A high temperature resistant electromagnetic pure iron surface electrical insulation coating and preparation method thereof

Abstract

A high-temperature resistant electromagnetic pure iron surface electrical insulation coating and its preparation method, belonging to the field of sensor preparation technology, in order to solve the problem that the existing high-temperature liquid metal level sensor cannot adapt to high-temperature environment. It includes: low-melting point glass powder, binder, dispersant, film-forming aid and deionized water; the proportion of the low-melting point glass powder is 50-85 parts, the proportion of the binder is 0.1-3.0 parts, the proportion of the dispersant is 0.1-2.0 parts, the proportion of the film-forming aid is 0-5 parts, and the proportion of the deionized water is 15-50 parts; after the low-melting point glass powder is melted, compressive stress is formed on the surface of the electromagnetic pure iron substrate to obtain a high bonding strength coating layer; the electrical insulation coating is sintered at high temperature on the outer surface of the iron core, so that the iron core is in an insulating state under high temperature conditions. The present invention is used in high-temperature liquid metal level sensors.

Description

Technical Field

[0001] The invention relates to a high-temperature resistant electromagnetic pure iron surface electrical insulation coating, belonging to the technical field of sensor preparation. Background Art

[0002] The sodium-cooled fast reactor is the fastest-developed and most technologically mature reactor type among the six fourth-generation advanced nuclear reactors announced by the Generation IV International Forum (GIF). The sodium-cooled fast reactor has gained increasing attention due to its inherent safety and advantages in proliferating nuclear fuel and transmuting long-lived radioactive waste. Due to the strict requirements of space systems on power level volume, quality and safety, the metal sodium-cooled fast neutron reactor has become the only power source for 50-400kW space power. All space powers have actively carried out application research on small space nuclear reactor power systems. The special uses of the sodium-cooled fast reactor in many fields such as seawater desalination, regional heating, ship power and space power have made it a research hotspot. It will be used to equip deep space exploration, conventional nuclear submarines, other nuclear power units and commercial nuclear power plants.

[0003] In liquid metal reactors and experimental devices, sodium is used as a heat carrier, and there is a large amount of liquid sodium surface, and its liquid level needs to be monitored. Each gas / liquid interface in the primary and secondary circuits of the reactor and its auxiliary systems requires accurate and reliable liquid level measurement to ensure the normal operation of the reactor and heat transfer system, determine whether the container is overflowing, and determine whether there is a sodium leak. Because sodium reacts with many substances, it is usually completely sealed in a stainless steel container, so its liquid level measurement method must use a sensor sealed in a stainless steel casing to give a remote reading. Since the temperature of the metal coolant is usually controlled at 500°C when it is in liquid state, the operating temperature of the liquid level sensor must be able to withstand temperatures as high as 500°C, and the measurement range can vary greatly from tens of millimeters to more than a few meters.

[0004] The high-temperature liquid metal level sensor uses two core wires in a double-core armored cable with stainless steel as the shell and magnesium oxide as the insulation layer, which are respectively used as the excitation winding and the output winding and are circumferentially wound on the iron core. The sensor operates at a temperature of 500°C. Long-term high-temperature environment directly causes the insulation resistance between the turns of the winding coil and the insulation resistance between the coil and the iron core to drop sharply, affecting the resolution of the sensor and even causing measurement failure. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the existing high-temperature liquid metal level sensor cannot adapt to high-temperature environment, and to provide a high-temperature resistant electromagnetic pure iron surface electrical insulation coating and a preparation method thereof.

[0006] The high temperature resistant electric insulating coating on the surface of electromagnetic pure iron of the present invention comprises: low melting point glass powder, binder, dispersant, film forming aid and deionized water;

[0007] The proportion of the low melting point glass powder is 50 to 85 parts, the proportion of the binder is 0.1 to 3.0 parts, the proportion of the dispersant is 0.1 to 2.0 parts, the proportion of the film-forming aid is 0 to 5 parts, and the proportion of the deionized water is 15 to 50 parts;

[0008] After the low melting point glass powder is melted, compressive stress is formed on the surface of the electromagnetic pure iron substrate to obtain a coating layer with high bonding strength;

[0009] The electrical insulation coating is sintered at high temperature on the outer surface of the iron core, so that the iron core is in an insulating state under high temperature conditions.

[0010] Preferably, the high temperature condition is 500°C; the long-term temperature resistance is greater than 550°C;

[0011] At room temperature, the dielectric high voltage resistance is 500V@50Hz, the insulation resistance is >500MΩ@500V, and the maximum is 1000MΩ@500V;

[0012] High temperature 500℃ continuous 1000h, insulation resistance>100MΩ@50V, maximum is 500MΩ@50V.

[0013] Preferably, the low melting point glass powder is: SiO2-B2O3-Al2O3 glass, with R2O, RO and fluoride added;

[0014] Specifically, the proportion of SiO2 is 30-70 parts, the proportion of B2O3 is 5-20 parts, the proportion of Al2O3 is 5-15 parts, the proportion of R2O is 0-10 parts, the proportion of RO is 0-20 parts, and the proportion of fluoride is 0-10 parts;

[0015] The electromagnetic pure iron material is DT4, and the expansion coefficient is 11.8×10 -6 / k,

[0016] The expansion coefficient of the low-melting-point glass composed of low-melting-point glass powder within 600°C is 8.0×10 -6 ~11.0×10 -6 / k;

[0017] The particle size D50 of the low-melting-point glass powder is 0.1-15 μm; the glass transition temperature Tg is higher than 550° C., and the initial melting temperature is 620-720° C.

[0018] Preferably, the binder is an organic binder, specifically one or more of polyvinyl alcohol, carboxymethyl cellulose, dextrin and cyanoacrylate.

[0019] Preferably, the dispersant is one or more of ammonium polyacrylate, polyethylene glycol, polyvinyl pyrrolidone and sodium dodecylbenzene sulfonate.

[0020] Preferably, the film-forming aid is water glass or silica sol, or a mixture of the two.

[0021] The present invention provides a method for preparing a high temperature resistant electrical insulation coating on the surface of electromagnetic pure iron, and the preparation method specifically comprises:

[0022] S1. Weigh SiO2, B2O3, Al2O3, R2O, RO and fluoride according to a proportional formula, put them into a ceramic ball mill, and perform planetary ball milling to obtain a low-melting-point glass raw material powder;

[0023] S2, weighing the low-melting-point glass raw material powder obtained in S1, a binder, a dispersant, a film-forming aid and deionized water according to a proportional formula, placing them in a ball mill, and subjecting them to horizontal ball milling to obtain a coating slurry;

[0024] S3, applying the coating slurry on the outer surface of the core by manual coating, spraying or printing process;

[0025] The iron core obtained in S4 and S3 is placed in a sintering furnace and sintered in three stages, namely, drainage, debinding and cladding, to form a high temperature resistant insulating layer on the surface of the iron core.

[0026] Preferably, the rotation speed of the planetary ball mill in S1 is 200-500 rpm, preferably 300 rpm;

[0027] The working time of the planetary ball mill is 0.5 to 4 hours, preferably 2 hours;

[0028] The obtained low melting point glass raw material powder has a particle size D50 of 0.1 to 15 μm, preferably 5 μm;

[0029] The rotation speed of the horizontal ball mill in S2 is 100-200 rpm, preferably 175 rpm;

[0030] The working time of the horizontal ball mill is 8 to 40 hours, preferably 16 hours;

[0031] The obtained coating slurry has a viscosity of 0.3-15 Pa·s, preferably 1 Pa·s.

[0032] Preferably, the manual coating described in S3 is performed using a brush or a writing brush;

[0033] The spraying is carried out using a spray gun with a caliber of 0.8 to 1.5 mm, preferably a 1.0 mm spray gun, and a pressure of the spray gun of 0.1 to 4.0 MPa, preferably 0.2 MPa;

[0034] The spraying distance is 1 to 25 cm, preferably 20 cm.

[0035] Preferably, the temperature of the drainage section in S4 is 100-200° C., preferably 150° C.; the insulation time is 10-30 minutes, preferably 20 minutes;

[0036] The temperature of the debinding section is 300-450°C, preferably 400°C; the insulation time is 10-60 minutes, preferably 30 minutes;

[0037] The temperature of the cladding section is 650-850°C, preferably 750°C;

[0038] The heat preservation time is 5 to 30 minutes, preferably 15 minutes.

[0039] Advantages of the present invention: The high-temperature resistant electromagnetic pure iron surface electrical insulation coating proposed by the present invention has a long-term temperature resistance of more than 550°C; at room temperature, the insulation resistance of the coating is greater than 500MΩ@500V, and can reach a maximum of 1000MΩ@500V; after continuous action at a high temperature of 500°C for 1000h, the insulation resistance is greater than 100MΩ@50V, and can reach a maximum of 500MΩ@50V, showing excellent high-temperature insulation performance.

[0040] The service life of the sensor is increased from 4 hours before coating to more than 1000 hours, which effectively ensures the high resolution and long life measurement of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flowchart of a method for preparing a high temperature resistant electromagnetic pure iron surface electrical insulation coating. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0044] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0045] Embodiment 1:

[0046] The high temperature resistant electromagnetic pure iron surface electrical insulation coating described in this embodiment includes: low melting point glass powder, binder, dispersant, film-forming aid and deionized water;

[0047] The proportion of the low melting point glass powder is 50 to 85 parts, the proportion of the binder is 0.1 to 3.0 parts, the proportion of the dispersant is 0.1 to 2.0 parts, the proportion of the film-forming aid is 0 to 5 parts, and the proportion of the deionized water is 15 to 50 parts;

[0048] After the low melting point glass powder is melted, compressive stress is formed on the surface of the electromagnetic pure iron substrate to obtain a coating layer with high bonding strength;

[0049] The electrical insulation coating is sintered at high temperature on the outer surface of the iron core, so that the iron core is in an insulating state under high temperature conditions.

[0050] Furthermore, the high temperature condition is 500°C; the long-term temperature resistance is greater than 550°C;

[0051] At room temperature, the dielectric high voltage resistance is 500V@50Hz, the insulation resistance is >500MΩ@500V, and the maximum is 1000MΩ@500V;

[0052] High temperature 500℃ continuous 1000h, insulation resistance>100MΩ@50V, maximum is 500MΩ@50V.

[0053] Furthermore, the low melting point glass powder is: SiO2-B2O3-Al2O3 glass, with R2O, RO and fluoride added;

[0054] Specifically, the proportion of SiO2 is 30-70 parts, the proportion of B2O3 is 5-20 parts, the proportion of Al2O3 is 5-15 parts, the proportion of R2O is 0-10 parts, the proportion of RO is 0-20 parts, and the proportion of fluoride is 0-10 parts;

[0055] The electromagnetic pure iron material is DT4, and the expansion coefficient is 11.8×10 -6 / k, the expansion coefficient of the low-melting-point glass composed of low-melting-point glass powder within 600℃ is 8.0×10 -6 ~11.0×10 -6 / k;

[0056] The particle size D50 of the low-melting-point glass powder is 0.1-15 μm; the glass transition temperature Tg is higher than 550° C., and the initial melting temperature is 620-720° C.

[0057] Furthermore, the binder is an organic binder, specifically one or more of polyvinyl alcohol, carboxymethyl cellulose, dextrin and cyanoacrylate.

[0058] Furthermore, the dispersant is specifically one or more of ammonium polyacrylate, polyethylene glycol, polyvinyl pyrrolidone and sodium dodecylbenzene sulfonate.

[0059] Furthermore, the film-forming aid is specifically water glass or silica sol, or a mixture of the two.

[0060] Embodiment 2:

[0061] Combine the following Figure 1 This embodiment describes a method for preparing a high temperature resistant electromagnetic pure iron surface electrical insulation coating, and the preparation method specifically includes:

[0062] S1. Weigh SiO2, B2O3, Al2O3, R2O, RO and fluoride according to a proportional formula, put them into a ceramic ball mill, and perform planetary ball milling to obtain a low-melting-point glass raw material powder;

[0063] S2, weighing the low-melting-point glass raw material powder obtained in S1, a binder, a dispersant, a film-forming aid and deionized water according to a proportional formula, placing them in a ball mill, and subjecting them to horizontal ball milling to obtain a coating slurry;

[0064] S3, applying the coating slurry on the outer surface of the core by manual coating, spraying or printing process;

[0065] The iron core obtained in S4 and S3 is placed in a sintering furnace and sintered in three stages, namely, drainage, debinding and cladding, to form a high temperature resistant insulating layer on the surface of the iron core.

[0066] Further, the rotation speed of the planetary ball mill in S1 is 200-500 rpm, preferably 300 rpm;

[0067] The working time of the planetary ball mill is 0.5 to 4 hours, preferably 2 hours;

[0068] The obtained low melting point glass raw material powder has a particle size D50 of 0.1 to 15 μm, preferably 5 μm;

[0069] The rotation speed of the horizontal ball mill in S2 is 100-200 rpm, preferably 175 rpm;

[0070] The working time of the horizontal ball mill is 8 to 40 hours, preferably 16 hours;

[0071] The obtained coating slurry has a viscosity of 0.3-15 Pa·s, preferably 1 Pa·s.

[0072] Furthermore, the manual coating described in S3 is performed using a brush or a writing brush;

[0073] The spraying is carried out using a spray gun with a caliber of 0.8 to 1.5 mm, preferably a 1.0 mm spray gun, and a pressure of the spray gun of 0.1 to 4.0 MPa, preferably 0.2 MPa;

[0074] The spraying distance is 1 to 25 cm, preferably 20 cm.

[0075] Furthermore, the temperature of the drainage section in S4 is 100-200°C, preferably 150°C; the insulation time is 10-30 minutes, preferably 20 minutes;

[0076] The temperature of the debinding section is 300-450°C, preferably 400°C; the insulation time is 10-60 minutes, preferably 30 minutes;

[0077] The temperature of the cladding section is 650-850°C, preferably 750°C;

[0078] The heat preservation time is 5 to 30 minutes, preferably 15 minutes.

[0079] In the present invention, a high-temperature resistant electromagnetic pure iron surface electrical insulation coating is composed of the following components: 50 to 85 parts of low-melting point glass powder, 0.1 to 3 parts of binder, 0.1 to 2.0 parts of dispersant, 0 to 5 parts of film-forming aid, and 15 to 50 parts of deionized water.

[0080] The low melting point glass powder is SiO2-B2O3-Al2O3 glass, and is added with modifiers such as R2O, RO and fluoride;

[0081] The binder is an organic binder, which is one or more of polyvinyl alcohol, carboxymethyl cellulose, dextrin and cyanoacrylate;

[0082] The dispersant is one or more of ammonium polyacrylate, polyethylene glycol, polyvinyl pyrrolidone and sodium dodecylbenzene sulfonate;

[0083] The film-forming aid is one or both of water glass and silica sol; the film-forming aid is used to ensure that the coating has a certain initial film strength after drying, so as to avoid cracking and peeling in the subsequent drainage and debinding process;

[0084] In the present invention, the low melting point glass powder is composed of the following components: SiO2 accounts for 30 to 70 parts, B2O3 accounts for 5 to 20 parts, Al2O3 accounts for 5 to 15 parts, R2O accounts for 0 to 10 parts, RO accounts for 0 to 20 parts and fluoride accounts for 0 to 10 parts; wherein SiO2 forms the main component of the glass phase; B2O3 is used to adjust the fluidity of the coating in the molten state; the addition of Al2O3 can adjust the strength and high temperature resistance performance of the coating; R2O is one or two of the alkali metals Na or K, and the addition of R2O is to adjust the expansion coefficient and Tg temperature; RO is one or more of the alkaline earth metals Ca, Mg and Ba, and the addition of RO is to prevent crystallization and improve chemical stability; fluoride is one or two of CaF2 or MgF2; the function of fluoride is mainly to adjust the glass transition temperature and the initial melting temperature;

[0085] Table 1 is the formula and properties of low melting point glass powder:

[0086] Table 1

[0087]

[0088] In the present invention, the electromagnetic pure iron material is DT4, and its expansion coefficient is 11.8×10 -6 / k, the expansion coefficient of the low melting point glass within 600°C is controlled to be 8.0×10 -6 / k~11.0×10 -6 / k, so that after the glass is melted, compressive stress is formed on the surface of the electromagnetic pure iron substrate to obtain a coating effect with high bonding strength;

[0089] The particle size D50 of the low melting point glass powder is 0.1um to 15um; the glass transition temperature Tg is higher than 550°C, and the initial melting temperature is 620°C to 720°C;

[0090] The present invention provides a method for preparing a high temperature resistant electromagnetic pure iron surface electrical insulation coating, the main steps of which are:

[0091] (1) SiO2, B2O3, Al2O3, R2O, RO and fluoride are weighed according to the formula and placed in a ceramic ball mill, and subjected to planetary ball milling to obtain a low melting point glass raw material powder;

[0092] (2) According to the formula requirements, low melting point glass raw material powder, binder, dispersant, film-forming aid and deionized water are weighed and placed in a ceramic or polyurethane ball mill, and subjected to horizontal ball milling to obtain a coating slurry with high fraction and good flowability;

[0093] (3) Apply the coating on the outer surface of the core by manual coating, spraying or printing;

[0094] (4) The coated iron core is placed in a sintering furnace and sintered in three stages, namely, drainage, debinding and cladding, so as to form a dense high-temperature resistant insulating coating on the surface of the iron core.

[0095] In step (1), the planetary ball mill has a rotation speed of 200 rpm to 500 rpm, preferably 300 rpm;

[0096] The ball milling time is 0.5h to 4h, preferably 2h;

[0097] The particle size D50 of the low melting point glass raw material powder is between 0.1um and 15um, preferably 5um;

[0098] In step (2), the horizontal ball milling speed is 100 rpm to 200 rpm, preferably 175 rpm; the ball milling time is 8 h to 40 h, preferably 16 h; and a coating slurry with a viscosity of 0.3 Pa·s to 15 Pa·s is obtained, preferably the coating slurry viscosity is 1 Pa·s;

[0099] The manual coating in step (3) is performed using tools such as a brush or a writing brush;

[0100] The spraying uses a spray gun caliber of 0.8 mm to 1.5 mm, preferably 1.0 mm; a spray gun pressure of 0.1 MPa to 4.0 MPa, preferably 0.2 MPa; a spraying distance of 15 cm to 25 cm, preferably 20 cm;

[0101] The temperature of the drainage section in step (4) is 100°C to 200°C, preferably 150°C;

[0102] The insulation time of the drainage section is 10 minutes to 30 minutes, preferably 20 minutes;

[0103] The temperature of the debinding section is 300℃~450℃, preferably 400℃;

[0104] The heat preservation time of the debinding section is 10 minutes to 60 minutes, preferably 30 minutes;

[0105] The temperature of the cladding section is 650°C to 850°C, preferably 750°C;

[0106] The insulation time of the cladding section is 5 minutes to 30 minutes, preferably 15 minutes.

[0107] In the present invention, the electromagnetic pure iron DT4 has low coercive force and good magnetic induction intensity, and the Curie temperature point is relatively high. It is used as a sensitive iron core in a high-temperature liquid metal level sensor to increase the output sensitivity of the sensor. When in use, two sets of coils are spirally wound on the iron core in a double-wire parallel winding manner. When the surface of the iron core is not insulated, the sensor can only work normally for 2 hours at a high temperature of 500°C. As time goes by, the coil insulation resistance will drop rapidly to 0. After the surface of the iron core is insulated, the sensor can work stably for 1000 hours at a high temperature of 500°C. The high-temperature liquid metal level sensor can be used to monitor the liquid level signal of a sodium-cooled fast reactor or other metal-cooled nuclear reactors, or in non-contact inductive high-temperature liquid level measurement environments in other harsh occasions. It has the characteristics of high temperature resistance (the liquid metal working temperature can reach up to 500°C, and this sensor can fully cover the working temperature), simple structure, safety and reliability, high accuracy, continuous measurement, and wide application occasions.

[0108] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A high temperature resistant electromagnetic pure iron surface electrical insulation coating, characterized in that: It includes: Low melting point glass powder, binder, dispersant, film-forming aid and deionized water; The proportion of the low melting point glass powder is 50-85 parts, the proportion of the binder is 0.1-3.0 parts, the proportion of the dispersant is 0.1-2.0 parts, the proportion of the film-forming aid is 0-5 parts, and the proportion of the deionized water is 15-50 parts; After the low melting point glass powder is melted, compressive stress is formed on the surface of the electromagnetic pure iron substrate to obtain a coating layer with high bonding strength; The electrical insulation coating is sintered at high temperature on the outer surface of the iron core, so that the iron core is in an insulating state under high temperature conditions; The high temperature condition is 500°C; the long-term temperature resistance is greater than 550°C; At room temperature, the dielectric high voltage resistance is 500V@50Hz, the insulation resistance is >500MΩ@500V, and the maximum is 1000MΩ@500V; High temperature 500℃ for 1000h continuously, insulation resistance>100MΩ@50V, maximum 500MΩ@50V; The low melting point glass powder is: SiO2-B2O3-Al2O3 glass, with R2O, RO and fluoride added; The R2O is one or both of alkali metals Na or K, the RO is one or more of alkaline earth metals Ca, Mg and Ba, and the fluoride is one or both of CaF2 and MgF2; Specifically: the proportion of SiO2 is 30 parts, the proportion of B2O3 is 20 parts, the proportion of Al2O3 is 20 parts, the proportion of Na2O is 5 parts, the proportion of K2O is 5 parts, the proportion of MgO is 10 parts, the proportion of CaO is 10 parts, the proportion of BaO is 0 parts, the proportion of MgF is 0 parts, and the proportion of CaF is 0 parts; Or: the proportion of SiO2 is 40 parts, the proportion of B2O3 is 15 parts, the proportion of Al2O3 is 16 parts, the proportion of Na2O is 3 parts, the proportion of K2O is 3 parts, the proportion of MgO is 7 parts, the proportion of CaO is 10 parts, the proportion of BaO is 0 parts, the proportion of MgF is 3 parts, and the proportion of CaF is 3 parts; Or: the proportion of SiO2 is 50 parts, the proportion of B2O3 is 12 parts, the proportion of Al2O3 is 12 parts, the proportion of Na2O is 2 parts, the proportion of K2O is 3 parts, the proportion of MgO is 5 parts, the proportion of CaO is 5 parts, the proportion of BaO is 10 parts, the proportion of MgF is 1 part, and the proportion of CaF is 0 parts; Or: SiO2 is 60 parts, B2O3 is 8 parts, Al2O3 is 7 parts, Na2O is 3 parts, K2O is 2 parts, MgO is 5 parts, CaO is 3 parts, BaO is 7 parts, MgF is 4 parts, and CaF is 1 part; Or: the proportion of SiO2 is 70 parts, the proportion of B2O3 is 5 parts, the proportion of Al2O3 is 5 parts, the proportion of Na2O is 0 parts, the proportion of K2O is 0 parts, the proportion of MgO is 0 parts, the proportion of CaO is 0 parts, the proportion of BaO is 15 parts, the proportion of MgF is 4 parts, and the proportion of CaF is 6 parts; The electromagnetic pure iron material is DT4, and the expansion coefficient is 11.8×10 -6 / k, the expansion coefficient of the low-melting-point glass composed of low-melting-point glass powder within 600℃ is 8.0×10 -6 ~11.0×10 -6 / k; The particle size D50 of the low-melting-point glass powder is 0.1-15 μm; the glass transition temperature Tg is higher than 550° C., and the initial melting temperature is 620-720° C.

2. The high temperature resistant electromagnetic pure iron surface electrical insulation coating according to claim 1, characterized in that: The binder is an organic binder, specifically one or more of polyvinyl alcohol, carboxymethyl cellulose, dextrin and cyanoacrylate.

3. The high temperature resistant electromagnetic pure iron surface electrical insulation coating according to claim 1, characterized in that: The dispersant is specifically one or more of ammonium polyacrylate, polyethylene glycol, polyvinyl pyrrolidone and sodium dodecylbenzene sulfonate.

4. The high temperature resistant electromagnetic pure iron surface electrical insulation coating according to claim 1, characterized in that: The film-forming aid is specifically water glass or silica sol, or a mixture of the two.

5. The method for preparing a high temperature resistant electromagnetic pure iron surface electrical insulation coating as claimed in claim 1, characterized in that: The preparation method specifically comprises: S1. Weigh SiO2, B2O3, Al2O3, R2O, RO and fluoride according to a proportional formula, put them into a ceramic ball mill, and perform planetary ball milling to obtain a low-melting-point glass raw material powder; S2, weighing the low-melting-point glass raw material powder obtained in S1, a binder, a dispersant, a film-forming aid and deionized water according to a proportional formula, placing them in a ball mill, and subjecting them to horizontal ball milling to obtain a coating slurry; S3, applying the coating slurry on the outer surface of the core by manual coating, spraying or printing process; The iron core obtained in S4 and S3 is placed in a sintering furnace and sintered in three stages, namely, drainage, debinding and cladding, to form a high temperature resistant insulating layer on the surface of the iron core.

6. The method for preparing a high temperature resistant electromagnetic pure iron surface electrical insulation coating according to claim 5, characterized in that: S1: The rotation speed of the planetary ball mill is 200-500 rpm; the working time of the planetary ball mill is 0.5-4 hours; the particle size D50 of the obtained low-melting-point glass raw material powder is 0.1-15 μm; The rotation speed of the horizontal ball mill in S2 is 100 to 200 rpm; the working time of the horizontal ball mill is 8 to 40 hours; and the viscosity of the obtained coating slurry is 0.3 to 15 Pa·s.

7. The method for preparing a high temperature resistant electrical insulation coating on the surface of electromagnetic pure iron according to claim 5, characterized in that: The manual coating described in S3 is performed by using a brush or a writing brush; The spraying adopts a spray gun with a caliber of 0.8-1.5 mm, a pressure of the spray gun of 0.1-4.0 MPa, and a spraying distance of 1-25 cm.

8. The method for preparing a high temperature resistant electrical insulation coating on the surface of electromagnetic pure iron according to claim 5, characterized in that: S4: the temperature of the drainage section is 100-200°C; the insulation time is 10-30 minutes; The temperature of the debinding section is 300-450°C; the insulation time is 10-60 minutes; The temperature of the cladding section is 650-850° C., and the insulation time is 5-30 minutes.

Images