KR102542012B1 - Method for forming high heat resistant coating film using liquid ceramic composition and high heat resistant coating film prepared thereby - Google Patents

Abstract

The present invention relates to a highly heat-resistant/oxidation-resistant/non-combustible liquid ceramic coating film for protecting the exterior of an aircraft from extreme environments, (a) a ceramic filler containing iron oxide (Fe ₃ O ₄ ) powder, a diluent, and an inorganic nanosol. preparing a liquid ceramic filler by mixing; (b) applying the liquid ceramic filler to at least one surface of a substrate; and (c) drying and curing the substrate.

Description

Method for forming high heat resistant coating film using liquid ceramic composition and high heat resistant coating film prepared thereby}

The present invention relates to a method for forming a high heat resistance coating film using a liquid ceramic composition capable of forming a flame retardant/nonflammable coating film having excellent heat resistance and oxidation resistance in a high temperature environment, and a high heat resistance coating film manufactured thereby.

A ceramic coating film is formed on the surface to improve corrosion resistance, heat resistance and wear resistance of metal, wood, fiber and plastic. The coating agent for forming the ceramic coating film may have a form of a liquid ceramic composition. The liquid ceramic coating agent is prepared by adding a functional filler material suitable for each purpose to a thermoplastic or thermosetting polymer resin that can be dissolved in a solvent in order to extend the function or lifespan of the substrate material. Coatings composed of general thermoplastic polymer resins or thermosetting polymer resins do not usually exceed 200 ° C. due to their low melting point. Polyaryl ether ketone (PEEK), a representative heat-resistant polymer, has a melting point of 343 ° C and high temperature durability up to 260 ° C, but is mainly used for injection molding or extrusion molding that is melted and used. PEEK is not suitable as a liquid resin for coating because it does not dissolve well in solvents. Therefore, a dispersion of PEEK powder dispersed in a dispersion medium is coated on a substrate in a powder coating form and then melted at a high temperature (400° C.) above the melting point to prepare a coating film. Polyimide (PI), another heat-resistant polymer coating, can be used in the range of 300 to 350 ° C by coating a substrate with polyamic acid (PAA), a precursor solution of PI, and then heat-treating it in a vacuum atmosphere at about 350 ° C. Forms a heat-resistant coating film. In extreme environments such as high heat resistance or non-combustibility, it is practically impossible to use the above-described polymeric heat-resistant material because high-temperature characteristics of 500 ° C. or more are required.

Among coating materials having high heat resistance, metals are easily oxidized, so they are not suitable for use in high-temperature oxidizing atmospheres. A coating material that can be suitably used here includes a ceramic material, and an inorganic paint containing such a ceramic material can be used as a heat-resistant coating film. In particular, the application of heat-resistant inorganic paint to the interior and exterior of industrial high-temperature equipment is essential for the creation of high value-added products and the development of a wide range of uses through functionalization of products. Ceramicization of the surface of metal and non-metal products that require high heat resistance is important in that it enables the development of high heat-resistant paints that can realize not only heat resistance but also high functions such as excellent adhesion and chemical resistance, enabling the extension of life and functionality of products. do.

As a manufacturing method for coating such a ceramic coating agent on a substrate, a dry coating method using vacuum equipment or plasma thermal spray coating equipment is mainly used. Although these dry coating methods have very good properties, they require the use of expensive equipment and are disadvantageous for large-area application due to high production costs. In the wet coating method, which is inexpensive and can be applied to a large area, heat-resistant ceramic powder is melted in a polymer resin and coated, and then the polymer resin is removed at a first high temperature and then fired at a second sintering temperature to obtain a coating film. However, this wet coating method is applied to coatings such as small electronic parts rather than large-area coatings because of the difficulty of firing ceramic fillers at a high temperature to the sintering temperature and the need for large-scale sintering furnaces for large-area coatings. In order to lower the firing temperature of wet ceramic coating, a ceramic sol coating method has been proposed. High-temperature ceramic sol can lower the firing temperature to 500 ° C or less when manufacturing a very thin thin film, so it is mainly applied to thin film coating, but it is not suitable for use in painting due to expensive sol precursors and limited thickness.

If the liquid ceramic coating is not fired at a high temperature, the physical properties of the coating film are very low and the coating surface is easily scratched or peeled off. or limited to specific products.

The present invention aims to provide a nanocomposite ceramic coating agent for low-temperature firing that can be fired at a low temperature and a coating method using the same in order to solve the peeling or destruction of the coating film that occurs during high-temperature firing of a liquid ceramic coating agent, which has been a problem in the past. do. Through this, it is possible to easily form a flame retardant/non-combustible coating agent having high heat resistance on various large-area substrates without high-temperature firing.

According to one aspect of the present invention for achieving the above object (a) preparing a liquid ceramic filler by mixing a ceramic filler containing iron oxide (Fe ₃ O ₄ ) powder, a diluent and inorganic nano-sol; (b) applying the liquid ceramic filler to at least one surface of a substrate; and (c) preparing a coating film by subjecting the substrate to a curing treatment to dry the substrate.

In one embodiment, the liquid ceramic filler may be prepared by mixing 10 to 50% by weight of the ceramic filler, 10 to 30% by weight of the diluent, and 20 to 80% by weight of the inorganic nanosol.

In one embodiment, the iron oxide (Fe ₃ O ₄ ) content may be 20 to 60 wt % based on the content of the ceramic filler.

In one embodiment, the iron oxide (Fe ₃ O ₄ ) content may be 30 to 50% by weight based on the content of the ceramic filler.

In one embodiment, the step (a) may be performed by simultaneously mixing the ceramic filler, the diluent, and the inorganic nano-sol, or adding and mixing the inorganic nano-sol to a solution in which the ceramic filler and the diluent are mixed.

In one embodiment, the ceramic filler is selected from the group consisting of barium titanate (BaTiO ₃ ), alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), silicon carbide (SiC), pearls, and mixtures thereof. Any one of the powders may be included.

In one embodiment, the ceramic filler may have a particle size of 500 to 1500 nm.

In one embodiment, the liquid ceramic filler may be mixed by a ball mill process.

In one embodiment, the diluent may be distilled water or alcohol.

In one embodiment, the alcohol may be IPA or n-butanol.

In one embodiment, the inorganic nano-sol may be a silica sol or a silica-hybrid sol.

In one embodiment, the step (b) is any one method selected from the group consisting of brush coating, spin coating, spray coating, and dip coating. can be performed with

In one embodiment, the inorganic nano-sol is obtained by adding a solvent to alkoxy silane and stirring, and the alkoxy silane is methyltrimethoxysilane, methyltrichlorosilane, ethyltrimethoxysilane ( ethyltrimethoxysilane), ethyltriethoxysilane, phenyltrimethoxysilane, phenyltrichlorosilane, phenylaminopropyltrimethoxysilane, octyltrimethoxysilane, octyl trichlorosilane, octadecyltrimethoxysilane, octadecyltrichlorosilane, propyltrimethoxysilane, n-propyltriethoxysilane, isopropyl Selected from the group consisting of isopropyltriethoxysilane, isobutyltrimethoxysilane, vinyltriethyloxysilane, vinyltrimethoxysilane and allyltrimethoxysilane It can be any one.

In one embodiment, the step (c) may be performed for 2 to 24 hours at a temperature range of 20 ℃ to 200 ℃.

In one embodiment, after step (c), (d) removing impurities remaining on the surface of the substrate; may further include.

In one embodiment, the substrate may be formed of aluminum, steel plate, titanium, copper or stainless alloy material.

In one embodiment, the step of surface treating the substrate may be further included before step (b).

A highly heat-resistant coating film prepared by the above method, formed on at least one surface of a substrate, and containing iron oxide (Fe ₃ O ₄ ) powder is provided.

In one embodiment, the heat resistance temperature of the high heat resistance coating film may be 900 ℃ to 1000 ℃.

In one embodiment, the thickness of the high heat resistance coating film may be 15 to 100 μm.

In one embodiment, the average particle size of the high heat resistance coating film may be 500 to 1500 nm.

In one embodiment, the substrate may be made of aluminum, steel plate, titanium, copper or stainless alloy material.

According to another aspect of the present invention for achieving the above object, after step (c), (d') preparing a water repellent solution by dispersing a silane solution in a diluent; (e) applying the water repellent solution to at least one surface of the curing-treated coating film; and (f) preparing a water-repellent coating film by subjecting the coating film coated with the water-repellent solution to a curing treatment to dry it.

In another embodiment, the water repellent solution may be prepared by mixing 10 to 30% by weight of the silane solution and 70 to 90% by weight of the diluent.

In another embodiment, the silane solution is hexadecyltrimethoxysilane (HDTMS), methyltriethoxysilane (MTES), phenyl triethoxysilane (PhTES), diethoxy(3-glycidyloxypropyl)methylsilane (GPTMS), tetraethylorthosilicate (TEOS), and octal triethoxysilane (OTES). It may include any one selected from the group consisting of

In another embodiment, the diluent may be distilled water or alcohol.

In another embodiment, the step (e) is any one method selected from the group consisting of brush coating, spin coating, spray coating and dip coating. can be performed with

In another embodiment, step (f) may be performed for 0.1 to 3 hours at a temperature range of 80 °C to 130 °C.

In another embodiment, after step (f), (g) removing impurities remaining on the surface; may further include.

A highly heat-resistant coating film comprising a water-repellent coating film prepared by the above method is provided.

In another embodiment, the thickness of the water-repellent coating layer may be 0.5 to 3 μm.

In the case of using the high heat resistance coating film prepared according to one embodiment of the present invention made as described above, it is possible to economically form a high heat resistance / oxidation resistance / flame retardant / incombustible coating film on various substrates of a large area without high temperature baking. there is. In addition, it can be easily applied by using a spray or brush, which has the effect of reducing the hassle and working time of the work.

1 is a SEM (Scanning Electron Microscope) image of a ceramic mixture powder according to an embodiment of the present invention.
Figure 2 is a result of observing the surface after performing a pencil hardness test for the coating film formed on the aluminum alloy (Al) and the iron alloy (Fe) according to an embodiment of the present invention.
Figure 3 is a picture showing the indentation traces after each hardness test using a Leeb hardness tester for the same specimen as the specimen of Figure 2 at 2x magnification.
Figure 4 is a graph showing the Leeb hardness according to the curing temperature change and time of the specimen according to an embodiment of the present invention.
Figure 5 is the result of observing before / after the flame test according to the composition change of the aluminum alloy (Al) and the iron alloy disc (Fe) according to an embodiment of the present invention.
6 to 10 are the results of observing before and after the flame test for the change in Fe ₃ O ₄ content for the same composition of aluminum alloy (Al) and iron alloy disc (Fe) according to an embodiment of the present invention.
Figure 11 (a) is the result of observing the surface after performing the heat resistance test according to the Fe ₃ O ₄ content change for the aluminum alloy (Al) and the iron alloy disc (Fe) according to an embodiment of the present invention, 11(b) shows the results of observation before and after the heat resistance test when the disc and Fe ₃ O ₄ were added to the titanium alloy (Ti).
12 is a state in which only inorganic nano-sols are coated on aluminum alloy (Al) and iron alloy (Fe).
13(a) shows a state in which corrosion of an iron steel sheet (Fe) is prevented by adding iron oxide (Fe ₃ O ₄ ) to a ceramic filler according to an embodiment of the present invention, and FIG. 13(b) shows this According to another embodiment of the present invention, water-repellent coating is performed to prevent corrosion of the iron steel sheet (Fe).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With the present invention described in detail, reference is made to the accompanying drawings which illustrate, by way of illustration, specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable one skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different from each other but are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in one embodiment in another embodiment without departing from the spirit and scope of the invention. Additionally, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. Accordingly, the detailed description set forth below is not to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, together with all equivalents as claimed by those claims. Similar reference numerals in the drawings indicate the same or similar functions in various aspects, and the length, area, thickness, and the like may be exaggerated for convenience. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate the present invention to those skilled in the art to which the present invention belongs.

Liquid ceramic filler according to an embodiment of the present invention is prepared by dispersing the ceramic filler in inorganic nanosol.

The composition of the ceramic filler may consist of 10 to 50% by weight of a ceramic filler containing iron oxide (Fe ₃ O ₄ ) powder, 10 to 30% by weight of a diluent selected from distilled water or alcohol, and 20 to 80% by weight of inorganic nanosol. .

When the substrate surface is coated with a ceramic filler, the substrate is corroded by reacting with an oxidizing agent such as water (H ₂ O) or oxygen. Corrosion of the substrate can be prevented by adding iron oxide (Fe ₃ O ₄ ) to the ceramic filler to suppress corrosion of the substrate. In addition, since the coefficient of thermal expansion of iron oxide (Fe ₃ O ₄ ) is similar to that of the substrate, adhesion between the substrate and the coating layer may be improved. The iron oxide (Fe ₃ O ₄ ) content may be 20 to 60 wt %, more preferably 30 to 50 wt %, based on the content of the ceramic filler. In addition, the ceramic filler is a material having high heat resistance and excellent strength, and may further include Al ₂ O ₃ , ZrO ₂ , SiC, BaTiO ₃ , pearl, and mixtures thereof in powder form. The ceramic powder particles constituting the ceramic filler may have a size ranging from 500 to 1500 nm. The ceramic filler may be a mixture of two or more ceramic powder fillers, a diluent, and an inorganic nanosol through a ball-mill process. When preparing the ceramic filler, the ceramic filler, diluent and inorganic nanosol may be simultaneously mixed. When the ceramic filler is stirred with the inorganic nano-sol for a long time, gelation may occur, and gelation can be prevented by adding the inorganic nano-sol to a solution in which the ceramic filler and the diluent are mixed later.

Among the diluents, the alcohol-based mixed solvent may include IPA or n-butanol, and may contain less than 20 wt% of water.

The inorganic nano-sol may include a silica sol or a silica-hybrid sol. It can be obtained by adding a solvent to the alkoxy silane of the inorganic nano-sol and stirring it. The alkoxy silane is methyltrimethoxysilane, methyltrichlorosilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltrichloro phenyltrichlorosilane, phenylaminopropyltrimethoxysilane, octyltrimethoxysilane, octyltrichlorosilane, octadecyltrimethoxysilane, octadecyltrichlorosilane ( octadecyltrichlorosilane, propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltriethoxysilane, isobutyltrimethoxysilane, vinyltriethyloxysilane ), may be any one or more of vinyltrimethoxysilane and allyltrimethoxysilane. The inorganic nano-sol may serve as a binder for improving adhesion to a substrate by combining liquid ceramic fillers into one.

The liquid ceramic filler may form a highly heat-resistant coating film on the surface of the substrate through a curing process in which the liquid ceramic filler is applied to the surface of the substrate and then dried. As a method of applying, any one or more of brush coating, spin coating, spray coating, and dip coating may be used.

The drying step may be performed for 2 to 24 hours at a temperature range of 20 to 200 ℃. After the drying step, a step of removing impurities remaining on the surface of the substrate may be further performed.

The substrate may be applied to any material requiring heat resistance, such as metal, ceramic, and polymer. For example, metals may include steel, stainless steel, aluminum alloy, titanium alloy, and copper alloy. The substrate may be surface-treated.

The high heat resistance coating film formed by being applied to the surface of the substrate as described above may have a thickness in the range of 15 to 100 μm. In addition, the heat resistance temperature of such a high heat resistance coating film may reach up to 1000 ℃. The average particle size of the high heat resistance coating film may be 500 to 1500 nm.

Hereinafter, manufacturing examples and experimental examples of a high heat resistance coating film will be described to aid understanding of the present invention. However, the following examples are only for helping understanding of the present invention, and the present invention is not limited to the following examples and experimental examples.

<Example 1> Formation of a coating film using a liquid ceramic composition

Table 1 shows the composition of the liquid ceramic filler for preparing a high heat resistance coating film according to an embodiment of the present invention. Substances corresponding to the symbols in Table 1 are indicated at the bottom of Table 1. The ZB sample is ball-milled with ceramic filler, diluent and inorganic nano-sol, and ZB-1 to ZB-5 are ball-milled with ceramic filler and diluent, and then ball-milled with inorganic nano-sol again for 6 hours. It is milled and mixed.

In addition, a coating film was formed on the surface of aluminum alloy (Al) and iron alloy (Fe) with the corresponding filler, and in each case, the thickness of the coating film was Sample 1 (Al: 85㎛, Fe: 63㎛), Sample 2 (Al: 85㎛) ㎛, Fe:51㎛), Sample 3 (Al: 33㎛, Fe:32㎛), Sample 4 (Al: 16㎛, Fe:15㎛), Sample 5 (Al: 65㎛, Fe:32㎛), Sample 6 (Al: 30㎛, Fe: 15㎛), Sample 7 (Al: 38㎛, Fe: 15㎛).

Sample psalm name A% Z% S% B% F% P% H% IPA% n-Butanol % importance One AZS-1 10 15.33 2.67 0 3.33 2 66.67 0 0 1.124 2 ZB 0 8.33 0 8.33 16.67 0 41.67 22.92 2.08 1.158 3 ZB-1 0 16.67 0 16.67 0 0 41.66 22.92 2.08 1.236 4 ZB-2 0 11.665 0 11.665 10 0 41.67 22.92 2.08 1.198 5 ZB-3 0 8.33 0 8.33 16.67 0 41.67 22.92 2.08 1.126 6 ZB-4 0 5 0 5 23.33 0 41.67 22.92 2.08 1.205 7 ZB-5 0 0 0 0 33.33 0 41.67 22.92 2.08 1.141 A: Al ₂ O ₃ , Z: ZrO ₂ , S: SiC, B: BaTiO ₃ , F: Fe ₃ O ₄ , P: Pearl, H: Hybrid sol binder

1 is a SEM (Scanning Electron Microscope) image of ceramic powders constituting specimen names ZB-1 to ZB-5 in Table 1. Referring to FIG. 1, it can be seen that ZB-2 and ZB-3 samples have good dispersion between Z, B, and F components, so that nanocomposite structures are best formed. On the other hand, the ZB-1 sample has a high B content and thus has a significantly aggregated nanocomposite structure, and ZB-4 and ZB-5 have coarser particles as the B content decreases and the F content increases. Generation of aggregates and coarsening of particles in samples ZB-1, ZB-4, and ZB-5 may have limitations in that crack generation increases after high-temperature thermal shock. At this time, the average particle size of the mixed powder is in the range of 500 to 1500 nm.

The compositions of Samples 1 to 7 in Table 1 were formed by mixing a ceramic filler with a silica hybrid sol and then stirring. The ceramic powders constituting the ceramic filler shown in Table 1 were mixed for 24 hours using a ball-mill. Then, the mixed ceramic filler was mixed with the silica hybrid sol and then stirred with a ball-mill for 6 hours. Next, the prepared liquid ceramic composition was applied to an aluminum substrate (Al) and a steel sheet (Fe) by a spray coating method and then cured to form a ceramic coating film. Curing treatment was performed by, for example, drying at room temperature for 24 hours. Finally, a high heat resistance coating film according to an embodiment of the present invention was prepared by removing impurities remaining on the substrate surface.

Figure 2 is a result of observing the surface after performing a pencil hardness test for the coating film formed on the aluminum alloy (Al) and the iron alloy (Fe) according to an embodiment of the present invention. Table 2 shows the pencil hardness test results of each specimen. AZS-1 (F) and ZB (F) were the flame tests performed on the coating films of AZS-1 and ZB.

In FIG. 2, (a) is the result observed by performing a pencil hardness test on the coating film corresponding to Sample 1 (AZS-1), and (b) is the result after performing a flame test on the same coating film. Figure 2 (c) is the pencil hardness test observation result of the coating film corresponding to Sample 2 (ZB), (d) is the result after performing a flame test for the same coating film. Referring to this, it can be confirmed that peeling or destruction of the coating film does not occur after the flame test as before the flame test.

Figures 2 (e), (f) and (g) are the results of performing a pencil hardness test using the filler of sample 5 having the same composition as Figure 2 (c). However, in (c) of FIG. 2, the ceramic filler and the silica hybrid sol were stirred together with a ball-mill for 24 hours, and in the case of (e) of FIG. 2, the ceramic powder constituting the ceramic filler at room temperature was first stirred with a ball-mill for 24 hours. After mixing the mixed ceramic filler and the silica hybrid sol, ball-mill stirring was performed for 6 hours, and FIG. There is a difference in that it was performed for 3 hours. 2 and Table 2, ZB-3 (RT) indicates room temperature curing, ZB-3 (100) curing at 100 ° C. for 3 hours, and ZB-3 (150) curing at 150 ° C. for 3 hours. Referring to this, it can be confirmed that the coating film was formed well under all conditions.

Table 2 summarizes the pencil strength test results for the same specimen as the specimen in FIG.

Sample No.# Substrate 1D 7D 14D 21D 28D AZS-1 Al X 9H 9H 9H 9H Fe X 5H 5H 6H 7H AZS-1(F) Al 9H 9H 9H 9H 9H Fe 9H 9H 9H 9H 9H ZB Al 8H 9H 9H 9H 9H Fe 8H 8H 8H 9H 9H ZB(F) Al 8H 9H 9H 9H 9H Fe 9H 9H 9H 9H 9H ZB-3(R.T) Al 9H 9H 9H 9H 9H Fe 9H 9H 9H 9H 9H ZB-3(100) Al 9H 9H 9H 9H 9H Fe 8H 9H 9H 9H 9H ZB-3(150) Al 9H 9H 9H 9H 9H Fe 9H 9H 9H 9H 9H

Referring to Table 2, the steel sheet (Fe) of Sample ZB shows a pencil hardness value of 8H until the elapsed time is 14 days, but the steel sheet (Fe) of ZB-3 (R.T) of the present invention is hardened 1 It represents the value from 9H to 9H. This difference is the ball-mill difference. Sample ZB was stirred with a ball-mill for 24 hours with a ceramic filler and inorganic nano-sol, and ZB-3 of the present invention was stirred with a ball-mill for 24 hours with a ceramic filler and then mixed with inorganic nano-sol and stirred with a ball-mill for 6 hours. There is a difference in that it was done. This is because the steel sheet (Fe) of ZB exhibits gelation of inorganic nanosols and has poor properties. In order to prevent the above phenomenon, ZB-3 of the present invention reduced the stirring time of the inorganic nanosol to 6 hours to prevent gelation.

)으로 기판위의 도막의 경도를 측정하는 것으로 수치가 클수록 도막의 경도가 높다는 것을 의미한다. Fe는 철 기판(강판)으로 경도가 높기 때문에 Hv비커스 경도로 측정하였고 Al 기판일 경우 기판경도가 낮게 때문에 HB브리넬 경도로 측정하였다. 표 2 및 표 3의 D는 경화시간(Day)을 의미하며 표 3에서 (RT)는 경화온도가 상온경화, (100)은 100℃ 3시간 경화, (150)은 150℃ 3시간 경화한 것을 나타낸다. ZB-1시편에서 기판이 Fe(강판)일 경우 상온 경화보다 100℃ 또는 150℃로 경화온도가 높고 경화시간이 21일로 증가할수록 높은 경도를 나타내었다. 3 is a view showing indentation traces after each hardness test using a Leeb hardness tester for the same specimen as the specimen in Table 3 at 2x magnification. The Leeb hardness test is a value expressed by dividing the recoil speed by the impact speed (

) to measure the hardness of the coating film on the substrate, and the higher the number, the higher the hardness of the coating film. Fe was measured by Hv Vickers hardness because the iron substrate (steel plate) has high hardness, and in the case of Al substrate, because the substrate hardness was low, it was measured by HB Brinell hardness. D in Tables 2 and 3 means curing time (Day), and in Table 3, (RT) is room temperature curing, (100) is curing at 100 ° C for 3 hours, and (150) is curing at 150 ° C for 3 hours. indicate In the ZB-1 specimen, when the substrate was Fe (steel plate), the curing temperature was higher at 100 ° C or 150 ° C than normal temperature curing and the hardness increased as the curing time increased to 21 days.

Figure 4 shows the Leeb hardness over time and the change in curing temperature of specimens according to an embodiment of the present invention, that is, ZB-1 to ZB-5 according to Table 3. 4 (a) is the HB hardness of the room temperature Al substrate, (b) is the Hv hardness of the room temperature Fe substrate, (c) is the HB hardness of the 100 ° C substrate, (d) is the Hv hardness of the 100 ° C substrate, (e) is the Hv hardness of the 150 ° C substrate HB hardness, (f) shows the measured value of the Hv hardness of the substrate at 150 ° C.

7D 14D 21D AZS-1 Al(HB) 124.6 144.8 Fe(Hv) 116.4 115.2 AZS-1(F) Al(HB) 82.8 98.4 100.8 Fe(Hv) 97.6 98.6 105.6 ZB Al(HB) 128.2 133.4 Fe(Hv) 111.4 151.8 ZB(F) Al(HB) 85 83 88.6 Fe(Hv) 128 125.8 125.2 ZB-1(R.T) Al(HB) 123 125.8 129.2 Fe(Hv) 130.4 157.6 162.6 ZB-1(100) Al(HB) 119.2 123.8 124.6 Fe(Hv) 148.2 159.8 163.8 ZB-1(150) Al(HB) 119.8 120.2 123 Fe(Hv) 150.6 159.6 159.6 ZB-2(R.T) Al(HB) 110.2 112.2 123.6 Fe(Hv) 107.6 118 136.8 ZB-2(100) Al(HB) 116.2 112 110.6 Fe(Hv) 131.2 139.2 161.8 ZB-2(150) Al(HB) 116.2 117.6 115.6 Fe(Hv) 126.6 128.2 159 ZB-3(R.T) Al(HB) 128.2 128.8 127 Fe(Hv) less than 80 104.8 119.4 ZB-3(100) Al(HB) 99 122.2 128 Fe(Hv) 167.8 162.4 168.4 ZB-3(150) Al(HB) 120.6 125.2 128.8 Fe(Hv) 142 152 160.4 ZB-4(R.T) Al(HB) 114.2 115.2 115.8 Fe(Hv) 84 105 115.2 ZB-4(100) Al(HB) 121 125.6 128.2 Fe(Hv) 143 148 157.4 ZB-4(150) Al(HB) 117.8 122.4 124.4 Fe(Hv) 143.4 154.8 161 ZB-5(R.T) Al(HB) 79.2 80.8 88.8 Fe(Hv) 119.2 143.2 147.6 ZB-5(100) Al(HB) 112.2 120.6 119.6 Fe(Hv) 141 145.8 144.8 ZB-5(150) Al(HB) 116 119.6 120.6 Fe(Hv) 148.6 147.4 150.2

5 is a result of observing before and after a flame test according to compositional changes of an aluminum alloy (Al) and an iron alloy disc (Fe) according to an embodiment of the present invention. In FIG. 5 (a) is an aluminum alloy substrate. (Al) and iron alloy disc (Fe) before and after the flame test. In the case of Al, it started to melt after the 600℃ flame test and the board itself was broken. In the case of Fe, cracks occurred after the 950 ° C flame test. On the other hand, referring to (c) of FIG. 5, in the case of Al and Fe having a ceramic coating, no melting or crack formation occurred. Also, peeling of the coating film did not occur.

Table 4 summarizes the cross cut test results for the same specimen as the specimen in FIG. 4. The adhesive strength test is the area that is attached to the tape when the tape is adhered to the coating film and then removed, converted into %. At the bottom of Table 4, the criteria for classification, which is the evaluation standard for adhesive strength, are shown. The adhesion between the substrate and the coating film is classified as follows. The amount of removal that comes off by attaching the tape to the surface drawn with a knife is classified into 0 to 5 stages. 0 is 0% removal, 1 is less than 5%, 2 is 5 to 15%, 3 is 15 to 35%, 4 is 35 to 65%, and 5 is 65% or more, and the lower the number, the higher the adhesion. As a result of the test, it can be seen that the AZS-1(Al) or ZB(Al) samples fall into the 3rd category, and the ZB-3(Al) falls under the 2nd category regardless of the curing temperature and shows excellent adhesion strength.

% of Area Removed Classification AZS-1 Al 17.5 (±0.168) 3 Fe 15.7 (±0.415) 3 ZB Al 19.8 (±0.553) 3 Fe 12.0 (±0.090) 2 ZB-3(R.T) Al 12.7 (±0.753) 2 Fe 11.8 (±0.146) 2 ZB-3(100) Al 5.4 (±0.180) 2 Fe 15.8 (±0.154) 3 ZB-3(150) Al 6.6 (±0.154) 2 Fe 16.9 (±1.152) 3

(0: 0% removal, 1: less than 5%, 2: 5 to 15%, 3: 15 to 35%, 4: 35 to 65%, 5: 65% or more)

Referring to Table 4, it can be confirmed that all specimens exhibit excellent adhesive strength of Classification 2 to 3 or less.

6 to 10 are the results of observing before and after the flame test for the change in Fe ₃ O ₄ content for the same composition of aluminum alloy (Al) and iron alloy disc (Fe) according to an embodiment of the present invention.

In FIG. 6, based on the liquid ceramic filler, ZB-1 has an Fe ₃ O ₄ content of 0 wt%, ZB-2 in FIG. 7 has an Fe ₃ O ₄ content of 10 wt%, and ZB-3 in FIG. ₃ O ₄ content 16.67% by weight, ZB _{-4 in FIG. 9 corresponds to 23.33% by weight Fe 3 O 4 content , and} ZB-5 in FIG. The Fe ₃ O ₄ content corresponds to 0, 30, 50, 70, and 100% by weight. Only the Fe ₃ O ₄ content was changed, and the contents of other materials were the same. The Fe ₃ O ₄ content composition range is preferably 20 to 60% by weight based on the content of the ceramic filler, and most preferably 50% by weight. This corresponds to 6.67 to 20% by weight of the Fe ₃ O ₄ content in the total weight% of the liquid ceramic filler.

Table 5 summarizes the results of the flame test according to the change in the Fe ₃ O ₄ filler content for the same specimens as the specimens of FIGS. 6 to 10. In ZB-1 or ZB-5, peeling or cracking of the iron steel sheet (Fe) was observed, and ZB-3 of the present invention showed excellent high heat resistance in aluminum alloy (Al) or iron steel sheet (Fe). can

Sample psalm name Al(600℃) Fe(950℃) 3 ZB-1(R.T) O X 3 ZB-1(100) O X 3 ZB-1(150) O X 4 ZB-2(R.T) O O 4 ZB-2(100) O O 4 ZB-2(150) O O 5 ZB-3(R.T) O O 5 ZB-3(100) O O 5 ZB-3(150) O O 6 ZB-4(R.T) X △ 6 ZB-4(100) X △ 6 ZB-4(150) X △ 7 ZB-5(R.T) O X 7 ZB-5(100) O X 7 ZB-5(150) X X

O: good △: generally good

X: melt, oxidize, crack, fracture

Figure 11 (a) is the result of observing the surface after performing the heat resistance test according to the Fe ₃ O ₄ content change for the aluminum alloy (Al) and the iron alloy disc (Fe) according to an embodiment of the present invention, Figure 11 (b) is the result of observing before and after the heat resistance test when the disk and Fe ₃ O ₄ are added to the titanium alloy (Ti) according to an embodiment of the present invention.

Referring to FIG. 11 (a), in ZB-1, ZB-4 and ZB-5, peeling or cracking of the iron steel sheet (Fe) and aluminum alloy (Al) appeared, whereas in ZB-2 and ZB-3, more Preferably, it can be seen that ZB-3 of the present invention exhibits excellent high heat resistance in iron steel sheet (Fe) and aluminum alloy (Al). Likewise, referring to FIG. 11 (b), it can be confirmed that even on a titanium alloy (Ti) substrate, the ZB-3 of the present invention exhibits excellent high heat resistance compared to a disc in which cracks occur.

12 is a state in which only inorganic nanosols are coated on an aluminum alloy (Al) and an iron steel sheet (Fe).

12 shows a phenomenon in which corrosion occurs when only the inorganic nano-sol is coated on the steel sheet (Fe). Iron steel sheet (Fe) generally reacts with water (H ₂ O) or an oxidizing agent such as oxygen to cause corrosion as shown in the formula below.

When Fe ₃ O ₄ , which is a pigment, is added to suppress the occurrence of corrosion, an oxidation-preventing reaction that adjusts the Fe ²⁺ /Fe ³⁺ ratio by redox potential occurs. OH ^- hydrolyzed by water and oxygen meets Fe ₃ O ₄ to produce FeOOH.

Corrosion can be prevented through a condensation reaction between FeOOH and silanol generated through the above reaction.

In addition, a grafting bond (MO-Si) is formed during the curing process of the heat-resistant oxides, thereby improving adhesion to the substrate. Through the above reaction, the browning phenomenon occurring in the steel sheet in which Fe ₃ O ₄ was not added could be prevented by adding Fe ₃ O ₄ .

13(a) shows a state in which corrosion of an iron steel sheet (Fe) is prevented by adding iron oxide (Fe ₃ O ₄ ) to a ceramic filler according to an embodiment of the present invention, and FIG. 13(b) shows this According to another embodiment of the present invention, water-repellent coating is performed to prevent corrosion of the iron steel sheet (Fe).

Referring to FIG. 13(a), iron steel sheet (Fe) and ZB-1 coated with only inorganic nanosol without Fe ₃ O ₄ were observed to be corroded through an electron microscope (I-CAMSCOPE) at 600 magnification. On the other hand, it can be confirmed that the other samples ZB-2, ZB-3, ZB-4, and ZB-5 to which Fe ₃ O ₄ was added showed much less corrosion. In particular, the ZB-3 sample according to one embodiment of the present invention maintained a particularly smooth surface with almost no corrosion, and even with reference to FIG. Almost no corrosion phenomenon was observed in the additionally formed ZB-3 sample as well.

<Example 2> Formation of an additional water-repellent coating film using a water-repellent solution

In the method for manufacturing a highly heat-resistant coating film according to another embodiment of the present invention, after the curing step of the method for manufacturing a high heat-resistant coating film according to an embodiment of the present invention, a water repellent solution is applied on the ceramic coating film on which the above-described curing treatment has been completed. A water-repellent coating may be further included.

The above-mentioned water repellent solution is at least selected from the group consisting of hexadecyltrimethoxysilane (HDTMS), methyltriethoxysilane (MTES), phenyl triethoxysilane (PhTES), diethoxy (3-glycidyloxypropyl) methylsilane (GPTMS), tetraethylorthosilicate (TEOS), and octal triethoxysilane (OTES). Any one silane solution may be included.

The water-repellent solution can be prepared by dispersing the above-described silane solution in distilled water and alcohol. More specifically, the composition of the water repellent solution is 10 to 30% by weight of a TEOS (tetraethyl orthosilicate) solution, HDTMS (hexadecyl trimethoxysilane), GPTMS (3-glycidyloxypropyl methoxysilane) and 70 to 90% by weight of a diluent selected from distilled water or alcohol. For example, it can be prepared by mixing TEOS (tetraethyl orthosilicate), HDTMS (hexadecyl trimethoxysilane) and GPTMS (3-glycidyloxypropyl methoxysilane) with alcohol, and then stirring and dispersing at room temperature (25 ° C. for 14 hours).

Thereafter, a water-repellent coating film was formed through a curing treatment in which the above-described water-repellent solution was applied on the coating film prepared according to an embodiment of the present invention and then dried. As a method of applying the water repellent solution, one or more of brush coating, spin coating, spray coating, and dip coating may be used. The thickness of the above-described water-repellent coating film may be, for example, 0.5 to 3 μm.

The curing treatment was performed by drying at a temperature range of 80° C. to 130° C. for 0.1 hour to 3 hours, more preferably at a temperature range of 100° C. to 120° C. for 0.5 hour to 2 hours.

Finally, by removing impurities remaining on the surface of the substrate, a high heat resistance coating film according to another embodiment of the present invention can be manufactured.

<Experimental example>

Table 6 summarizes the acid/moisture/flame resistance test results performed on the high heat resistance coating film according to another embodiment of the present invention including aluminum alloy (Al), iron steel sheet (Fe) or titanium alloy (Ti) as a substrate. there is. Each of the ZB-3 samples listed in Table 6 was prepared by additionally performing water-repellent coating according to the manufacturing method of a high heat resistance coating film according to another embodiment of the present invention on the ZB-3 sample according to one embodiment of the present invention. In addition, ZB-3 (RT) means curing at room temperature, ZB-3 (100) curing at 100 ° C for 3 hours, and ZB-3 (150) curing at 150 ° C for 3 hours.

The oxidation resistance test of the high heat resistance coating film according to another embodiment of the present invention was carried out by supporting it in 5% sulfuric acid (H ₂ SO ₄ ) for 24 hours.

The high temperature/moisture resistance test of the high heat resistance coating film according to another embodiment of the present invention was conducted in a constant temperature/humidity chamber at 85°C/85%RH for 100 hours.

The salt water test of the high heat resistance coating film according to another embodiment of the present invention was carried out by supporting it in 5% NaCl for 100 hours.

As shown in Table 6, it can be confirmed that the high heat resistance coating film according to another embodiment of the present invention has excellent acid resistance/moisture resistance/salt resistance under all temperature conditions in which the experiment was performed.

Sample 5% H2SO4 (24hr) 5% NaCl (100hr) 85℃/85%RH (100hr) ZB-3 (RT)
Hydrophobic coating Al O O O Fe O O O Ti O O O ZB-3(100)
Hydrophobic coating Al O O O Fe O O O ZB-3(150)
Hydrophobic coating Al O O O Fe O O O

O: good

Claims (31)

(a) 10 to 50 wt % of a ceramic filler including triiron tetroxide (Fe ₃ O ₄ ), barium titanate (BaTiO ₃ ) and zirconia (ZrO ₂ ) powders, 10 to 30 wt % of a diluent, and 20 to 80 wt % of an inorganic nanosol preparing a liquid ceramic filler by mixing %;
(b) applying the liquid ceramic filler to at least one surface of a substrate; and
(c) preparing a coating film by subjecting the substrate to a curing treatment for drying; Method for producing a high heat resistance coating film comprising a. delete According to claim 1,
The trioxide (Fe ₃ O ₄ ) content is 20 to 60% by weight based on the ceramic filler content,
A method for producing a high heat resistance coating film. According to claim 3,
The triiron tetroxide (Fe ₃ O ₄ ) content is 30 to 50% by weight based on the ceramic filler content,
A method for producing a high heat resistance coating film. According to claim 1,
In step (a),
Mixing the ceramic filler, diluent, and inorganic nanosol at the same time, or adding and mixing the inorganic nanosol to a solution in which the ceramic filler and diluent are mixed,
A method for producing a high heat resistance coating film. delete According to claim 1,
The ceramic filler,
Having a particle size of 500 to 1500 nm,
A method for producing a high heat resistance coating film. According to claim 1,
The liquid ceramic filler is mixed by a ball mill process,
A method for producing a high heat resistance coating film. According to claim 1,
The diluent is distilled water or alcohol,
A method for producing a high heat resistance coating film. According to claim 9,
The alcohol is IPA or n-butanol,
A method for producing a high heat resistance coating film. According to claim 1,
The inorganic nano-sol is a silica sol or a silica-hybrid sol,
A method for producing a high heat resistance coating film. According to claim 1,
In step (b),
Performed by any one method selected from the group consisting of brush coating, spin coating, spray coating and dip coating,
A method for producing a high heat resistance coating film. According to claim 1,
The inorganic nanosol is obtained by adding a solvent to alkoxy silane and stirring, and the alkoxy silane is methyltrimethoxysilane, methyltrichlorosilane, ethyltrimethoxysilane, ethyl trie Ethyltriethoxysilane, phenyltrimethoxysilane, phenyltrichlorosilane, phenylaminopropyltrimethoxysilane, octyltrimethoxysilane, octyltrichlorosilane , octadecyltrimethoxysilane, octadecyltrichlorosilane, propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltriethoxysilane ), isobutyltrimethoxysilane, vinyltriethyloxysilane, vinyltrimethoxysilane, and allyltrimethoxysilane. Any one selected from the group consisting of,
A method for producing a high heat resistance coating film. According to claim 1,
Step (c) is carried out for 2 to 24 hours at a temperature range of 20 ° C to 200 ° C,
A method for producing a high heat resistance coating film. According to claim 1,
After step (c),
(d) removing impurities remaining on the surface of the substrate; further comprising,
A method for producing a high heat resistance coating film. According to claim 1,
The substrate is formed of aluminum, steel plate, titanium, copper or stainless alloy material,
A method for producing a high heat resistance coating film. According to claim 1,
(b) further comprising the step of surface treating the substrate before step,
A method for producing a high heat resistance coating film. According to claim 1,
After step (c),
(d') preparing a water-repellent solution by dispersing the silane solution in a diluent;
(e) applying the water repellent solution to at least one surface of the curing-treated coating film; and
(f) preparing a water-repellent coating film by subjecting the coating film to which the water-repellent solution is applied to a curing treatment to dry it;
A method for producing a high heat resistance coating film. According to claim 18,
The water repellent solution is prepared by mixing 10 to 30% by weight of the silane solution and 70 to 90% by weight of the diluent,
A method for producing a high heat resistance coating film. According to claim 18,
The silane solution,
hexadecyltrimethoxysilane (HDTMS), methyltriethoxysilane (MTES), phenyl triethoxysilane (PhTES), diethoxy (3-glycidyloxypropyl) methylsilane (GPTMS), tetraethylorthosilicate (TEOS), and octal triethoxysilane (OTES) Including any one selected from the group consisting of,
A method for producing a high heat resistance coating film. According to claim 18,
The diluent is distilled water or alcohol,
A method for producing a high heat resistance coating film. According to claim 18,
In step (e),
Performed by any one method selected from the group consisting of brush coating, spin coating, spray coating and dip coating,
A method for producing a high heat resistance coating film. According to claim 18,
The step (f) is carried out for 0.1 to 3 hours at a temperature range of 80 ℃ to 130 ℃,
A method for producing a high heat resistance coating film. According to claim 18,
After step (f),
(g) removing impurities remaining on the surface; further comprising,
A method for producing a high heat resistance coating film. It is prepared by any one of claims 1, 3 to 5, and 7 to 17,
Formed on at least one surface of the substrate, comprising triiron tetroxide (Fe ₃ O ₄ ), barium titanate (BaTiO ₃ ) and zirconia (ZrO ₂ ) powder,
High heat resistance coating film. 26. The method of claim 25,
The heat resistance temperature of the coating film is 900 ℃ to 1000 ℃,
High heat resistance coating film. 26. The method of claim 25,
The thickness of the coating film is 15 to 100㎛,
High heat resistance coating film. 26. The method of claim 25,
The average particle size of the coating film is 500 to 1500 nm,
High heat resistance coating film. 26. The method of claim 25,
The substrate is made of aluminum, steel plate, titanium, copper or stainless alloy material,
High heat resistance coating film. It is prepared by any one of claims 18 to 24,
a coating film formed on at least one surface of the substrate and containing triiron tetroxide (Fe ₃ O ₄ ), barium titanate (BaTiO ₃ ), and zirconia (ZrO ₂ ) powder; and
A water-repellent coating film formed on at least one surface of the coating film and containing a silane compound;
High heat resistance coating film. 31. The method of claim 30,
The thickness of the water-repellent coating film is 0.5 to 3 μm,
High heat resistance coating film.

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