improved.

Although the process of the spray deposition method is relatively short, and the process and technology are relatively simple, the cost of the equipment is high, and the utilization rate of the powder raw material is low, generally only 20-30%, and the obtained composite material has a large porosity. Generally, further processing and densification in combination with hot isostatic pressing or extrusion is required.

Contents of the invention

In view of this, the present disclosure provides a method for preparing an aluminum silicon carbide material based on plasma deposition to obtain an aluminum silicon carbide material with a high volume fraction, low porosity, high thermal conductivity, and high bending strength.

The technical solution provided by the present invention is specifically, a method for preparing an aluminum silicon carbide material based on plasma deposition, comprising the following steps:

1) Particle gradation: select silicon carbide powder and aluminum alloy powder with different particle sizes respectively; obtain spare silicon carbide powder and aluminum alloy powder;

2) The silicon carbide powder and aluminum alloy powder prepared in the mixing step 1) are mixed to obtain a mixed powder, and the mixed powder is initially coated by adding a modifier by mechanical means;

3) performing thermal spray coating on the preliminarily coated powder to obtain aluminum alloy coated silicon carbide powder;

4) Plasma depositing the aluminum alloy coated silicon carbide powder to obtain a rough blank of aluminum silicon carbide material;

5) Hot isostatic pressing the rough billet to finally obtain aluminum silicon carbide.

In the step 1), two or more silicon carbide powders with different particle sizes are selected, and the mass ratio of small particles: medium particles: large particles in the silicon carbide powders with different particle sizes is: 3/3/4-2 /3/5; the particle size of the silicon carbide powder is 0.1-500 μm; the particle size of the aluminum alloy powder is 0.1-100 μm.

The aluminum alloy powder is one of high-purity aluminum powder, 6061 aluminum alloy powder, and 7050 aluminum alloy powder.

Step 2) The volume ratio of silicon carbide in the mixed powder is 40-50%.

The mechanical means in step 2) is to use a high-energy ball mill, the high-energy ball mill is zirconia balls, the material/ball mass ratio is 1/2; the rotation speed of the high-energy ball mill is 2000-3000rpm, and the ball milling time is 2-5h.

The mass percentage of modifier added in step 2) is less than or equal to 3%.

The modifying agent is one of stearic acid, paraffin and resin.

Step 3) specifically includes:

a. Add the preliminarily coated powder into the mixer, and then add water as a solvent, wherein the mass ratio of material to water is 1/1-1/2;

b. Then add a binder to the above solution, the added mass percentage of the binder is less than or equal to 3%; stir after adding the binder, the stirring time is 0.5-2h; wherein the binder is PVA, one of the resins;

c. Perform thermal spray coating treatment on the stirred slurry, wherein the nozzle size is Ф0.5-2mm, the spray temperature is 150-190°C, and the spray pressure is 0.05-0.1Mpa, and finally aluminum alloy coated silicon carbide powder is obtained.

The parameters involved in the plasma deposition described in step 4) are sequentially set as follows:

The diameter of the nozzle outlet is 6-12mm; the distance between the spray gun and the substrate is 5-15cm, the argon gas flow rate is 1000-2000 L/min; the arcing current is 500-800A; the hydrogen gas flow rate is controlled by the voltage, and the voltage is 60-80V; The powder feeding speed of the spray gun in the powder machine is 5-50g/min; the deposition times of the manipulator is 5-30 times/time.

Step 5) The conditions of the medium hot isostatic pressing are: the protective gas is nitrogen, the pressure is 10-20MPa, the temperature is 800-1000°C, and the holding time is 1-5h.

The invention provides a method for preparing an aluminum silicon carbide material based on plasma deposition, using silicon carbide and aluminum alloy powders of different types and particle sizes for reasonable particle gradation, and combining mechanical coating and thermal spray coating Combined, a single, uniform coating powder suitable for plasma spray deposition is prepared, which is beneficial to the progress of plasma deposition and the improvement of product performance.

The high-performance aluminum-silicon carbide composite material prepared by the method of the present invention has a volume fraction of silicon carbide between 40-50%, a density of 3±0.1g/cm ³ , and a thermal conductivity of more than 200W/(m·k). , the coefficient of thermal expansion (6.5-12.5)*10 ^-6 /k can be adjusted within the range, the size meets the needs of products, and has a good application prospect.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure.

Detailed ways

Exemplary embodiments will be described here in detail. The implementations described in the following exemplary examples do not represent all implementations consistent with the present invention. Rather, they are merely examples of systems consistent with aspects of the invention as recited in the appended claims.

In order to solve the problems of low utilization rate of aluminum silicon carbide materials and large porosity of composite materials in the prior art, this embodiment provides a preparation method of aluminum silicon carbide materials based on plasma deposition, and different particle sizes are selected according to requirements. Carry out reasonable particle gradation for silicon carbide and aluminum alloy powders; then perform high-energy ball milling on the powders, and use mechanical forces such as extrusion, impact, shearing, and friction to evenly distribute the modifier on the outer surface of the powder particles, so that each The two components infiltrate and diffuse each other to form a preliminary coating; then add appropriate dispersants and binders, mix and ball mill to form a slurry, and thermally spray the slurry to complete the final coating of the powder , through the reaction to generate a uniform mixed powder that meets the deposition conditions; through the parameter control of the plasma deposition process, the utilization rate of the powder will be improved, and the rough billet of the aluminum silicon carbide material will be precipitated; the rough billet will be subjected to hot isostatic pressing. Finally, a silicon carbide material with high volume fraction, low porosity, high thermal conductivity and high bending strength is prepared.

The process of preparing aluminum silicon carbide materials by plasma deposition mainly includes powder selection, mechanical coating, thermal spray coating, plasma deposition, hot isostatic pressing and post-processing.

The specific implementation steps are as follows:

1) Particle gradation: select silicon carbide powder and aluminum alloy powder with different particle sizes respectively; obtain spare silicon carbide powder and aluminum alloy powder;

According to the requirements of silicon carbide volume fraction, density, thermal conductivity, and thermal expansion coefficient of the target product, within the range of 0.1-500um, select two or more silicon carbide powders with different particle sizes for use, and the particle gradation is: small particles The mass ratio of /medium particle/large particle is 3/3/4 to 2/3/5, and the size difference of particles of different grades is usually more than 10 times; choose different types of aluminum alloy powders with a particle size of 0.1-100um, such as high Pure aluminum powder, 6061 aluminum alloy powder, 7050 aluminum alloy powder;

2) The spare silicon carbide powder and aluminum alloy powder selected in the mixing step 1) to obtain a mixed powder, and the mixed powder is initially coated by adding a modifier by mechanical means;

Add the above-mentioned selected powder into the high-energy ball mill, wherein the volume ratio of silicon carbide is 40-50%; add stearic acid, paraffin, resin and other modifiers to the additives, and the mass ratio thereof does not exceed 3%; then use zirconia grinding balls, the material/ball mass ratio is 1/2; the rotation speed of the high-energy ball mill is 2000-3000rpm, and the ball milling time is 2-5h;

3) performing thermal spray coating on the preliminarily coated powder to obtain aluminum alloy coated silicon carbide powder;

Put the pre-coated powder into the mixer, then add water as a solvent, the mass ratio of material to water is 1/1-1/2; add PVA, resin and other modifiers to the binder, and the mass ratio does not exceed 3%; The stirring time is 0.5-2h; thermal spray coating treatment is carried out on the stirred slurry, the nozzle size is Ф0.5-2mm, the spray temperature is 150-190°C, and the spray pressure is 0.05-0.1Mpa to obtain uniform particle size and good fluidity aluminum alloy coated silicon carbide powder.

4) Plasma depositing the aluminum alloy coated silicon carbide powder to obtain a rough blank of aluminum silicon carbide material;

Adjust the spray gun nozzle according to the volume fraction, density, thermal conductivity, and thermal expansion coefficient of silicon carbide. The nozzle outlet diameter is 6-12mm; adjust the distance between the spray gun and the substrate to 5-15cm, and the main power supply of the spray deposition equipment; turn on the hydrogen, Argon and nitrogen main switches, turn on the switch of the water cooling device; on the deposition control cabinet, press power start and work preparation in sequence, and manually adjust whether the argon flow is 1000-2000L/min. After the arc is successfully started, adjust the current on the deposition control cabinet to 500- 800A; the hydrogen flow rate is controlled by the voltage, adjust the voltage to 60-80V; start the powder feeder, send the coated powder into the spray gun, and the powder feeding speed is 5-50g/min; start the manipulator, and the deposition times are 5-30 times/ After the deposition is completed, turn off the switches of the manipulator, powder feeder, gas, electric control device, and water cooling device in order to complete the deposition.

The above-mentioned spray deposition is carried out in a single-fluid manner, which avoids the mutual interference of the two-fluid deposition, ensures the performance of the material, and reduces energy consumption and production cycle at the same time.

Under lower pressure, using single-fluid powder-feeding plasma jet deposition, the utilization rate of the powder can be increased to 40-50%, the crystal grains of the product can be significantly refined, macro segregation can be avoided, and interface reactions can be reduced, which is beneficial Improve product performance

5) Hot isostatic pressing the rough billet to finally obtain aluminum silicon carbide.

Place the rough billet of aluminum silicon carbide material in the kiln furniture, and carry out hot isostatic pressing treatment on the rough billet. Choose nitrogen that does not react with silicon carbide and aluminum alloy as the protective gas, pressure 10-20MPa, temperature 800-1000°C, and holding time 1-5h. After cooling, the aluminum-silicon carbide composite material is obtained. According to the requirements of the product size, it is processed in the later stage to prepare the aluminum-silicon carbide product.

This embodiment uses silicon carbide and aluminum alloy powders of different types and particle sizes for reasonable particle gradation, and combines mechanical coating and thermal spray coating to prepare a single, uniform coating suitable for plasma spray deposition. Coated powder is conducive to the progress of plasma deposition and the improvement of product performance.

Example 1

1) Powder selection: select silicon carbide powders with particle sizes of 0.1um, 1um, and 10um in three different particle sizes for standby, and the mass ratio of small particles/medium particles/large particles in the particle gradation is 3/3/4 for standby;

Select the 6061 aluminum alloy powder with a particle size of 0.1um and 5um for later use.

2) Mechanical cladding:

According to the density requirement that the product density is greater than 3g/cm ³ , add the above powder into the high-energy ball mill, and the volume ratio of silicon carbide is 50%;

Add stearic acid as modifier, and its mass ratio is 1%;

Use zirconia grinding balls, the material/ball mass ratio is 1/2;

The rotation speed of the high-energy ball mill is 3000rpm, and the ball milling time is 5h;

3) Thermal spray coating:

Put the above powder into the mixer, then add water as a solvent, the mass ratio of material to water is 1/2;

The binder is added with resin and other modifiers, the mass ratio is 1%; the stirring time is 2h;

The stirred slurry is subjected to thermal spray coating treatment, the nozzle size is Ф0.5mm, the spray temperature is 190°C, and the spray pressure is 0.1Mpa to obtain an aluminum alloy coated silicon carbide powder with uniform particle size and good fluidity.

4) Plasma deposition:

Adjust the nozzle of the spray gun according to the product requirements, and the diameter of the nozzle outlet is 6mm;

Adjust the distance between the spray gun and the substrate to 5cm, the main power supply of the spray deposition equipment; turn on the main switches of hydrogen, argon, and nitrogen, and turn on the switch of the water cooling device;

On the deposition control cabinet, press power start and work preparation in sequence, and manually adjust the argon gas flow rate to 1000L/min. After the arc is started successfully, adjust the current to 500A on the deposition control cabinet; the hydrogen gas flow rate is controlled by the voltage, and the voltage is adjusted to 60V;

Start the powder feeder, send the coated powder into the spray gun, and the powder feeding speed is 5g/min;

Start the manipulator, the number of deposits is 5 times/time

After the deposition is completed, turn off the switches of the manipulator, powder feeder, gas, electric control device, and water cooling device in sequence to complete the deposition and obtain a rough billet of aluminum silicon carbide material.

5) Hot isostatic pressing and post-processing

The rough blank of silicon carbide material is placed in the kiln furniture, and the rough blank is subjected to hot isostatic pressing treatment.

Choose nitrogen that does not react with silicon carbide and aluminum alloy as the protective gas, the pressure is 10MPa, the temperature is 80°C, and the holding time is 1h.

After cooling, the aluminum-silicon carbide composite material is obtained. According to the requirements of the product size, it is processed in the later stage to prepare an aluminum-silicon carbide product of 200mm*200mm.

Example 2

1) Powder selection:

Select silicon carbide powders with particle sizes of 1um, 10um, and 150um in three different sizes for use, and the mass ratio of small particles/medium particles/large particles in the particle gradation is 2/3/5 for use;

(2) Select the 7050 aluminum alloy powder with a particle size of 0.1um or 1um for later use.

2) Mechanical cladding:

According to the performance requirement that the thermal expansion coefficient of the product is greater than 10*10 ^-6 /°C, the appeal powder is added to the high-energy ball mill, and the volume ratio of silicon carbide is 45%;

The additive is added to paraffin as a modifying agent, and its mass ratio is 2%;

Use zirconia grinding balls, the material/ball mass ratio is 1/2;

The rotation speed of the high-energy ball mill is 2500rpm, and the ball milling time is 3h;

3) Thermal spray coating:

Put the above powder into the mixer, then add water as a solvent, the mass ratio of material to water is 2/3;

Add PVA as modifier, its mass percent content is 2%; Stirring time is 1h;

The stirred slurry is subjected to thermal spray coating treatment, the nozzle size is Ф1mm, the spray temperature is 190°C, and the spray pressure is 0.1Mpa to obtain an aluminum alloy coated silicon carbide powder with uniform particle size and good fluidity.

4) Plasma deposition:

Adjust the nozzle of the spray gun according to the product requirements, and the diameter of the nozzle outlet is 9mm;

Adjust the distance between the spray gun and the substrate to 10cm, the main power supply of the spray deposition equipment; turn on the main switches of hydrogen, argon, and nitrogen, and turn on the switch of the water cooling device;

On the deposition control cabinet, press power start and work preparation in sequence, and manually adjust the argon gas flow rate to 1500L/min. After the arc is started successfully, adjust the current to 700A on the deposition control cabinet; the hydrogen gas flow rate is controlled by the voltage, and the voltage is adjusted to 70V;

Start the powder feeder, send the coated powder into the spray gun, and the powder feeding speed is 30g/min;

Start the manipulator, the number of deposits is 15 times/time

After the deposition is completed, turn off the switches of the manipulator, powder feeder, gas, electric control device, and water cooling device in sequence to complete the deposition and obtain a rough billet of aluminum silicon carbide material.

5) Hot isostatic pressing and post-processing

The rough billet obtained from the aluminum silicon carbide material is placed in kiln furniture, and the rough billet is subjected to hot isostatic pressing treatment.

Nitrogen that does not react with silicon carbide and aluminum alloy is selected as the protective gas, the pressure is 15MPa, the temperature is 900°C, and the holding time is 3h.

After cooling, the aluminum silicon carbide composite material is obtained, and according to the requirements of the product size, it is processed in the later stage to prepare an aluminum silicon carbide product of 100mm*100mm

Example 3

1) Powder selection:

Select two silicon carbide powders with particle size of 50um and 500um for standby, and the particle gradation is 7/3 for standby;

Select the 7050 aluminum alloy powder with a particle size of 50um and 100m for later use.

2) Mechanical cladding:

According to the performance requirement that the thermal conductivity of the product is greater than 200W/(m·k)(25°C), the appeal powder is added to the high-energy ball mill, and the volume ratio of silicon carbide is 40%;

Add resin as modifier, its mass ratio is 3%;

Use zirconia grinding balls, the material/ball mass ratio is 1/2;

The rotation speed of the high-energy ball mill is 2000rpm, and the ball milling time is 2h;

3) Thermal spray coating:

Put the above powder into the mixer, then add water as a solvent, the mass ratio of material to water is 1/1;

Add resin and other modifiers, the mass ratio is 0.5%; stirring time is 0.5h;

The stirred slurry is subjected to thermal spray coating treatment, the nozzle size is Ф2mm, the spray temperature is 150°C, and the spray pressure is 0.05Mpa to obtain an aluminum alloy coated silicon carbide powder with uniform particle size and good fluidity.

4) Plasma deposition:

Adjust the nozzle of the spray gun according to the product requirements, and the diameter of the nozzle outlet is 12mm;

Adjust the distance between the spray gun and the substrate to 15cm, the main power supply of the spray deposition equipment; turn on the main switches of hydrogen, argon, and nitrogen, and turn on the switch of the water cooling device;

On the deposition control cabinet, press power start and work preparation in sequence, and manually adjust the argon gas flow rate to 2000L/min. After the arc is started successfully, adjust the current to 800A on the deposition control cabinet; the hydrogen gas flow rate is controlled by the voltage, and the voltage is adjusted to 80V;

Start the powder feeder, send the coated powder into the spray gun, and the powder feeding speed is 50g/min;

Start the manipulator, and the number of deposits is 30 times/time;

After the deposition is completed, turn off the switches of the manipulator, powder feeder, gas, electric control device, and water cooling device in sequence to complete the deposition.

5) Hot isostatic pressing and post-processing

Put the silicon carbide preform and the aluminum alloy profile into the kiln furniture, and perform hot isostatic pressing on the rough billet.

Nitrogen which does not react with silicon carbide and aluminum alloy is selected as the protective gas, the pressure is 20MPa, the temperature is 1000°C, and the holding time is 5h.

After cooling, the aluminum-silicon carbide composite material is obtained. According to the requirements of the product size, it is processed in the later stage to prepare an aluminum-silicon carbide product of 100mm*50mm.

Comparative example 1

Using the process steps in the prior art: including: powder selection and mixing, plasma deposition, hot isostatic pressing, post-processing and other steps; the results obtained are compared with the data results of this embodiment as follows:

This implementation plan Other Deposition Processes Powder utilization 40-50% 20-30% Silicon carbide volume fraction% 40-50% 30-40% density% 3±0.1 2.5±0.3 Thermal conductivityW/(m·k)(25℃) >200 180±10 Coefficient of thermal expansion*10 ^-6 /℃ 6-12.5 7-9

Other embodiments of the invention will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present invention, these modifications, uses or adaptations follow the general principles of the present invention and include common knowledge or conventional technical means in the technical field not disclosed in the present invention . The specification and examples are to be considered exemplary only, with the true scope and spirit of the invention indicated by the appended claims.

It should be understood that the present invention is not limited to the precise constructions that have been described above, and various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims (10)

1. A method for preparing an aluminum silicon carbide material based on plasma deposition, characterized in that, comprising the steps: 1) Particle gradation: select silicon carbide powder and aluminum alloy powder with different particle sizes respectively; obtain spare silicon carbide powder and aluminum alloy powder; 2) The silicon carbide powder and aluminum alloy powder prepared in the mixing step 1) are mixed to obtain a mixed powder, and the mixed powder is initially coated by adding a modifier by mechanical means; 3) performing thermal spray coating on the preliminarily coated powder to obtain aluminum alloy coated silicon carbide powder; 4) Plasma depositing the aluminum alloy coated silicon carbide powder to obtain a rough blank of aluminum silicon carbide material; 5) Hot isostatic pressing the rough billet to finally obtain aluminum silicon carbide. 2. a kind of preparation method based on the aluminum silicon carbide material of plasma deposition according to claim 1, it is characterized in that, in described step 1), select two or more than two kinds of silicon carbide powders of different particle sizes, described The mass ratio of small particles: medium particles: large particles in silicon carbide powders of different particle sizes is: 3/3/4-2/3/5; the particle size of the silicon carbide powder is 0.1-500 μm; the aluminum alloy powder The particle size of the body is 0.1-100 μm. 3. a kind of preparation method based on the aluminum silicon carbide material of plasma deposition according to claim 2, is characterized in that, described aluminum alloy powder is high-purity aluminum powder, 6061 aluminum alloy powder, 7050 aluminum alloy powder kind of. 4. A method for preparing an aluminum silicon carbide material based on plasma deposition according to claim 1, characterized in that the volume ratio of silicon carbide in the mixed powder in step 2) is 40-50%. 5. a kind of preparation method based on the aluminum silicon carbide material of plasma deposition according to claim 1, is characterized in that, step 2) described mechanical means is to adopt high-energy ball mill, and described high-energy ball mill is zirconia grinding ball, The material/ball mass ratio is 1/2; the rotation speed of the high-energy ball mill is 2000-3000rpm, and the ball milling time is 2-5h. 6 . A method for preparing an aluminum silicon carbide material based on plasma deposition according to claim 1 , wherein the modifier is added in a mass percentage of less than or equal to 3% in step 2). 7 . 7. A method for preparing an aluminum silicon carbide material based on plasma deposition according to claim 6, wherein the modifying agent is one of stearic acid, paraffin, and resin. 8. a kind of preparation method based on the aluminum silicon carbide material of plasma deposition according to claim 1, is characterized in that, step 3) specifically comprises: a. Add the preliminarily coated powder into the mixer, and then add water as a solvent, wherein the mass ratio of material to water is 1/1-1/2; b. Then add a binder to the above solution, the added mass percentage of the binder is less than or equal to 3%; stir after adding the binder, the stirring time is 0.5-2h; wherein the binder is PVA, one of the resins; c. Perform thermal spray coating treatment on the stirred slurry, wherein the nozzle size is Ф0.5-2mm, the spray temperature is 150-190°C, and the spray pressure is 0.05-0.1Mpa, and finally aluminum alloy coated silicon carbide powder is obtained. 9. A method for preparing an aluminum silicon carbide material based on plasma deposition according to claim 1, wherein the parameters involved in the plasma deposition in step 4) are sequentially set as follows: The diameter of the nozzle outlet is 6-12mm; the distance between the spray gun and the substrate is 5-15cm, the argon gas flow rate is 1000-2000L/min; the arcing current is 500-800A; the hydrogen gas flow rate is controlled by the voltage, and the voltage is 60-80V; The powder feeding speed of the spray gun in the device is 5-50g/min; the deposition times of the manipulator is 5-30 times/time. 10. A method for preparing an aluminum silicon carbide material based on plasma deposition according to claim 1, wherein the conditions of hot isostatic pressing in step 5) are: the protective gas is nitrogen, the pressure is 10-20MPa, and the temperature 800-1000℃, holding time 1-5h.