Silicon aluminum target and method for manufacturing the same

Abstract

The application discloses a silicon-aluminum target material and a preparation method thereof, and belongs to the technical field of target material preparation.The preparation method of the silicon-aluminum target material is different from the prior art, wherein the silicon powder and the aluminum powder are subjected to specific pretreatment to obtain a uniform silicon-aluminum alloy, and then the silicon-aluminum alloy is crushed into powder to be subjected to plasma spraying to finally obtain the silicon-aluminum target material.The product has low requirements on equipment, can realize scale production, and effectively solves the problems of aluminum element loss and uneven distribution in the preparation of the silicon-aluminum target material by the plasma spraying, and the aluminum element distribution error of different sites of the silicon-aluminum target material is only 0.2 wt%.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of target material preparation, in particular to a silicon-aluminum target material and a preparation method thereof. BACKGROUND

[0002] In the field of electronic packaging, due to the excellent heat conduction performance, high basic mechanical strength, good plating performance with various metals (gold, silver, etc.), high weldability and easy processing of silicon-aluminum alloy, it is a very popular material for use. However, the existing silicon-aluminum alloy is mostly prepared into a target material by a plasma spraying method. The specific steps are as follows: first, silicon powder and aluminum powder are mixed, then the mixed powder is heated to be molten or semi-molten by using plasma as a heat source, then the molten or semi-molten powder is sprayed at a high speed to the surface of a target substrate to form a dense silicon-aluminum alloy coating, and finally a silicon-aluminum target material is obtained. However, due to the high processing temperature (usually reaching 10000℃) of the existing method, the loss of raw materials, especially the loss of aluminum element, often occurs, which leads to that the aluminum element in the sprayed silicon-aluminum alloy coating is less than the expected amount and is not uniformly distributed. SUMMARY

[0003] Based on the defects of the prior art, the purpose of the present application is to provide a preparation method of a silicon-aluminum target material. The method is different from the prior art. First, silicon powder and aluminum powder are subjected to specific pretreatment to obtain a uniform silicon-aluminum alloy, and then the silicon-aluminum alloy is crushed into powder for plasma spraying to finally obtain a silicon-aluminum target material. The product not only has low requirements for equipment and can realize mass production, but also effectively solves the problem of uneven distribution of aluminum element in the existing plasma sprayed silicon-aluminum target material.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] A preparation method of a silicon-aluminum target material, comprising the following steps:

[0006] (1) mixing and homogenizing a predetermined amount of silicon powder and aluminum powder to obtain a silicon-aluminum mixed powder;

[0007] (2) placing the silicon-aluminum mixed powder into a heating device, removing air in the device with an inert atmosphere, then introducing hydrogen and heating to 400-450℃ for 30-45min in the first stage, and then heating to 580-650℃ for 60-90min in the second stage, and cooling to obtain a silicon-aluminum alloy;

[0008] (3) crushing the silicon-aluminum alloy into a powder with a particle size of 30-150μm, and then spraying the powder on a target substrate by a plasma spraying process to obtain a silicon-aluminum target material.

[0009] Compared with the prior art of directly mixing silicon powder and aluminum powder and then directly preparing a target material by plasma spraying, the raw materials are pre-heated by two-stage heating treatment to form a silicon-aluminum alloy in the preparation method of the silicon-aluminum target material, the aluminum element is effectively fixed and uniformly dispersed in the form of the alloy, and then the silicon-aluminum alloy can be uniformly sprayed on the target material substrate during plasma spraying, the loss of the aluminum element is small, and the aluminum content error of different points of the prepared silicon-aluminum target material is not more than 0.3 wt%.

[0010] Preferably, in the step (1), the particle size of the silicon powder and the aluminum powder is ≤45 μm.

[0011] More preferably, the purity of the silicon powder is ≥3N, and the purity of the aluminum powder is ≥3N.

[0012] Preferably, in the step (1), the mass ratio of the silicon powder to the aluminum powder is (8:2)~(9.5:0.5).

[0013] Preferably, in the step (1), the silicon powder and the aluminum powder are homogenized in a mixer, the total loading amount of the silicon powder and the aluminum powder is 1 / 2~3 / 4 of the solvent of the mixer, the homogenization rate is 30~50 rpm, and the time is 3~5 h.

[0014] In the technical scheme, since the uniformity of the silicon-aluminum mixed powder plays a key role in the quality of the subsequently prepared silicon-aluminum alloy, the two raw materials need to be uniformly mixed by a specific homogenization treatment method.

[0015] Preferably, in the step (2), the heating device is a tube-type atmosphere furnace, and the silicon-aluminum mixed powder is placed in a graphite boat in the tube-type atmosphere furnace.

[0016] Preferably, in the step (2), the heating rate of the first-stage heating and the second-stage heating is 3~5 ℃ / min, and the flow rate of the hydrogen gas is 4~10 L / min.

[0017] In order to guarantee the purity and uniformity of the alloy, the silicon-aluminum mixed powder needs to be heated at a specific heating rate, and a specific flow rate of reducing atmosphere needs to be introduced for protection and reduction. If the heating rate is too fast or too slow, part of the aluminum powder may be oxidized and not reduced, resulting in an unsatisfactory purity and uniformity of the product.

[0018] Preferably, in the step (3), the device for plasma spraying includes a back tube and a spray gun, the spray gun is located at 80~130 mm from the center axis of the back tube, the moving distance is 0.15~0.3 mm / once, the back tube moves back and forth around the center axis during plasma spraying, the rotation speed is 15~25 rpm, the axial movement rate is 40~60 mm / min, and the powder feeding amount is 4~6 kg / h.

[0019] Another object of the present application is to provide the silicon aluminum target prepared by the preparation method.

[0020] A great feature of the silicon aluminum target prepared by the preparation method is that the silicon aluminum alloy has high uniformity and good quality. According to experiments, the error rate of the aluminum element content distribution at different positions of the silicon aluminum target is not more than 0.3wt%, and products with different silicon aluminum element ratios can be prepared according to actual requirements.

[0021] The present application has the advantages that the present application provides a preparation method of a silicon aluminum target. The method is different from the prior art. The silicon powder and the aluminum powder are first subjected to specific pretreatment to obtain a uniform silicon aluminum alloy, and then the silicon aluminum alloy is crushed into powder for plasma spraying to finally obtain a silicon aluminum target. The product has low requirements for equipment, can realize mass production, and effectively solves the problems of aluminum element loss and uneven distribution in the preparation of the silicon aluminum target by the existing plasma spraying. The aluminum element distribution error at different positions of the silicon aluminum target is only 0.2wt%. DETAILED DESCRIPTION

[0022] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples and comparative examples, the purpose of which is to understand the content of the present application in detail, rather than to limit the present application. All other examples obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. The experimental reagents, raw materials and instruments designed in the present application and comparative examples are common ordinary reagents, raw materials and instruments unless otherwise specified.

[0023] Example 1

[0024] An embodiment of the silicon aluminum target and the preparation method thereof, the preparation method comprises the following steps:

[0025] (1) A predetermined amount of silicon powder and aluminum powder (mass ratio 90:10) with an average particle size of 40μm are mixed and placed in a mixer (the amount of placement is 3 / 4 of the volume of the mixer) under the protection of an inert atmosphere and homogenized at a speed of 40rpm for 5h to obtain a silicon aluminum mixed powder;

[0026] (2) The silicon aluminum mixed powder is placed in a graphite boat and placed in a tubular atmosphere furnace. After removing the internal air by introducing an inert atmosphere with a volume of 3 times the volume of the tubular atmosphere furnace, hydrogen gas is introduced at a flow rate of 5L / min and heated to 450℃ for 35min in the first stage, and then heated to 600℃ for 60min in the second stage. After cooling, switch to an inert atmosphere until it cools to room temperature to obtain a silicon aluminum alloy. The heating rate of the heating is 5℃ / min;

[0027] (3) crushing the silicon-aluminum alloy into a powder with a particle size of 30-150 μm, and then spraying the powder on a target substrate by plasma spraying to obtain the silicon-aluminum target; the device used for plasma spraying comprises a back tube and a spray gun, the spray gun is located at a distance of 100 mm from the central axis of the back tube, and the moving distance is 0.2 mm per time; the back tube moves back and forth along the central axis during plasma spraying, the rotating speed is 20 rpm, the axial moving speed is 50 mm / min, and the powder feeding amount is 5 kg / h.

[0028] Example 2

[0029] In an embodiment of the silicon-aluminum target and the preparation method thereof, the preparation method comprises the following steps:

[0030] (1) mixing a predetermined amount of silicon powder and aluminum powder (mass ratio 92:8) with an average particle size of 40 μm under the protection of an inert atmosphere, and placing the mixture in a mixer (the amount of the mixture is 1 / 2 of the volume of the mixer) at a speed of 40 rpm for 4 h to obtain a silicon-aluminum mixed powder;

[0031] (2) placing the silicon-aluminum mixed powder in a graphite boat and placing the graphite boat in a tube-type atmosphere furnace, removing the internal air by introducing an inert atmosphere with a volume of 3 times the volume of the tube-type atmosphere furnace, then introducing hydrogen at a flow rate of 5 L / min and heating to 400 ℃ for 45 min in the first stage, and then heating to 600 ℃ for 90 min in the second stage, switching to an inert atmosphere after cooling to reduce the temperature, and cooling to room temperature to obtain a silicon-aluminum alloy; the heating rate is 10 ℃ / min;

[0032] (3) crushing the silicon-aluminum alloy into a powder with a particle size of 30-150 μm, and then spraying the powder on a target substrate by plasma spraying to obtain the silicon-aluminum target; the device used for plasma spraying comprises a back tube and a spray gun, the spray gun is located at a distance of 100 mm from the central axis of the back tube, and the moving distance is 0.2 mm per time; the back tube moves back and forth along the central axis during plasma spraying, the rotating speed is 20 rpm, the axial moving speed is 50 mm / min, and the powder feeding amount is 5 kg / h.

[0033] Example 3

[0034] In an embodiment of the silicon-aluminum target and the preparation method thereof, the preparation method comprises the following steps:

[0035] (1) mixing a predetermined amount of silicon powder and aluminum powder (mass ratio 95:5) with an average particle size of 40 μm under the protection of an inert atmosphere, and placing the mixture in a mixer (the amount of the mixture is 3 / 4 of the volume of the mixer) at a speed of 40 rpm for 4 h to obtain a silicon-aluminum mixed powder;

[0036] (2) the silicon-aluminum mixed powder is placed in a graphite boat and put into a tube atmosphere furnace, after removing the internal air by passing in an inert atmosphere with a volume of 2.5 times the volume of the tube atmosphere furnace, hydrogen is passed in at a flow rate of 6 L / min and heated to 430℃ for 45 min in a first heating stage, then heated to 580℃ for 90 min in a second heating stage, after cooling, the inert atmosphere is switched until the temperature is cooled to room temperature, to obtain a silicon-aluminum alloy; the heating rate of the heating is 5℃ / min;

[0037] (3) the silicon-aluminum alloy is crushed into a powder with a particle size of 30-150 μm, and then sprayed on a target substrate by plasma spraying to obtain a silicon-aluminum target material; the device used for plasma spraying includes a back tube and a spray gun, the spray gun is located at 100 mm from the center axis of the back tube, and the moving distance is 0.2 mm / time; the back tube moves back and forth around the axis during plasma spraying, the rotating speed is 20 rpm, the axial movement rate is 50 mm / min, and the powder feeding amount is 5 kg / h.

[0038] Example 4

[0039] One embodiment of the silicon-aluminum target material and the preparation method thereof according to the application is different from example 1 only in that the heating rate of the heating in step (2) is 8℃ / min.

[0040] Comparative Example 1

[0041] A silicon-aluminum target material and a preparation method thereof, which are different from example 1 only in that the preparation method comprises the following steps:

[0042] (1) a predetermined amount of silicon powder and aluminum powder (mass ratio of 90:10) with an average particle size of 40 μm are mixed under the protection of an inert atmosphere and put into a mixer (the amount of the put-in is 3 / 4 of the volume of the mixer) to homogenize at a speed of 40 rpm for 5 h, to obtain a silicon-aluminum mixed powder;

[0043] (2) the silicon-aluminum mixed powder is sprayed on a target substrate by plasma spraying to obtain a silicon-aluminum target material; the device used for plasma spraying includes a back tube and a spray gun, the spray gun is located at 100 mm from the center axis of the back tube, and the moving distance is 0.2 mm / time; the back tube moves back and forth around the axis during plasma spraying, the rotating speed is 20 rpm, the axial movement rate is 50 mm / min, and the powder feeding amount is 5 kg / h.

[0044] Comparative Example 2

[0045] A silicon-aluminum target material and a preparation method thereof, which are different from example 1 only in that step (2) is:

[0046] The silicon-aluminum mixed powder is placed in a graphite boat and put into a tube atmosphere furnace. After removing the internal air by introducing an inert atmosphere with a volume of 3 times the volume of the tube atmosphere furnace, hydrogen is introduced at a flow rate of 5 L / min and heated to 600°C for 95 min. After cooling, the inert atmosphere is switched until it cools to room temperature, and a silicon-aluminum alloy is obtained. The heating rate is 5°C / min.

[0047] Comparative Example 3

[0048] A silicon-aluminum target and a method for preparing the same, the difference from Example 1 is only that the step (2) is:

[0049] The silicon-aluminum mixed powder is placed in a graphite boat and put into a tube atmosphere furnace. After removing the internal air by introducing an inert atmosphere with a volume of 3 times the volume of the tube atmosphere furnace, hydrogen is introduced at a flow rate of 5 L / min and heated to 600°C for 95 min. After cooling, the inert atmosphere is switched until it cools to room temperature, and a silicon-aluminum alloy is obtained. The heating rate is 5°C / min.

[0050] Comparative Example 4

[0051] A silicon-aluminum target and a method for preparing the same, the difference from Example 1 is only that the step (2) is:

[0052] The silicon-aluminum mixed powder is placed in a graphite boat and put into a tube atmosphere furnace. After removing the internal air by introducing an inert atmosphere with a volume of 3 times the volume of the tube atmosphere furnace, hydrogen is introduced at a flow rate of 5 L / min and heated to 600°C for 95 min. After cooling, the inert atmosphere is switched until it cools to room temperature, and a silicon-aluminum alloy is obtained. The heating rate is 5°C / min.

[0053] Comparative Example 5

[0054] A silicon-aluminum target and a method for preparing the same, the difference from Example 1 is only that the step (2) is:

[0055] The silicon-aluminum mixed powder is placed in a graphite boat and put into a tube atmosphere furnace. After removing the internal air by introducing an inert atmosphere with a volume of 3 times the volume of the tube atmosphere furnace, hydrogen is introduced at a flow rate of 5 L / min and heated to 600°C for 95 min. After cooling, the inert atmosphere is switched until it cools to room temperature, and a silicon-aluminum alloy is obtained. The heating rate is 5°C / min.

[0056] Example 1

[0057] The aluminum content of the three same parts, head, middle and tail, of the silicon-aluminum targets prepared in the examples and comparative examples was tested, and the results are shown in Table 1.

[0058] Table 1

[0059]

[0060] As can be seen from Table 1, the content of aluminum in the products of each embodiment of the present invention is substantially the same as the expected amount, and there is substantially no loss during the preparation process, while the content error at different sites is maintained within 0.3wt%. As can be seen from the comparison of the products of Example 1 and Example 4, when the rate of heating of the product during the preparation process is too fast, the deviation amplitude of the aluminum content may increase. In contrast, the product preparation process described in Comparative Example 1 is to directly use the mixed aluminum powder and silicon powder for plasma spraying. This process not only makes the actual value of the aluminum content of the product less than the theoretical value, but also increases the content deviation at different sites. The condition parameters for the preparation of silicon aluminum alloy by two-stage heating in the products of Comparative Examples 2 to 5 are not within the scope of the present invention, and the prepared products are also unable to take into account the maintenance of the aluminum content and uniformity.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the actual technical solutions of the present invention.

Claims

1. A method for preparing a silicon-aluminum target, characterized in that: The following steps are involved: (1) Mixing and homogenizing predetermined amounts of silicon powder and aluminum powder to obtain silicon-aluminum mixed powder; (2) placing the silicon-aluminum mixed powder in a heating device, removing the air in the device with an inert atmosphere, introducing hydrogen and heating to 400-450°C in a first stage and keeping the temperature for 30-45 minutes, then heating to 580-650°C in a second stage and keeping the temperature for 60-90 minutes, cooling, and obtaining a silicon-aluminum alloy; the heating rate of the first and second stage heating is 3-5°C / min, and the flow rate of the hydrogen is 4-10 L / min; (3) After the silicon-aluminum alloy is crushed into powder with a particle size of 30~150μm, it is sprayed on the target substrate through a plasma spraying process to obtain a silicon-aluminum target.

2. The method for preparing a silicon-aluminum target according to claim 1, wherein: In the step (1), the particle sizes of silicon powder and aluminum powder are ≤45 μm; and the mass ratio of silicon powder to aluminum powder is (8:2) to (9.5:0.5).

3. The method for preparing a silicon-aluminum target according to claim 1, wherein: In the step (1), silicon powder and aluminum powder are homogenized in a mixer, the total loading amount of silicon powder and aluminum powder is 1 / 2 to 3 / 4 of the solvent in the mixer, the homogenization speed is 30 to 50 rpm, and the time is 3 to 5 hours.

4. The method for preparing a silicon-aluminum target according to claim 1, wherein: In the step (3), the device used for plasma spraying includes a back tube and a spray gun, the spray gun is located at 80~130mm from the central axis of the back tube, and the movement distance is 0.15~0.3mm / time; the back tube moves back and forth during plasma spraying, the rotation speed is 15~25rpm, the axial movement rate is 40~60mm / min, and the powder feeding amount is 4~6kg / h.

5. The silicon-aluminum target material prepared by the method for preparing a silicon-aluminum target material according to any one of claims 1 to 4.

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