Composite ceramic crucible for intermediate frequency furnace

Abstract

The invention relates to a composite ceramic crucible for an intermediate frequency furnace. The composite ceramic crucible comprises powder and a dispersing agent accounting for 0.05-0.2 wt% of the powder, the powder material comprises the following components in percentage by weight: 32-36% of graphite powder; 43 to 46 wt% of silicon carbide; 6.5 to 10 wt% of electrolytic chromium powder; 6-10 wt% of magnesium oxide powder; 1-3 wt% of silicon powder; 1.5 to 3 wt% of aluminum dihydrogen phosphate; and 0.5 to 1 wt% of yttrium oxide. Compared with the prior art, the composite ceramic crucible for the intermediate frequency furnace has the advantages that the thermal shock resistance is improved; the mechanical strength is improved; the toughness is enhanced; the oxidation resistance is improved; the service life of the crucible is prolonged; the crucible for the intermediate frequency furnace is prevented from being frequently aged, damaged and replaced, and materials and labor cost are saved.

Description

Technical Field

[0001] The invention relates to the technical field of crucible materials for medium frequency induction furnaces, in particular to a composite ceramic crucible for medium frequency furnaces. Background Art

[0002] Medium frequency induction furnace is a kind of high temperature smelting equipment commonly used in the steel industry and non-ferrous metal and precious metal industries. It has the characteristics of fast heating speed, intermittent operation, convenient operation, low pollution and high efficiency and energy saving. The crucible for medium frequency furnace is one of the components of medium frequency furnace smelting. It is used for metal smelting, including ferrous metals, non-ferrous metals, precious metals, semiconductor materials and rare earth metals. In the use of medium frequency furnace smelting, the temperature of special metal liquid reaches 1900℃, which puts forward the requirements of thermal shock resistance, oxidation resistance, strong mechanical properties and crack resistance for the application of crucible at high temperature. The service life of crucible directly affects the production cost.

[0003] At present, the crucible materials for medium frequency induction furnaces are generally made of graphite silicon carbide and graphite clay. Due to the single material, the refractoriness and oxidation resistance are difficult to guarantee. The crucibles often age quickly, crack and have a short life, which increases the cost. Summary of the invention

[0004] In order to overcome the deficiencies in the background technology, the present invention discloses a composite ceramic crucible for a medium frequency furnace.

[0005] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme: A composite ceramic crucible for a medium frequency furnace, comprising a powder and a dispersant accounting for 0.05-0.2wt% of the powder; the powder comprises: 32-36wt% of graphite powder; 43-46wt% of silicon carbide; 6.5-10wt% of electrolytic chromium powder; 6-10wt% of magnesium oxide powder; 1-3wt% of silicon powder; 1.5-3wt% of aluminum dihydrogen phosphate; 0.5-1wt% of yttrium trioxide; The preparation method of the composite ceramic crucible for the medium frequency furnace: (1) Weighing and mixing ingredients: weigh and mix the above powder and dispersant in a certain proportion; (2) Mixing and grinding: Grind and stir the weighed ingredients under an argon atmosphere to mix them evenly; (3) Isostatic pressing: The uniformly mixed ingredients are isostatically pressed to obtain a blank; (4) Primary sintering: The blank is placed in an argon atmosphere for sintering at a heating rate of 1 to 5 °C / min from room temperature to 1000 °C, and then kept at 1000 °C for 2 to 4 hours; (5) Secondary sintering: The primary sintered blank is subjected to secondary sintering in an argon atmosphere at a heating rate of 5 to 10 °C / min from 1000 °C to 2200 °C; (6) Cooling: The secondary sintered blank is cooled from 2200°C to 400°C at a cooling rate of 0.5-2°C / min, and then naturally cooled to room temperature.

[0006] Preferably, the graphite powder has a particle size of 5 to 10 μm.

[0007] Preferably, the silicon carbide particle size is 1 to 10 μm.

[0008] Preferably, the particle size of the electrolytic chromium powder is ≤1 μm.

[0009] Preferably, the particle size of the magnesium oxide powder is 0.5 to 5 μm.

[0010] Preferably, the silicon powder particles have a particle size of 1 to 5 μm.

[0011] Preferably, the particle size of the yttrium oxide particles is 1 to 5 μm.

[0012] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: The crucible made by the invention has good thermal expansion coefficient, high temperature resistance, good oxidation resistance, high impact resistance, high mechanical strength, good thermal shock resistance and long service life due to the addition of metal chromium, magnesium oxide, silicon powder and yttrium trioxide, which is of great significance to reducing production costs and safety.

[0013] The invention avoids oxidation of metal chromium by using argon atmosphere protection during mixed grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a flow chart of the preparation method of composite ceramic crucible for medium frequency furnace. DETAILED DESCRIPTION

[0015] The present invention can be explained in detail by the following examples, and the purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. Example 1

[0016] The invention comprises a powder and a dispersant accounting for 0.05wt% of the powder; the powder comprises: 32wt% of graphite powder; 43.5wt% of silicon carbide; 10wt% of electrolytic chromium powder; 10wt% of magnesium oxide powder; 1wt% of silicon powder; 3wt% of aluminum dihydrogen phosphate; and 0.5wt% of yttrium trioxide. (1) Weighing and mixing ingredients: weigh and mix the above powder and dispersant in a certain proportion; (2) Mixing and grinding: Grind and stir the weighed ingredients under an argon atmosphere to mix them evenly; (3) Isostatic pressing: The uniformly mixed ingredients are isostatically pressed to obtain a blank; (4) Primary sintering: The blank is placed in an argon atmosphere for sintering at a heating rate of 1 to 5 °C / min from room temperature to 1000 °C, and then kept at 1000 °C for 4 hours; (5) Secondary sintering: The primary sintered blank is subjected to secondary sintering in an argon atmosphere at a heating rate of 5 to 10 °C / min from 1000 °C to 2200 °C; (6) Cooling: The secondary sintered blank is cooled from 2200°C to 400°C at a cooling rate of 0.5-2°C / min, and then naturally cooled to room temperature to obtain the product. Example 2

[0017] The invention comprises a powder and a dispersant accounting for 0.1wt% of the powder; the powder comprises: 34wt% of graphite powder; 45wt% of silicon carbide; 8wt% of electrolytic chromium powder; 8wt% of magnesium oxide powder; 2wt% of silicon powder; 2.5wt% of aluminum dihydrogen phosphate; and 0.5wt% of yttrium trioxide. (1) Weighing and mixing ingredients: weigh and mix the above powder and dispersant in a certain proportion; (2) Mixing and grinding: Grind and stir the weighed ingredients under an argon atmosphere to mix them evenly; (3) Isostatic pressing: The uniformly mixed ingredients are isostatically pressed to obtain a blank; (4) Primary sintering: The blank is placed in an argon atmosphere for sintering at a heating rate of 1 to 5 °C / min from room temperature to 1000 °C, and then kept at 1000 °C for 2 hours; (5) Secondary sintering: The primary sintered blank is subjected to secondary sintering in an argon atmosphere at a heating rate of 5 to 10 °C / min from 1000 °C to 2200 °C; (6) Cooling: The secondary sintered blank is cooled from 2200°C to 400°C at a cooling rate of 0.5-2°C / min, and then naturally cooled to room temperature to obtain the product. Example 3

[0018] The invention comprises a powder and a dispersant accounting for 0.2 wt% of the powder; the powder comprises: 36 wt% of graphite powder; 46 wt% of silicon carbide; 6.5 wt% of electrolytic chromium powder; 6 wt% of magnesium oxide powder; 3 wt% of silicon powder; 1.5 wt% of aluminum dihydrogen phosphate; and 1 wt% of yttrium trioxide. (1) Weighing and mixing ingredients: weigh and mix the above powder and dispersant in a certain proportion; (2) Mixing and grinding: Grind and stir the weighed ingredients under an argon atmosphere to mix them evenly; (3) Isostatic pressing: The uniformly mixed ingredients are isostatically pressed to obtain a blank; (4) Primary sintering: The blank is placed in an argon atmosphere for sintering at a heating rate of 1 to 5 °C / min from room temperature to 1000 °C, and then kept at 1000 °C for 3 hours; (5) Secondary sintering: The primary sintered blank is subjected to secondary sintering in an argon atmosphere at a heating rate of 5 to 10 °C / min from 1000 °C to 2200 °C; (6) Cooling: The secondary sintered blank is cooled from 2200°C to 400°C at a cooling rate of 0.5-2°C / min, and then naturally cooled to room temperature to obtain the product.

[0019] Comparative Example 1 Existing graphite silicon carbide material medium frequency furnace crucible.

[0020] Table 1 Performance comparison of composite ceramic crucibles for medium frequency furnace

[0021] pass Figure 1 It can be seen that the present invention uses argon gas for protection during mixed grinding, primary sintering and secondary sintering to avoid metal chromium oxidation. Combining the test performance of Examples 1 to 3 in Table 1 with the prior art (Comparative Example 1), it can be seen that compared with Comparative Example 1, Examples 1 to 3 not only have a longer service life, but also have mechanical properties that exceed those of the existing graphite silicon carbide material medium frequency furnace crucible.

[0022] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and it is intended that all changes that fall within the meaning and scope of equivalent elements are included in the present invention.

Claims

1. A composite ceramic crucible for a medium frequency furnace, characterized in that: The invention comprises a powder and a dispersant accounting for 0.05-0.2wt% of the powder; the powder comprises: 32-36wt% of graphite powder; 43-46wt% of silicon carbide; 6.5-10wt% of electrolytic chromium powder; 6-10wt% of magnesium oxide powder; 1-3wt% of silicon powder; 1.5-3wt% of aluminum dihydrogen phosphate; and 0.5-1wt% of yttrium trioxide. The preparation method of the composite ceramic crucible for the medium frequency furnace: (1) Weighing and mixing ingredients: weigh and mix the above powder and dispersant in a certain proportion; (2) Mixing and grinding: Grind and stir the weighed ingredients under an argon atmosphere to mix them evenly; (3) Isostatic pressing: The uniformly mixed ingredients are isostatically pressed to obtain a blank; (4) Primary sintering: The blank is placed in an argon atmosphere for sintering at a heating rate of 1 to 5 °C / min from room temperature to 1000 °C, and then kept at 1000 °C for 2 to 4 hours; (5) Secondary sintering: The primary sintered blank is subjected to secondary sintering in an argon atmosphere at a heating rate of 5 to 10 °C / min from 1000 °C to 2200 °C; (6) Cooling: The secondary sintered blank is cooled from 2200°C to 400°C at a cooling rate of 0.5-2°C / min, and then naturally cooled to room temperature.

2. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: The graphite powder has a particle size of 5 to 10 μm.

3. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: The silicon carbide particle size is 1 to 10 μm.

4. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: The particle size of the electrolytic chromium powder is ≤1 μm.

5. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: The particle size of the magnesium oxide powder is 0.5 to 5 μm.

6. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: The particle size of the silicon powder particles is 1 to 5 μm.

7. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: The particle size of the yttrium oxide particles is 1 to 5 μm.

8. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: The invention comprises powder and a dispersant accounting for 0.05wt% of the powder; the powder comprises: 32wt% of graphite powder; 43.5wt% of silicon carbide; 10wt% of electrolytic chromium powder; 10wt% of magnesium oxide powder; 1wt% of silicon powder; 3wt% of aluminum dihydrogen phosphate; and 0.5wt% of yttrium trioxide.

9. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: It comprises powder and a dispersant accounting for 0.1wt% of the powder; the powder comprises: 34wt% of graphite powder; 45wt% of silicon carbide; 8wt% of electrolytic chromium powder; 8wt% of magnesium oxide powder; 2wt% of silicon powder; 2.5wt% of aluminum dihydrogen phosphate; and 0.5wt% of yttrium trioxide.

10. The composite ceramic crucible for medium frequency furnace according to claim 1, characterized in that: The invention comprises powder and a dispersant accounting for 0.2wt% of the powder; the powder comprises: 36wt% of graphite powder; 46wt% of silicon carbide; 6.5wt% of electrolytic chromium powder; 6wt% of magnesium oxide powder; 3wt% of silicon powder; 1.5wt% of aluminum dihydrogen phosphate; and 1wt% of yttrium trioxide.

Images