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CN-121988700-A - Quick-curing high-strength investment casting coating and preparation method thereof

CN121988700ACN 121988700 ACN121988700 ACN 121988700ACN-121988700-A

Abstract

The invention relates to the technical field of investment casting, in particular to a fast-curing high-strength investment casting coating and a preparation method thereof, which are used for solving the problems of long curing time and low strength of the existing investment casting coating in terms of curing speed and strength, taking refractory powder as a framework of the coating, ensuring that the coating can form a smooth and uniform coating with higher fineness and high sphericity, improving the compactness and integral strength of the coating, providing the advantages of fast curing and high strength by a modified binder, providing good thixotropy by a thickening rheological agent, preventing the sedimentation of the refractory powder when the coating is stationary, reducing the surface tension of the coating by a wetting agent, preventing bubbles from being generated when the coating is hung, preventing crack propagation by fibers, improving the thermal shock resistance and integral toughness of a shell, forming a three-dimensional network in the coating, improving the strength of the shell, and controlling the curing speed and enhancing the bonding force between the coatings by adding the modified quick-drying agent.

Inventors

  • LAN YONG
  • WANG YONGHUA

Assignees

  • 东风精密铸造有限公司

Dates

Publication Date
20260508
Application Date
20260128

Claims (10)

  1. 1. The fast-curing high-strength investment casting coating is characterized by comprising the following components in parts by weight: 50-70 parts of refractory powder, 20-40 parts of modified binder, 0.1-0.5 part of thickening rheological agent, 0.05-0.2 part of wetting agent, 0.05-0.2 part of defoamer, 0.5-2 parts of modified quick-drying agent and 1-3 parts of fiber; Wherein, the modified binder is prepared by the following steps: Step a1, adding silica sol into a flask, mixing and stirring, regulating the pH value by using dilute hydrochloric acid, heating in a water bath, adding siloxane and SiO 2 , stirring at constant temperature, naturally cooling, adding a stabilizer, mixing and stirring to obtain modified silica sol; Step a2, adding n-octyl triethoxysilane and ethanol solution into a three-neck flask, mixing and stirring, adding deionized water and an acidic catalyst, continuously stirring, mixing and stirring polymethyl hydrosiloxane and absolute ethanol, adding into the three-neck flask, stirring for reaction, aging, and filtering to obtain an intermediate product; Step a3, adding the intermediate product into a flask, stirring, adding absolute ethyl alcohol, continuously stirring, adding modified silica sol, stirring, adjusting pH with dilute hydrochloric acid, and sieving with a 100-200-mesh screen to obtain the modified binder.
  2. 2. The quick-setting high-strength investment casting coating according to claim 1, wherein the refractory powder is a composition of mullite powder, ball-milled mullite powder and Raymond mullite powder according to a mass ratio of 1:3:2, the thickening rheological agent is one of lithium bentonite, carboxymethyl cellulose and attapulgite, the wetting agent is ethylene alkyl alcohol ether, the defoaming agent is one of n-butanol and n-octanol, and the fiber is one or more compositions of aluminum silicate fiber, cattail fiber and carbon fiber.
  3. 3. The quick-setting high-strength investment casting coating according to claim 2, wherein the mullite powder is produced by a flame melting method, the specification is 200 meshes (different grain size gradations), the particle sphericity is 0.98-1.0, the ball-milled mullite powder is produced by a ball mill, the specification is 200 meshes (different grain size gradations), the particle sphericity is 0.69-0.75, the Raymond mullite powder is produced by a Raymond mill, namely the Raymond mill, and the specification is 200 meshes (different grain size gradations), and the particle sphericity is 0.54-0.60.
  4. 4. The quick-setting high-strength investment casting coating according to claim 1, wherein the dosage ratio of silica sol to siloxane to SiO 2 to stabilizer in the step a1 is 100mL:5-10mL:1.5-6g:2-5mL, the content of the effective component of the silica sol is 30-40%, the siloxane is one of methyltrimethoxysilane, gamma-aminopropyl triethoxysilane, gamma- (methacryloyloxy) propyl trimethoxysilane and methyltriethoxysilane, the particle size of SiO 2 is less than or equal to 2 mu m, and the stabilizer is one of ethanol and n-butanol.
  5. 5. The rapid curing high strength investment casting coating of claim 1, wherein the dosage ratio of n-octyl triethoxysilane, ethanol solution, deionized water, acid catalyst, polymethylhydrosiloxane and absolute ethanol in step a2 is 100ml:150-200ml:20-40ml:5-15ml:80-100ml:50-100mL, the mass fraction of the ethanol solution is 70%, the acid catalyst is 0.1mol/L dilute hydrochloric acid, and the polymethylhydrosiloxane is produced by mikrin with the product number P750098.
  6. 6. The rapid-curing high-strength investment casting coating of claim 1, wherein the intermediate product, the absolute ethyl alcohol and the modified silica sol in the step a3 are used in a ratio of 30-70mL:10-30mL:30-70mL, and the mass fraction of the dilute hydrochloric acid is 10%.
  7. 7. The rapid-curing high-strength investment casting coating of claim 1, wherein the modified rapid-drying agent is prepared by the steps of: Step b1, magnetically stirring 1, 4-butanediol, hydrobromic acid and toluene, heating, condensing, refluxing, reacting, sequentially washing with a sodium carbonate solution and a saturated sodium chloride solution, distilling under reduced pressure, adding a developing agent, purifying with a silica gel column to obtain 4-bromo-1-butanol, adding concentrated hydrochloric acid, ice bath, adding 3, 4-dihydro-2H-pyran, stirring, rotary steaming, adding absolute ethyl alcohol, 4' -dihydroxybiphenyl and sodium hydroxide for reacting, adding p-toluenesulfonic acid, mixing, stirring, cooling, washing, drying, recrystallizing to obtain a biphenyl compound; And b2, adding toluene diisocyanate and dimethyl sulfoxide into a three-neck flask, introducing nitrogen for protection, mixing and stirring, adding a biphenyl compound for reaction, heating for reaction, cooling, introducing dimethylamine gas for reaction, adding deionized water into an ice water bath, standing, suction filtering, washing, adding isopropanol for stirring, suction filtering, washing a filter cake with tetrahydrofuran, and drying to obtain the modified quick-drying agent.
  8. 8. The rapid-cure high strength investment casting coating of claim 7, wherein the 1, 4-butanediol, hydrobromic acid, toluene, developing agent, concentrated hydrochloric acid, 3, 4-dihydro-2H-pyran, absolute ethanol, 4' -dihydroxybiphenyl, sodium hydroxide and p-toluenesulfonic acid in step b1 are used in a ratio of 18-20g:24-26ml:350ml:200ml:3-5ml:8-10ml:100ml:6-8g:3-4g:4-5g, the mass fraction of hydrobromic acid is 47%, the molar concentration of sodium carbonate solution is 1mol/L, the developing agent is petroleum ether, and the mass fraction of concentrated hydrochloric acid is 38%.
  9. 9. The rapid cure high strength investment casting coating of claim 7, wherein the toluene diisocyanate, dimethyl sulfoxide, biphenyl compound, deionized water and isopropyl alcohol in step b2 are used in a ratio of 0.9-1g:100ml:0.8-1g:100ml:100ml.
  10. 10. A method of preparing a fast setting high strength investment casting coating as claimed in any one of claims 1 to 9, comprising the steps of: weighing 50-70 parts of refractory powder, 20-40 parts of modified binder, 0.1-0.5 part of thickening rheological agent, 0.05-0.2 part of wetting agent, 0.05-0.2 part of defoamer, 0.5-2 parts of modified quick-drying agent and 1-3 parts of fiber according to parts by weight; Adding the modified binder and the thickening rheological agent into a stirring barrel, mixing and stirring, adding the wetting agent and the defoaming agent, mixing and stirring, adding the refractory powder, stirring at a high speed, adding the modified quick-drying agent and the fibers, continuing stirring, standing and aging to obtain the quick-setting high-strength investment casting coating.

Description

Quick-curing high-strength investment casting coating and preparation method thereof Technical Field The invention relates to the technical field of investment casting, in particular to a fast-curing high-strength investment casting coating and a preparation method thereof. Background Investment casting is a widely applied metal casting molding technology, is particularly suitable for producing parts with complex shapes and high precision, the traditional investment casting technology relies on the combination of investment and paint to ensure the surface quality and dimensional precision of castings, and along with the development of modern manufacturing industry, the investment casting technology is widely applied due to the high precision and the complex shape manufacturing capability, and in the investment casting process, a coating material is used as a protective film on the surface of a mold, so that the improvement of the wear resistance of the mold and the quality of castings are very important. However, the investment casting coating commonly used in the market at present has certain limitations in terms of curing speed and strength, the low curing speed can cause low production efficiency and influence the production progress, and the insufficient strength of the coating can influence the surface quality and the integrity of the internal structure of the casting, so that the casting is easy to deform or damage in subsequent machining, and time and resources are wasted. Therefore, the quick-curing high-strength investment casting coating and the preparation method thereof have important significance in the technical field of investment casting. Disclosure of Invention In order to overcome the technical problems, the invention aims to provide the quick-curing high-strength investment casting coating and the preparation method thereof, and solves the problems of long curing time and low strength of the existing investment casting coating in terms of curing speed and strength. The aim of the invention can be achieved by the following technical scheme: In a first aspect, the application provides a fast-curing high-strength investment casting coating, which comprises the following components in parts by weight: 50-70 parts of refractory powder, 20-40 parts of modified binder, 0.1-0.5 part of thickening rheological agent, 0.05-0.2 part of wetting agent, 0.05-0.2 part of defoamer, 0.5-2 parts of modified quick-drying agent and 1-3 parts of fiber; The refractory powder is a composition of mullite powder, ball-milled mullite powder and Raymond mullite powder according to a mass ratio of 1:3:2, the thickening rheological agent is one of lithium bentonite, carboxymethyl cellulose and attapulgite, the wetting agent is ethylene alkyl alcohol ether, the defoaming agent is one of n-butyl alcohol and n-octyl alcohol, the fiber is one or more compositions of aluminum silicate fiber, cattail fiber and carbon fiber, the mullite powder is produced by a flame melting method, the specification is 200 meshes (different particle size grading type), the particle sphericity is 0.98-1.0, the ball-milled mullite powder is produced by a ball mill, the specification is 200 meshes (different particle size grading type), the particle sphericity is 0.69-0.75, the Raymond mullite powder is produced by a Raymond mill (namely, the Raymond mill), the specification is 200 meshes (different particle size grading type), and the particle sphericity is 0.54-0.60; As a preferred embodiment of the present invention, the modified binder is prepared by the steps of: Adding silica sol into a three-neck flask with a stirrer and a thermometer, mixing and stirring for 30min at a rotating speed of 200-400r/min, regulating the pH to 3.5-5.5 by using dilute hydrochloric acid, heating the silica sol with the regulated pH to 50-70 ℃ in a water bath, adding siloxane and SiO 2, stirring at a constant temperature of 50-70 ℃ for 1-2h, naturally cooling to 25 ℃, adding a stabilizer, mixing and stirring for 10-20min to obtain modified silica sol; Step a2, adding n-octyl triethoxysilane and ethanol solution into a three-neck flask provided with a stirrer and a thermometer, mixing and stirring for 30min at 200-300r/min, adding deionized water and an acidic catalyst, continuing stirring for 2-4h at 25-40 ℃, adding polymethyl hydrosiloxane and absolute ethanol into the beaker, mixing and stirring for 30min, adding into the three-neck flask, stirring and reacting for 1-2h at 25-40 ℃, aging for 24-48h at 25 ℃ and in a dark condition, and filtering to obtain an intermediate product; step a3, adding the intermediate product into a three-neck flask with a stirrer and a thermometer, mixing and stirring for 30min at the rotating speed of 200-300r/min, adding absolute ethyl alcohol, continuously stirring for 5-10min, adding modified silica sol, stirring for 1-2h at the temperature of 25-35 ℃ and the temperature of 300-400r/min, regulating the pH value to 4-6 by dilute