Wear-resistant ceramic impeller and method of manufacturing the same

Abstract

The application discloses a wear-resistant ceramic impeller, which comprises a front cover plate, a rear cover plate and blades, the blades are provided with pre-sintered ceramic blocks embedded in the front cover plate or / and the rear cover plate; the pre-sintered ceramic blocks are provided with embedding parts, the front cover plate or / and the rear cover plate are provided with cavities which are embedded with the embedding parts of the pre-sintered ceramic blocks, and the embedding parts and the cavities are adapted to each other in profile. The application further provides a manufacturing method of the wear-resistant ceramic impeller. The wear-resistant ceramic impeller and the manufacturing method thereof belong to the technical field of rotary power pump equipment, have better wear resistance, better anti-cavitation performance, appropriate cost and are easy to be enlarged, the pre-sintered ceramic blocks with better wear resistance and smoother surface are arranged on the working surface of the blades, which is beneficial to improving the anti-cavitation performance of the impeller and the efficiency of the pump, the pre-sintered ceramic blocks are extended into the front cover plate or the rear cover plate along the axial direction of the impeller, which is beneficial to fixing the pre-sintered ceramic blocks and improving the strength of the impeller.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rotary power pump equipment production, more particularly, it relates to a wear-resistant ceramic impeller and a manufacturing method thereof. BACKGROUND

[0002] In the industry of ore dressing and smelting, centrifugal pumps are often used to transport some solid-liquid two-phase flow with abrasion, at this time, wear-resistant pumps are often selected. Common wear-resistant pumps are usually made of wear-resistant alloys such as Cr26, Cr15Mo3 or wear-resistant materials such as rubber. The pumps made of these wear-resistant alloys are difficult to meet the use requirements in many working conditions.

[0003] As is known to all, wear-resistant ceramics have much higher wear resistance than wear-resistant alloys, such as silicon carbide ceramics, silicon nitride ceramics, alumina ceramics, silicon nitride combined silicon carbide ceramics, etc., and their wear resistance is several times or even tens of times higher than that of wear-resistant alloys. Therefore, CN202100535U, CN205687817U, CN107654414A, CN108302043A, CN202100546U and other technical solutions of ceramic impellers are disclosed. From the current technical situation, the ceramic materials for manufacturing impellers mainly include five materials: alumina (Al2O3), silicon nitride (Si3N4), silicon carbide (SiC), silicon nitride combined silicon carbide (SiC-Si3N4) and oxide combined silicon carbide. Among them, the wear resistance of alumina ceramics is poor, and it is difficult to be large-sized, which is obviously limited in the field of wear-resistant pumps which require wear resistance and large size; due to the process reason, the cost of silicon nitride ceramics is high, and the large-scale process is difficult, which is also difficult to apply; the reaction sintered silicon carbide ceramic has excellent wear resistance and relatively low cost, but due to the process reason, it is difficult to be large-sized, and the cost is also high, which limits its application; the microstructure of silicon nitride combined silicon carbide and oxide combined silicon carbide is similar, including main phase silicon carbide particles and combined phase, the combined phase of the former is network-shaped silicon nitride, and the combined phase of the latter is network-shaped alumina, silicon oxide, calcium oxide or mixture thereof. Silicon nitride combined silicon carbide or oxide combined silicon carbide has almost no change in size during sintering, and contains a certain amount of micro-pores, which not only helps to avoid cracking and other defects during sintering, but also helps to absorb impact energy during operation of the impeller, improving the impact resistance of the impeller. Therefore, these two materials have developed rapidly in the field of wear-resistant pumps in recent years, not only the manufacturing cost is lower than the above-mentioned materials, but also the wear resistance is better, and currently they can be used to manufacture large-sized impellers. Figure 12 、 Figure 13FIG. 1 is a schematic diagram of a conventional silicon nitride bonded silicon carbide or oxide bonded silicon carbide impeller. The impeller comprises a front cover plate 100 ′, a rear cover plate 300 ′, and blades 200 ′, all of which are made of silicon nitride bonded silicon carbide or oxide bonded silicon carbide. The weight ratio of silicon carbide is approximately 70-75%, and the weight ratio of silicon nitride or oxide is approximately 25-30%. The manufacturing process of silicon nitride bonded silicon carbide is to uniformly mix 70-75% (weight) silicon carbide particles, 15-25% (weight) silicon powder and a binder, and then form the mixture. After drying, the mixture is placed in a nitriding furnace for heating, and 99.99% high-purity nitrogen is introduced. At around 1430°C, the silicon powder and nitrogen react to form silicon nitride. After the reaction is completed, the silicon nitride bonded silicon carbide product is obtained. Silicon oxide bonded silicon carbide is to uniformly mix 70-75% (weight) silicon carbide particles, 15-25% (weight) silicon powder, 5-15% oxides such as aluminum oxide and calcium oxide and a binder, and then form the mixture. After drying, the mixture is placed in a sintering furnace, and at around 1430°C, the silicon powder and oxygen react to form silicon oxide. Since the silicon nitride or oxide generated by the reaction completely covers the silicon carbide particles in a network shape, and the silicon nitride or oxide generated by the reaction has certain strength and wear resistance, the wear resistance of the impeller of silicon nitride combined with silicon carbide material or oxide combined with silicon carbide is greatly improved compared with the wear-resistant alloy impeller.

[0004] However, there are also some problems in the application of silicon nitride bonded silicon carbide or oxide bonded silicon carbide impellers: First, the impeller is a two-phase material composed of a main phase of silicon carbide and a binding phase material. The wear resistance of the main phase of silicon carbide is significantly higher than that of the binding phase. Therefore, during use, the surface of the impeller will have pits due to the different wear rates of the two materials, making the surface roughness of the impeller higher. This not only leads to a decrease in efficiency, but more importantly, when the roughness of the blade surface is high, it will cause the pump's anti-cavitation performance to drop significantly and greatly affect the performance of the pump. Second, when there are large particles in the medium, the wear rate of the blade head and working surface will be much higher than that of other parts. The severe wear of the blade head and working surface will further deteriorate the pump's anti-cavitation performance and reduce the pump's performance.

[0005] CN 209041168 U discloses an impeller, which provides a wear-resistant block in the middle of the impeller to improve the wear resistance of the blades and the cavitation resistance of the impeller. However, this solution can only improve the wear resistance of the blade head, with limited effect. In addition, the shape of the wear-resistant block is complex and the cost is high. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. One of the purposes of the present invention is to provide a wear-resistant ceramic impeller with better wear resistance, better cavitation resistance, appropriate cost, and easy large-scale production.

[0007] A second object of the present invention is to provide a method for manufacturing a wear-resistant ceramic impeller.

[0008] To achieve the above-mentioned purpose one, the present invention provides a wear-resistant ceramic impeller, comprising a front cover plate, a rear cover plate and blades, wherein the blades include pre-sintered ceramic blocks embedded in the front cover plate and / or the rear cover plate; the pre-sintered ceramic blocks are provided with an embedded portion, and the front cover plate and / or the rear cover plate are provided with a concave cavity that is embedded with the embedded portion of the pre-sintered ceramic block, and the contours of the embedded portion and the concave cavity are adapted to each other.

[0009] Furthermore, the blade also includes a blade connection portion that is sintered together with the front cover plate and the rear cover plate and is arranged between the front cover plate and the rear cover plate, and the blade connection portion is adapted to the back side of the pre-sintered ceramic block; the pre-sintered ceramic block is embedded in the front cover plate and / or the rear cover plate along the axial direction of the impeller.

[0010] Furthermore, the pre-sintered ceramic block is made of silicon carbide or silicon nitride; the front cover plate and the rear cover plate are both made of silicon nitride combined with silicon carbide or oxide combined with silicon carbide.

[0011] As a further improvement, an anti-slip protrusion is provided on the outside of the embedded part of the pre-sintered ceramic block, and a groove is provided on the inner wall of the concave cavity of the front cover plate and / or the rear cover plate, and the groove on the inner wall of the concave cavity is wrapped around the outside of the anti-slip protrusion of the embedded part.

[0012] Furthermore, the joint between the pre-sintered ceramic block and the front cover plate and / or the rear cover plate is dipped in adhesive.

[0013] As a further improvement, at least two pre-sintered ceramic blocks are provided at the working surface of each blade, and a blade connecting portion supporting the pre-sintered ceramic block is provided on the back side of the pre-sintered ceramic block.

[0014] As a further improvement, the pre-sintered ceramic block is provided with a connection portion forming hole arranged along the axial direction of the impeller, and the connection portion forming hole is filled with a blade connection portion integrally formed with the front cover plate and the rear cover plate.

[0015] To achieve the above-mentioned second objective, the present invention further provides a method for manufacturing a wear-resistant ceramic impeller, the method comprising:

[0016] First, pre-sintered ceramic blocks, impeller core boxes, and impeller casting molds are manufactured;

[0017] Then, the pre-sintered ceramic block coated with organic glue is fixed at the corresponding position of the impeller core box and placed into the impeller casting mold;

[0018] Next, the mixed material is poured into the impeller casting mold. After hardening, the mold is removed and the impeller core box is removed to obtain an impeller blank embedded with pre-sintered ceramic blocks.

[0019] Next, the organic glue on the surface of the pre-sintered ceramic block is ablated to form an air gap at the junction of the pre-sintered ceramic block and the impeller blank, and the impeller blank is sintered to obtain a sintered impeller product;

[0020] Finally, the air gap between the pre-sintered ceramic block and the impeller body is filled with grease to obtain a hardened impeller.

[0021] Furthermore, the resin filling method includes: dipping the sintered impeller into resin, taking it out after the resin fills the air gap between the pre-sintered ceramic block and the impeller body, removing excess resin on the impeller, and hardening the resin dipped on the impeller to obtain a hardened impeller.

[0022] Furthermore, the steps of organic glue ablation and nitriding sintering include: placing the impeller blank into a sintering furnace, heating it to 300-500°C, and ablating the organic glue coated on the surface of the pre-sintered ceramic block to form an air gap at the junction of the pre-sintered ceramic block and the impeller blank; the sintering step includes: introducing high-purity nitrogen into the sintering furnace, heating it to 1400°C-1500°C for nitriding sintering; or heating it to 1400°C-1500°C in an oxidizing environment for oxidizing sintering.

[0023] Beneficial effects

[0024] Compared with the prior art, the wear-resistant ceramic impeller and the manufacturing method thereof of the present invention have the following beneficial effects:

[0025] (1) The wear-resistant ceramic impeller and its manufacturing method are characterized by the main body material of the impeller being silicon nitride bonded with silicon carbide or oxide bonded with silicon carbide, which is not only easy to scale up the impeller but also low in cost; since the outer dimensions of the pre-sintered ceramic block are relatively small and the shape is simple, the use of silicon carbide or silicon nitride material is easy to realize in terms of process and relatively low in cost;

[0026] (2) The pre-sintered ceramic blocks are made of single-phase ceramic materials, such as reaction-sintered silicon carbide, pressureless-sintered silicon carbide, hot-pressed silicon nitride, etc. The wear of the blades during use is more uniform than that of the two-phase materials of silicon nitride combined with silicon carbide or oxide combined with silicon carbide, and the surface roughness will not increase significantly due to uneven wear, thereby avoiding the deterioration of the anti-cavitation performance of the impeller;

[0027] (3) The pre-sintered ceramic block adopts reaction-sintered silicon carbide or hot-pressed sintered silicon nitride. Under wear conditions, the material itself has self-lubricating properties, which not only reduces its own wear, but also makes itself smoother and smoother through wear. Therefore, it is beneficial to increase the life of the blades and the efficiency of the impeller, and improve the anti-cavitation performance of the pump;

[0028] (4) The pre-sintered ceramic block adopts silicon carbide or silicon nitride, the expansion coefficient of which is close to that of silicon nitride combined silicon carbide or oxide combined silicon carbide, so that the impeller blank or the pre-sintered ceramic block will not be broken due to thermal expansion during sintering or cooling, provided that appropriate measures are taken;

[0029] (5) The reaction sintered silicon carbide, pressureless sintered silicon carbide or hot-pressed sintered silicon nitride with better wear resistance is used in the blade head with serious wear, so that the wear speed of these parts can be significantly slowed down and the service life of the impeller can be obviously prolonged;

[0030] (6) The pre-sintered ceramic block with better wear resistance and smoother surface is arranged on the working surface of the blade, which is beneficial to improving the service life of the impeller, the anti-cavitation performance of the impeller and the efficiency of the pump;

[0031] (7) During pouring, the impeller blank will naturally form a recess cavity in the combined part with the pre-sintered ceramic block, which is adapted to the profile of the embedded part of the pre-sintered ceramic block, so that the two can completely match at the embedded part, which is beneficial to the fixation of the pre-sintered ceramic block;

[0032] (8) The pre-sintered ceramic block extends into the front cover plate or the rear cover plate in the axial direction of the impeller, which is beneficial to the firm fixation of the pre-sintered ceramic block;

[0033] (9) The protrusion for preventing the blade from being detached is arranged at the part where the pre-sintered ceramic block extends into the front cover plate or the rear cover plate in the axial direction of the impeller, which is beneficial to improving the strength of the impeller;

[0034] (10) The organic glue with a proper thickness (generally 0.2-0.5 mm) is applied on the pre-sintered ceramic block before pouring the mixed material of silicon nitride combined silicon carbide or oxide combined silicon carbide, so that the organic glue will be burned and lost to form a gas at about 300-500℃, thereby forming a proper air gap between the pre-sintered ceramic block and the impeller blank, which can prevent the two from being broken due to the difference in thermal expansion coefficient during high-temperature sintering;

[0035] (11) The impeller with the pre-sintered ceramic block embedded is immersed in the adhesive for bonding, so that the original air gap between the pre-sintered ceramic block and the impeller body can be filled, and the pre-sintered ceramic block and the impeller body are firmly combined together. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a sectional view of embodiment 1 of the present application;

[0037] Figure 2 is Figure 1 is a sectional view in A-A direction;

[0038] Figure 3Schematic diagram of the pre-sintered ceramic block 201 assembled in the core box in Example 1 of the present invention;

[0039] Figure 4 is a cross-sectional view of embodiment 2 of the present invention;

[0040] Figure 5 for Figure 4 Cross-sectional view in the BB direction;

[0041] Figure 6 Schematic diagram of the pre-sintered ceramic block 201 assembled in the core box in Example 2 of the present invention;

[0042] Figure 7 is a cross-sectional view of embodiment 3 of the present invention;

[0043] Figure 8 for Figure 7 Cross-sectional view in CC direction;

[0044] Figure 9 Schematic diagram of the pre-sintered ceramic block 201 assembled in the core box in Example 3 of the present invention;

[0045] Figure 10 is a cross-sectional view of embodiment 4 of the present invention;

[0046] Figure 11 for Figure 10 Cross-sectional view in DD direction;

[0047] Figure 12 It is a cross-sectional view of a ceramic impeller in the prior art;

[0048] Figure 13 for Figure 12 Cross-sectional view at EE.

[0049] In the figure: 100, front cover; 200, blade; 201, pre-sintered ceramic block; 202, blade connection; 2011, anti-drop protrusion; 204, connection forming hole; 300, rear cover; 400, impeller core box. DETAILED DESCRIPTION

[0050] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0051] The specific embodiment of the present invention is as follows:

[0052] Example 1

[0053] like Figure 1-3As shown, a wear-resistant ceramic impeller, the main body of the impeller is made of silicon nitride combined with silicon carbide, which is not only easy to scale up the impeller but also has low cost. It includes a front cover plate 100, a rear cover plate 300 and blades 200. The blades 200 include a pre-sintered ceramic block 201 embedded in the front cover plate 100 and / or the rear cover plate 300. The pre-sintered ceramic block 201 is provided with an embedded portion, and the front cover plate 100 and / or the rear cover plate 300 are provided with a cavity that fits with the embedded portion of the pre-sintered ceramic block 201. The contours of the embedded portion and the cavity are adapted to each other. The pre-sintered ceramic block 201 is a ceramic sheet that has been sintered when the impeller is formed. Since the outer dimensions of the pre-sintered ceramic block 201 are relatively small, the use of silicon carbide or silicon nitride material is easy to implement in terms of technology and relatively low cost. Furthermore, the pre-sintered ceramic block 201 is embedded within the front and rear cover plates 100, 300, and is tightly connected to them, making the structure more secure and less susceptible to loosening. The front side of the pre-sintered ceramic block 201 serves as the working surface of the blades 200. The pre-sintered ceramic block 201 has a smooth and wear-resistant surface, minimizing wear during operation and preventing solids from accumulating within the pump, potentially preventing clogging.

[0054] In this embodiment, the blade 200 also includes a blade connection portion 202 that is sintered once and is arranged between the front cover plate 100 and the rear cover plate 300, and the blade connection portion 202 is adapted to the back side of the pre-sintered ceramic block 201; the pre-sintered ceramic block 201 is embedded in the front cover plate 100 and / or the rear cover plate 300 along the axial direction of the impeller; the pre-sintered ceramic block 201 is arranged at the working surface of the blade 200, the front side of the pre-sintered ceramic block 201 is the working surface, and the blade connection portion 202 is a supporting structure that can support the front cover plate 100, the rear cover plate 300 and position the pre-sintered ceramic block 201, thereby ensuring that the pre-sintered ceramic block 201 is not easily damaged.

[0055] A concave cavity is provided on the front cover plate 100 and / or the rear cover plate 300, conforming to the contour of the embedded portion of the pre-sintered ceramic block 201. This concave cavity contour is naturally formed during casting at the junction of the impeller blank and the pre-sintered ceramic block 201, ensuring a perfect fit between the two at the junction and facilitating the securement of the pre-sintered ceramic block 201.

[0056] In this embodiment, pre-sintered ceramic block 201 is constructed of silicon carbide or silicon nitride. Using a single-phase ceramic material, such as reaction-sintered silicon carbide, pressureless-sintered silicon carbide, or hot-pressed silicon nitride, pre-sintered ceramic block 201 allows for more uniform blade wear during use than dual-phase materials such as silicon nitride combined with silicon carbide. This prevents a significant increase in surface roughness due to uneven wear, thereby preventing deterioration in the impeller's cavitation resistance.

[0057] If the pre-sintered ceramic block 201 is made of reaction-sintered silicon carbide or hot-pressed silicon nitride, the material itself has self-lubricating properties under wear conditions, which not only reduces its own wear, but also makes itself increasingly smooth through wear, thereby helping to increase the life of the blades and the efficiency of the impeller, and improving the anti-cavitation performance of the pump. The silicon carbide or silicon nitride used in the pre-sintered ceramic block 201 has an expansion coefficient close to that of silicon nitride combined with silicon carbide. As long as appropriate measures are taken, the impeller blank or pre-sintered ceramic block 201 can be prevented from cracking during the sintering or cooling process due to thermal expansion. Using reaction-sintered silicon carbide, pressureless-sintered silicon carbide or hot-pressed silicon nitride with better wear resistance at the blade heads that are severely worn can significantly slow down the wear rate of these parts and significantly extend the life of the impeller.

[0058] In this embodiment, an anti-slip protrusion 2011 is provided on the outer side of the embedded portion of the pre-sintered ceramic block 201, and a groove is provided on the inner wall of the concave cavity of the front cover plate 100 and / or the rear cover plate 300. The groove of the inner wall of the concave cavity wraps around the outer side of the anti-slip protrusion 2011 of the embedded portion. The anti-slip protrusion 2011 can prevent the pre-sintered ceramic block 201 from falling off, which helps to improve the strength of the impeller. The cross-sectional width of the anti-slip protrusion 2011 is larger than the cross-sectional width of the pre-sintered ceramic block 201. The joints between the pre-sintered ceramic block 201, the front cover plate 100, and the rear cover plate 300 are dipped in an adhesive.

[0059] A method for manufacturing a wear-resistant ceramic impeller, the method comprising:

[0060] First, a pre-sintered ceramic block 201, an impeller core box 400 and an impeller casting mold are manufactured;

[0061] Then, the pre-sintered ceramic block 201 coated with organic glue is fixed to the corresponding position of the impeller core box 400 and placed into the impeller casting mold;

[0062] Next, the prepared mixed material is poured into the impeller casting mold. After hardening, the mold is removed and the impeller core box 400 is removed to obtain an impeller blank embedded with the pre-sintered ceramic block 201.

[0063] Next, the impeller blank is subjected to nitriding sintering to obtain an impeller sintered product;

[0064] Finally, the air gap between the pre-sintered ceramic block 201 and the impeller body is filled with grease to obtain a hardened impeller.

[0065] As attached Figure 3As shown in the figure, the pre-sintered ceramic block 201 is fixed in the impeller core box 400 during impeller forming in this embodiment. The corresponding positions of the pre-sintered ceramic block 201 and the impeller core box 400 are matched, and the pre-sintered ceramic block 201 is fixed in the corresponding position of the core box 400 by using an adhesive. The impeller core box 400 can adopt a lost foam mold. The impeller core box 400 fixed with the pre-sintered ceramic block 201 is placed in a mold, and a mixture of silicon carbide particles, metal silicon powder and a binder is poured into the mold. The mold is formed according to the process. After the mixture hardens, the mold is removed. After drying, the impeller core box 400 with the lost foam structure is heated and melted to obtain an impeller blank. The blank is placed in a sintering furnace for nitriding sintering. Silicon nitride generated by the reaction of metal silicon powder and nitrogen can cover the surface of the silicon carbide particles to form an impeller body with high mechanical strength. Resin is dipped at the joint. When the resin hardens, the pre-sintered ceramic block 201 can be reliably fixed on the impeller.

[0066] The purpose of applying an appropriate thickness (generally 0.2-0.5 mm) of organic glue on the pre-sintered ceramic block 201 before pouring is that the organic glue will be burned and turned into gas at around 300-500°C, thereby forming a suitable air gap between the pre-sintered ceramic block 201 and the impeller blank, which can prevent the two from cracking due to the difference in thermal expansion coefficients during high-temperature sintering.

[0067] The resin filling method includes: dipping the fired impeller into resin, removing it after the resin has completely filled the air gap between the pre-sintered ceramic block 201 and the impeller body, removing the excess resin from the impeller, and hardening the impeller's impeller resin to obtain a hardened impeller. The fired impeller, with the pre-sintered ceramic block 201 embedded therein, is then dipped into an adhesive to fill the existing air gap between the pre-sintered ceramic block 201 and the impeller body, thereby firmly bonding the pre-sintered ceramic block 201 and the impeller body.

[0068] The pre-sintered ceramic block 201 is provided with an anti-slip protrusion 2011 that can be axially embedded in the front cover plate 100 and the rear cover plate 300 , and the impeller core box 400 is provided with a mold cavity adapted to the anti-slip protrusion 2011 .

[0069] The method for removing the impeller core box 400 includes: setting up the impeller core box 400 with a lost foam structure, pouring the mixture into the impeller casting mold and hardening it, removing the mold, and then drying and heating the blank to remove the impeller core box 400.

[0070] The mixture includes silicon carbide particles, metallic silicon powder and a binder. The silicon carbide particles, metallic silicon powder and the binder are mixed in proportion to form a uniform mixture, and the mixture is poured into an impeller casting mold.

[0071] The steps of organic glue ablation and nitriding sintering include: placing the impeller blank into a sintering furnace, heating it to 300-500°C, ablating the organic glue coated on the surface of the pre-sintered ceramic block 201, and forming an air gap at the junction of the pre-sintered ceramic block and the impeller blank; introducing high-purity nitrogen into the sintering furnace, and heating it to 1400-1500°C for nitriding sintering.

[0072] The fired impeller is impregnated with a binder so that the air gaps between the pre-sintered ceramic sheets 201 are filled with the binder. The binder is hardened to form a solid whole, thereby obtaining a finished impeller.

[0073] Example 2

[0074] As attached Figure 4-6 As shown, this embodiment is substantially the same as Example 1, except that the material of the front cover plate 100 and the rear cover plate 300 is oxide-bonded silicon carbide, the pre-sintered ceramic block 201 is a hot-pressed sintered silicon nitride structure, two pre-sintered ceramic blocks 201 are provided on the working surface of the blade 200, and the back sides of the two pre-sintered ceramic blocks 201 are provided with a blade connection portion 202 that supports the two pre-sintered ceramic blocks 201. The two pre-sintered ceramic blocks 201 are thin sheet-like structures and are closely attached to the blade connection portion 202. Anti-stripping protrusions 2011 are provided at the portion of the pre-sintered ceramic block 201 that extends along the impeller axial direction to the front cover plate 100 or the rear cover plate 300 to prevent the pre-sintered ceramic block 201 from falling out.

[0075] Example 3

[0076] This embodiment is substantially the same as embodiment 1, except that the pre-sintered ceramic block 201 is a pressureless sintered silicon carbide structure, and the pre-sintered ceramic block 201 is provided with a connection forming hole 204 arranged along the axial direction of the impeller, and the connection forming hole 204 is filled with a blade connection portion 202 integrally formed with the front cover plate 100 and the rear cover plate 300. The pre-sintered ceramic block 201 is a closed ring structure surrounding the blade connection portion 202, has a large contact area with the blade connection portion 202, and has a more solid structure.

[0077] The impeller body is made of silicon nitride combined with silicon carbide.

[0078] Example 4

[0079] As attached Figure 10 , Attachment Figure 11 As shown, this embodiment is substantially the same as embodiment 1, except that each blade 200 is composed of a pre-sintered ceramic block 201, that is, the material of the blade 200 is all silicon carbide ceramic or silicon nitride ceramic, so the blade has very good wear resistance and cavitation resistance, and an anti-sintering protrusion 2011 is provided at the position where the pre-sintered ceramic block 201 extends along the axial direction of the impeller to the front cover plate 100 or the rear cover plate 300 to prevent the pre-sintered ceramic block 201 from falling out.

[0080] The wear-resistant ceramic impeller was used in a bench test. The flow rate at the cavitation generating point of the impeller was increased by about 17% compared with the cavitation generating point of the impeller in the prior art, that is, the anti-cavitation performance of the impeller was greatly improved.

[0081] The wear-resistant ceramic impeller was used in a mine, and the results were compared with those of the existing technology. The results showed that the wear rate of the blade head was reduced by about 85%, making the wear rate of the blade head lower than that of other parts of the impeller, greatly improving the life of the impeller.

[0082] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for manufacturing a wear-resistant ceramic impeller, characterized in that: The invention comprises a front cover plate (100), a rear cover plate (300) and a blade (200), characterized in that the blade (200) comprises a pre-sintered ceramic block (201) embedded in the front cover plate (100) and / or the rear cover plate (300); the pre-sintered ceramic block (201) is provided with an embedding portion, the front cover plate (100) and / or the rear cover plate (300) are provided with a cavity embedded with the embedding portion of the pre-sintered ceramic block (201), and the contours of the embedding portion and the cavity are adapted to each other; the blade (200) further comprises a pre-sintered ceramic block (201) formed by one-time sintering with the front cover plate (100) and the rear cover plate (300) and arranged on A blade connection portion (202) is provided between the front cover plate (100) and the rear cover plate (300), and the blade connection portion (202) is adapted to the back side of the pre-sintered ceramic block (201); the pre-sintered ceramic block (201) is embedded in the front cover plate (100) and / or the rear cover plate (300) along the axial direction of the impeller; an anti-slip protrusion (2011) is provided on the outer side of the embedded portion of the pre-sintered ceramic block (201); a groove is provided on the inner wall of the concave cavity of the front cover plate (100) and / or the rear cover plate (300), and the groove on the inner wall of the concave cavity wraps around the outer side of the anti-slip protrusion (2011) of the embedded portion; The method comprises: First, a pre-sintered ceramic block (201), an impeller core box (400), and an impeller casting mold are manufactured; Then, the pre-sintered ceramic block (201) coated with organic glue is fixed to the corresponding position of the impeller core box (400) and placed into the impeller casting mold; Next, the mixed material is prepared and poured into an impeller casting mold, and after hardening, the mold is removed and the impeller core box (400) is removed to obtain an impeller blank embedded with pre-sintered ceramic blocks (201); Next, the organic glue on the surface of the pre-sintered ceramic block (201) is ablated to form an air gap at the junction of the pre-sintered ceramic block (201) and the impeller blank, and the impeller blank is sintered to obtain a sintered impeller product; Finally, the air gap between the pre-sintered ceramic block (201) and the impeller body is filled with grease to obtain a hardened impeller; The resin filling treatment method comprises: dipping the sintered impeller into resin, taking it out after the resin has filled the air gap between the pre-sintered ceramic block (201) and the impeller body, removing excess resin from the impeller, and hardening the resin dipped on the impeller to obtain a hardened impeller; The organic glue ablation step comprises: placing the impeller blank into a sintering furnace, heating it to 300-500°C, and ablating the organic glue coated on the surface of the pre-sintered ceramic block (201) to form an air gap at the junction of the pre-sintered ceramic block (201) and the impeller blank; the sintering step comprises: introducing high-purity nitrogen into the sintering furnace, heating it to 1400°C-1500°C for nitriding sintering; or heating it to 1400°C-1500°C in an oxidizing environment for oxidizing sintering.

2. The method for manufacturing a wear-resistant ceramic impeller according to claim 1, characterized in that: The pre-sintered ceramic block (201) is made of silicon carbide or silicon nitride; the front cover plate (100) and the rear cover plate (300) are both made of silicon nitride combined with silicon carbide or oxide combined with silicon carbide.

3. The method for manufacturing a wear-resistant ceramic impeller according to claim 1, characterized in that: The pre-sintered ceramic block (201), the front cover plate (100), and the rear cover plate (300) are dipped in adhesive.

4. A method for manufacturing a wear-resistant ceramic impeller according to any one of claims 1 to 3, characterized in that: At least two pre-sintered ceramic blocks (201) are provided on the working surface of each blade (200), and a blade connection portion (202) supporting the pre-sintered ceramic block (201) is provided on the back side of the pre-sintered ceramic block (201).

5. A method for manufacturing a wear-resistant ceramic impeller according to any one of claims 1 to 3, characterized in that: The pre-sintered ceramic block (201) is provided with a connection portion forming hole (204) arranged along the axial direction of the impeller, and the connection portion forming hole (204) is filled with a blade connection portion (202) integrally formed with the front cover plate (100) and the rear cover plate (300).

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