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CN-121991587-A - High-temperature-resistant metal casting mold release coating and preparation method thereof

CN121991587ACN 121991587 ACN121991587 ACN 121991587ACN-121991587-A

Abstract

The invention discloses a high-temperature-resistant metal casting and demolding coating and a preparation method thereof, and belongs to the technical field of coatings. According to the invention, components of the coating are optimized, a composite binder formed by compounding an organic binder and an inorganic binder is adopted, and a high-temperature resistant auxiliary agent consisting of zircon powder, corundum powder and nano cerium oxide is combined, so that the resistant temperature and the service life of the coating are remarkably improved, the added hexagonal boron nitride can form a compact and smooth coating surface, and the high-temperature resistant auxiliary agents with different gradations are combined, so that the synergistic effect of filling-supporting-lubricating of different scale particles is utilized, the adhesion between a metal melt and a die can be effectively reduced, the efficient and stable demolding performance is realized, the nano aluminum oxide can form chemical bonding with the hexagonal boron nitride and the composite binder, the interface binding force is further enhanced, the layering peeling of the coating under high-temperature impact is avoided, the thermal impact of a metal liquid on the die is effectively buffered, and the service life of the die is prolonged.

Inventors

  • ZHANG MINGYUAN
  • HU HAIHONG
  • LIANG ZHUQIANG

Assignees

  • 广东鑫皇冠新材料有限公司

Dates

Publication Date
20260508
Application Date
20260325

Claims (10)

  1. 1. The high-temperature-resistant metal casting and demolding coating is characterized by comprising the following raw materials in parts by weight: 25-30 parts of a composite binder, 15-25 parts of hexagonal boron nitride, 1-3 parts of nano aluminum oxide, 4-10 parts of a high temperature resistant auxiliary agent, 5-8 parts of a suspending agent, 0.5-2 parts of a dispersing agent, 0.1-2 parts of a leveling agent, 5-15 parts of a pigment and 20-40 parts of water; Wherein the composite binder consists of an organic binder and an inorganic binder in a mass ratio of (0.5-2); The high-temperature-resistant auxiliary agent consists of zircon powder, corundum powder and nano cerium oxide with the mass ratio of (1-3) (1-5) (1-2).
  2. 2. The metal casting mold release coating according to claim 1, wherein the organic binder is at least one of silicone resin, acrylic resin, and epoxy resin, and the inorganic binder is at least one of phosphate, silicate, and aluminum sol.
  3. 3. The metal casting mold release coating according to claim 1, wherein the hexagonal boron nitride consists of nano-scale h-BN, submicron-scale h-BN and micron-scale h-BN in a mass ratio of (1-2): 1-3): 1-2.
  4. 4. The metal casting mold release coating according to claim 1, wherein the high-temperature resistant auxiliary agent has a particle size distribution of 300-350 meshes, which accounts for 40-50% of the total mass of the high-temperature resistant auxiliary agent, 500-800 meshes, which accounts for 30-40% of the total mass of the high-temperature resistant auxiliary agent, and more than 1000 meshes, which accounts for 10-20% of the total mass of the high-temperature resistant auxiliary agent.
  5. 5. The metal casting mold release coating according to claim 1, wherein the suspending agent is a mixture of sodium bentonite and xanthan gum in a mass ratio of (1-5): 1.
  6. 6. The metal casting mold release coating according to claim 1, wherein the dispersant is at least one of fatty alcohol polyoxyethylene ether and ammonium polyacrylate salt.
  7. 7. The metal casting mold release coating according to claim 1, wherein the leveling agent is at least one of polyether modified polydimethylsiloxane and polyacrylate leveling agent.
  8. 8. A method for preparing the metal casting release coating according to any one of claims 1 to 7, comprising the steps of: S1, adding hexagonal boron nitride, nano aluminum oxide and a high-temperature resistant auxiliary agent into a ball mill, and performing ball milling treatment to obtain a mixture A; S2, adding the composite binder, the suspending agent, the dispersing agent, the leveling agent, the pigment and the water into a mixing kettle, and uniformly stirring to obtain a mixture B; S3, adding the mixture A into the mixture B, and uniformly stirring to obtain a mixture C; s4, placing the mixture C in an ultrasonic oscillator, and carrying out ultrasonic oscillation treatment to obtain the metal casting demoulding coating.
  9. 9. The preparation method according to claim 8, wherein in the step S1, the rotation speed of the ball milling treatment is 100r/min to 300r/min, and the time is 30min to 60min.
  10. 10. The method according to claim 8, wherein in step S4, the frequency of the ultrasonic oscillation treatment is 20khz to 40khz, and the time is 10min to 30min.

Description

High-temperature-resistant metal casting mold release coating and preparation method thereof Technical Field The invention relates to the technical field of coatings, in particular to a high-temperature-resistant metal casting and demolding coating and a preparation method thereof. Background In the metal casting (such as casting, forging, die casting and the like), high-temperature molten metal directly contacts with the surface of a die, and is easy to cause physical adhesion or chemical reaction, so that the quality of the surface of a casting is reduced, the service life of the die is shortened, and the production efficiency is reduced. To solve the above problems, a mold release coating is generally applied to the surface of the mold to achieve physical-chemical separation between the molten metal and the mold. However, in the process of pouring or filling high-temperature molten metal, the molten metal is extremely prone to physical and chemical reactions (such as infiltration, corrosion and alloying) with the surface of the metal mold, so that serious mold sticking phenomenon is caused. The mold is difficult to demold, the production efficiency is reduced, the surface of the mold is extremely damaged, the service life of the mold is shortened, and meanwhile, the quality defects such as black spots, cold partitions, air holes and the like are generated on the surface of a casting, so that the appearance and the internal quality of a product are affected. At present, the mold release coating is generally coated on the surface of a mold in the industry, and common mold release materials comprise graphite, silicone oil, metal oxide coating and the like, but the technical problems that 1. The traditional organic mold release agent is easy to decompose and lose efficacy under the high temperature (> 800 ℃) condition, and the inorganic mold release agent is good in temperature resistance, but is generally required to be sintered and solidified at high temperature, so that the mold is easy to be damaged by heat and has poor normal-temperature adhesive force still exist. 2. The demolding effect is poor, the demolding is difficult easily caused when the compactness of the coating is high, and the molten metal is easy to permeate and adhere to the mold when the compactness is low. 3. The coating has a single function, and the existing coating only pays attention to isolation, and neglects the heat conduction uniformity of the coating. For example, in the ingot casting process, excessive or uneven thermal resistance of the coating can lead to inconsistent cooling rates of the molten metal, causing uneven crystal structure of the ingot, shrinkage cavity or internal stress. 4. The traditional solvent release coating contains a large amount of Volatile Organic Compounds (VOC) and does not meet the increasingly strict environmental protection regulation requirements. In the prior art, although some aqueous boron nitride coatings attempt to solve the problems, the problems of poor synergy between the binder and boron nitride, uneven dispersion, insufficient high-temperature stability of the coating, low continuous demolding times and the like still exist. Therefore, the water-based metal casting and demolding coating with excellent high temperature resistance, good demolding performance, high adhesion and environment friendliness is developed, and the water-based metal casting and demolding coating has important industrial application value and market prospect. Disclosure of Invention Based on the above, in order to solve one of the technical problems, the invention provides a high-temperature-resistant metal casting and demolding coating and a preparation method thereof, and the specific technical scheme is as follows: the high-temperature-resistant metal casting release coating comprises the following raw materials in parts by weight: 25-30 parts of a composite binder, 15-25 parts of hexagonal boron nitride, 1-3 parts of nano aluminum oxide, 4-10 parts of a high temperature resistant auxiliary agent, 5-8 parts of a suspending agent, 0.5-2 parts of a dispersing agent, 0.1-2 parts of a leveling agent, 5-15 parts of a pigment and 20-40 parts of water; Wherein the composite binder consists of an organic binder and an inorganic binder in a mass ratio of (0.5-2); The high-temperature-resistant auxiliary agent consists of zircon powder, corundum powder and nano cerium oxide with the mass ratio of (1-3) (1-5) (1-2). Further, the organic binder is at least one of silicone resin, acrylic resin and epoxy resin, and the inorganic binder is at least one of phosphate, silicate and aluminum sol. Further, the hexagonal boron nitride consists of nanoscale h-BN, submicron h-BN and micron h-BN with the mass ratio of (1-2) (1-3) (1-2). Further, the granularity grading of the high-temperature resistant auxiliary agent is that the granularity is 300-350 meshes, and the granularity is 40-50% of the total mass of the high-temperature resi