A beryllium oxide-coated intermediate bag and its preparation method

Abstract

This invention discloses a beryllium oxide-coated intermediate package and its preparation method, relating to the field of intermediate package coating preparation technology. The preparation method includes: step S1, preparing a first mixture with phosphoric acid and deionized water, then adding beryllium oxide powder and an antifoaming agent to obtain a beryllium oxide dispersion; step S2, immersing the sandblasted intermediate package in the beryllium oxide dispersion for 2-3 coating treatments; and step S3, calcining the coated intermediate package to obtain an intermediate package with a beryllium oxide coating of 1.5-2.0 mm thickness. This invention first uses phosphoric acid as a binder to prepare the beryllium oxide dispersion, and then obtains a beryllium oxide-coated intermediate package by repeatedly coating the inner wall of the inexpensive intermediate package with the beryllium oxide dispersion followed by calcination. This method can resist the thermal shock of molten beryllium metal and ensure the purity of the beryllium powder.

Description

Technical Field

[0001] This invention belongs to the field of intermediate tundish coating preparation technology, and particularly relates to an intermediate tundish containing beryllium oxide coating and its preparation method. Background Technology

[0002] Beryllium metal possesses many excellent properties, including high elastic modulus, high toughness, easy processing, light weight, high specific stiffness, high specific strength, good thermal stability, high toughness, and corrosion resistance. It has broad application prospects in fields such as computer manufacturing, automotive industry, and high-precision, high-speed welding machine manufacturing. Due to its very strong thermal neutron scattering ability, beryllium components can maintain their original dimensions even when subjected to changes of hundreds of degrees in thermal conductivity. This makes beryllium a special functional and structural material with important applications in weapon systems, aerospace, and nuclear industries. It has always been a highly regarded defense and military material both domestically and internationally.

[0003] The main method for producing metallic beryllium is powder metallurgy. Furthermore, beryllium powder is primarily produced using two methods: air jet impingement and inert gas atomization. Beryllium powder prepared by air jet impingement exhibits significant anisotropy. However, powder produced by inert gas atomization typically has spherical particles, which can significantly reduce or eliminate the anisotropy of the billet. Simultaneously, spherical powder possesses excellent flowability and high packing density.

[0004] Intermediate tumblers are an indispensable part of inert gas atomization powder production. Using pre-fabricated intermediate tumblers made of other materials will reduce the purity of beryllium powder, severely affecting the performance of the powder metallurgy product. Using beryllium oxide intermediate tumblers is costly, increasing the production cost of atomized beryllium powder and thus limiting the development of atomized beryllium powder technology.

[0005] Therefore, existing technologies need to be improved. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a beryllium oxide-coated intermediate bag and its preparation method. The method first uses phosphoric acid as a binder to prepare a beryllium oxide dispersion, and then obtains a beryllium oxide-coated intermediate bag by repeatedly coating the inner wall of the inexpensive intermediate bag with the beryllium oxide dispersion and then calcining it. This method can both resist the thermal shock of molten beryllium metal and ensure the purity of the beryllium powder.

[0007] The first aspect of this invention provides a method for preparing a beryllium oxide-coated intermediate package, wherein the beryllium oxide-coated intermediate package is used for beryllium metal atomization powder production, and the preparation method includes the following steps:

[0008] Step S1: Under the first stirring speed condition, phosphoric acid and deionized water are mixed and stirred for a first preset time to obtain a first mixture. Under the second stirring speed condition, beryllium oxide powder is slowly added to the first mixture and then an antifoaming agent is added to obtain a second mixture. Then, the second mixture is stirred at the second speed for a second preset time to obtain a beryllium oxide dispersion.

[0009] The mass ratio of phosphoric acid to deionized water is 1:1 to 2:1, the mass ratio of beryllium oxide powder to the first mixture is 1:2 to 1:3, the volume content of the defoamer is 0.8 to 1.2%, and the rate at which the beryllium oxide powder is added to the first mixture is 200 to 300 g / min.

[0010] Step S2: Immerse the sandblasted intermediate bag in the beryllium oxide dispersion for 2 to 3 coating treatments;

[0011] Step S3: The coated intermediate package is calcined to obtain an intermediate package with a beryllium oxide coating with a thickness of 1.5 to 2.0 mm.

[0012] According to the method for preparing a beryllium oxide-coated intermediate package according to the first aspect of the present invention, the specific process of the coating treatment in step S2 is as follows:

[0013] The intermediate package, after being sandblasted, is tilted at a preset angle and immersed in the beryllium oxide dispersion for a third preset time. Then, the intermediate package coated with the beryllium oxide dispersion is taken out and left to stand in the air until no liquid drips, and then placed in a constant temperature and humidity environment to dry.

[0014] According to the method for preparing a beryllium oxide-coated intermediate package according to the first aspect of the present invention, the intermediate package after sandblasting is immersed in the beryllium oxide dispersion at an angle of 30° to 45°.

[0015] According to the method for preparing a beryllium oxide-coated intermediate package according to the first aspect of the present invention, during the second or third coating, the intermediate package is immersed in the beryllium oxide dispersion for 4 to 6 seconds.

[0016] According to the method for preparing a beryllium oxide-coated intermediate ladle according to the first aspect of the present invention, the constant temperature is 24-25°C, the constant humidity is 60-70%, and the drying time is 5-7 hours.

[0017] According to the method for preparing a beryllium oxide-coated intermediate ladle according to the first aspect of the present invention, in step S3, the heating rate of the calcination is 1.8 to 2.2 °C / min, the target temperature of the calcination is 1050 to 1350 °C, and the holding time of the calcination is 1.8 to 2.2 h.

[0018] According to the preparation method of the beryllium oxide-coated intermediate bag according to the first aspect of the present invention, in step S1, the first rotation speed is 180-220 r / min, and the first preset time is 13-17 min;

[0019] The second rotational speed is 480–520 r / min, and the second preset time is 4–6 min.

[0020] According to the method for preparing a beryllium oxide-coated intermediate package according to the first aspect of the present invention, in step S1, the average particle size of the beryllium oxide powder is 1.0 to 1.5 μm, and the purity of the beryllium oxide powder is higher than 98.5 wt.%.

[0021] The phosphoric acid has a mass concentration of 98%.

[0022] According to the method for preparing a beryllium oxide-coated intermediate package according to the first aspect of the present invention, the intermediate package is an alumina intermediate package.

[0023] The second aspect of the present invention provides a beryllium oxide-coated intermediate package prepared by the aforementioned method, wherein the vacuum degree of the storage environment of the beryllium oxide-coated intermediate package is 0.01 to 10 Pa.

[0024] The solution proposed in this invention has the following technical effects:

[0025] This invention first uses phosphoric acid as a binder to prepare a beryllium oxide dispersion. Then, by repeatedly coating the inner wall of an inexpensive intermediate ladle with the beryllium oxide dispersion and then calcining it, a beryllium oxide-coated intermediate ladle is obtained that can resist the thermal shock of molten beryllium metal and ensure the purity of the beryllium powder.

[0026] Furthermore, the beryllium oxide-coated intermediate package prepared by the present invention is tightly bonded to the substrate intermediate package and there is no residue shedding. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The first aspect of this embodiment proposes a method for preparing a beryllium oxide-coated intermediate package, wherein the beryllium oxide-coated intermediate package is used for beryllium metal atomization powder production, and the preparation method includes the following steps:

[0029] Step S1: Under the first stirring speed condition, phosphoric acid and deionized water are mixed and stirred for a first preset time to obtain a first mixture. Under the second stirring speed condition, beryllium oxide powder is slowly added to the first mixture and then an antifoaming agent is added to obtain a second mixture. Then, the second mixture is stirred at the second speed for a second preset time to obtain a beryllium oxide dispersion.

[0030] The mass ratio of phosphoric acid to deionized water is 1:1 to 2:1, preferably 3:2; the mass ratio of beryllium oxide powder to the first mixture is 1:2 to 1:3, preferably 3:7; the volume content of the defoamer is 0.8% to 1.2%, preferably 1%; and the rate at which the beryllium oxide powder is added to the first mixture is 200 to 300 g / min, preferably 240 to 260 g / min.

[0031] Step S2: Immerse the sandblasted intermediate bale in the beryllium oxide dispersion for 2 to 3 coating treatments.

[0032] Step S3: The coated intermediate package is calcined to obtain an intermediate package with a beryllium oxide coating with a thickness of 1.5 to 2.0 mm.

[0033] In step S1, phosphoric acid and deionized water are mixed under a first stirring speed and stirred for a first preset time to obtain a first mixture. Under a second stirring speed, beryllium oxide powder is slowly added to the first mixture and then an antifoaming agent is added to obtain a second mixture. The second mixture is then stirred at a second stirring speed for a second preset time to obtain a beryllium oxide dispersion.

[0034] In this embodiment, phosphoric acid is used as a binder to enhance the viscosity of the beryllium oxide dispersion.

[0035] In preparing the beryllium oxide dispersion, this embodiment employs continuous stirring to ensure more uniform mixing of the raw materials, thereby guaranteeing the uniform dispersion of beryllium oxide in the solution and the uniform coating of beryllium oxide on the intermediate ladle. Simultaneously, mixing phosphoric acid and deionized water under stirring allows for rapid heat dissipation, preventing potential hazards.

[0036] In addition, by adding defoamers and controlling the addition rate of beryllium oxide powder, the risk of excessive bubbles in the beryllium oxide dispersion affecting the bonding strength between the beryllium oxide coating and the intermediate liner substrate or causing the coating to peel off can be avoided.

[0037] In some embodiments, in step S1, the first rotational speed is 180-220 r / min, and the first preset time is 13-17 min;

[0038] The second rotational speed is 480–520 r / min, and the second preset time is 4–6 min.

[0039] As beryllium oxide powder is continuously added, the viscosity of the mixture increases, so it is necessary to increase the stirring speed. However, in order to reduce the generation of bubbles in the mixture, the stirring speed should not be too high and the stirring time should not be too long.

[0040] In some embodiments, in step S1, the average particle size of the beryllium oxide powder is 1.0 to 1.5 μm, and the purity of the beryllium oxide powder is higher than 98.5 wt.%.

[0041] The phosphoric acid has a mass concentration of 98%.

[0042] Beryllium oxide powder with an average particle size of less than 1.0 μm or greater than 1.5 μm is prone to agglomeration in solution, affecting the coating effect. In addition, beryllium oxide is highly toxic, and powder with a small particle size can be easily inhaled by the human body.

[0043] In some embodiments, the defoamer is a polyether-modified silicone.

[0044] In some embodiments, the intermediate package is an alumina intermediate package.

[0045] In step S2, the intermediate bale after sandblasting is immersed in the beryllium oxide dispersion for 2 to 3 coating treatments, preferably 2 times.

[0046] Compared to a single coating, this embodiment uses multiple coatings to achieve a more uniform coating, while also increasing the bonding strength between the coating and the intermediate substrate and its resistance to thermal shock. However, an excessively thick beryllium oxide coating can increase the risk of peeling off. Therefore, this invention limits the number of coatings to 2 to 3, resulting in a coating thickness of 1.5 to 2.0 mm.

[0047] In some embodiments, the coating treatment in step S2 is performed as follows:

[0048] The intermediate package, after being sandblasted, is tilted at a preset angle and immersed in the beryllium oxide dispersion for a third preset time. Then, the intermediate package coated with the beryllium oxide dispersion is taken out and left to stand in the air until no liquid drips, and then placed in a constant temperature and humidity environment to dry.

[0049] Preferably, the intermediate tundish is rotated continuously during the coating process to ensure that the beryllium oxide dispersion is coated more evenly on the surface of the intermediate tundish substrate.

[0050] In some embodiments, the sandblasted intermediate bale is immersed in the beryllium oxide dispersion at a tilt of 30° to 45°.

[0051] The beryllium oxide dispersion in this embodiment has a certain viscosity. If the intermediate package is horizontally or vertically immersed in the beryllium oxide dispersion during the coating process, air bubbles will be generated, making it impossible for the coating to bond tightly with the intermediate package substrate, increasing the risk of coating peeling off later.

[0052] In some embodiments, during the second or third coating, the intermediate bag is immersed in the beryllium oxide dispersion for 4 to 6 seconds to avoid prolonged immersion in the beryllium oxide dispersion, which could cause the first coating to peel off.

[0053] In some embodiments, the constant temperature is 24–25°C, the constant humidity is 60–70%, and the drying time is 5–7 hours.

[0054] A constant temperature and humidity environment can prevent the coating from cracking during the drying process.

[0055] Specifically, the sandblasting process is as follows:

[0056] A sandblasting machine is used to spray 90-mesh alumina powder onto the inner wall of the tundish to increase the surface roughness of the inner wall of the tundish, and then the tundish is cleaned.

[0057] In step S3, the coated intermediate package is calcined to obtain an intermediate package with a beryllium oxide coating with a thickness of 1.5 to 2.0 mm.

[0058] In some embodiments, in step S3, the heating rate of the calcination is 1.8 to 2.2 °C / min, the target temperature of the calcination is 1050 to 1350 °C, and the holding time of the calcination is 1.8 to 2.2 h, so as to enhance the bonding strength between the coating and the intermediate liner substrate and prevent the coating from falling off.

[0059] The second aspect of this embodiment provides a beryllium oxide-coated intermediate package prepared by the aforementioned method, wherein the vacuum degree of the storage environment of the beryllium oxide-coated intermediate package is 0.01 to 10 Pa.

[0060] Preserving beryllium oxide-coated intermediate packages under vacuum can effectively reduce the risk of coating peeling.

[0061] Example 1

[0062] The first step involves mixing 98% phosphoric acid and deionized water at a stirring speed of 200 rpm for 15 minutes to obtain a first mixture. Then, beryllium oxide powder with an average particle size of 1.2 μm and a purity higher than 98.5 wt.% is added to the first mixture at a stirring speed of 500 rpm, followed by the addition of a polyether-modified silicone defoamer to obtain a second mixture. The second mixture is then stirred at 500 rpm for 5 minutes to obtain a beryllium oxide dispersion. The mass ratio of phosphoric acid to deionized water is 3:2, the mass ratio of beryllium oxide powder to the first mixture is 3:7, the volume content of the polyether-modified silicone defoamer is 1.0%, and the rate at which the beryllium oxide powder is added to the first mixture is 240–260 g / min.

[0063] The second step is to use a sandblasting machine to spray 90-mesh alumina powder onto the inner wall of the tundish, and then clean the tundish.

[0064] The third step involves immersing the sandblasted intermediate package at a 40° angle in a beryllium oxide dispersion for two coating treatments. During the second coating, the intermediate package is immersed in the beryllium oxide dispersion for 5 seconds. Each time, the intermediate package coated with the beryllium oxide dispersion is removed and allowed to remain suspended in the air until no liquid drips, then placed in a drying room at a constant temperature of 24.5°C and a constant humidity of 65% for 6 hours to dry.

[0065] The fourth step involves calcining the coated intermediate ladle to obtain an intermediate ladle with a beryllium oxide coating of 1.8 mm thickness. The calcination heating rate is 2℃ / min, the target calcination temperature is 1200℃, and the calcination holding time is 2 hours.

[0066] The fifth step involves storing the beryllium oxide-coated intermediate package in a vacuum environment of 0.01–10 Pa after the coating quality is inspected.

[0067] The beryllium oxide coating of the intermediate tundish prepared in Example 1 has a thickness of 1.8 mm. The coating is tightly bonded to the substrate intermediate tundish with no residue falling off. Furthermore, the beryllium oxide coating did not exhibit microcracks after being impacted by molten beryllium metal at 1350–1380°C, and the beryllium oxide content of the prepared beryllium powder meets the usage standards.

[0068] Example 2

[0069] The first step involves mixing 98% phosphoric acid and deionized water at a stirring speed of 180 rpm for 17 minutes to obtain a first mixture. Then, beryllium oxide powder with an average particle size of 1.0 μm and a purity higher than 98.5 wt.% is added to the first mixture at a stirring speed of 480 rpm, followed by the addition of a polyether-modified silicone defoamer to obtain a second mixture. The second mixture is then stirred at 480 rpm for 6 minutes to obtain a beryllium oxide dispersion. The mass ratio of phosphoric acid to deionized water is 1:1, the mass ratio of beryllium oxide powder to the first mixture is 1:2, the volume content of the polyether-modified silicone defoamer is 1.2%, and the rate at which the beryllium oxide powder is added to the first mixture is 240–300 g / min.

[0070] The second step is to use a sandblasting machine to spray 90-mesh alumina powder onto the inner wall of the tundish, and then clean the tundish.

[0071] The third step involves immersing the sandblasted intermediate package at a 30° angle in a beryllium oxide dispersion for two coating treatments. During the second coating, the intermediate package is immersed in the beryllium oxide dispersion for 4 seconds. Each time, the intermediate package coated with the beryllium oxide dispersion is removed and allowed to remain suspended in the air until no liquid drips, then placed in a drying room at a constant temperature of 24°C and a constant humidity of 60% for 7 hours to dry.

[0072] The fourth step involves calcining the coated intermediate ladle to obtain an intermediate ladle with a beryllium oxide coating of 2.0 mm thickness. The calcination heating rate is 1.8 °C / min, the target calcination temperature is 1050 °C, and the calcination holding time is 2.2 h.

[0073] The fifth step involves storing the beryllium oxide-coated intermediate package in a vacuum environment of 0.01–10 Pa after the coating quality is inspected.

[0074] The beryllium oxide coating of the intermediate tundish prepared in Example 2 has a thickness of 2.0 mm. The coating is tightly bonded to the substrate intermediate tundish with no residue falling off. Furthermore, the beryllium oxide coating did not exhibit microcracks after being impacted by molten beryllium metal at 1350–1380°C, and the beryllium oxide content of the prepared beryllium powder meets the usage standards.

[0075] Example 3

[0076] The first step involves mixing 98% phosphoric acid and deionized water at a stirring speed of 220 rpm for 13 minutes to obtain a first mixture. Then, beryllium oxide powder with an average particle size of 1.5 μm and a purity higher than 98.5 wt.% is added to the first mixture at a stirring speed of 520 rpm, followed by the addition of a polyether-modified silicone defoamer to obtain a second mixture. The second mixture is then stirred at 520 rpm for 4 minutes to obtain a beryllium oxide dispersion. The mass ratio of phosphoric acid to deionized water is 2:1, the mass ratio of beryllium oxide powder to the first mixture is 1:3, the volume content of the polyether-modified silicone defoamer is 0.8%, and the rate at which the beryllium oxide powder is added to the first mixture is 200–240 g / min.

[0077] The second step is to use a sandblasting machine to spray 90-mesh alumina powder onto the inner wall of the tundish, and then clean the tundish.

[0078] The third step involves immersing the sandblasted intermediate package at a 45° angle in a beryllium oxide dispersion for three coating treatments. During the second coating, the intermediate package is immersed in the beryllium oxide dispersion for 6 seconds. Each time, the intermediate package coated with the beryllium oxide dispersion is removed and allowed to remain suspended in the air until no liquid drips, then placed in a drying room at a constant temperature of 25°C and a constant humidity of 70% for 5 hours to dry.

[0079] The fourth step involves calcining the coated intermediate ladle to obtain an intermediate ladle with a beryllium oxide coating of 1.5 mm thickness. The calcination heating rate is 2.2 °C / min, the target calcination temperature is 1350 °C, and the calcination holding time is 1.8 h.

[0080] The fifth step involves storing the beryllium oxide-coated intermediate package in a vacuum environment of 0.01–10 Pa after the coating quality is inspected.

[0081] The beryllium oxide coating of the intermediate tundish prepared in Example 3 has a thickness of 1.5 mm. The coating is tightly bonded to the substrate intermediate tundish with no residue falling off. Furthermore, the beryllium oxide coating did not exhibit microcracks after being impacted by molten beryllium metal at 1350–1380°C, and the beryllium oxide content of the prepared beryllium powder meets the usage standards.

[0082] In summary, the solution proposed in this invention has the following technical effects:

[0083] This invention first uses phosphoric acid as a binder to prepare a beryllium oxide dispersion. Then, by repeatedly coating the inner wall of an inexpensive intermediate ladle with the beryllium oxide dispersion and then calcining it, a beryllium oxide-coated intermediate ladle is obtained that can resist the thermal shock of molten beryllium metal and ensure the purity of the beryllium powder.

[0084] Furthermore, the beryllium oxide-coated intermediate package prepared by the present invention is tightly bonded to the substrate intermediate package and there is no residue shedding.

[0085] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a beryllium oxide-coated intermediate package, wherein the beryllium oxide-coated intermediate package is used for beryllium metal atomization powder production, characterized in that, The preparation method includes the following steps: Step S1: Under the first stirring speed condition, phosphoric acid and deionized water are mixed and stirred for a first preset time to obtain a first mixture. Under the second stirring speed condition, beryllium oxide powder is slowly added to the first mixture and then an antifoaming agent is added to obtain a second mixture. Then, the second mixture is stirred at the second speed for a second preset time to obtain a beryllium oxide dispersion. The mass ratio of phosphoric acid to deionized water is 1:1 to 2:1, the mass ratio of beryllium oxide powder to the first mixture is 1:2 to 1:3, the volume content of the defoamer is 0.8 to 1.2%, and the rate at which the beryllium oxide powder is added to the first mixture is 200 to 300 g / min. Step S2: Immerse the sandblasted intermediate bag in the beryllium oxide dispersion for 2 to 3 coating treatments; Step S3: The coated intermediate package is calcined to obtain an intermediate package with a beryllium oxide coating with a thickness of 1.5 to 2.0 mm.

2. The method for preparing a beryllium oxide-coated intermediate package according to claim 1, characterized in that, In step S2, the specific process of the coating treatment is as follows: The intermediate package, after being sandblasted, is tilted at a preset angle and immersed in the beryllium oxide dispersion for a third preset time. Then, the intermediate package coated with the beryllium oxide dispersion is taken out and left to stand in the air until no liquid drips, and then placed in a constant temperature and humidity environment to dry.

3. The method for preparing a beryllium oxide-coated intermediate bag according to claim 2, characterized in that, The intermediate tundish, after being sandblasted, is tilted at 30° to 45° and immersed in the beryllium oxide dispersion.

4. The method for preparing a beryllium oxide-coated intermediate bag according to claim 2, characterized in that, During the second or third coating, the intermediate bag is immersed in the beryllium oxide dispersion for 4 to 6 seconds.

5. The method for preparing a beryllium oxide-coated intermediate package according to claim 2, characterized in that, The constant temperature is 24-25°C, the constant humidity is 60-70%, and the drying time is 5-7 hours.

6. The method for preparing a beryllium oxide-coated intermediate bag according to claim 1, characterized in that, In step S3, the heating rate of the calcination is 1.8 to 2.2 °C / min, the target temperature of the calcination is 1050 to 1350 °C, and the holding time of the calcination is 1.8 to 2.2 h.

7. The method for preparing a beryllium oxide-coated intermediate ladle according to claim 1, characterized in that, In step S1, the first rotational speed is 180-220 r / min, and the first preset time is 13-17 min; The second rotational speed is 480–520 r / min, and the second preset time is 4–6 min.

8. The method for preparing a beryllium oxide-coated intermediate bag according to claim 1, characterized in that, In step S1, the average particle size of the beryllium oxide powder is 1.0 to 1.5 μm, and the purity of the beryllium oxide powder is higher than 98.5 wt.%. The phosphoric acid has a mass concentration of 98%.

9. The method for preparing a beryllium oxide-coated intermediate package according to claim 1, characterized in that, The intermediate package is an alumina intermediate package.

10. A beryllium oxide-coated intermediate package prepared by the method for preparing a beryllium oxide-coated intermediate package according to any one of claims 1-9, characterized in that, The storage environment of the beryllium oxide-coated intermediate ladle is in the vacuum level of 0.01 to 10 Pa.