Green and environment-friendly anti-bonding composition for high-temperature annealing of uncoated silicon steel

Abstract

The invention relates to the technical field of metal annealing materials, and discloses a green and environment-friendly anti-bonding composition for high-temperature annealing of uncoated silicon steel, which comprises the following components in parts by weight: 10-25 parts of fibrous silicate mineral, 0.5-3.5 parts of sodium aluminate, 2-8 parts of nanoscale magnesium aluminate spinel and the balance of deionized water, and the anti-bonding composition is prepared from the following components in parts by weight: 10-25 parts of fibrous silicate mineral, 0.5-3.5 parts of sodium aluminate, 2-8 parts of nanoscale magnesium aluminate spinel and the balance of deionized water. The preparation method comprises the following steps: filling end lattice defects of fibrous silicate minerals with aluminate ions generated by dissociation of sodium aluminate, inducing directional anchoring of nanoscale magnesium aluminate spinel and constructing a localized interface coupling structure, and establishing a solid-phase reaction dynamic barrier in a heating process by utilizing the localized interface coupling structure; the active silicon dioxide is induced to generate in-situ crystalline phase transformation at the moment of release, the migration path of the active silicon dioxide to the surface of the metal substrate is blocked, and the generation of a low-melting-point glass phase is inhibited.

Description

Technical Field

[0001] This invention relates to a green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel, belonging to the technical field of metal annealing materials. Background Technology

[0002] Currently, in the high-temperature annealing process of uncoated silicon steel, magnesium oxide slurry is commonly used as an anti-adhesion agent to prevent the steel coil layers from sticking together during annealing. To maintain the magnesium oxide particles in a suspended state in the slurry and ensure coating uniformity, the industry typically adds layered silicates such as lithium montmorillonite. These silicates utilize the interaction of their surface charges to construct a cardboard structure to support the heavy magnesium oxide particles. Magnesium oxide undergoes a partial hydration reaction in water-based slurries, causing the pH of the system to rise above 10.5. In this high-alkalinity environment with high ionic strength, the diffused double layer of the layered silicates is compressed, causing the pre-designed cardboard structure to collapse and triggering slurry aggregation. The rheological instability of the slurry directly affects the continuity and thickness consistency of the coating, thereby causing defects in subsequent processes.

[0003] To address the aforementioned rheological stability issues, simply increasing the amount of silicate clay can lead to excessive inorganic clay components undergoing a low-melting-point phase transition and releasing active silica during annealing at temperatures above 1000°C. These active components react with magnesium oxide, forming glassy spots on the steel plate surface that are difficult to remove. If organic thickeners are used, carbon contamination will be introduced during annealing, and the migration of carbon atoms into the silicon steel will cause magnetic domain pinning, increasing the magnetic loss of the material. Optimizing the precision of the coating machinery or adjusting the shape of the rollers are hardware methods to improve the physical isolation effect of the initial coating. However, existing technologies for controlling the reaction path of the high-temperature surface layer are insufficient. For example, Chinese invention patent CN118048599A discloses a surface treatment method for uncoated silicon steel cores. It improves the oxidation resistance and magnetic properties of the core through multiple subsequent treatment processes such as degreasing, nitriding, and bluing. However, the post-processing makes the production process cumbersome and cannot intercept active components during the core high-temperature annealing stage, making it difficult to prevent silica from penetrating and migrating to the substrate surface from the source.

[0004] Therefore, how to construct a rheological system with self-stabilizing properties under extremely alkaline conditions and achieve micro-region interception of active components during annealing to suppress the generation of low-melting-point phases has become the technical problem to be solved by this invention. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: A green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel, comprising the following components: 10 to 25 parts by weight of fibrous silicate minerals, wherein the fibrous silicate minerals are at least one of attapulgite or sepiolite; 0.5 to 3.5 parts of sodium aluminate; 2 to 8 parts of nano-sized magnesium aluminate spinel; And, replenish to 100 parts of deionized water; In this composition, under a pH environment of 11.2 to 11.8, the aluminate ions generated by the dissociation of sodium aluminate fill the lattice defects at the fiber ends of the fibrous silicate mineral, forming a localized negative charge concentration region at the fiber ends; the average particle size of the nano-sized magnesium aluminate spinel is 40 nm to 60 nm, and the nano-sized magnesium aluminate spinel is adsorbed onto the localized negative charge concentration region through interfacial electrostatic attraction, forming a localized interfacial coupling structure composed of fibrous silicate mineral and nano-sized magnesium aluminate spinel; Under heat, the localized interface coupling structure induces a solid-state reaction between active silica and nano-sized magnesium aluminate spinel within the diffusion radius of active silica generated by the decomposition of fibrous silicate minerals, generating a high-melting-point magnesium aluminate crystalline phase to block the migration path of active silica to the surface of the metal substrate.

[0006] Preferably, the fibrous silicate minerals are shear-activated at a rotation speed of 4000 r / min to 4500 r / min to expose lattice defects at the ends of the fibrous silicate minerals; nano-sized magnesium aluminate spinel is added in the form of an aqueous slurry with a mass fraction of 15% to 25%, the aqueous slurry exhibits shear-thinning characteristics under pH conditions, and the dynamic viscosity of the aqueous slurry is modulated by the ionic strength of sodium aluminate.

[0007] Preferably, a three-dimensional support skeleton is constructed by interconnecting localized interface coupling structures, and the static yield stress of the three-dimensional support skeleton is not less than 15 Pa; the composition also includes magnesium oxide particles suspended in the pores of the three-dimensional support skeleton, the median particle size of the magnesium oxide particles is 5 μm to 15 μm, and the magnesium oxide particles maintain a dispersed state under the spatial confinement effect generated by the three-dimensional support skeleton.

[0008] Preferably, the composition further includes 0.1 to 0.8 parts of a surfactant modifier, wherein the surfactant modifier is at least one of sodium lignosulfonate or polyvinyl alcohol, used to regulate the charge repulsion on the sides of the fibrous silicate mineral to maintain the porosity of the three-dimensional support framework.

[0009] Preferably, the nano-sized magnesium aluminate spinel has a positive spinel structure with a lattice constant of 0.808 nm to 0.810 nm and an isoelectric point of 8.5 to 9.2.

[0010] Preferably, the composition is coated onto the surface of a metal substrate and dried to form a porous dry film. The porous dry film is formed by the controlled shrinkage of a localized interfacial coupling structure during the moisture removal process. The mechanical interlocking force between the residue of the porous dry film after high-temperature annealing and the surface of the metal substrate is less than 5 N / m.2 .

[0011] Preferably, the temperature range for removing bound water from fibrous silicate minerals is 200°C to 450°C, and the starting temperature for triggering solid-phase reactions by the localized interface coupling structure is lower than the critical temperature at which the fibrous silicate mineral skeleton collapses.

[0012] Preferably, each component in the composition meets the interface anchoring index η requirement, and the interface anchoring index η conforms to the following relationship: η=(S a ·σ s ) / M f , of which S a The specific surface area of ​​nano-sized magnesium aluminate spinel is expressed in m². 2 / g;σ s The surface charge density at the fiber tip, expressed in C / m. 2 M f The weight percentage of fibrous silicate minerals; the interface anchoring index η is used to define the adsorption density of nano-sized magnesium aluminate spinel at the ends of fibrous silicate minerals.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. In the green and environmentally friendly anti-adhesion composition, the strong alkaline environment generated by the continuous hydration of magnesium oxide in the aqueous phase is utilized to induce the aluminate ions in sodium aluminate to undergo in-situ coordination modification at the broken bonds at the ends of fibrous silicates. This constructs a heterogeneous charge interlocking grid between fibrous silicates and magnesium oxide particles. The grid transforms the ionic strength that originally caused the system instability into the driving force for the generation of controlled electrostatic attraction between components, establishing a three-dimensional support framework with high yield stress. This ensures that heavy magnesium oxide particles achieve long-term uniform suspension in the strong alkaline slurry, overcoming the salting-out and agglomeration phenomenon caused by the collapse of the diffuse double layer in the extremely high ionic strength environment of traditional layered silicate thickeners, and maintaining the dynamic stability of the slurry's rheological properties.

[0014] 2. By directional anchoring of the negative charge sites at the ends of fibrous silicates with nano-sized magnesium aluminate spinel, a heterogeneous topological structure of fibers and nanocrystals is pre-constructed in the dry film of the anti-adhesion layer. During the high-temperature annealing stage, the nano-sized magnesium aluminate spinel acts as a phase change interceptor. At the moment when the fibrous silicates decompose and release active silica, it guides the active silica to undergo a solid-phase reaction within the nano-scale diffusion radius and transform into the high-melting-point spinel phase. This process physically cuts off the kinetic path of the active silica migrating to the magnesium oxide surface and inhibits the formation of the low-melting-point silicate glass phase.

[0015] 3. By utilizing nano-magnesium aluminate spinel to precisely guide the high-temperature phase transformation path, the residual layer after annealing evolves into a porous honeycomb skeleton composed of stable oxides, rather than a dense, continuous glassy material. While maintaining the anti-sticking performance between boards, the honeycomb skeleton weakens the mechanical interlocking force and intermolecular forces between the residue and the substrate surface. This non-invasive structural feature makes the anti-sticking layer after annealing a fragile powder state, which can be removed by rinsing with room temperature water, meeting the extremely high cleanliness requirements of silicon steel surfaces and improving the reliability of subsequent processing. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the preparation process and surface anti-adhesion mechanism of the anti-adhesion composition of the present invention; Figure 2 This is a diagram showing the bimodal particle size distribution and gradation characteristics of the surface particles in the anti-adhesion composition of the present invention. Figure 3 This is a diagram showing the relationship between the multi-dimensional technical elements and performance implementation of this invention. Figure 4 This is an electron microscope image of the steel-silicon surface after annealing according to the present invention; Figure 5 This is a diagram of the three-dimensional porous mesh structure of the present invention. Detailed Implementation

[0017] The following embodiments are intended to explain the present invention, and not to limit the scope of protection of the present invention. Unless otherwise specified, the following embodiments and their technical features can be combined with each other.

[0018] This invention provides a green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel. By utilizing the interfacial charge polarity reconstruction and surface topology design in a strongly alkaline aqueous environment, a three-dimensional support framework with high yield stress is constructed. Furthermore, a localized interfacial coupling structure is used to establish a solid-phase reaction kinetic barrier during heating to intercept active silica and block the migration path of harmful components to the metal substrate surface. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel comprises the following components by weight: 10 to 25 parts of fibrous silicate minerals, selected from at least one of attapulgite or sepiolite; 0.5 to 3.5 parts of sodium aluminate; 2 to 8 parts of nano-sized magnesium aluminate spinel; and up to 100 parts of deionized water. The continuous hydration of magnesium oxide in the aqueous phase leads to an increase in the pH value of the system to the range of 11.2 to 11.8, causing the collapse of traditional thickening systems. This invention utilizes a high-intensity alkaline field to drive aluminate ions generated by the dissociation of sodium aluminate to fill the end lattice defects of shear-activated fibrous silicate minerals, creating a localized negative charge concentration region at the end of the fibrous silicate minerals. By introducing nanoscale magnesium aluminate spinel with an average particle size of 40 nm to 60 nm and an isoelectric point between 8.5 and 9.2, a localized interface coupling structure is constructed using the electrostatic attraction between the positive charge on the surface of the nanoscale magnesium aluminate spinel and the localized negative charge concentration region. The adsorption density of the nanoscale magnesium aluminate spinel at the fiber ends is determined by the interface anchoring index η, which follows the following relationship: η = (S a ·σ s ) / M f Where η is the interface anchoring index; S a The specific surface area of ​​nano-sized magnesium aluminate spinel is expressed in m². 2 / g;σ s The surface charge density at the ends of fibrous silicate minerals, expressed in C / m³. 2 M f It refers to the weight parts of fibrous silicate minerals.

[0019] This invention incorporates magnesium oxide particles as the functional load in the anti-adhesion composition. The spontaneous hydration behavior of magnesium oxide particles in an aqueous environment stabilizes the pH of the system within the range of 11.2 to 11.8. In this strongly alkaline field, sodium aluminate dissociates to generate aluminate ions, which preferentially adsorb at the broken bonds at the ends of fibrous silicate mineral fibers. Through aluminum-oxygen bridging, nano-sized magnesium aluminate spinel is guided to oriented on the surface. When crossing the isoelectric point environment of the nano-sized magnesium aluminate spinel, chemical bonding forces replace single electrostatic attraction to maintain the mechanical stability of the localized interface coupling structure. When the interface anchoring index η is controlled within the range of 0.4 to 1.2, the nano-sized magnesium aluminate spinel exhibits active... A dense interception network forms around the silica release source, preventing the absence of interception sites due to component content below the lower limit and the excessive physical accumulation of fiber mesh due to content above the upper limit, which would increase the difficulty of residue removal. During high-temperature annealing, the localized interface coupling structure induces an in-situ solid-state reaction between the active silica released from the decomposition of fibrous silicate minerals and the adjacent nanoscale magnesium aluminate spinel, generating a magnesium aluminate crystalline phase with a melting point above 1400℃ to block the migration path of active silica to the surface of the metal substrate. The residue after annealing exhibits a fragile porous honeycomb skeleton, and the mechanical interlocking force between it and the surface of the metal substrate is less than 5 N / m. 2 .

[0020] The preparation process of the composition includes the following steps: fibrous silicate minerals and sodium aluminate are added to deionized water, and a high-shear exfoliation treatment is performed at a rotation speed of 4000 r / min to 4500 r / min to achieve coordination modification of aluminate ions at the fiber ends; nano-sized magnesium aluminate spinel is added at a system pH of 11.2 to 11.8 to construct a localized interface coupling structure using interfacial electrostatic attraction and interconnect to form a three-dimensional support framework; finally, magnesium oxide particles with a median particle size of 5 μm to 15 μm are added to maintain the rheological stability of the system using the spatial confinement effect of the framework mesh; during the preparation of the composition, high-shear homogeneous units are exfoliated from fibrous silicate minerals at a rotation speed of 4000 r / min to 4500 r / min. For the addition of magnesium aluminate spinel, the degree of fiber dissociation was characterized by real-time measurement of the oil absorption value of the suspension. Shearing was stopped when the value rose to 1.25 to 1.35 times the initial value to ensure that the exposure of lattice defects reached the saturation point without damaging the fiber aspect ratio. During the addition of nano-sized magnesium aluminate spinel, the endpoint of the three-dimensional support framework formation was determined by monitoring the viscosity of the system in response to ionic strength modulation. When the static yield stress of the system reached 15 Pa and the absolute value of the Zeta potential decreased, the interconnection of the localized interface coupling structure was considered to be completed. The magnesium oxide particles were confined in the pores of the framework and maintained in a dispersed state. After drying, a porous dry film was formed, which played a solid-phase reaction barrier function during the high-temperature annealing stage, ensuring that the mechanical interlocking force between the residue and the substrate surface was less than 5 N / m. 2 .

[0021] Example 1: In an industrial setting for producing high magnetic orientation silicon steel coils with a thickness of 0.23 mm, the silicon steel coils are annealed at 1200°C for 20 hours. The continuous hydration of magnesium oxide particles in the aqueous phase causes the pH value of the slurry system to rise to about 11.5. This alkaline field causes a shift in the charge balance of the layered silicate components and triggers rheological instability in the slurry. As the plate temperature rises above 800°C, the active silica released by the decomposition of fibrous silicate minerals migrates disorderly to the surface of the metal substrate. Under the interlayer pressure of the steel plate, the active silica reacts with magnesium oxide particles in a solid phase and forms glassy silicate spots on the surface of the steel plate. To address the aforementioned risks of rheological instability and phase transformation induced by the alkaline field, 18 parts by weight of fibrous silicate minerals and 1.2 parts by weight of sodium aluminate are used. A shear activation operation at a speed of 4200 r / min is performed to fill the lattice defects at the ends of the fibrous silicate minerals with the dissociated aluminate ions, and a local negative charge concentration area is generated at the fiber ends.

[0022] Four parts by weight of nano-sized magnesium aluminate spinel with an average particle size of 50 nm were added to the system at a pH of 11.4. Utilizing the electrostatic attraction between the positive charge on the surface of the nano-sized magnesium aluminate spinel and the negative charge centers at the fiber ends, the nano-sized magnesium aluminate spinel was oriented and anchored around the potential release source of active silica. The resulting localized interface coupling structure confines the magnesium oxide particles within the pores of a three-dimensional support framework constructed by the interconnected localized interface coupling structure, enabling the static yield stress of the slurry to reach 18 Pa and ensuring the coating adheres to the steel. The thickness uniformity of the plate surface; when the annealing temperature rises above 1000℃, the nano-sized magnesium aluminate spinel anchored at the reaction site instantly captures the active silica released by the decomposition of fibrous silicate minerals and induces a solid-state reaction within the micro-region, generating magnesium aluminate silicate crystalline phase with a melting point higher than 1400℃. This process blocks the penetration path of active silica to the surface of the metal substrate, making the surface of the silicon steel after the annealing cycle exhibit a porous structure that is easily broken. Under normal temperature water rinsing conditions, the mechanical interlocking force with the surface of the metal substrate is less than 5N / m. 2 Ultimately, the silicon steel sheet surface had no visible residual spots and the surface oxygen content fluctuation value was less than 0.2 g / m². 2 The magnetic loss index of this high magnetic induction oriented silicon steel is reduced by about 8%.

[0023] Example 2: In the verification of high-temperature annealing at 1200℃ for 0.23mm thick high-magnetic-induction oriented silicon steel, the continuous hydration of magnesium oxide particles in the aqueous phase caused the pH value of the slurry system to rise to about 11.5. A physical experimental platform simulating the industrial annealing environment was established, including a vacuum annealing furnace with a temperature control accuracy better than ±1℃ and a rheological parameter monitoring unit with a sampling frequency of not less than 10Hz. All test data were derived from the actual measurement records of the physical experimental platform. In order to simulate the influence of industrial water quality fluctuations on charge distribution, impurity ions with a conductivity of 550μS / cm were actively introduced as environmental disturbances during the preparation process. When setting the shear activation speed of fibrous silicate minerals, the technical consideration was to achieve a balance between the exposure of lattice defects at the fiber ends and the fiber length retention rate. When the speed was lower than 4000r / min, the mechanical peeling force was insufficient to completely open the fibers. Lattice defects in the fiber bundles lead to a decrease in the in-situ modification efficiency of aluminate ions. When the rotation speed exceeds 4500 r / min, excessive shear stress can cause physical fracture of the fiber matrix, reducing the mechanical strength of the three-dimensional support skeleton. In this experiment, the shear activation rotation speed was determined to be 4250 r / min in an engineering example, and the activation time was controlled to 25 min to ensure that aluminate ions preferentially fill the lattice defects at the ends of the fibrous silicate minerals under shear induction and form a local negative charge concentration region. To verify the synergistic effect between components and identify the performance inflection point, a multi-dimensional control system was designed, including the sample group of this invention, a partially missing control group, and an out-of-range control group. By monitoring the correlation between the interface anchoring index η and the performance of the final annealing residue, the effect of interface charge polarization reconstruction on the stability of the system was observed. The specific performance verification results are shown in Table 1.

[0024] Table 1: Results of the correlation between component ratio and performance of the anti-adhesion composition

[0025] Analysis of the data trends in Table 1 reveals that when the amount of sodium aluminate is below the lower limit of 0.50 parts, the interfacial anchoring index η is at a low level below 0.20. This indicates that the fiber ends fail to generate a sufficiently dense negative charge region, leading to disordered diffusion of the nano-sized magnesium aluminate spinel and the inability to establish a localized interception barrier, thus increasing the spot coverage. When the amount of fibrous silicate mineral exceeds 25.00 parts, although the static yield stress continues to increase, the excessively high fiber mesh density causes a physical accumulation effect, resulting in a nonlinear increase in the mechanical interlocking force between the residue and the substrate. This confirms that the defined parameter range is an optimized range that balances rheological stability and ease of cleaning. Follows the following mathematical relationship: η=(S a ·σ s ) / M f Where η is the interface anchoring index; Sa The specific surface area of ​​nano-sized magnesium aluminate spinel is expressed in m². 2 / g;σ s The surface charge density at the fiber tip, expressed in C / m. 2 M f It refers to the weight parts of fibrous silicate minerals.

[0026] The final preparation procedure of the anti-adhesion composition of the present invention is as follows: A measured amount of deionized water is added to a reaction vessel, stirring is started at 500 r / min, and sodium aluminate and fibrous silicate minerals are added sequentially. The stirring speed is increased to 4250 r / min to perform high-shear exfoliation for 25 min. The material temperature is controlled at 30±2℃ using an external cooling jacket to prevent heat accumulation. After the shearing is completed, the pH value of the system is adjusted using a 5% sodium hydroxide solution to stabilize the value displayed on the monitor at approximately 11.5. Then, a 20% sodium hydroxide solution is added dropwise at a uniform speed of 800 r / min. A nano-sized magnesium aluminate spinel aqueous slurry was prepared and added at a dropping rate controlled at 50 mL / min. Finally, magnesium oxide particles with a median particle size of 10 μm were added, and the mixture was homogenized at a low shear speed of 600 r / min for 15 min to obtain the final product. The experimental results confirmed the synergistic effect generated by interfacial charge coupling between the components. The data show that this invention can construct a stable self-supporting rheological system in a strongly alkaline field without the use of organic thickeners, and utilizes a localized interfacial coupling structure to achieve in-situ interception of active silica, thereby reducing the mechanical interlocking force between annealing residues and the substrate to 5 N / m. 2 the following.

[0027] Example 3: This example combines Figures 1 to 5 This describes a green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel, such as... Figure 1 As shown, the process begins with the formulation of the raw materials. Fibrous silicate minerals, sodium aluminate, and nano-sized magnesium aluminate spinel are introduced into an alkaline environment. Sodium aluminate dissociates to generate aluminate ions, which fill the lattice defects to fill the ends of the fibrous silicate minerals. The inductive effect generated by this process causes the nano-sized magnesium aluminate spinel to complete directional anchoring, thereby constructing a localized interface coupling structure that can establish a solid-phase reaction kinetic barrier. When the system is thermally decomposed, causing the decomposition products of the fibrous minerals to release active silica, the localized interface coupling structure plays a kinetic barrier role. It induces the generation of a high-melting-point crystal phase through in-situ crystal phase transformation, thereby cutting off the diffusion channel to the metal substrate and blocking the migration path. Finally, by inhibiting the formation of a low-melting-point glass phase, a green and environmentally friendly anti-adhesion technical effect is achieved.

[0028] like Figure 2As shown, the particle size distribution characteristics of each component in the composition exhibit a bimodal distribution in a coordinate system with the horizontal axis representing the logarithmic scale of particle size and the vertical axis representing the distribution frequency or volume percentage. The left peak corresponds to nanoscale magnesium aluminate spinel with an average particle size of 40 to 60 nanometers, whose main function is clearly lattice anchoring and phase transition interception. The right peak corresponds to magnesium oxide particles with a median particle size of 5 to 15 micrometers, whose main function is to construct a three-dimensional support framework. The particle size span between the two types of particles reaches three orders of magnitude, or 1000 times. This differentiated gradation design aims to construct a porous and breathable structure within the system.

[0029] like Figure 3 As shown, the technical architecture is a multi-dimensional interconnected structure. Its core focuses on a green and environmentally friendly anti-adhesive composition characterized by high magnetic induction, easy cleaning, and no carbon residue. The component system includes fibrous silicate minerals, sodium aluminate as a modifier, and nano-sized magnesium aluminate spinel. The surface mechanism involves aluminate lattice filling, the formation of localized negative charge regions, and localized interface coupling structures. The environmental advantages are reflected in the absence of organic thickeners and the lack of carbon pollution risk. The key process includes high shear activation at 4250 rpm, pH control at 11.5, and dynamic potential monitoring. These elements work together in the performance realization branch to establish a kinetic barrier, promote in-situ crystal phase transformation, and block silica migration. Ultimately, in the usage characteristics branch, a mechanical interlocking force of less than 5 N / m is achieved. 2 The porous honeycomb-like residue.

[0030] like Figure 4 As shown in the figure, the surface of the metal substrate exhibits extremely high cleanliness and smoothness (as indicated by the large smooth area in the figure). There are no continuous glassy silicate spots common in traditional magnesium oxide systems. The small amount of porous material remaining in the figure is in an edge-curled or detached state, further confirming that the mechanical interlocking force between the three-dimensional skeleton formed by the localized interface coupling structure and the substrate is extremely low (<5 N / m). 2 ).

[0031] like Figure 5 As shown, the image center displays a three-dimensional porous mesh structure interwoven with fibrous silicate minerals. Tiny nano-sized magnesium aluminate spinel particles are uniformly anchored on the fiber surface, forming a localized interface coupling structure. The overall morphology is extremely loose and porous, exhibiting a clear sintering neck but without the feel of glassy phase melting.

[0032] Example 4: In the full-cycle annealing process of high magnetic induction oriented silicon steel with a thickness of 0.27 mm, the transient temperature deviation of ±15℃ occurred in some areas due to power fluctuations in the radiant tubes within the annealing furnace. Furthermore, interlayer radial stress exceeding the design baseline by 10% was present in the center of the steel coil. This boundary stress state easily induces premature structural collapse of the fibrous silicate minerals, leading to the instantaneous release of high concentrations of active silica onto the metal substrate surface. A dynamic redundancy calibration procedure was implemented to adjust the amount of nano-sized magnesium aluminate spinel added. This utilized the self-healing mechanism of the localized interface coupling structure under extreme thermal stress to establish a targeted solid-phase reaction barrier. The input parameters of the calibration procedure included the weight fraction M of the fibrous silicate minerals. f The specific surface area S of nano-sized magnesium aluminate spinel a and the surface charge density σ at the fiber tip s In the specific deployment of this embodiment, a material with a weight ratio of 20.00 parts and an end surface charge density of 0.15 C / m is selected. 2 Attapulgite was used as the fiber matrix, and a specific surface area of ​​85.00 m² was matched. 2 / g of nano-sized magnesium aluminate spinel was used to calculate the interfacial anchoring index η. The value of η under the current working condition was determined to be 0.6375 by substituting these physical quantities into the calculation formula of the interfacial anchoring index η. Based on this index, the amount of nano-sized magnesium aluminate spinel to be added was determined to be 5.50 parts.

[0033] In the preparation process, homogeneous units with a shear frequency of 4500 r / min are used to activate attapulgite to ensure aluminate ions fill the lattice defects at the ends of attapulgite under shear field induction, generating stable local negative charge concentration regions. During the dropwise addition of nano-sized magnesium aluminate spinel slurry, the Zeta potential of the system is monitored in real time using an online potential monitor. Dropwise addition is stopped when the potential value exceeds the preset isoelectric point transition range, thereby constructing a charge-interlocked grid at the surface layer to cope with transient thermal shock. The above-mentioned localized interface coupling structure is maintained... Under protective conditions, when a localized temperature difference occurs within the annealing furnace, leading to an increased release rate of active silica, the nano-sized magnesium aluminate spinel pre-anchored to the fiber ends undergoes an in-situ phase transformation with the generated active silica within microseconds by shortening the mass transfer distance of the solid-phase reaction, producing a high-melting-point magnesium aluminate phase. Scanning electron microscopy observation of the annealed silicon steel surface revealed no continuous glassy liquid phase layer caused by silica migration. The mechanical interlocking force between the residue and the metal substrate surface, as measured in the experiment, remained at 3.50 N / m. 2 The oxygen content at low elevations and on the surface is controlled within 0.15 g / m². 2 Within.

[0034] Example 5: In an engineering evaluation scenario regarding the impact of different coating thicknesses on the surface cleanliness and environmental emission indicators of metal substrates, fluctuations in the heating rate during the annealing process can cause residual structural water or trace amounts of impurities in the composition to vaporize instantaneously. If the porosity distribution of the porous dry film fails to provide sufficient overflow channels during the critical venting period of 300°C to 600°C, gas will accumulate at the interface, increasing the surface adhesion between the porous layer and the metal substrate surface. In this example, an adaptive calibration procedure is performed on the surface active agent and film thickness, and the venting flux threshold of the porous dry film is determined using a pressure balance model to eliminate the risk that the sintered layer is difficult to detach by water rinsing under annealing conditions.

[0035] The adaptive calibration procedure utilizes an experimental system equipped with a laser particle size analyzer and an infrared flue gas monitoring unit to evaluate the steric hindrance effect of a 0.4% (w / w) surfactant modifier in the system. The median particle size of magnesium oxide was set to 10 μm, and the viscosity change curve of the system was measured after a shear force of 4250 r / min. Based on the measured viscosity change curve, the mesh interconnection density of the localized interface coupling structure was determined, and the theoretical porosity Φ of the porous layer was calculated using the obtained mesh interconnection density. The theoretical porosity Φ conforms to the following formula: Φ = 1 - (ρ bulk / ρ true ), where Ф is the theoretical porosity; ρ bulk The bulk density of the porous layer is expressed in g / cm³. 3 ;ρ true The true density of the composition components is expressed in g / cm³. 3 In practice, the theoretical porosity Ф is maintained within the range of 0.45 to 0.65 by adjusting the weight fraction of the surfactant. This ensures that the volume of flue gas generated during annealing can penetrate the film layer and that the measured flue gas volume is below 10 mL / g. When the theoretical porosity Ф stabilizes within the above range, the final measured mechanical interlocking force decreases to 3.2 N / m. 2 Up to 4.5 N / m 2 between.

[0036] Example 6: In the sodium aluminate saturation point calibration procedure performed to address the fluctuation in the number of end lattice defects caused by batch differences in fibrous silicate minerals from different origins, the polarization characteristics of the current batch of fibrous silicate minerals were scanned using a calibration system equipped with an automatic titration unit and a potentiometer. The solid-liquid mass ratio of deionized water to fibrous silicate minerals was set to 20:1, and continuous shearing was performed at a rotation speed of 4250 r / min to remove the end bindings of the fibrous silicate minerals. A 0.1 mol / L sodium aluminate solution was injected at a rate of 0.1 mL / min, and the change curve of the Zeta potential of the system with the injected volume was collected in real time. The first derivative extreme point of the potential change rate was captured by the built-in differential calculation unit to determine the saturation charge state of the fiber end, and the surface charge density σ of the end of the current batch of fibrous silicate minerals was calculated based on the solute consumption corresponding to the extreme point. s The specific calibration steps are as follows: The calibration system collects the millivolt value of the potentiometer every 100 milliseconds and records the cumulative volume of the injected sodium aluminate solution with a concentration of 0.1 mol / L; the differential processing unit calculates the ratio of the potential change to the volume increase between two adjacent sampling points in real time. When the ratio reaches its maximum peak value, it is determined to be the saturation inflection point of lattice defect filling; at this time, the surface charge density value of the fiber end is directly calculated and output through the preset conversion coefficient, that is, the charge increment corresponding to each milliliter of consumed volume is 0.05 coulombs per square meter. This value is used as the reference input for subsequent adjustment of the drip rate.

[0037] In the field application of importing the above calibration parameters into the homogenization control unit of the production line and preparing the composition, an ultrasonic transmitter installed on the side wall of the homogenization pipe is used to obtain the ultrasonic energy attenuation spectrum of the composition under dynamic flow conditions. The homogenization control unit calculates the energy absorption peak of the ultrasonic energy attenuation spectrum in the frequency range of 1.50MHz to 3.00MHz, and analyzes the porosity characteristic parameters of the three-dimensional support skeleton in real time. The analysis logic adopts a preset energy attenuation discrete mapping table: the ultrasonic transmitter extracts the energy attenuation decibel value at the center frequency of 2.25 MHz in real time. When the attenuation value is between 15 dB and 25 dB, the system determines that the porosity of the three-dimensional support skeleton is between 0.45 and 0.6 dB. In the ideal range of 5, the feeding speed is kept constant. If the attenuation value decreases by 1 dB, the system determines that the skeleton mesh is too dense and automatically controls the speed of the magnesium oxide feed pump to decrease by 50 rpm. By reducing the particle duty cycle, the static yield stress is brought back to around 18.50 Pa. The feeding pump speed of magnesium oxide particles is adjusted according to the pore characteristic parameters to change the particle duty cycle so that the magnesium oxide particles reach the maximum filling and packing state in the confined space of the localized interface coupling structure, and the static yield stress is maintained at around 18.50 Pa. This procedure ensures that the three-dimensional mesh formed by the interconnection of the localized interface coupling structure maintains the stability of the surface topology when faced with slight changes in pH value caused by temperature fluctuations in the preparation environment.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel, characterized in that, Includes the following components: 10 to 25 parts by weight of fibrous silicate minerals, wherein the fibrous silicate minerals are at least one of attapulgite or sepiolite; 0.5 to 3.5 parts of sodium aluminate; Two to eight parts of nano-sized magnesium aluminate spinel with an average particle size of 40 nm to 60 nm; Magnesium oxide particles, with a median particle size of 5 μm to 15 μm; And, replenish to 100 portions of deionized water.

2. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, The fibrous silicate minerals are shear-activated at a rotation speed of 4000 r / min to 4500 r / min to expose lattice defects at the ends of the fibrous silicate minerals. Nano-sized magnesium aluminate spinel is added in the form of an aqueous slurry with a mass fraction of 15% to 25%. The aqueous slurry exhibits shear-thinning characteristics under pH conditions, and the dynamic viscosity of the aqueous slurry is modulated by the ionic strength of sodium aluminate.

3. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, A three-dimensional support skeleton is constructed by interconnecting localized interface coupling structures, and the static yield stress of the three-dimensional support skeleton is not less than 15 Pa. The composition also includes magnesium oxide particles suspended in the pores of the three-dimensional support skeleton, and the magnesium oxide particles maintain a dispersed state under the spatial confinement effect generated by the three-dimensional support skeleton.

4. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, The composition also includes 0.1 to 0.8 parts of a surfactant modifier, which is at least one of sodium lignosulfonate or polyvinyl alcohol, used to regulate the charge repulsion on the sides of the fibrous silicate mineral to maintain the porosity of the three-dimensional support framework.

5. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, Nanoscale magnesium aluminate spinel has a positive spinel structure with a lattice constant of 0.808 nm to 0.810 nm and an isoelectric point of 8.5 to 9.

2.

6. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, The composition is coated onto the surface of a metal substrate and dried to form a porous dry film. The porous dry film is formed by the controlled shrinkage of a localized interfacial coupling structure during the moisture removal process. The mechanical interlocking force between the residue of the porous dry film and the surface of the metal substrate after high-temperature annealing is less than 5 N / m. 2 .

7. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, The temperature range for the removal of bound water from fibrous silicate minerals is 200℃ to 450℃. The onset temperature of solid-phase reaction triggered by the localized interface coupling structure is lower than the critical temperature at which the fibrous silicate mineral skeleton collapses.

8. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, Each component in the composition meets the interface anchoring index η requirement, and the interface anchoring index η conforms to the following relationship: η=(S a ·σ s ) / M f , of which S a The specific surface area of ​​nano-sized magnesium aluminate spinel is expressed in m². 2 / g;σ s The surface charge density at the fiber tip, expressed in C / m. 2 M f The weight percentage of fibrous silicate minerals; the interface anchoring index η is used to define the adsorption density of nano-sized magnesium aluminate spinel at the ends of fibrous silicate minerals.

9. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, In a pH environment of 11.2 to 11.8, the aluminate ions generated by the dissociation of sodium aluminate fill the lattice defects at the fiber ends of the fibrous silicate mineral, forming a localized negative charge concentration region at the fiber ends; the nano-sized magnesium aluminate spinel is adsorbed onto the localized negative charge concentration region through interfacial electrostatic attraction, forming a localized interfacial coupling structure composed of fibrous silicate mineral and nano-sized magnesium aluminate spinel.

10. The green and environmentally friendly anti-adhesion composition for high-temperature annealing of uncoated silicon steel according to claim 1, characterized in that, Under heat, the localized interface coupling structure induces a solid-state reaction between active silica and nano-sized magnesium aluminate spinel within the diffusion radius of active silica generated by the decomposition of fibrous silicate minerals, generating a high-melting-point magnesium aluminate crystalline phase to block the migration path of active silica to the surface of the metal substrate.

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