CN115156477A - Graphite powder casting coating and preparation method thereof - Google Patents
Graphite powder casting coating and preparation method thereof Download PDFInfo
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- CN115156477A CN115156477A CN202210808096.9A CN202210808096A CN115156477A CN 115156477 A CN115156477 A CN 115156477A CN 202210808096 A CN202210808096 A CN 202210808096A CN 115156477 A CN115156477 A CN 115156477A
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B22C—FOUNDRY MOULDING
- B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
Abstract
The application relates to the technical field of casting industry, and particularly discloses graphite powder casting coating and a preparation method thereof. The graphite powder casting coating comprises the following components in parts by weight: 80-100 parts of graphite powder, 10-15 parts of titanium dioxide, 5-10 parts of graphene coated waste glass microspheres, 12-20 parts of waste incineration fly ash, 100-150 parts of water, 3-6 parts of gum arabic, 0.1-0.5 part of defoaming agent and 0.5-1 part of surfactant; the preparation method comprises the following steps: mixing waste incineration fly ash, graphite powder, gum arabic, titanium dioxide, graphene coated waste glass beads and water, adding a defoaming agent and a surfactant, and fully stirring to obtain the graphite powder casting coating. The graphite powder casting coating has the advantages of being good in strength, good in heat conductivity, not prone to cracking, strong in anti-sand adhesion performance, capable of effectively improving the surface precision of castings and improving the quality of the castings.
Description
Technical Field
The application relates to the technical field of casting industry, in particular to graphite powder casting coating and a preparation method thereof.
Background
The casting coating is a layer of casting auxiliary material which is used for being attached to a casting mould and a core in the casting process, plays a role in isolating molten metal and has a specific function. The casting paint is prepared with refractory stuffing, liquid carrier, adhesive, suspending stabilizer, other assistant and other material. In general, casting coatings are required to have good specific functions, such as prevention of sand sticking to castings, improvement of surface finish of castings, reinforcement of sand mold surfaces, shielding or insulation.
In the prior art, a chinese patent application with application number 200610046059.X discloses a pollution-free water-based dip coating, which is prepared from the following components in percentage by weight: 17-30% of zircon powder, 20-35% of brown fused alumina, 5-15% of mullite, 5-15% of graphite, 5-15% of forsterite, 1-4% of polyvinyl alcohol, 1.5-3.5% of a suspending agent and 30-45% of water. Wherein polyvinyl alcohol is used as a binder, and the suspending agent is prepared from illite, sepiolite and bentonite according to the ratio of 1: 0.5.
In view of the above-mentioned related technologies, the inventors found that the chemical stability of the casting coating with graphite is good, but the coating with polyvinyl alcohol organic binder has poor anti-sand sticking performance, which can cause sand sticking on the surface of the casting and affect the appearance quality of the casting.
Disclosure of Invention
In order to prevent sand from adhering to the surface of a casting and improve the appearance quality of the casting, the application provides the graphite powder casting coating and the preparation method thereof.
In a first aspect, the application provides a graphite powder casting coating, which adopts the following technical scheme:
the graphite powder casting coating comprises the following components in parts by weight: 80-100 parts of graphite powder, 10-15 parts of titanium dioxide, 5-10 parts of graphene coated waste glass beads, 12-20 parts of waste incineration fly ash, 100-150 parts of water, 3-6 parts of gum arabic, 0.1-0.5 part of defoaming agent and 0.5-1 part of surfactant.
By adopting the technical scheme, the graphite powder is used as a main raw material of the casting coating, and raw materials such as waste incineration fly ash and graphene coated waste glass beads are added, the graphite powder has high refractoriness and small thermal expansion, and has good coating performance, when iron liquid is poured, the wetting angle of the graphite powder to the iron liquid is larger than 90 degrees, namely, a sand mold is not wetted by the iron liquid, pores on the gradual surface are blocked by the graphite powder, the iron liquid is not easy to permeate and penetrate into sand grains, the gradual sand sticking can be prevented, the gradual surface smoothness can be improved, the graphite powder also has good lubricating effect, the compaction fluidity of molding sand is improved, and the air permeability is reduced; during casting, iron oxide such as ferrous oxide is continuously produced on the surface of iron or steel, the graphite powder contains silicon dioxide, the iron oxide and the ferrous oxide form low-melting-point iron olivine which is firmly adhered to the gradual surface to form a chemical sticky sand layer, and after the iron olivine is gradually cooled, the solidified iron olivine is automatically peeled off from the gradual surface to obtain a smooth gradual surface; the particle size incineration fly ash contains silicon dioxide, aluminum oxide and other substances, when the iron liquid is poured, the waste incineration fly ash forms an enamel layer with a ceramic-like structure in a high-temperature environment, after the temperature is cooled, the enamel layer is peeled off without forming sand bonding, and the poured gradual surface is smooth and clean without the sand bonding phenomenon; the graphene coated waste glass beads comprise graphene, waste glass beads and the like, the graphene has the characteristics of excellent thermal conductivity and surface contact of a two-dimensional structure, the graphene and the waste glass beads are used as a casting coating, the thermal conductivity coefficient of the casting coating can be increased, the compactness of a coating is improved, the strength and the high-temperature crack resistance of the coating are improved, and the wear resistance and the surface smoothness are enhanced.
Optionally, the graphene coated waste glass beads are prepared by the following method:
cleaning, crushing and grinding the waste glass to prepare waste glass powder;
mixing the waste glass powder and the electro-chromic manganese slag according to the mass ratio of 1.2-1.28, sieving, adding water, mixing, spheroidizing, drying until the water content is less than or equal to 3%, calcining for 30-40min to prepare calcined microspheres, cooling the temperature of the calcined microspheres to 130-150 ℃, adding phenolic resin and graphene, mixing and stirring uniformly, adding a silane coupling agent, mixing uniformly, cooling to 70-80 ℃, adding a curing agent and a lubricant, mixing uniformly, cooling to room temperature, mechanically crushing, and sieving.
By adopting the technical scheme, after the waste glass powder and the electrochromic manganese slag are calcined at high temperature, anorthite, mullite and forsterite are generated, the strength is high, the heat resistance is good, the phenolic resin and the graphene are connected with the calcined microspheres, the graphene has adsorbability and is attached to the surfaces of the calcined microspheres, the phenolic resin is used as a binder, and the graphene and the calcined microspheres are bonded together, so that graphene sheets coated by the resin are arranged on the surfaces of the calcined microspheres, and the dispersed graphene can transfer heat to the periphery during pouring, so that the casting coating can rapidly transfer heat, the phenolic resin is heated and melted, the surfaces of the castings are coated, the possibility of contact between the castings and sand grains is reduced, the high-temperature crack resistance of the casting coating is improved, and the mold forming performance of molding sand is improved.
Optionally, the particle size and the proportion of the graphene coated waste glass beads are as follows: the percentage of graphene coated waste glass beads with the particle size of 53-75 mu m is 0.7-0.9%, the percentage of graphene coated waste glass beads with the particle size of 75-109 mu m is 10.1-11%, the percentage of graphene coated waste glass beads with the particle size of 109-150 mu m is 35.2-36%, the percentage of graphene coated waste glass beads with the particle size of 150-212 mu m is 47.5-48%, and the percentage of graphene coated waste glass beads with the particle size of 212-270 mu m is 4-6.5%.
Through adopting above-mentioned technical scheme, the graphite alkene tectorial membrane abandonment glass microballon of different particle sizes forms the gradation, can fully block up the hole on sand mould surface, makes the foundry goods surface smooth, and the compactness of molding sand increases, and the gas permeability descends.
Optionally, the graphite powder is pretreated by:
mixing graphite powder and aluminum nitride according to the mass ratio of 1-3, adding polyvinyl alcohol aqueous solution, spheroidizing to prepare a mixed sphere, drying the mixed sphere at 200-250 ℃, soaking the mixed sphere, acrylic resin aqueous solution, polytetrafluoroethylene particles and silicon carbide under negative pressure, filtering, and drying the mixed sphere.
By adopting the technical scheme, the graphite powder is firstly mixed with the aluminum nitride, the thermal conductivity of the graphite powder is increased, a polyvinyl alcohol aqueous solution is added to prepare a mixed sphere, the polyvinyl alcohol is used as a pore-forming agent, the polyvinyl alcohol is volatilized after being dried at high temperature, the porosity of the mixed sphere is increased, then an acrylic resin aqueous solution is used as a binder, polytetrafluoroethylene particles and silicon carbide are adhered to the pores of mixed gas under negative pressure impregnation to fill the pores, and the compactness of the mixed sphere is increased; when the high temperature molten iron of pouring gets into the sand mould, the polytetrafluoroethylene granule melts under high temperature to forming the separation coating, preventing molten iron and molding sand contact, carborundum discharges along with the polytetrafluoroethylene granule in the mixed spheroid that graphite powder and aluminium nitride formed in addition, blocks up the hole of sand mould, and the compactness of increase sand mould improves the surface smoothness of foundry goods.
Optionally, the concentration of the polyvinyl alcohol aqueous solution is 3-5wt%, and the using amount of the polyvinyl alcohol aqueous solution is 5-7% of the total weight of the graphite powder and the aluminum nitride; the concentration of the acrylic resin aqueous solution is 10-20wt%;
the mass ratio of the mixed spheres to the aqueous solution of acrylic resin to the polytetrafluoroethylene particles to the silicon carbide is 1.
By adopting the technical scheme, the graphite powder and the aluminum nitride can be bonded by utilizing the polyvinyl alcohol aqueous solution with the concentration of 3-5wt%, so that the graphite powder and the aluminum nitride can be conveniently formed into balls, the polyvinyl alcohol aqueous solution with the mass of 5-7% of the total weight of the graphite powder and the aluminum nitride can form more pores in a mixed sphere, the porosity is improved, the acrylic resin aqueous solution, the polytetrafluoroethylene particles and the silicon carbide can fully fill the pores, the compactness of mixed gas is improved, the coating strength of the casting coating is improved, the heat resistance of the polytetrafluoroethylene after film forming is good, the silicon carbide has good heat conductivity coefficient, and the high-temperature crack resistance of the coating can be improved.
Optionally, before mixing the aluminum nitride with the graphite powder, mixing the aluminum nitride with ethanol and a silane coupling agent KH550, filtering, and then washing with ethanol for 3-5 times to obtain the aminated aluminum nitride, wherein the mass ratio of the aluminum nitride to the silane coupling agent KH550 to the ethanol is (1-3);
although the thermal conductivity of the aluminum nitride is high, the enhancement effect of the aluminum nitride is not good, by adopting the technical scheme, graphene oxide, deionized water, graphene oxide and deionized water are subjected to ultrasonic dispersion to obtain graphene dispersion liquid, the graphene and aminated aluminum nitride are mixed to prepare graphene-coated aluminum nitride, a layer of graphene is attached to the surface of the aluminum nitride, the surface of the aluminum nitride is electronegative because the graphene oxide contains a large number of oxygen-containing groups such as hydroxyl groups and carboxyl groups, the aluminum nitride is functionalized through aminosilane, so that the surface of the aluminum nitride is positively charged, and after the aluminum nitride and the aluminum nitride are fully mixed, the graphene oxide is coated on the surface of the aluminum nitride by utilizing an electrostatic chemical assembly principle to obtain graphene/aluminum nitride composite coated powder.
Optionally, the graphite powder comprises graphite powder A with a particle size of 80-100 μm, graphene powder B with a particle size of 20-30 μm, and graphite powder C with a particle size of 5-15 μm, wherein the mass ratio of the graphite powder A to the graphite powder B to the graphite powder C is 3.
By adopting the technical scheme, the graphite powders with different particle sizes are matched with each other and are bridged to form a three-dimensional network structure, so that a compact and uniform coating is formed, the mechanical strength of the casting coating is greatly enhanced by coating the waste incineration fly ash, the fineness matching of the graphite powders is good, and the casting coating has good suspension stability and coating property.
Optionally, the chemical composition of the waste incineration fly ash is as follows: caO 33.8%, siO 2 37.8％、Al 2 O 3 1.2％、Fe 2 O 3 2.6％、Na 2 O 5.4％、K 2 O 5.9％、SO 3 6.7％、MgO 1.89％、Cl 4.71％。
Preferably, the defoamer is polydimethylsiloxane and the surfactant is sodium dodecyl sulfate.
By adopting the technical scheme, the polydimethylsiloxane is used as the defoaming agent and the sodium dodecyl sulfate is used as the surfactant in the casting coating, so that the defects of air holes and the like on the surface of the coating formed by curing the coating can be eliminated, and the coating is compact and uniform.
In a second aspect, the application provides a preparation method of a graphite powder casting coating, which adopts the following technical scheme: the graphite powder casting coating comprises the following steps:
mixing the waste incineration fly ash, graphite powder, gum arabic, titanium dioxide, graphene coated waste glass microspheres and water, adding a defoaming agent and a surfactant, and fully stirring to obtain the graphite powder casting coating.
By adopting the technical scheme, substances such as waste incineration fly ash and the like are mixed, the suspension stability of the casting coating is improved, the preparation process is simple, and the prepared coating can be mixed more uniformly and compactly.
Optionally, mixing the waste incineration fly ash and water according to a mass ratio of 1.
By adopting the technical scheme, the waste incineration fly ash is firstly subjected to water washing treatment, most soluble salt pollutants in the waste incineration fly ash can be reduced by the water washing treatment, the hot melting temperature is reduced, the waste incineration fly ash can be subjected to hot melting at a lower temperature and is coated on the surface of a casting to protect the surface of the casting, the waste incineration fly ash after the water washing is mixed with sodium stearate for ball milling, the fly ash can be more fully crushed and refined, sodium carboxylate groups in the sodium stearate can react with ionic groups on the surface of the waste incineration fly ash, so that chemical adsorption is generated on the surface of the waste incineration fly ash, and the fatty acid long chain end connected with the surface of the waste incineration fly ash through chemical bonds can enable the waste incineration fly ash to have better compatibility with gum arabic.
In summary, the present application has the following beneficial effects:
1. as the casting coating is prepared from the raw materials such as graphite powder, incineration fly ash, graphene coated waste glass beads and the like, a protective coating capable of automatically peeling off can be formed between a casting and a sand mold, sand is not easy to stick, and the casting coating is good in high-temperature strength and strong in crack resistance.
2. In the application, the graphene film-coated waste glass microspheres are prepared by preferably adopting the components such as graphene, phenolic resin, a coupling agent, waste glass, electro-chromic manganese slag and the like, the graphene is bonded on the surface of the phenolic resin after the electro-chromic manganese slag and the waste glass powder are calcined into spheres, and the graphene is lapped on the surface of the calcined spheres to increase the thermal conductivity and the strength of the graphene; the incineration fly ash generates an enamel layer with a ceramic structure at the high temperature of the pouring molten iron, has higher strength and excellent stripping property, can ensure that no sand is adhered to the surface of a casting, improves the quality of the casting, and reduces subsequent processing procedures.
3. The casting coating has a density of 1.1-1.6g/cm 3 The suspension rate is more than or equal to 96 percent after the mixture is placed for 6 hours, the suspension rate is more than or equal to 93 percent after the mixture is placed for 24 hours, the gas evolution is less than 35 percent, no crack and no bubble are generated after the mixture is coated, the coating is uniform, the surface quality is good, and the mixture completely meets the requirements of sand castingThe requirements of the manufacturing coating (JB/T9226-2008) are met, and the reflection effect is good through the production and application of a foundry manufacturer, the gradual surface quality of the production is good, and the manufacturing is widely popularized.
Detailed Description
Preparation examples 1 to 4 of graphene-coated waste glass beads
In preparation examples 1 to 4, the phenolic resin has a product number of A045 and a cas number of 2873 to 16 to 5; the graphene has a cargo number of XT-C4-07, is multi-layer and flaky, and has a specific surface area of 120-230m 3 The grain diameter is less than 10 mu m.
Preparation example 1: (1) Washing, crushing and grinding the waste glass to prepare waste glass powder;
(2) Mixing 1kg of waste glass powder and electrochromic manganese slag according to a mass ratio of 1.2, sieving, adding water, wherein the adding amount of the water is 5% of the total amount of the waste glass powder and the electrochromic manganese slag, spheroidizing after mixing, the feeding amount during spheroidizing is 50kg/h, the rotating speed is 100rpm, the spheroidizing time is 45min, drying is carried out until the water content is less than or equal to 3%, calcining is carried out for 30min at 950 ℃ to prepare calcined microspheres, when the temperature of the calcined microspheres is cooled to 130 ℃, 0.55kg of phenolic resin and 0.44kg of graphene are added, mixing and stirring are carried out uniformly, 0.05kg of silane coupling agent KH550 is added, mixing is carried out, when the temperature of the calcined microspheres is cooled to 70 ℃, 0.09kg of curing agent and 0.05kg of lubricating agent are added, mixing is carried out uniformly, cooling is carried out to the room temperature, mechanical powder is sieved, and the curing agent is hexamethylenetetramine.
Preparation example 2: (1) Cleaning, crushing and grinding the waste glass to prepare waste glass powder; (2) Mixing 1kg of waste glass powder and the electrochromic manganese slag according to a mass ratio of 1.28, sieving, adding water, wherein the adding amount of the water is 8% of the total amount of the waste glass powder and the electrochromic manganese slag, mixing and spheroidizing, the feeding amount during spheroidizing is 50kg/h, the rotating speed is 100rpm, the spheroidizing time is 45min, drying is carried out until the water content is less than or equal to 3%, calcining is carried out for 40min at 900 ℃ to prepare calcined microspheres, when the temperature of the calcined microspheres is cooled to 150 ℃, 0.6kg of phenolic resin and 0.5kg of graphene are added, mixing and stirring are carried out uniformly, 0.06kg of silane coupling agent KH550 is added, mixing is carried out, when the temperature of the calcined microspheres is cooled to 80 ℃, 0.1kg of curing agent and 0.06kg of lubricating agent are added, mixing is carried out uniformly, cooling is carried out to room temperature, mechanical powder is used for sieving, and the curing agent is hexamethylenetetramine.
Preparation example 3: the difference from the preparation example 1 is that the electrochromic manganese slag is not added.
Preparation example 4: the difference from preparation example 1 is that no silane coupling agent KH550 was added.
Examples
Example 1: the graphite powder casting coating comprises the following raw materials in parts by weight: 100kg of graphite powder, 15kg of titanium dioxide, 10kg of graphene coated waste glass microspheres, 20kg of waste incineration fly ash, 150kg of water, 6kg of gum arabic, 0.5kg of defoaming agent and 1kg of surfactant, wherein the defoaming agent is polydimethylsiloxane, the surfactant is sodium dodecyl sulfate, the graphene coated waste glass microspheres are prepared by preparation example 1, and the particle sizes of the graphene coated waste glass microspheres are as follows: 0.7 percent of graphene coated waste glass microspheres with the particle size of 530-75 microns, 10.1 percent of graphene coated waste glass microspheres with the particle size of 75-109 microns, 35.2 percent of graphene coated waste glass microspheres with the particle size of 109-150 microns, 47.5 percent of graphene coated waste glass microspheres with the particle size of 109-150 microns, 6.5 percent of graphene coated waste glass microspheres with the particle size of 212-270 microns, and the chemical composition of the waste incineration fly ash is as follows: caO 33.8%, siO 2 37.8％、Al 2 O 3 1.2％、Fe 2 O 3 2.6％、Na 2 O 5.4％、K 2 O 5.9％、SO 3 6.7%, mgO 1.89%, and Cl 4.71%, wherein the graphite powder is crystalline graphite powder and comprises graphene A with the particle size of 100 μm, graphite powder B with the particle size of 30 μm, and graphite powder C with the particle size of 15 μm, in a mass ratio of 3.
The preparation method of the graphite powder casting coating comprises the following steps: mixing the waste incineration fly ash and water according to the mass ratio of 1.
Example 2: the graphite powder casting coating comprises the following raw materials in parts by weight:80kg of graphite powder, 10kg of titanium dioxide, 5kg of graphene coated waste glass microbeads, 12kg of waste incineration fly ash, 100kg of water, 3kg of gum arabic, 0.1kg of defoaming agent and 0.5kg of surfactant, wherein the defoaming agent is polydimethylsiloxane, the surfactant is sodium dodecyl sulfate, the graphene coated waste glass microbeads are prepared by the preparation example 2, and the particle sizes of the graphene coated waste glass microbeads are as follows: the proportion of graphene coated waste glass beads with the particle size of 53-75 mu m is 0.9%, the proportion of graphene coated waste glass beads with the particle size of 75-109 mu m is 11%, the proportion of graphene coated waste glass beads with the particle size of 109-150 mu m is 36%, the proportion of graphene coated waste glass beads with the particle size of 150-212 mu m is 48%, the proportion of graphene coated waste glass beads with the particle size of 212-270 mu m is 4.1%, and the chemical composition of the waste incineration fly ash is as follows: caO 33.8%, siO 2 37.8％、Al 2 O 3 1.2％、Fe 2 O 3 2.6％、Na 2 O 5.4％、K 2 O 5.9％、SO 3 6.7%, mgO 1.89%, and Cl 4.71%, wherein the graphite powder comprises graphene A with the particle size of 80 μm, graphite powder B with the particle size of 20 μm, and graphite powder C with the particle size of 5 μm, in a mass ratio of 3.
The preparation method of the graphite powder casting coating comprises the following steps: mixing the waste incineration fly ash and water according to a mass ratio of 1.
Example 3: a graphene foundry coating, which is different from example 1 in that graphene-coated waste glass microbeads were prepared according to preparation example 3.
Example 4: a graphene foundry coating, which is different from example 1 in that graphene-coated waste glass microspheres were prepared according to preparation example 4.
Example 5: a graphite powder casting coating, which is different from the graphite powder casting coating in example 1 in that the graphite powder is pretreated by the following steps: mixing graphite powder and aluminum nitride according to the mass ratio of 1;
drying the mixed sphere at 200 ℃ for 3h, mixing the mixed sphere with an aqueous solution of acrylic resin with a mass concentration of 20%, polytetrafluoroethylene particles and silicon carbide, impregnating the mixture for 3h under-0.05 MPa, filtering the mixture, and drying the mixed sphere, wherein the mass ratio of the mixed sphere, the aqueous solution of acrylic resin, the polytetrafluoroethylene particles and the silicon carbide is (1).
Example 6: a graphite powder casting coating which differs from example 1 in that graphite powder is pretreated as follows: mixing graphite powder and aluminum nitride according to the mass ratio of 1;
drying the mixed sphere at 250 ℃ for 2h, mixing the mixed sphere with an aqueous solution of acrylic resin with a mass concentration of 20%, polytetrafluoroethylene particles and silicon carbide, impregnating the mixture at-0.1 MPa for 1h, and drying the mixed sphere, wherein the mass ratio of the mixed sphere, the aqueous solution of acrylic resin, the polytetrafluoroethylene particles and the silicon carbide is 1.
Example 7: a graphite powder casting coating, differing from example 6 in that no polytetrafluoroethylene particles were added during graphite powder pretreatment.
Example 8: a graphite powder casting coating differing from example 6 in that no silicon carbide particles were added during pretreatment of the graphite powder.
Example 9: a graphite powder casting coating, differing from example 6 in that no aluminium nitride was added during the graphite powder pretreatment.
Example 10: a graphite powder casting coating is different from that in example 6 in that before aluminum nitride is mixed with graphite powder, the aluminum nitride is mixed with ethanol and a silane coupling agent KH550, the mixture is filtered and then washed with ethanol for 3 times to prepare aminated aluminum nitride, and the mass ratio of the aluminum nitride to the silane coupling agent KH550 to the ethanol is 1;
and (2) mixing the aminated aluminum nitride with graphene oxide and deionized water, ultrasonically dispersing the mixture to prepare a graphene dispersion liquid with the mass concentration of 20%, filtering, and drying, wherein the mass ratio of the aminated aluminum nitride to the graphene dispersion liquid is 1.
Example 11: a graphite powder casting coating is different from the graphite powder casting coating in example 6 in that before aluminum nitride is mixed with graphite powder, the aluminum nitride is mixed with ethanol and a silane coupling agent KH550, after filtration, the mixture is washed with ethanol for 5 times, and aminated aluminum nitride is prepared, wherein the mass ratio of the aluminum nitride to the silane coupling agent KH550 to the ethanol is 3;
and mixing the aminated aluminum nitride with graphene oxide and deionized water, ultrasonically dispersing the mixture to prepare a graphene dispersion liquid with the mass concentration of 30%, filtering, and drying, wherein the mass ratio of the aminated aluminum nitride to the graphene dispersion liquid is 1.
Example 12: a graphite powder casting coating, which differs from example 1 in that waste incineration fly ash is directly mixed with graphite powder and the like without water washing and sodium stearate pretreatment.
Comparative example
Comparative example 1: a graphite powder casting coating, which is different from example 1 in that graphene-coated waste glass beads are not added.
Comparative example 2: a graphite powder casting coating, which is different from example 1 in that no waste incineration fly ash is added.
Comparative example 3: the graphite powder casting coating is prepared from the following raw materials in parts by weight: 50 parts of graphite powder, 10 parts of diatomite, 9 parts of sodium dodecyl sulfate, 2 parts of titanium dioxide, 6 parts of vegetable oil, 5 parts of acrylic resin, 15 parts of hard amide and 20 parts of ethanol, wherein the graphite powder and the titanium dioxide are sieved by a 200-mesh sieve, the content of silicon dioxide in the diatomite is more than 90 percent, and the content of ferric oxide is 1-1.5 percent; the preparation method comprises the following steps: placing the graphite powder and titanium dioxide which are sieved by a 200-mesh sieve, diatomite and sodium dodecyl sulfate in a ball mill according to a ratio of ball to material of 1.
Performance test
Graphite powder casting paint was prepared according to the above method, and performance test was performed on the graphite powder casting paint with reference to the following method, and the test results are recorded in table 1.
1. Surface roughness: coating a graphite powder casting coating on a sample with the diameter of 50 mm multiplied by 30mm, wherein the coating thickness is 1mm, then placing the sample in a furnace with the furnace temperature of 1150 ℃ for firing for 3min, taking out the sample and cooling to the room temperature, and detecting the surface roughness of the coating by using a Dutch TQC SP1562 type coating roughness meter;
2. heat transfer coefficient: GB/T3651-2008 'method for measuring high temperature coefficient of thermal conductivity of metal';
3. coating strength: coating graphite powder casting paint on a glass plate, wherein the coating thickness is 1.5mm, putting the glass plate into a drying oven, drying the glass plate for 24 hours at 50 ℃, taking the glass plate out, and detecting the strength of the coating according to GB/T39686 'test method for the elastic modulus and strength of thick ceramic coatings';
4. high-temperature crack resistance: coating a layer of graphite powder casting coating on a sample with the diameter of 50 mm multiplied by 30mm, wherein the coating thickness is 1mm, after the sample is subjected to rapid thermal ignition for 3min at the temperature of 1150 ℃ in a furnace, the I-IV grade represents the capability of the coating layer for resisting the generation of cracks and peeling under the high-temperature exposure condition;
table 1 performance testing of graphite powder casting coatings
It can be known from table 1 and examples 1-2 that the amount of each raw material in the graphite powder casting coating is adjusted, and the graphene coated waste glass microspheres prepared in preparation example 1 can form a uniform, compact and smooth coating with good heat conduction and heat preservation performance on a casting, so that the casting has high surface quality and high molding rate.
The difference between example 3 and example 1 is that the graphite powder casting paint prepared in example 3 has a reduced heat transfer coefficient and a reduced high temperature crack resistance, as shown in table 1, when the graphene-coated waste glass beads prepared in preparation example 3 are used.
Example 4 is different from example 1 in that the coating material prepared in example 4, which uses the graphene-coated waste glass beads prepared in preparation example 4, has a decreased coating strength.
Examples 5 and 6 compared to example 1, graphite powder was also pretreated with aluminum nitride, acrylic resin, polytetrafluoroethylene particles, and silicon carbide particles, and table 1 shows that the coatings prepared in examples 5-6 have small surface roughness, increased thermal conductivity, improved coating strength, and improved high temperature cracking resistance at high temperature.
In example 7, compared to example 6, the surface roughness was increased and the coating strength was decreased without adding polytetrafluoroethylene particles when the graphite powder was pretreated, and in example 8, compared to example 6, the data in table 1 shows that the high temperature heat transfer coefficient was decreased with the coating prepared in example 8 without adding silicon carbide particles when the graphite powder was pretreated.
In example 9, compared to example 6, when the graphite powder was pretreated, no aluminum nitride was added, and the data in table 1 shows that the heat transfer coefficient of the coating prepared in example 9 was reduced at high temperature, and the coating strength was reduced.
In examples 10 and 11, aluminum nitride was also pretreated with graphene, and table 1 shows that the coatings prepared in examples 10 and 11 have reduced surface roughness, improved coating strength, and increased heat transfer coefficient.
Example 12 compared to example 1, the cast coating prepared in example 12 had a lower coating strength and an increased surface roughness without the water washing pretreatment and the sodium stearate blending ball milling pretreatment of the fly ash from waste incineration.
Compared with the embodiment 1, the graphene coated waste glass beads are not added, the roughness of the coating formed by the coating is increased, the heat conductivity coefficient is reduced, and the performances such as the strength of the coating are weakened. In comparative example 2, no waste incineration fly ash was added, and the coating strength of the casting coating prepared in comparative example 2 was decreased.
Comparative example 3 is a graphite powder casting coating prepared by the prior art, and compared with example 1, the casting coating prepared by comparative example 3 has the advantages of large surface roughness, easy sand adhesion, low coating strength and easy crack generation.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.
Claims (10)
1. The graphite powder casting coating is characterized by comprising the following components in parts by weight: 80-100 parts of graphite powder, 10-15 parts of titanium dioxide, 5-10 parts of graphene coated waste glass beads, 12-20 parts of waste incineration fly ash, 100-150 parts of water, 3-6 parts of gum arabic, 0.1-0.5 part of defoaming agent and 0.5-1 part of surfactant.
2. The graphite powder casting coating according to claim 1, wherein the graphene coated waste glass microspheres are prepared by the following method:
cleaning, crushing and grinding the waste glass to prepare waste glass powder;
mixing the waste glass powder and the electro-chromic manganese slag according to the mass ratio of 1.2-1.28, sieving, adding water, mixing, spheroidizing, drying until the water content is less than or equal to 3%, calcining for 30-40min to prepare calcined microspheres, adding phenolic resin and graphene when the temperature of the calcined microspheres is cooled to 130-150 ℃, mixing and stirring uniformly, adding a silane coupling agent, mixing uniformly, cooling to 70-80 ℃, adding a curing agent and a lubricant, mixing uniformly, cooling to room temperature, mechanically crushing, and sieving.
3. The graphite powder casting coating according to claim 1, wherein the particle size and the proportion of the graphene coated waste glass beads are as follows: the percentage of graphene coated waste glass beads with the particle size of 53-75 mu m is 0.7-0.9%, the percentage of graphene coated waste glass beads with the particle size of 75-109 mu m is 10.1-11%, the percentage of graphene coated waste glass beads with the particle size of 109-150 mu m is 35.2-36%, the percentage of graphene coated waste glass beads with the particle size of 150-212 mu m is 47.5-48%, and the percentage of graphene coated waste glass beads with the particle size of 212-270 mu m is 4-6.5%.
4. The graphite powder casting coating of claim 1, wherein the graphite powder is pretreated by:
mixing graphite powder and aluminum nitride according to the mass ratio of 1-3, adding a polyvinyl alcohol aqueous solution, spheroidizing to prepare a mixed sphere, drying the mixed sphere at 200-250 ℃, mixing the mixed sphere with an acrylic resin aqueous solution, polytetrafluoroethylene particles and silicon carbide, soaking under negative pressure, filtering, and drying the mixed sphere.
5. The graphite powder casting coating as claimed in claim 4, wherein the aluminum nitride is mixed with ethanol and the silane coupling agent KH550 before being mixed with the graphite powder, and the mixture is filtered and then washed with ethanol for 3 to 5 times to prepare the aminated aluminum nitride, wherein the mass ratio of the aluminum nitride to the silane coupling agent KH550 to the ethanol is 1 to 3;
and (2) mixing the aminated aluminum nitride with graphene oxide and deionized water, ultrasonically dispersing the mixture to obtain a graphene dispersion liquid with the mass concentration of 20-30%, filtering, and drying, wherein the mass ratio of the aminated aluminum nitride to the graphene dispersion liquid is (1).
6. The graphite powder casting coating of claim 1, wherein: the graphite powder comprises a graphite powder A with the particle size of 80-100 mu m, a graphene part B with the particle size of 20-30 mu m and a graphite powder C with the particle size of 5-15 mu m, wherein the mass ratio of the graphite powder A to the graphite powder B to the graphite powder C is 3.
7. The graphite powder casting coating of claim 1, wherein the chemical composition of the waste incineration fly ash is: caO 33.8%, siO2 37.8%, al2O3 1.2%, fe2O3 2.6%, na2O 5.4%, K2O 5.9%, SO3 6.7%, mgO 1.89%, cl 4.71%.
8. The graphite powder casting coating of claim 1, wherein the defoamer is polydimethylsiloxane and the surfactant is sodium lauryl sulfate.
9. The method of preparing a graphite powder casting coating according to any one of claims 1 to 8, comprising the steps of:
mixing the waste incineration fly ash, graphite powder, gum arabic, titanium dioxide, graphene coated waste glass microspheres and water, adding a defoaming agent and a surfactant, and fully stirring to obtain the graphite powder casting coating.
10. The preparation method of the graphite powder casting coating according to claim 9, wherein the waste incineration fly ash is subjected to washing pretreatment, and the specific method comprises the following steps: mixing the waste incineration fly ash and water according to the mass ratio of 1.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117282922A (en) * | 2023-09-23 | 2023-12-26 | 河北北方铸业有限公司 | Non-contact thermal repairing technology for castings |
| CN117282922B (en) * | 2023-09-23 | 2024-04-26 | 河北北方铸业有限公司 | Non-contact thermal repairing technology for castings |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117282922A (en) * | 2023-09-23 | 2023-12-26 | 河北北方铸业有限公司 | Non-contact thermal repairing technology for castings |
| CN117282922B (en) * | 2023-09-23 | 2024-04-26 | 河北北方铸业有限公司 | Non-contact thermal repairing technology for castings |
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