A method for preparing aluminum silicon carbide material based on plasma deposition

Abstract

The application discloses a preparation method of aluminum silicon carbide material based on plasma deposition, which comprises the following steps: 1) particle grading; 2) preliminary coating; 3) thermal spray coating; 4) plasma deposition; and 5) hot isostatic pressing of the rough blank, and finally aluminum silicon carbide is obtained. The application discloses a preparation method of aluminum silicon carbide material based on plasma deposition, and aluminum silicon carbide material with high silicon carbide volume fraction, low porosity, high thermal conductivity and adjustable thermal expansion coefficient is obtained.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of aluminum silicon carbide material preparation, and particularly relates to a preparation method of aluminum silicon carbide material based on plasma deposition. BACKGROUND

[0002] The aluminum silicon carbide material is a kind of inorganic non-metallic particle reinforced metal matrix material which is compounded by using aluminum alloy as a matrix and a certain form, proportion and distribution state of silicon carbide as a reinforcing body according to design requirements. Due to excellent mechanical and thermophysical properties such as light weight, high specific strength, high thermal conductivity and adjustable thermal expansion coefficient, the aluminum silicon carbide material is widely used in the fields of electronic packaging, precision instruments, automobile parts, aerospace and the like.

[0003] There are many methods for preparing the aluminum silicon carbide material, and common methods include stirring casting, powder metallurgy, infiltration casting and spray deposition. Among them, the spray deposition method is a forming process for preparing metal composites under the action of inert gas by combining the processes of metal liquid atomization and deposition. The process includes melting of the matrix metal, atomization of the liquid metal, mixing of the particles and the atomized metal flow, deposition and solidification and the like. The spray deposition method utilizes the characteristics of rapid solidification, and the required temperature is relatively low, the contact time between particles is very short, the grains can be significantly refined, macrosegregation can be avoided, the interface reaction can be reduced, the oxidation degree can be reduced, the volume fraction and size of the reinforcing body are not limited, and the comprehensive performance of the product is greatly improved.

[0004] 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 relatively high, and the utilization rate of the powder raw material is relatively low, generally only 20-30%, the porosity of the prepared composite material is relatively large, and generally it is necessary to combine hot isostatic pressing or extrusion for further processing and densification. SUMMARY

[0005] In view of this, the present disclosure provides a preparation method of aluminum silicon carbide material based on plasma deposition, so as to obtain aluminum silicon carbide material with high volume fraction, low porosity, high thermal conductivity and high bending strength.

[0006] The technical scheme provided by the present disclosure is specifically a preparation method of aluminum silicon carbide material based on plasma deposition, which comprises the following steps:

[0007] 1) Particle grading: selecting silicon carbide powder and aluminum alloy powder with different particle sizes respectively; obtaining standby silicon carbide powder and aluminum alloy powder;

[0008] 2) mixing the standby silicon carbide powder and aluminum alloy powder in step 1) to obtain a mixed powder, and adding a modifier to the mixed powder by mechanical means for preliminary coating;

[0009] 3) the primary coated powder is subjected to thermal spray coating to obtain an aluminum alloy coated silicon carbide powder;

[0010] 4) the aluminum alloy coated silicon carbide powder is subjected to plasma deposition to obtain a rough blank of aluminum silicon carbide material;

[0011] 5) the rough blank is subjected to hot isostatic pressing to obtain aluminum silicon carbide.

[0012] In step 1), two or more different particle sizes of silicon carbide powder are selected, and the mass ratio of small particles: medium particles: large particles in the different particle sizes of silicon carbide powder is 3 / 3 / 4-2 / 3 / 5; the particle size of the silicon carbide powder is 0.1-500 μm; and the particle size of the aluminum alloy powder is 0.1-100 μm.

[0013] The aluminum alloy powder is one of high-purity aluminum powder, 6061 aluminum alloy powder, and 7050 aluminum alloy powder.

[0014] In step 2), the volume ratio of silicon carbide in the mixed powder is 40-50%.

[0015] In step 2), the mechanical means is a high-energy ball mill, the high-energy ball mill is a zirconia grinding ball, and the mass ratio of material to ball is 1 / 2; the rotation speed of the high-energy ball mill is 2000-3000 rpm, and the ball milling time is 2-5 h.

[0016] In step 2), the addition amount of the modifier is less than or equal to 3%.

[0017] The modifier is one of stearic acid, paraffin, and resin.

[0018] Step 3) specifically includes:

[0019] a. The primary coated powder is added to a stirrer, and water is added as a solvent, wherein the mass ratio of material to water is 1 / 1-1 / 2;

[0020] b. A binder is further added to the above solution, the addition amount of the binder is less than or equal to 3%, and stirring is performed after the binder is added, the stirring time is 0.5-2 h; wherein the binder is one of PVA and resin;

[0021] c. The stirred slurry is subjected to thermal spray coating treatment, wherein the nozzle size is Ф0.5-2 mm, the spray temperature is 150-190℃, the spray pressure is 0.05-0.1 Mpa, and finally the aluminum alloy coated silicon carbide powder is obtained.

[0022] In step 4), the parameters involved in the plasma deposition are set as follows:

[0023] The diameter of the nozzle outlet is 6-12mm; the distance between the spray gun and the base body is 5-15cm, the argon flow is 1000-2000 L / min; the arc current is 500-800A; the hydrogen flow is controlled by voltage, the voltage is 60-80V; the powder feeding speed of the spray gun in the powder feeder is 5-50g / min; the deposition times of the mechanical hand are 5-30 times / time.

[0024] The hot isostatic pressing condition in step 5) is that the protective gas is nitrogen, the pressure is 10-20MPa, the temperature is 800-1000℃, and the holding time is 1-5h.

[0025] The application provides a preparation method of an aluminum silicon carbide material based on plasma deposition, different types and different particle sizes of silicon carbide and aluminum alloy powder are reasonably graded, a mechanical coating and a thermal spray coating are combined, a single and uniform coated powder suitable for plasma jet deposition is prepared, and the plasma deposition is facilitated and the product performance is improved.

[0026] The high-performance aluminum silicon carbide composite material prepared by the method has a silicon carbide volume fraction of 40-50%, a density of 3±0.1g / cm 3 , a thermal conductivity of more than 200W / (m·k), an adjustable thermal expansion coefficient of (6.5-12.5)*10 -6 / k, and a size meeting the product requirement, and has a good application prospect.

[0027] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the disclosure of the application. DETAILED DESCRIPTION

[0028] The exemplary embodiments will be described in detail here. The embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. Instead, they are only examples of systems consistent with some aspects of the present application as detailed in the appended claims.

[0029] To solve the problems of low utilization rate of aluminum silicon carbide material and large porosity of composite material in the prior art, the embodiment provides a preparation method of aluminum silicon carbide material based on plasma deposition. Silicon carbide and aluminum alloy powder of different particle sizes are selected according to requirements for reasonable particle grading. Then, the powder is subjected to high-energy ball milling, and mechanical forces such as extrusion, impact, shearing and friction are used to uniformly distribute the modifier on the outer surface of the powder particles, so that various components penetrate and diffuse into each other to form a preliminary coating. Then, appropriate dispersants and binders are added, mixed and ball milled to form a slurry, and the slurry is subjected to thermal spray treatment to complete the final coating of the powder. The reaction generates a uniform mixed powder that meets the deposition conditions. Through parameter control in the plasma deposition process, the utilization rate of the powder is improved, and the aluminum silicon carbide material is deposited. The roughcast is subjected to hot isostatic pressing. Finally, the silicon carbide material with high volume fraction, low porosity, high thermal conductivity and high bending strength is prepared.

[0030] The process for preparing aluminum silicon carbide material by plasma deposition mainly includes powder selection, mechanical coating, thermal spray coating, plasma deposition, hot isostatic pressing and post-processing.

[0031] The specific implementation steps are as follows:

[0032] 1) Particle grading: select silicon carbide powder and aluminum alloy powder of different particle sizes respectively; obtain the standby silicon carbide powder and aluminum alloy powder;

[0033] According to the requirements of the target product for the volume fraction, density, thermal conductivity and thermal expansion coefficient of silicon carbide, two or more than two kinds of silicon carbide powder of different particle sizes in the range of 0.1-500um are selected for standby, and the particle grading is 3 / 3 / 4 to 2 / 3 / 5 in mass ratio of small particles / medium particles / large particles. The size of different grades of particles usually differs by more than 10 times. Different types of aluminum alloy powder with particle sizes of 0.1-100um are selected, such as high-purity aluminum powder, 6061 aluminum alloy powder and 7050 aluminum alloy powder.

[0034] 2) Mix the standby silicon carbide powder and aluminum alloy powder selected in step 1) to obtain a mixed powder, and use mechanical means to preliminarily coat the mixed powder by adding a modifier;

[0035] The above selected powder is added to a high-energy ball mill, and the volume ratio of silicon carbide is 40-50%; stearic acid, paraffin, resin and other modifiers are added as modifiers, and the mass ratio is not more than 3%; zirconia grinding balls are used, and the mass ratio of material to ball is 1 / 2; the high-energy ball mill rotates at 2000-3000rpm, and the ball milling time is 2-5h;

[0036] 3) The preliminarily coated powder is subjected to thermal spray coating to obtain aluminum alloy coated silicon carbide powder;

[0037] The primary coated powder is added into a stirring machine, and water is added as a solvent, with a material-to-water mass ratio of 1 / 1-1 / 2; a binder is added, with a mass ratio of no more than 3% of a modified agent such as PVA and resin; the stirring time is 0.5-2 h; the stirred slurry is subjected to hot spray coating treatment, with a spray port size of Ф0.5-2 mm, a spray temperature of 150-190℃, and a spray pressure of 0.05-0.1 Mpa, to obtain an aluminum alloy coated silicon carbide powder with uniform particle size and good fluidity.

[0038] 4) Plasma deposition of the aluminum alloy coated silicon carbide powder to obtain a rough blank of an aluminum silicon carbide material;

[0039] The spray gun nozzle is adjusted according to the performance requirements of the volume fraction, density, thermal conductivity, and thermal expansion coefficient of the silicon carbide, with a nozzle outlet diameter of 6-12 mm; the distance between the spray gun and the substrate is adjusted to 5-15 cm, the main power supply of the spray deposition equipment is adjusted, the main switches of hydrogen, argon, and nitrogen are opened, and the water cooling device switch is opened; the power supply start and work preparation on the deposition control cabinet are sequentially pressed, and whether the argon flow is within 1000-2000 L / min is manually adjusted, after the arc striking is successful, the current on the deposition control cabinet is adjusted to 500-800 A; the hydrogen flow is controlled by the voltage, and the voltage is adjusted to 60-80 V; the powder feeder is started, the coated powder is fed into the spray gun, the powder feeding speed is 5-50 g / min; the manipulator is started, and the deposition frequency is 5-30 times / time; after the deposition is completed, the manipulator, the powder feeder, the gas, the electric control device, and the water cooling device switches are sequentially closed, and the deposition is completed.

[0040] The above spray deposition is performed in a single fluid mode, which avoids the mutual interference of double fluid deposition, ensures the performance of the material, and reduces energy consumption and production cycle.

[0041] The utilization rate of the powder is increased to 40-50% by using single fluid powder feeding plasma spray deposition at a low pressure, the product grain is significantly refined, macrosegregation is avoided, and interface reaction is reduced, which is conducive to improving the performance of the product

[0042] 5) Hot isostatic pressing of the rough blank to finally obtain an aluminum silicon carbide.

[0043] The rough blank of the aluminum silicon carbide material is placed in a kiln, and the rough blank is subjected to hot isostatic pressing treatment. Nitrogen, which does not react with silicon carbide and aluminum alloy, is selected as a protective gas, with a pressure of 10-20 MPa, a temperature of 800-1000℃, and a holding time of 1-5 h. After cooling, an aluminum silicon carbide composite material is obtained, which is subjected to post-processing according to the size requirements of the product to prepare an aluminum silicon carbide product.

[0044] The present embodiment uses different kinds and different particle sizes of silicon carbide and aluminum alloy powder, and combines mechanical coating and thermal spray coating to prepare a single and uniformly coated powder suitable for plasma jet deposition, which is beneficial to plasma deposition and improvement of product performance.

[0045] Example 1

[0046] 1) Powder selection: three different particle sizes of silicon carbide powder with particle sizes of 0.1 um, 1 um and 10 um are selected for standby, and the particle size grading of small particles / middle particles / large particles is 3 / 3 / 4 by mass ratio;

[0047] 6061 aluminum alloy powder with particle sizes of 0.1 um and 5 um is selected for standby.

[0048] 2) Mechanical coating:

[0049] According to the density requirement of the product with a density greater than 3 g / cm 3 , the above powder is added to a high-energy ball mill, and the volume ratio of silicon carbide is 50%;

[0050] Stearic acid is added as a modifier, and the mass ratio is 1%;

[0051] Zirconium oxide grinding balls are used, and the material / ball mass ratio is 1 / 2;

[0052] The high-energy ball mill rotates at 3000 rpm, and the ball milling time is 5h;

[0053] 3) Thermal spray coating:

[0054] The above powder is added to a stirrer, and water is added as a solvent, and the material / water mass ratio is 1 / 2;

[0055] A binder is added to a resin modifier, and the mass ratio is 1%; the stirring time is 2h;

[0056] The stirred slurry is subjected to thermal spray coating treatment, the nozzle size is Ф0.5mm, the spray temperature is 190℃, the spray pressure is 0.1Mpa, and the aluminum alloy coated silicon carbide powder with uniform particle size and good flowability is obtained.

[0057] 4) Plasma deposition:

[0058] According to the product requirements, the spray gun nozzle is adjusted, and the nozzle outlet diameter is 6mm;

[0059] The distance between the spray gun and the substrate is adjusted to 5cm, the main power supply of the spray deposition equipment is turned on, the main switches of hydrogen, argon and nitrogen are turned on, and the water cooling device switch is turned on;

[0060] Deposition control cabinet in turn press the power start, work preparation, manual adjustment of argon flow is 1000L / min, after the arc success, deposition control cabinet to adjust the current to 500A; hydrogen flow is controlled by voltage, adjust the voltage to 60V;

[0061] Start the powder feeder, the powder coated into the spray gun, powder feeding speed is 5g / min;

[0062] Start the manipulator, deposition times 5 times / time

[0063] Deposition end in turn off the manipulator, powder feeder, gas, electric control device, water cooling device switch, complete the deposition, get the aluminum silicon carbide material rough.

[0064] 5) hot isostatic pressing and later processing

[0065] The silicon carbide material rough placed in the kiln, the rough heat isostatic pressing treatment.

[0066] Selecting nitrogen gas which does not react with silicon carbide and aluminum alloy as protective gas, pressure 10MPa, 80℃ temperature, holding time 1h.

[0067] After cooling, get the aluminum silicon carbide composite material, according to the product size requirements, to its later processing, preparation of 200mm*200mm aluminum silicon carbide products.

[0068] Example 2

[0069] 1) powder selection:

[0070] Selecting three different particle size silicon carbide powder with particle size of 1um, 10um, 150um, the mass ratio of particle gradation small particles / medium particles / large particles is 2 / 3 / 5, standby;

[0071] (2) selecting 7050 aluminum alloy powder with particle size of 0.1um, 1um, standby.

[0072] 2) mechanical coating:

[0073] According to the performance requirements of the product thermal expansion coefficient greater than 10*10 -6 / ℃, the above powder is added into the high energy ball mill, the volume ratio of silicon carbide is 45%;

[0074] Additives added paraffin as modifier, the mass ratio is 2%;

[0075] Using zirconium oxide grinding ball, the mass ratio of material / ball is 1 / 2;

[0076] High energy ball mill rotation is 2500rpm, ball milling time is 3h;

[0077] 3) Thermal spray coating:

[0078] The above powder is added to the blender, and water is added as a solvent, with a material-to-water mass ratio of 2 / 3.

[0079] PVA is added as a modifier, with a mass percentage of 2%; the stirring time is 1 h.

[0080] The stirred slurry is subjected to thermal spray coating treatment, with a spray port size of Φ1 mm, a spray temperature of 190°C, and a spray pressure of 0.1 Mpa, to obtain an aluminum alloy-coated silicon carbide powder with uniform particle size and good flowability.

[0081] 4) Plasma deposition:

[0082] The spray gun nozzle is adjusted according to product requirements, with a nozzle outlet diameter of 9 mm.

[0083] The distance between the spray gun and the substrate is adjusted to 10 cm, and the main power supply of the spray deposition equipment is turned on; the main switches of hydrogen, argon, and nitrogen are opened, and the water cooling device switch is turned on.

[0084] The power supply start and work preparation switches on the deposition control cabinet are pressed in sequence; the argon flow rate is manually adjusted to 1500 L / min; after successful arcing, the current on the deposition control cabinet is adjusted to 700 A; the hydrogen flow rate is controlled by voltage, and the voltage is adjusted to 70 V.

[0085] The powder feeder is started, and the coated powder is fed into the spray gun at a feed rate of 30 g / min.

[0086] The robot is started, and the deposition frequency is 15 times per time.

[0087] After deposition, the robot, powder feeder, gas, electric control device, and water cooling device switches are turned off in sequence, the deposition is completed, and an aluminum silicon carbide material roughcast is obtained.

[0088] 5) Hot isostatic pressing and post-processing

[0089] The aluminum silicon carbide material roughcast is placed in a kiln fixture and subjected to hot isostatic pressing treatment.

[0090] Nitrogen, which does not react with silicon carbide and aluminum alloy, is selected as the protective gas, with a pressure of 15 MPa, a temperature of 900°C, and a holding time of 3 h.

[0091] After cooling, an aluminum silicon carbide composite material is obtained, which is subjected to post-processing according to product size requirements to prepare a 100 mm*100 mm aluminum silicon carbide product.

[0092] Example 3

[0093] 1) Powder selection:

[0094] Selecting silicon carbide powder with particle size of 50um and 500um, particle gradation of 7 / 3, standby;

[0095] Selecting 7050 aluminum alloy powder with particle size of 50um and 100m, standby.

[0096] 2) Mechanical coating:

[0097] According to the performance requirement that the thermal conductivity of the product is greater than 200W / (m·k)(25℃), the above powder is added to a high-energy ball mill, and the volume ratio of silicon carbide is 40%;

[0098] Adding resin as modifier, mass ratio of 3%;

[0099] Using zirconium oxide grinding balls, the mass ratio of material to ball is 1 / 2;

[0100] The high-energy ball mill rotates at 2000rpm, and the ball milling time is 2h;

[0101] 3) Thermal spray coating:

[0102] The above powder is added to a stirrer, and water is added as solvent, the mass ratio of material to water is 1 / 1;

[0103] Adding resin and other modifiers, mass ratio of 0.5%; stirring time is 0.5h;

[0104] The stirred slurry is subjected to thermal spray coating treatment, the nozzle size is Ф2mm, the spray temperature is 150℃, the spray pressure is 0.05Mpa, and the aluminum alloy coated silicon carbide powder with uniform particle size and good flowability is obtained.

[0105] 4) Plasma deposition:

[0106] According to the product requirements, adjust the nozzle of the spray gun, the nozzle outlet diameter is 12mm;

[0107] Adjust the distance between the spray gun and the substrate to 15cm, and turn on the main power supply of the spray deposition equipment; turn on the main switches of hydrogen, argon and nitrogen, and turn on the water cooling device switch;

[0108] Press the power start and work preparation on the deposition control cabinet in turn, manually adjust the argon flow to 2000L / min, after successful arc starting, adjust the current on the deposition control cabinet to 800A; the hydrogen flow is controlled by voltage, and the voltage is adjusted to 80V;

[0109] Start the powder feeder and send the coated powder into the spray gun, the powder feeding speed is 50g / min;

[0110] Start the manipulator, and the deposition frequency is 30 times / time;

[0111] After the deposition, the mechanical hand, the powder feeder, the gas, the electric control device and the water cooling device are closed in sequence to complete the deposition.

[0112] 5) Hot isostatic pressing and post-processing

[0113] The silicon carbide preform and the aluminum alloy profile are placed in the kiln furniture, and the rough blank is subjected to hot isostatic pressing treatment.

[0114] Nitrogen, which does not react with silicon carbide and aluminum alloy, is selected as the protective gas, the pressure is 20 MPa, the temperature is 1000°C, and the holding time is 5h.

[0115] After cooling, the aluminum silicon carbide composite material is obtained, and according to the size requirements of the product, the post-processing is carried out to prepare the aluminum silicon carbide product with a size of 100mm*50mm.

[0116] Comparative Example 1

[0117] The process steps in the prior art are used, 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 the present embodiment as follows:

[0118] This embodiment 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 conductivity W / (m-k) (25 °C) >200 180±10 Thermal expansion coefficient * 10 -6 / °C 6-12.5 7-9

[0119] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0120] It should be understood that the application is not limited to the precise construction that has been described above and that various modifications and changes can be made by those skilled in the art that follow from the above description and that the scope of the application should be limited only by the appended claims.

Claims

1. A method for preparing aluminum silicon carbide material based on plasma deposition, characterized in that, Includes the following steps: 1) Particle size distribution: Select silicon carbide powder and aluminum alloy powder of different particle sizes respectively; to obtain silicon carbide powder and aluminum alloy powder for use; 2) The silicon carbide powder and aluminum alloy powder prepared in step 1) are mixed to obtain a mixed powder. The mixed powder is initially coated by adding a modifier using mechanical means. 3) The pre-coated powder is then subjected to thermal spray coating to obtain aluminum alloy coated silicon carbide powder; 4) Plasma deposition of the aluminum alloy coated with silicon carbide powder to obtain a blank of aluminum silicon carbide material; 5) The billet is hot isostatically pressed to finally obtain aluminum silicon carbide; In step 1), two or more silicon carbide powders of different particle sizes are selected, wherein the mass ratio of small particles: medium particles: large particles in the silicon carbide powders of different particle sizes is 3:3:4-2:3:5; the particle size of the silicon carbide powder is 0.1-500μm; and the particle size of the aluminum alloy powder is 0.1-100μm. Step 2) The volume ratio of silicon carbide in the mixed powder is 40-50%; The mechanical means mentioned in step 2) is to use a high-energy ball mill, wherein the high-energy ball mill uses zirconia grinding balls, the material-to-ball mass ratio is 1:2, the high-energy ball mill speed is 2000-3000 rpm, and the ball milling time is 2-5 hours; Step 3) specifically includes: a. Add the pre-coated powder to the mixer, and then add water as a solvent, wherein the mass ratio of powder to water is 1:1-1:2; b. Add a binder to the obtained solution, wherein the mass percentage of the binder added is less than or equal to 3%; after adding the binder, stir for 0.5-2 hours; wherein the binder is one of PVA or resin. c. The mixed slurry is subjected to thermal spray coating treatment, with a nozzle size of Ф0.5-2mm, a spray temperature of 150-190℃, and a spray pressure of 0.05-0.1Mpa, to finally obtain aluminum alloy coated silicon carbide powder; The parameters involved in the plasma deposition described in step 4) are set sequentially as follows: The nozzle outlet diameter is 6-12mm; the distance between the spray gun and the substrate is 5-15cm; the argon flow rate is 1000-2000 L / min; the arc ignition current is 500-800A; the hydrogen flow rate is controlled by voltage, which is 60-80V; the powder feeding speed of the spray gun in the powder feeder is 5-50g / min; the number of deposition cycles by the robotic arm is 5-30 times / cycle. Step 5) The conditions for hot isostatic pressing are: nitrogen as the protective gas, pressure 10-20 MPa, temperature 800-1000℃, and holding time 1-5 h.

2. The method for preparing aluminum silicon carbide material based on plasma deposition according to claim 1, characterized in that, The aluminum alloy powder is one of high-purity aluminum powder, 6061 aluminum alloy powder, or 7050 aluminum alloy powder.

3. The method for preparing aluminum silicon carbide material based on plasma deposition according to claim 1, characterized in that, The mass percentage of the modifier added in step 2) is less than or equal to 3%.

4. The method for preparing aluminum silicon carbide material based on plasma deposition according to claim 1, characterized in that, The modifier is one of stearic acid, paraffin, or resin.