Modified binder for metal ceramic composite material and preparation method thereof

Abstract

The invention discloses a modified binder for a metal ceramic composite material and a preparation method thereof, the modified binder is prepared by taking sodium silicate and potash water glass as a basic system, adding sodium methyl silicate as an anti-moisture absorption agent and isooctyl alcohol polyoxyethylene ether (JFC-5) as a surfactant, optimizing the raw material ratio and the preparation process, and preparing the modified binder for the metal ceramic composite material. The technical problems of moisture absorption pulverization, poor high-temperature stability, many forming defects and the like of a traditional single water glass binder are solved. The modified binder disclosed by the invention has good bonding strength, moisture resistance, high-temperature stability and process flowability, and can effectively improve the structural integrity and compactness of a ceramic preform, so that the mechanical property, wear resistance and interface bonding quality of a metal ceramic composite material are guaranteed; the metal ceramic composite material is especially suitable for metal ceramic composite parts with extremely high requirements on wear resistance and impact resistance, such as roller sleeves of coal mills, and has a wide industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of auxiliary materials technology for metal-ceramic composite materials, specifically to a modified binder for metal-ceramic composite materials and its preparation method, which is particularly suitable for the preparation of ceramic preforms for metal-ceramic composite components such as coal mill roller sleeves and crusher liners that have extremely high requirements for wear resistance and impact resistance. Background Technology

[0002] Metal-ceramic composites combine the high hardness and wear resistance of ceramics with the high toughness and impact resistance of metals, showing broad application prospects in machinery manufacturing, mining, and power generation. Components such as coal mill roller sleeves, operating under high load and high wear conditions, place particularly stringent performance requirements on metal-ceramic composites. The ceramic preform, as the core framework of the metal-ceramic composite, directly determines the final composite's mechanical properties, wear resistance, and reliability through its molding quality, structural stability, and high-temperature performance. Ceramic binders are crucial auxiliary materials ensuring the molding and performance of the ceramic preform.

[0003] Currently, the commonly used binder for ceramic preforms is water glass (sodium silicate or potassium silicate aqueous solution). Sodium water glass is widely used in the preparation of ceramic preforms due to its low cost, good solubility at room temperature, and excellent wettability with ceramic powder. However, using sodium water glass alone as a binder has several technical drawbacks: First, after curing, sodium water glass contains a large number of free sodium ions, which easily absorb moisture from the air and deliquesce, leading to pulverization, reduced strength, and even structural collapse of the ceramic preform, seriously affecting its storage and transport stability. Second, the viscosity of sodium water glass fluctuates significantly with temperature; at low temperatures, the system is too thick, making it difficult to uniformly coat the ceramic powder; at high temperatures, the system is too thin, leading to problems such as delamination and uneven porosity during preform molding, resulting in a narrow applicable process window. Third... Sodium silicate has poor high-temperature resistance and is prone to softening and melting in the high-temperature casting environment (usually above 1500℃) of metal-ceramic composite processes, resulting in excessive shrinkage of the preform. Furthermore, alkali metal ions tend to migrate to the metal matrix at high temperatures, causing corrosion of the metal matrix and affecting the interfacial bonding quality of the composite material. Fourthly, when sodium silicate is used as a binder, the ceramic powder tends to agglomerate during stirring, and the system is prone to air entrapment, forming bubbles. This leads to defects such as pores and cracks inside the preform, reducing the density and structural integrity of the preform.

[0004] To address the aforementioned shortcomings of sodium silicate alone, existing technologies have attempted to partially replace it with potassium silicate. Potassium silicate possesses a more stable silicon-oxygen network structure, which can improve the moisture resistance and high-temperature stability of the binder. However, potassium silicate is expensive, and when used alone as a binder, its wettability with ceramic powder and room-temperature flowability are poor, making it difficult to meet the needs of large-scale production. Furthermore, existing technologies have also attempted to add anti-hygroscopic agents or surfactants, but due to a lack of systematic optimization of raw material ratios, additive selection, and preparation processes, the modification effect is limited, and problems such as high moisture absorption risk, numerous molding defects, and insufficient high-temperature performance still exist.

[0005] Therefore, this invention proposes a modified binder that combines good bonding strength, moisture resistance, high temperature stability, and process flowability, while maintaining controllable cost. This is of great significance for improving the performance of metal-ceramic composite ceramic preforms and expanding their industrial applications. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to overcome the technical problems of existing single water glass binders, such as moisture absorption and powdering, poor high-temperature stability, numerous molding defects, and narrow applicable process window. It provides a modified binder for metal-ceramic composite materials. By optimizing the basic system ratio and additive selection, combined with a scientific preparation process, the performance of the binder is comprehensively improved, while taking into account reasonable cost, thus providing a guarantee for the preparation of high-performance metal-ceramic composite materials.

[0007] Technical solution: The modified binder for metal-ceramic composite materials of the present invention comprises the following raw materials in parts by weight:

[0008] Basic raw materials: 100 parts of sodium silicate with a modulus of 2.8-3.5 and a Baume degree of 38-50;

[0009] Potassium silicate: Potassium silicate with a modulus of 2.2-3.0 and a Baume degree of 35-45, accounting for 20%-30% of the weight of the basic raw materials;

[0010] Sodium silicate is low in cost, has good solubility at room temperature, and excellent wettability with ceramic powders (alumina, silicon carbide, titanium carbide, etc.), enabling it to uniformly coat ceramic particles and prevent agglomeration. Potassium silicate has a more stable silicon-oxygen network structure and excellent high-temperature resistance. When combined with sodium silicate, they can cross-link through silicon-oxygen chains, reducing the content of free sodium ions, improving the moisture resistance and deliquescence resistance of the adhesive film, while also widening the viscosity-applicable temperature window of the adhesive, reducing the shrinkage rate of the preform at high temperatures, and minimizing the migration of alkali metal ions to the metal matrix. By controlling the addition amount of potassium silicate to 20% of sodium silicate, performance improvement can be ensured while avoiding excessive costs, achieving a balance between performance and cost.

[0011] Anti-hygroscopic agent: Sodium methylsilicate, with a weight of 3-5% of the total weight of the base raw materials and potassium silicate; the sodium methylsilicate molecule contains silanol groups, which can undergo a cross-linking reaction with the silicon-oxygen network of the silicate to form a dense silicate gel film that is insoluble in water. This gel film can reduce the exposure of free ions, block the capillary pores inside the binder, significantly reduce the risk of moisture absorption by the preform in a humid environment, and prevent the preform from pulverizing and disintegrating. Choosing an addition amount of 3-5% ensures the anti-hygroscopic effect without causing abnormal viscosity or excessively fast gelation due to excessive addition.

[0012] Surfactant: Isooctanol polyoxyethylene ether (JFC-5), the weight of which is 0.5-2% of the total weight of the base raw materials and potassium silicate. The addition of 0.5-2% can ensure the dispersion and defoaming effect, and avoid the decrease in system stability due to excessive addition.

[0013] In some embodiments, the purity of the sodium methylsilicate is ≥98%; the HLB value of the isooctanol polyoxyethylene ether is 12-14. When the HLB value is 12-14, it has good wetting, penetration and dispersion properties, which can enhance the interaction between the binder and the ceramic powder, improve the bonding uniformity and reduce particle agglomeration; at the same time, its molecular structure can inhibit the generation of bubbles during stirring, promote the rapid rupture of the generated microbubbles, and reduce defects such as pores and cracks inside the preform, which is especially suitable for ceramic preforms with high density requirements.

[0014] On the other hand, the present invention also discloses a method for preparing a modified binder for metal-ceramic composite materials, comprising the following steps:

[0015] S1. Raw material pretreatment:

[0016] a. Dilute sodium methylsilicate with 5 times its mass of deionized water and stir until transparent to obtain a diluted sodium methylsilicate solution; avoid excessively high local concentrations that could cause premature gelation and affect the dispersion of the additive.

[0017] b. Dilute isooctanol polyoxyethylene ether with 10 times its mass of deionized water, stir evenly to enhance dispersibility, and obtain a diluted isooctanol polyoxyethylene ether solution; enhance its dispersibility in the water glass system and avoid excessively high local concentrations that could damage the interfacial tension of the system;

[0018] S2, Basic System Hybridization:

[0019] a. Pour the sodium silicate into a container equipped with a stirring device and turn on the stirring;

[0020] b. Slowly add potassium silicate to sodium silicate and stir continuously for 10-20 minutes to obtain a sodium-potassium silicate mixture.

[0021] S3, Additive Mixing:

[0022] a. Slowly add the sodium methylsilicate dilution prepared in step S1 to the sodium potassium water glass mixture, and continue stirring for 10-20 minutes until the system is homogeneous, to ensure that the sodium methylsilicate reacts fully with the water glass system, preferentially forming a dense silica gel film and improving the water resistance of the system;

[0023] b. Add the isooctanol polyoxyethylene ether dilution prepared in step S1 to the above system and stir continuously for 5-10 minutes. The surfactant should be added last to avoid prematurely disrupting the interfacial tension of the system. This ensures that the surfactant is uniformly dispersed in the system to exert its wetting, dispersing, and defoaming effects. The order of additive addition must be strictly controlled. If JFC-5 is added first, its surface activity will disrupt the cross-linking reaction environment between sodium methylsilicate and water glass, leading to a decrease in the moisture resistance and affecting the uniformity of dispersion of each additive.

[0024] In some embodiments, the stirring speed in step S2a is 150-200 rpm, and the ambient temperature is maintained at 20-30°C. This speed and temperature range can ensure the stability of the sodium water glass system and avoid introducing too many air bubbles.

[0025] In some embodiments, the preparation method further includes the following steps:

[0026] S4. Concentration and pH adjustment:

[0027] a. Measure the Baumé degree of the system using a Baumé meter. If the Baumé degree is higher than 40, add a small amount of deionized water to fine-tune it. Each 10g of deionized water added can reduce the Baumé degree by 1-2 units. If the Baumé degree is lower than 40, heat at ≤50℃ to evaporate a small amount of water. Stir continuously during the heating process to avoid local overheating that could cause the system to gel or decompose. Stop heating when the Baumé degree reaches 40.

[0028] b. Monitor the pH value of the system. If the pH value deviates from the 10.5-11.5 range, lower the pH value by adding lithium silicate or raise the pH value by adding low-modulus sodium silicate. If the pH value is higher than 11.5, add a small amount of lithium silicate to the system, stir well, and remeasure until the pH value drops to the target range. If the pH value is lower than 10.5, add a small amount of low-modulus sodium silicate (modulus 2.0-2.2, Baumé degree 35-38), stir well, and remeasure until the target pH value is reached. pH control is crucial for the stability and performance of the adhesive. Too high or too low a pH value will affect the degree of cross-linking of the silicon-oxygen network, leading to a decrease in properties such as bond strength and moisture resistance.

[0029] In some embodiments, the preparation method further includes the following steps:

[0030] S5, Aging and Detection:

[0031] a. Seal the adjusted system and let it stand for aging for 24 - 48 hours; during the aging process, all components react fully and the system structure tends to be stable;

[0032] b. Observe whether there is stratification, gelation or precipitation in the aged system. If there is no such phenomenon, it is a qualified product. After the aging is completed, observe whether there is stratification, gelation or precipitation in the system. If the system is homogeneous, transparent, without stratification, gelation and precipitation, it is a qualified product; if any of the above abnormal phenomena occur, it indicates that there is a deviation in the raw material ratio or the preparation process, and it needs to be adjusted and prepared again.

[0033] The qualified modified binder is stored at room temperature (20 - 30 °C) after being sealed. The storage environment needs to be kept dry and ventilated, and avoid contact with carbon dioxide (sodium silicate is prone to form silicic acid precipitation when encountering carbon dioxide, resulting in the failure of the system curing). The shelf life is about 1 month. Before use, the binder needs to be stirred evenly. If there is a slight increase in viscosity, a small amount of deionized water can be added to adjust to the appropriate viscosity before use.

[0034] In some embodiments, the addition rate of the sodium methyl silicate diluent in step S3 a is 5 - 10 mL / min; the addition rate of the polyoxyethylene octyl ether diluent in step S3 b is 3 - 5 mL / min.

[0035] In some embodiments, the modulus of the low-modulus sodium silicate is 2.0 - 2.2, and the Baume degree is 35 - 38.

[0036] On the other hand, the present invention also discloses the application of the above-mentioned modified binder in the preparation of ceramic preforms of metal-ceramic composites. The metal-ceramic composites include alumina-steel, silicon carbide-steel, titanium carbide-steel composite systems, and the ceramic preforms are used for coal mill roller sleeves, crusher liners or other wear-resistant and impact-resistant components.

[0037] In some embodiments, the preparation process of the ceramic preform includes coating molding, slip casting molding or pressing molding.

[0038] Advantages: The modified binder of the present invention has the following remarkable advantages compared with the prior art through scientific raw material selection, optimized ratio design and standardized preparation process:

[0039] (1) Significantly improved moisture resistance: By combining sodium silicate and potassium silicate and adding sodium methylsilicate, a dense silica gel film is formed, which effectively reduces the exposure of free ions and capillary pores. This reduces the moisture absorption rate of the ceramic preform to below 5% when stored and transported in a humid environment, completely solving the problems of preform pulverization, strength reduction, and structural collapse caused by traditional sodium silicate binders, and ensuring the structural integrity of the preform. Sodium methylsilicate is an anti-hygroscopic agent. After water glass (especially sodium silicate) is cured, it is easy to deliquesce due to the absorption of moisture from the air by free ions, which leads to pulverization and strength reduction of the ceramic preform. After the addition of sodium methylsilicate, the silanol groups in its molecules will cross-link with the silicon-oxygen network of water glass to form a dense silica gel film that is insoluble in water. This film can reduce the exposure of free ions and block the capillary pores inside the binder, significantly reducing the risk of moisture absorption of the preform when stored and transported in a humid environment, and avoiding structural collapse.

[0040] (2) Excellent high-temperature stability: The addition of potassium silicate increases the high-temperature softening point of the binder, enabling the modified binder to maintain a stable structure in a high-temperature casting environment above 1500℃. The high-temperature shrinkage rate of the preform is reduced from 8-10% of the traditional sodium silicate binder to below 3%. At the same time, it reduces the migration of alkali metal ions to the metal matrix at high temperatures, and the corrosion rate of the metal matrix is ​​reduced to below 0.1%, which significantly improves the interfacial bonding quality of the metal-ceramic composite material and ensures the mechanical properties of the composite material.

[0041] (3) Wide process adaptability: The viscosity of the modified binder fluctuates little with temperature changes. Within the temperature range of 10-50℃, the viscosity remains at 500-1500 mPa·s, making it suitable for various ceramic preform preparation processes such as coating molding, slurry molding, and pressing molding. At the same time, the addition of JFC-5 enhances the wetting and dispersion effects, reducing the agglomeration rate of ceramic powder to below 3% and the bubble defect rate to below 2%. The porosity of the preform is controllable and uniformly distributed (porosity ≤5%), and the density is significantly improved. Isooctanol polyoxyethylene ether JFC-5 can enhance wetting and penetration, improve the uniformity of bonding, optimize the dispersion effect, reduce particle agglomeration, and inhibit bubble generation during preform production, reducing preform defects. Air is easily entrained and forms bubbles during the stirring process of preform production. If bubbles remain, it will lead to defects such as pores and cracks in the preform. JFC-5 is a low-foaming surfactant. Its molecular structure can inhibit the generation of bubbles and promote the rapid rupture of existing microbubbles. This can reduce air bubble defects inside the preform after molding, and is especially suitable for ceramic preforms with high density requirements.

[0042] (4) High bonding strength: The cross-linked network structure of sodium silicate and potassium silicate forms a strong bonding interface with the ceramic powder. At the same time, the cross-linking effect of sodium methylsilicate further enhances the strength of the bonding film. The room temperature compressive strength of the ceramic preform is increased from 15-20MPa of traditional sodium silicate adhesive to 35-40MPa, which meets the requirements of metal-ceramic composite components for the structural stability of the preform.

[0043] (5) Cost controllable: By optimizing the ratio of sodium silicate and potassium silicate (potassium silicate accounts for 20-30% of sodium silicate), while ensuring performance, the problem of excessive cost caused by the large-scale use of potassium silicate is avoided. The total cost of the modified binder is reduced by 40-50% compared with the single potassium silicate binder, making it more suitable for large-scale industrial application. Detailed Implementation

[0044] To make the technical solution of the present invention clearer and easier to understand, the present invention will be further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0045] Example 1

[0046] (a) Raw material preparation

[0047] 1. Sodium silicate: Modulus 3, Baumé degree 40, 100g;

[0048] 2. Potassium silicate: Modulus 2.5, Baumé degree 38, 20g (20% of the weight of sodium silicate);

[0049] 3. Sodium methylsilicate: 98% purity, 3.6g (3% of the total weight of sodium silicate and potassium silicate, 120g);

[0050] 4. Isooctanol polyoxyethylene ether (JFC-5): HLB value 13, 0.6g (0.5% of the total weight of sodium silicate and potassium silicate 120g).

[0051] 5. Auxiliary materials: deionized water, lithium silicate, low-modulus sodium silicate (modulus 2.1, Baumé degree 36).

[0052] (II) Preparation steps

[0053] 1. Raw material pretreatment:

[0054] a. Dilution of sodium methylsilicate: Take 3.6g of sodium methylsilicate, add 18g of deionized water (5 times the mass), stir with a magnetic stirrer for 12 minutes until the solution is clear, and obtain a diluted sodium methylsilicate solution;

[0055] b. JFC-5 dilution: Take 0.6g of JFC-5, add 6g of deionized water (10 times the mass), stir for 6 minutes to obtain a diluted JFC-5 solution.

[0056] 2. Hybridization of basic systems:

[0057] a. Pour 100g of sodium silicate into a stainless steel container equipped with an anchor stirrer, turn on the stirrer, set the speed to 180rpm, and keep the ambient temperature at 25℃;

[0058] b. Add 20g of potassium silicate to sodium silicate at a rate of 12mL / min and stir continuously for 10 minutes to obtain a sodium-potassium silicate mixture.

[0059] 3. Additive mixing:

[0060] a. Add sodium methylsilicate diluent at a rate of 8 mL / min and stir continuously for 10 minutes until the system remains homogeneous and transparent;

[0061] b. Add JFC-5 diluent at a rate of 4 mL / min and stir continuously for 5 minutes.

[0062] 4. Concentration and pH adjustment:

[0063] a. Baumé measurement: The Baumé degree of the system was measured to be 41 using a precision Baumé meter. After adding 5g of deionized water to the system and stirring it evenly, the Baumé degree was measured again and dropped to 40.

[0064] b. pH measurement: The pH value of the system was measured using a precision pH meter and was 11.2, which is within the range of 10.5-11.5 and requires no adjustment.

[0065] 5. Curing and Testing:

[0066] a. Seal the container and place it in a dry environment at 25°C for 24 hours to allow it to mature.

[0067] b. After maturation, the system is uniform and transparent, without layering, gelation, or precipitation, indicating a qualified product.

[0068] Example 2

[0069] (a) Raw material preparation

[0070] 1. Sodium silicate: Modulus 2.8, Baumé degree 38, 100g;

[0071] 2. Potassium silicate glass: Modulus 2.2, Baumé degree 35, 30g;

[0072] 3. Sodium methylsilicate: 98% purity, 6.5g (5% of the total weight of sodium silicate and potassium silicate, 130g);

[0073] 4. Isooctanol polyoxyethylene ether (JFC-5): HLB value 12, 2.6g (2% of the total weight of sodium silicate and potassium silicate 130g).

[0074] 5. Auxiliary materials: deionized water, lithium silicate, low-modulus sodium silicate (modulus 2.0, Baumé degree 35).

[0075] (II) Preparation steps

[0076] 1. Raw material pretreatment:

[0077] a. Dilution of sodium methylsilicate: Take 6.5g of sodium methylsilicate, add 32.5g of deionized water, and stir for 15 minutes until transparent;

[0078] b. JFC-5 dilution: Take 2.6g of JFC-5, add 26g of deionized water, and stir for 8 minutes until homogeneous.

[0079] 2. Hybridization of basic systems:

[0080] a. Pour 100g of sodium silicate into a container, stir at 150rpm, and maintain an ambient temperature of 20℃;

[0081] b. Add 30g of potassium silicate at a rate of 10mL / min and stir for 10 minutes.

[0082] 3. Additive mixing:

[0083] a. Add sodium methylsilicate dilution at a rate of 5 mL / min and stir for 10 minutes;

[0084] b. Add JFC-5 diluent at a rate of 3 mL / min and stir for 5 minutes.

[0085] 4. Concentration and pH adjustment:

[0086] a. Baumé measurement: The Baumé value of the system was 39. The container was placed in a 45°C water bath to heat and evaporate the water. The measurement was continuously taken during the stirring process. After evaporation for 10 minutes, the Baumé value rose to 40, and heating was stopped.

[0087] b. pH measurement: The pH value of the system is 10.3. After adding 0.5g of low-modulus sodium silicate to the system and stirring evenly, the pH value was measured and rose to 10.6, which meets the requirements.

[0088] 5. Curing and Testing:

[0089] a. After sealing, age in a dry environment at 20°C for 24 hours;

[0090] b. After maturation, the system is uniform and transparent, with no abnormalities, indicating it is a qualified product.

[0091] Example 3

[0092] (a) Raw material preparation

[0093] 1. Sodium silicate: Modulus 3.5, Baumé degree 50, 100g;

[0094] 2. Potassium silicate glass: Modulus 3.0, Baumé degree 45, 25g;

[0095] 3. Sodium methylsilicate: 98% purity, 5g (4% of the total weight of sodium silicate and potassium silicate, which is 125g).

[0096] 4. Isooctanol polyoxyethylene ether (JFC-5): HLB value 14, 1.25g (1% of the total weight of sodium silicate and potassium silicate 125g).

[0097] 5. Auxiliary materials: deionized water, lithium silicate, low-modulus sodium silicate (modulus 2.2, Baumé degree 38).

[0098] (II) Preparation steps

[0099] 1. Raw material pretreatment:

[0100] a. Dilution of sodium methylsilicate: Take 5g of sodium methylsilicate, add 25g of deionized water, and stir for 13 minutes until transparent;

[0101] b. JFC-5 dilution: Take 1.25g of JFC-5, add 125g of deionized water, and stir for 7 minutes until homogeneous.

[0102] 2. Hybridization of basic systems:

[0103] a. Pour 100g of sodium silicate into a container, stir at 200rpm, and maintain an ambient temperature of 30℃;

[0104] b. Add 25g of potassium silicate at a rate of 15mL / min and stir for 10 minutes.

[0105] 3. Additive mixing:

[0106] a. Add sodium methylsilicate dilution at a rate of 10 mL / min and stir for 10 minutes;

[0107] b. Add JFC-5 diluent at a rate of 5 mL / min and stir for 5 minutes.

[0108] 4. Concentration and pH adjustment:

[0109] a. Baumé measurement: The Baumé value of the system is 40, no adjustment is required;

[0110] b. pH measurement: The pH value of the system was 11.6. After adding 0.3g of lithium silicate to the system and stirring evenly, the pH value dropped to 11.3, which met the requirements.

[0111] 5. Curing and Testing:

[0112] a. After sealing, age in a dry environment at 30℃ for 24 hours;

[0113] b. After maturation, the system is uniform and transparent, with no abnormalities, indicating it is a qualified product.

[0114] The modified adhesives prepared in Examples 1-3 above and the traditional single sodium silicate adhesive (control group) were subjected to performance tests. The test items included moisture resistance, high temperature stability, bond strength, and process adaptability. The test results are shown in the table below:

[0115]

[0116] The test results show that the modified binder of the present invention is significantly superior to the traditional single sodium silicate binder in terms of moisture absorption rate, high temperature shrinkage rate, metal matrix corrosion rate, bonding strength, particle agglomeration rate, bubble defect rate and applicable temperature window. It can effectively improve the performance of ceramic preforms and meet the preparation requirements of metal-ceramic composite materials.

[0117] The modified binder of this invention can be widely used in the preparation of ceramic preforms in metal-ceramic composite systems such as alumina-steel, silicon carbide-steel, and titanium carbide-steel, and is particularly suitable for components with extremely high requirements for wear resistance and impact resistance, such as coal mill roller sleeves and crusher liners. In specific applications, the ceramic preform can be prepared by coating molding, slip casting, or pressing. The relative humidity of the molding environment must be controlled at ≤60% to avoid excessive moisture affecting the preform's molding quality. After uniformly mixing the modified binder of this invention with ceramic powder, a ceramic preform is prepared through a corresponding molding process. After drying and curing, it is composited with a metal matrix to form a metal-ceramic composite material under high-temperature casting conditions. This composite material possesses excellent mechanical properties, wear resistance, and interfacial bonding quality, significantly extending the service life of the components.

[0118] This invention, through the compounding of sodium silicate and potassium silicate, combined with the synergistic effect of sodium methylsilicate and isooctyl alcohol polyoxyethylene ether (JFC-5), optimizes the preparation process and successfully develops a high-performance, cost-controllable modified binder. This binder overcomes many technical defects of traditional water glass binders, possessing excellent moisture resistance, high-temperature stability, bonding strength, and process flowability. It effectively improves the molding quality and structural stability of ceramic preforms, thereby ensuring the performance of metal-ceramic composite materials, and has significant industrial application value and broad market prospects.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A modified binder for cermet composites, characterized in that: Comprising raw materials by weight Composition: Base raw material: sodium water glass with modulus 2.8-3.5, Baume degree 38-50, 100 parts; Potassium water glass: potassium water glass with modulus 2.2-3.0, Baume degree 35-45, 20%-30% of the weight of the base raw material; Anti-hygroscopic agent: sodium methyl silicate, 3-5% of the total weight of the base raw material and potassium water glass; Surface active agent: isooctanol polyoxyethylene ether, 0.5-2% of the total weight of the base raw material and potassium water glass.

2. A modified binder for cermet composites according to claim 1, characterized in that: The purity of the sodium methyl silicate is ≥98%; the HLB value of the isooctanol polyoxyethylene ether is 12-14.

3. A method for producing a modified binder for cermet composites according to claim 1 or 2, characterized in that: Comprising the following steps: S1, raw material pretreatment: a. Dilute the sodium methyl silicate with 5 times the mass of deionized water, stir until transparent to obtain a sodium methyl silicate diluent; b. Dilute the isooctanol polyoxyethylene ether with 10 times the mass of deionized water, stir evenly, and enhance dispersibility to obtain an isooctanol polyoxyethylene ether diluent; S2, base system mixing: a. Pour the sodium water glass into a container with a stirring device, and turn on the stirring; b. Slowly add the potassium water glass to the sodium water glass, continue stirring for 10-20 minutes to obtain a sodium-potassium water glass mixed system; S3, additive mixing: a. Slowly add the sodium methyl silicate diluent prepared in step S1 to the sodium-potassium water glass mixed system, continue stirring for 10-20 minutes until the system is uniform to improve water resistance; b. Add the isooctanol polyoxyethylene ether diluent prepared in step S1 to the above system, continue stirring for 5-10 minutes, and the surface active agent needs to be added last to avoid prematurely destroying the interfacial tension of the system.

4. The method for preparing a modified binder for cermet composite materials according to claim 3, characterized in that: The stirring speed in step a of S2 is 150-200 rpm, and the environmental temperature is maintained at 20-30℃.

5. The method for preparing a modified binder for metal-ceramic composite materials according to claim 3, characterized in that: Also comprising: S4, concentration and pH value adjustment: a. Measure the Baume degree of the system with a Baume meter, if the Baume degree is higher than 40, add a small amount of deionized water to fine-tune, each addition of 10g deionized water can reduce the Baume degree by 1-2 units; if the Baume degree is lower than 40, evaporate a small amount of water under the condition of ≤50℃, continue stirring during heating to prevent local overheating; b. Detect the pH value of the system, if the pH value deviates from the range of 10.5-11.5, reduce the pH value by adding lithium silicate or increase the pH value by adding low modulus sodium water glass.

6. A method for preparing a modified binder for cermet composites according to claim 5, characterized in that: Also comprising: S5, curing and detection: a. Seal the adjusted system and let it stand for 24-48 hours for curing; b. Observe whether there are stratification, gel or precipitation phenomena in the system after curing, and if there are no such phenomena, it is a qualified product.

7. The method for preparing a modified binder for metal-ceramic composite materials according to claim 3, characterized in that: The addition speed of the sodium methyl silicate diluent in step a of S3 is 5-10 mL / min; the addition speed of the isooctanol polyoxyethylene ether diluent in step b of S3 is 3-5 mL / min.

8. The method for preparing a modified binder for metal-ceramic composite materials according to claim 5, characterized in that: The modulus of the low modulus sodium water glass is 2.0-2.2, and the Baume degree is 35-38.

9. Use of the modified binder according to claim 1 or 2 for the production of a ceramic preform for cermet composite materials, characterized in that: The cermet composite material includes alumina-steel, silicon carbide-steel, titanium carbide-steel composite systems, and the ceramic preform is used for a coal mill roller sleeve, a crusher liner plate or other wear-resistant and impact-resistant parts.

10. Use according to claim 9, characterized in that: The preparation process of the ceramic preform includes coating forming, slip casting or pressing forming.

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