A high-temperature resistant inorganic coating material, its preparation method and application

Abstract

This invention discloses a high-temperature resistant inorganic coating material, its preparation method, and its application. The raw materials for preparing the high-temperature resistant inorganic coating material include the following components by weight: 30-35 parts modified potassium silicate resin, 10-15 parts sodium silicate, up to 15 parts silica sol, 1-40 parts flake alumina, 1-10 parts flake chromium oxide, 2-50 parts glass powder, 1-15 parts water, and 0.5-1.0 parts anti-settling agent; wherein the modified potassium silicate resin is a potassium silicate resin modified with lithium silicate and magnesium silicate. The high-temperature resistant inorganic coating provided by this invention has a simple preparation process, can be cured at room temperature, and exhibits excellent chemical stability, high-temperature resistance, and gas barrier properties.

Description

Technical Field

[0001] This invention belongs to the field of coating protection technology, specifically relating to a high-temperature resistant inorganic coating material, its preparation method, and its application. Background Technology

[0002] Chambers constructed from surrounding rock and concrete are one of the main forms of protective engineering. They must not only possess excellent mechanical properties but also have high gas-tightness capabilities. However, the surrounding rock and retaining walls contain macroscopic and microscopic cracks and pores. Therefore, effective measures are needed to improve the gas-tightness of the chamber structure and enhance the safety, reliability, and environmental comfort of the protective engineering.

[0003] Applying coatings to surface-treat and seal potential gas leakage channels within chambers can improve the gas sealing capability of engineering structures at a lower cost and with less engineering effort. While organic polymer sealing materials can seal gas permeation channels and improve the sealing performance of chamber structures, their durability is low, and they are prone to decomposition at temperatures above 200°C, leading to a decrease in sealing performance. The gases produced by decomposition can also reduce the safety and comfort of the chamber environment. Compared to organic sealing materials, inorganic coating materials have better temperature resistance, durability, and weather resistance, and can effectively prevent gas permeation through engineering cracks and pores for a long time, thus improving the gas sealing capability of engineering structures and providing technical support for the sealing safety of engineering structures. However, inorganic coating preparation technology has the following drawbacks, such as the limited application of self-propagating high-temperature synthesis technology, which is only suitable for large-scale, rapid production of pipeline protective coatings. Thermal spraying is the most common method for depositing inorganic coatings in industrial production. It is efficient, flexible, and easy to automate, but its high process requirements, low utilization rate of spraying materials, and serious dust pollution limit its widespread application in engineering environments. Although the development of sol-gel technology and vapor deposition technology has greatly reduced coating cracks and improved coating performance, their complex preparation process and high cost have limited their application.

[0004] Therefore, with the increasing demands for protective engineering, the currently used organic airtight coating materials are insufficient to meet engineering requirements in terms of durability, heat resistance (≥1000℃), and sealing performance. There is a need to develop coatings for chamber sealing. In particular, these coatings must meet the following requirements: simple and easy-to-operate preparation process to meet low cost; strong adaptability to construction operations, not limited by site or environmental conditions to meet low-security requirements; and minimal pollutant generation and disturbance to the substrate during coating preparation to meet high safety requirements. Summary of the Invention

[0005] The main objective of this invention is to provide a high-temperature resistant inorganic coating material, its preparation method, and its application, so as to overcome the shortcomings of the prior art.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0007] This invention provides a high-temperature resistant inorganic coating material. The raw materials for preparing the high-temperature resistant inorganic coating material include the following components calculated by weight: 30-35 parts modified potassium silicate resin, 10-15 parts sodium silicate, less than 15 parts silica sol, 140 parts flake alumina, 1-10 parts flake chromium oxide, 2-50 parts glass powder, 1-15 parts water, and 0.5-1.0 parts anti-settling agent; wherein the modified potassium silicate resin is a potassium silicate resin modified with lithium silicate and magnesium silicate.

[0008] This invention also provides a method for preparing the aforementioned high-temperature resistant inorganic coating material, comprising:

[0009] Modified potassium silicate resin was prepared by modifying potassium silicate with lithium silicate.

[0010] Sodium silicate, water and the modified potassium silicate resin are mixed, and then flake alumina, flake chromium oxide, glass powder, anti-settling agent and silica sol are added and ultrasonically stirred to obtain a coating composition.

[0011] The coating composition is uniformly applied to the surface of a concrete substrate and then cured to form the high-temperature resistant inorganic coating material.

[0012] This invention also provides a high-temperature resistant inorganic coating, which is prepared by the aforementioned method.

[0013] The embodiments of the present invention also provide the use of the aforementioned high-temperature resistant inorganic coating material or high-temperature resistant inorganic coating in chamber sealing.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] (1) The high-temperature resistant inorganic coating in this invention has the advantages of being water-based and environmentally friendly, having good thermal stability and excellent gas barrier properties;

[0016] (2) The high-temperature resistant inorganic coating in this invention is mainly composed of lithium silicate and magnesium silicate modified potassium silicate (which can improve the water resistance of the coating after film formation compared with ordinary potassium silicate) and compounded with sodium silicate to form the film-forming material; among them, the silicate resin contains a large number of silicon oxidation chemical bonds, which can form a cross-linked spatial network structure after being compounded with silica sol, forming a dense protective coating on the concrete surface. At the same time, the flake-shaped alumina and chromium oxide are interspersed in the cross-linked spatial network structure, further improving the density of the coating;

[0017] (3) The high-temperature resistant inorganic coating of the present invention has stable chemical properties and good high-temperature resistance;

[0018] (4) The high-temperature resistant inorganic coating of the present invention can be prepared at room temperature;

[0019] (5) The high-temperature resistant inorganic coating of the present invention has a thermal weight loss of <2wt% at 1000℃ and can withstand high temperature of 1500℃ for a long time (continuous resistance to 1500℃ for ≥240h); it has better thermal stability than the domestic competitor Youlian (Ningxia) Technology Co., Ltd.'s AEY coating (AEY coating has a thermal weight loss of 8.9wt% at 900℃) and stronger adhesion to concrete (adhesion to concrete is grade 0, while the adhesion of AEY coating to concrete is grade 1).

[0020] (6) The air permeability index of the high temperature resistant inorganic coating of the present invention is zero. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the curing mechanism of the coating in a typical embodiment of the present invention;

[0023] Figure 2 This is a picture of the coating in Comparative Example 1 of the present invention;

[0024] Figure 3 This is a picture of the coating in Comparative Example 2 of the present invention;

[0025] Figure 4 These are images of the coating in Comparative Example 5 of the present invention;

[0026] Figures 5a-5f This is a test diagram of the coating's adhesion, impact resistance, and flexibility in a typical embodiment of the present invention.

[0027] Figures 6a-6b These are photos of pull-out adhesion tests of the coating on carbon steel and concrete in a typical embodiment of the present invention.

[0028] Figure 7 This is an XRD pattern showing the phase composition change of the silicate coating after high-temperature testing in a typical embodiment of the present invention.

[0029] Figures 8a-8d This is a surface morphology image of the coating after undergoing a high-temperature test at 400°C in a typical embodiment of the present invention;

[0030] Figures 9a-9d This is a surface morphology image of the coating after undergoing a high-temperature test at 600°C in a typical embodiment of the present invention;

[0031] Figures 10a-10d This is a surface morphology diagram of the coating after undergoing a high-temperature test at 1000℃ in a typical embodiment of the present invention;

[0032] Figure 11 This is a graph showing the thermogravimetric changes of the coating in a typical embodiment of the present invention within the temperature range of 0-1000℃;

[0033] Figure 12 This is a graph showing the thermogravimetric changes of the high-temperature resistant filler in a typical embodiment of the present invention within the range of 0-1000℃. Detailed Implementation

[0034] In view of the deficiencies of the prior art, the inventors of this case, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] Specifically, as one aspect of the technical solution of this invention, the raw materials for preparing a high-temperature resistant inorganic coating material include the following components calculated by weight: 30-35 parts modified potassium silicate resin, 10-15 parts sodium silicate, less than 15 parts silica sol, 1-40 parts flake alumina, 1-10 parts flake chromium oxide, 2-50 parts glass powder, 1-15 parts water, and 0.5-1.0 parts anti-settling agent; wherein the modified potassium silicate resin is a potassium silicate resin modified with lithium silicate and magnesium silicate.

[0036] Furthermore, the fraction of the silica sol is 0.

[0037] In some preferred embodiments, the raw materials of the high-temperature resistant inorganic coating material include the following components calculated by weight: 35 parts modified potassium silicate resin, 15 parts sodium silicate, 0-1 parts silica sol, 35 parts flake alumina, 1 part flake chromium oxide, 14 parts glass powder, 5 parts deionized water, and 0.5 parts anti-settling agent, wherein the number of parts of silica sol is not 0.

[0038] In some preferred embodiments, the mass ratio (i.e. pigment-to-binder ratio) of filler to base material in the raw materials of the high-temperature resistant inorganic coating material is 0.9:1 to 1.2:1; wherein the filler includes flake alumina, flake chromium oxide and glass powder, and the base material includes modified potassium silicate resin and sodium silicate.

[0039] Furthermore, the mass ratio of filler to base material in the raw materials of the high-temperature resistant inorganic coating material is 1:1.

[0040] In some preferred embodiments, the volume ratio of filler to the sum of filler and base material in the raw materials of the high-temperature resistant inorganic coating material is 50:100 to 60:100, wherein the filler includes flake alumina, flake chromium oxide and glass powder, and the base material includes modified potassium silicate resin and sodium silicate.

[0041] Furthermore, the volume ratio of filler to the sum of filler and matrix in the raw materials of the high-temperature resistant inorganic coating material is 55:100.

[0042] In some preferred embodiments, the solid content in the raw materials of the high-temperature resistant inorganic coating material is 70-75 wt%.

[0043] Furthermore, the solid content in the raw materials of the high-temperature resistant inorganic coating material is 75 wt%.

[0044] In some preferred embodiments, the method for preparing the modified potassium silicate resin includes: mixing lithium silicate and magnesium silicate with potassium silicate resin at room temperature, and stirring at 500-1000 r / min to form a uniform and stable dispersion, thereby obtaining the modified potassium silicate resin.

[0045] Furthermore, the mass ratio of lithium silicate, magnesium silicate and potassium silicate resin is 2-5:1-2:30-50.

[0046] In some preferred embodiments, the alumina flakes have a purity of 99 wt% or higher, a flake diameter of 20–50 μm, and a thickness of 3–10 nm.

[0047] In some preferred embodiments, the chromium oxide flakes have a purity of 99 wt% or higher, a flake diameter of 10–20 μm, and a thickness of 3–20 nm.

[0048] In some preferred embodiments, the glass powder has a particle size of 10–50 μm.

[0049] In some preferred embodiments, the silica sol includes alkaline silica sol and / or neutral silica sol.

[0050] In some preferred embodiments, the anti-settling agent comprises fumed silica and / or bentonite.

[0051] Another aspect of the present invention provides a method for preparing the aforementioned high-temperature resistant inorganic coating material, comprising:

[0052] Modified potassium silicate resin was prepared by modifying potassium silicate with lithium silicate.

[0053] Sodium silicate, water and the modified potassium silicate resin are mixed, and then flake alumina, flake chromium oxide, glass powder, anti-settling agent and silica sol are added and ultrasonically stirred to obtain a coating composition.

[0054] The coating composition is uniformly applied to the surface of a concrete substrate and then cured to form the high-temperature resistant inorganic coating material.

[0055] In some preferred embodiments, the curing temperature is 5–40°C.

[0056] Another aspect of the present invention provides a high-temperature resistant inorganic coating, which is prepared by the aforementioned preparation method.

[0057] In some preferred embodiments, the high-temperature resistant inorganic coating exhibits a thermal weight loss of <2wt% at 1000°C.

[0058] In some more specific embodiments, the method for preparing the high-temperature resistant inorganic coating includes:

[0059] First, sodium silicate and deionized water are added to a potassium silicate resin modified with lithium silicate and magnesium silicate (solid content 50%; compared with ordinary potassium silicate, it can improve the water resistance of the coating after film formation), and stirred at 200 r / min for 5 min to obtain a colorless and transparent solution; then alumina, chromium oxide and glass powder are added in sequence, and the mixture is stirred at high speed to obtain a viscous flowing liquid; finally, an anti-settling agent and silica sol are added, and ultrasonic stirring is performed to obtain a high-temperature resistant inorganic coating; the obtained inorganic silicate coating is applied to a concrete substrate by compressed air spraying, brushing or rolling to obtain a fully cured coating.

[0060] Through multiple parallel experiments, the coating can be cured at room temperature (5–40℃). The surface drying time of the coating on concrete substrate is 2 hours, and the complete drying time is 16–24 hours (temperature 25℃, humidity RH 70%). Furthermore, the curing time can be shortened by baking the coating at 80℃ for 60 minutes after spraying.

[0061] This invention addresses the sealing requirements of chambers constructed from surrounding rock and concrete. It utilizes lithium silicate and magnesium silicate-modified potassium silicate as the main film-forming materials, combined with sodium silicate and high-temperature resistant, antioxidant fillers. Through polymerization-condensation reactions, the spatial structure of Si-O-Si molecular groups is regulated and reorganized to develop a high-temperature resistant inorganic coating (such as...). Figure 1 As shown in the figure, the coating process and film-forming properties of inorganic coatings were studied, providing technical support for improving the gas sealing capability of the chamber structure and enhancing the safety, reliability and environmental comfort of the protective engineering.

[0062] Another aspect of the present invention provides the use of the aforementioned high-temperature resistant inorganic coating material or high-temperature resistant inorganic coating in chamber sealing.

[0063] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0064] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0065] Example 1

[0066] A high-temperature resistant inorganic coating material comprises the following components by weight: 35 parts modified potassium silicate resin, 15 parts sodium silicate, 0.5 parts silica sol, 30 parts flake alumina, 5 parts flake chromium oxide, 14 parts glass powder, 5 parts deionized water, and 0.5 parts anti-settling agent (bentonite), with a pigment-to-binder ratio of 1:1; wherein the filler includes flake alumina, flake chromium oxide, and glass powder, and the base material includes modified potassium silicate resin and sodium silicate.

[0067] A method for preparing a high-temperature resistant inorganic coating includes the following steps:

[0068] First, sodium silicate and deionized water were added to a lithium silicate and magnesium silicate modified potassium silicate resin (solid content 50%; compared with ordinary potassium silicate, it can improve the water resistance of the coating after film formation), and stirred at 200 r / min for 5 min to obtain a colorless and transparent solution; then alumina, chromium oxide and glass powder were added in sequence, and stirred at high speed to mix evenly to obtain a viscous flowing liquid; finally, an anti-settling agent and silica sol were added, and ultrasonic stirring was performed to obtain a high-temperature resistant inorganic coating; the obtained inorganic silicate coating was applied to a concrete substrate by compressed air spraying, brushing or rolling to obtain a fully cured coating; the properties of the coating are shown in Table 1.

[0069] The coating can be cured at room temperature (5-40℃). The surface drying time of the coating on concrete substrate is 2 hours, and the actual drying time is 16-24 hours (temperature 25℃, humidity RH 70%).

[0070] Comparative Example 1

[0071] The method is the same as in Example 1, except that the pigment-to-binder ratio is 1.3:1, meaning the raw materials for the high-temperature resistant inorganic coating material include the following components by weight: 35 parts modified potassium silicate resin, 15 parts sodium silicate, 0.5 parts silica sol, 5 parts flake alumina, 1 part flake chromium oxide, 31.5 parts glass powder, 11.5 parts deionized water, and 0.5 parts anti-settling agent (bentonite). The coating properties are shown in Table 1.

[0072] Comparative Example 2

[0073] The method is the same as in Example 1, except that the pigment-to-binder ratio is 0.8:1, meaning the raw materials for the high-temperature resistant inorganic coating material include the following components by weight: 30 parts modified potassium silicate resin, 10 parts sodium silicate, 0.5 parts silica sol, 5 parts flake alumina, 1 part flake chromium oxide, 43 parts glass powder, 10 parts deionized water, and 0.5 parts anti-settling agent (bentonite). The coating properties are shown in Table 1.

[0074] Table 1. Basic properties of coatings with different pigment-to-binder ratios in Example 1 and Comparative Examples 1-2

[0075]

[0076] Table 1 shows that when the pigment-to-binder ratio is 1.3:1, the coating exhibits poor impact resistance, an adhesion grade of 2, and cannot form a continuous film. Figure 2 As shown; when the pigment-to-binder ratio is reduced to 0.8:1, the prepared coating has a long surface drying time and poor anti-sagging properties, such as... Figure 3 As shown. Therefore, a pigment-to-binder ratio of 1:1 is preferred.

[0077] Comparative Example 3

[0078] The method is the same as in Example 1, except that the filler volume concentration is 40%, meaning the raw materials for the high-temperature resistant inorganic coating material include the following components by weight: 35 parts modified potassium silicate resin, 10 parts sodium silicate, 1 part silica sol, 6 parts flake alumina, 1 part flake chromium oxide, 31.5 parts glass powder, 15 parts deionized water, and 0.5 parts anti-settling agent (bentonite). The coating properties are shown in Table 2.

[0079] Comparative Example 4

[0080] The method is the same as in Example 1, except that the filler volume concentration is 65%, meaning the raw materials for the high-temperature resistant inorganic coating material include the following components by weight: 35 parts modified potassium silicate resin, 15 parts sodium silicate, 1 part silica sol, 10 parts flake alumina, 1 part flake chromium oxide, 32.5 parts glass powder, 5 parts deionized water, and 0.5 parts anti-settling agent (bentonite). The coating properties are shown in Table 2.

[0081] Table 2. Basic properties of coatings with different pigment-to-binder ratios in Example 1 and Comparative Examples 3-4

[0082]

[0083]

[0084] The filler volume concentration (PVC) of a coating is calculated as: Powder volume / (Powder volume + Resin volume). PVC significantly affects the performance of the dry film. The PVC value characterizes the coating coverage and basic properties. In experiments, a PVC content of 65% resulted in poor water resistance, while a PVC content of 40% prevented continuous film formation. Therefore, a PVC content of 55% is preferred.

[0085] Comparative Example 5

[0086] The method is the same as in Example 1, except that the solid content is 60%, meaning the raw materials for the high-temperature resistant inorganic coating material include the following components by weight: 35 parts modified potassium silicate resin, 15 parts sodium silicate, 1 part silica sol, 3 parts flake alumina, 3 parts flake chromium oxide, 38.5 parts glass powder, 4 parts deionized water, and 0.5 parts anti-settling agent (bentonite). The coating properties are shown in Table 3.

[0087] Comparative Example 6

[0088] The method is the same as in Example 1, except that the solid content is 80%, that is, the raw materials of the high-temperature resistant inorganic coating material include the following components by weight: 35 parts modified potassium silicate resin, 15 parts sodium silicate, 1 part silica sol, 4 parts flake alumina, 2 parts flake chromium oxide, 41.5 parts glass powder, 1 part deionized water, and 0.5 parts anti-settling agent (bentonite). The properties of the coating are shown in Table 3.

[0089] Table 3. Basic properties of coatings with different pigment-to-binder ratios in Example 1 and Comparative Examples 5-6

[0090]

[0091] The solids content of a coating is related not only to the product price but also to its film-forming performance. By adjusting the type of filler and the resin content, it was found that when the solids content was 80%, all the basic indicators of the coating were good, but the cost of inorganic silicates was relatively high (approximately 52 yuan / kg); when the solids content of the coating was adjusted to 60% (cost approximately 48.2 yuan / kg), the surface drying time was long and the film-forming properties were poor. Figure 4 As shown, a slight orange peel effect appears on the surface. Therefore, the preferred solids content of the coating is 75%.

[0092] Test example:

[0093] I. Adhesion Test

[0094] The high-temperature resistant inorganic coating from Example 1 was applied to a concrete substrate, and the coating showed good film-forming properties. After curing at room temperature (approximately 25°C), the effect of different coating thicknesses on the curing performance was investigated. It was found that when the coating thickness was between 50 and 100 μm, the surface drying time was 60 minutes and the actual drying time was 24 hours. When the coating thickness was ≥100 μm, the surface drying time was 60 minutes, but the actual drying time was prolonged; a dry film thickness of 400 μm required 48 hours for complete curing. When the coating thickness was ≥600 μm, microcracks appeared. Therefore, it is recommended that the coating thickness be controlled within 400 μm.

[0095] Because concrete substrates have poor toughness, tinplate is used as a substrate for evaluating the impact resistance, flexibility, and adhesion of inorganic silicate coatings. Figures 5a-5f As shown. According to the test results, the basic properties of the coating are: cross-cut adhesion grade 0-1, impact resistance 50cm, and flexibility 2mm.

[0096] The pull-out adhesion of the coating on concrete and carbon steel was tested using a PosiTest AT-M Adhesion Tester. The results showed that the pull-out adhesion on carbon steel reached 5.24 MPa, and the pull-out adhesion on concrete reached 4.64 MPa. The test results are as follows: Figures 6a-6b As shown in the figure, five pull-out adhesion tests were conducted on concrete, with results of 2.52 MPa, 2.33 MPa, 3.65 MPa, 4.87 MPa, and 4.64 MPa, respectively. The results revealed that the pull-out adhesion of the coating was related to the material of the concrete substrate: some silicate coating had penetrated into the concrete substrate. During the pull-out process, due to the good bonding between the spindle and the coating and the cracking of the concrete substrate, the adhesion of the inorganic silicate coating was low. This indicates that the substrate condition must be considered when testing and evaluating the adhesion of inorganic silicate coatings on concrete. Therefore, the cross-cut adhesion test was used for adhesion testing. Figures 6a-6b Meanwhile, the coating was subjected to a cross-cut adhesion test, and the results showed that the cross-cut adhesion was grade 0.

[0097] II. Temperature resistance and gas barrier performance test

[0098] (1) Coating temperature resistance test

[0099] The silicate coating was tested for high temperature resistance at 400℃, 600℃ and 1000℃. Figure 7 The XRD pattern of the silicate coating after high-temperature testing is shown. After high-temperature testing at 400℃, 600℃ and 1000℃, the phase composition of the silicate coating remained consistent, mainly composed of alumina filler and silicate, without significant changes. This indicates that the coating has good stability at high temperatures and excellent high-temperature resistance.

[0100] After high-temperature testing, the surface morphology of the coating was observed using SEM, such as... Figures 8a-8d , Figures 9a-9d and Figures 10a-10d As shown, the silicate coating remained dense and intact after high-temperature tests at 400℃, 600℃, and 1000℃, without the formation of any visible defects.

[0101] The elemental changes of silicate coatings after high-temperature testing were tested using EDS. Three points were measured for each sample at different temperatures, and the average value was taken. The results are shown in Table 4. The study found that the elemental composition of the silicate coating did not change significantly during heating. The oxygen content continuously increased from 62.34% at room temperature to 66.64% at 1000℃; the contents of aluminum, potassium, and silicon decreased slowly, while sodium remained relatively unchanged. This may be because during the high-temperature testing, the coating was in a high-temperature oxidizing environment, where oxygen diffused more easily into the filler within the coating film, thus increasing the oxygen content and decreasing the contents of other elements. The potassium silicate and aluminum oxide components in the coating film remained generally unchanged; only the chemical valence states of elements such as Si, K, and Al slightly increased due to the entry of oxygen.

[0102] Table 4. Element content and changes (wt%) of the coating after high-temperature testing

[0103]

[0104]

[0105] The thermogravimetric analysis (TGA) of the inorganic silicate coating was performed using differential scanning calorimetry (DSC). The changes in coating mass were as follows: Figure 11 As shown, the mass loss of silicate coatings initially decreases and then increases with increasing ambient temperature. At 500℃, the thermal weight loss is approximately 2%, while at 1000℃, the total weight of the coating increases, possibly due to the formation of some metal oxides.

[0106] To investigate the reason for the increase in the quality of the silicate coating after 500℃, the high-temperature resistant filler (mainly composed of alumina) was subjected to thermogravimetric analysis (TGA) alone. The test results are as follows: Figure 12 As shown, the thermal weight loss of the high-temperature filler is basically consistent with the trend of the inorganic silicate coating, indicating that the main reason for the weight gain of the coating after 500℃ is the alumina powder. The alumina powder contains some elemental aluminum, which undergoes an oxidation reaction at high temperature to form alumina. This experimental result is consistent with Table 4 (the oxygen content in the coating gradually increases after 1000℃), indicating that the high-temperature weight gain of the silicate coating comes from oxygen.

[0107] Therefore, based on the above weight loss test results, the inorganic phase content of the inorganic silicate coating is 98%.

[0108] (2) Coating gas barrier performance test

[0109] The gas barrier properties of the coating were tested using an Autoclam tester. First, the coating was applied to a cement board measuring 150mm × 70mm × 3mm, with a coating thickness of 400 micrometers. The gas permeability test was then initiated. Nitrogen gas at a pressure greater than 500 mbar (1 mbar = 100 Pa) was rapidly injected into the Autoclam tester through a syringe via a catheter. The pressure was recorded every minute for 6–15 minutes. The test automatically ended after 15 minutes. The measured gas permeability index of the coating was zero, indicating that the coating effectively sealed the pores of the concrete.

[0110] Comparative Example 7

[0111] The method is the same as in Example 1, except that the flake alumina and flake chromium oxide are replaced with granular alumina and chromium oxide. The prepared coating has a weight loss of 3.5 wt% at 600°C and is air-barrier: impermeable.

[0112] Comparative Example 8

[0113] The method is the same as in Example 1, except that the lithium silicate and magnesium silicate modified potassium silicate resin in Example 1 is replaced with potassium silicate resin; the prepared coating has a weight loss of 2.8 wt% at 600℃, gas barrier properties: impermeable; water resistance: 25h.

[0114] Comparative Example 9

[0115] The method is the same as in Example 1, except that the lithium silicate and magnesium silicate modified potassium silicate resin in Example 1 is replaced with lithium silicate modified potassium silicate resin; the prepared coating has a weight loss of 1.8 wt% at 800℃, gas barrier properties: air impermeable; water resistance is 40h.

[0116] Example 2

[0117] A high-temperature resistant inorganic coating material comprises the following components by weight: 30 parts modified potassium silicate resin, 10 parts sodium silicate, 15 parts silica sol, 40 parts flake alumina, 10 parts flake chromium oxide, 50 parts glass powder, 15 parts deionized water, and 1.0 part anti-settling agent (bentonite). The filler includes flake alumina, flake chromium oxide, and glass powder, and the base material includes modified potassium silicate resin and sodium silicate.

[0118] First, sodium silicate and deionized water were added to a lithium silicate and magnesium silicate modified potassium silicate resin (solid content 50%; compared with ordinary potassium silicate, it can improve the water resistance of the coating after film formation), and stirred at 200 r / min for 5 min to obtain a colorless and transparent solution; then alumina, chromium oxide and glass powder were added in sequence, and stirred at high speed to mix evenly to obtain a viscous flowing liquid; finally, an anti-settling agent and silica sol were added, and ultrasonic stirring was performed to obtain a high-temperature resistant inorganic coating; the obtained inorganic silicate coating was applied to a concrete substrate by compressed air spraying, brushing or rolling to obtain a fully cured coating; the properties of the coating are shown in Table 1.

[0119] The coating can cure at room temperature (5–40°C). The surface drying time of the coating on concrete substrate is 2 hours, and the complete drying time is 16–24 hours (temperature 25°C, humidity RH 70%). Tests have shown that the coating exhibits excellent stability, high temperature resistance, and gas barrier properties.

[0120] Example 3

[0121] A high-temperature resistant inorganic coating material comprises the following components by weight: 33 parts modified potassium silicate resin, 13 parts sodium silicate, 5 parts silica sol, 1 part flake alumina, 1 part flake chromium oxide, 2 parts glass powder, 1 part deionized water, and 0.8 parts anti-settling agent (bentonite); wherein the filler includes flake alumina, flake chromium oxide, and glass powder, and the base material includes modified potassium silicate resin and sodium silicate.

[0122] First, sodium silicate and deionized water were added to a lithium silicate and magnesium silicate modified potassium silicate resin (solid content 50%; compared with ordinary potassium silicate, it can improve the water resistance of the coating after film formation), and stirred at 200 r / min for 5 min to obtain a colorless and transparent solution; then alumina, chromium oxide and glass powder were added in sequence, and stirred at high speed to mix evenly to obtain a viscous flowing liquid; finally, an anti-settling agent and silica sol were added, and ultrasonic stirring was performed to obtain a high-temperature resistant inorganic coating; the obtained inorganic silicate coating was applied to a concrete substrate by compressed air spraying, brushing or rolling to obtain a fully cured coating; the properties of the coating are shown in Table 1.

[0123] The coating can cure at room temperature (5–40°C). The surface drying time of the coating on concrete substrate is 2 hours, and the complete drying time is 16–24 hours (temperature 25°C, humidity RH 70%). Tests have shown that the coating exhibits excellent stability, high temperature resistance, and gas barrier properties.

[0124] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0125] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A high temperature resistant inorganic coating material, characterized by, The raw material of the high-temperature-resistant inorganic coating material comprises the following components in parts by weight: 30-35 parts of modified potassium silicate resin, 10-15 parts of sodium silicate, less than 15 parts of silica sol, 1-40 parts of flaky alumina, 1-10 parts of flaky chromium oxide, 2-50 parts of glass powder, 1-15 parts of water, and 0.5-1.0 parts of anti-settling agent; wherein the modified potassium silicate resin is potassium silicate resin modified by lithium silicate and magnesium silicate. The mass ratio of the filler to the base material in the raw material of the high-temperature-resistant inorganic coating material is 0.9:1-1.2:1, the volume ratio of the filler to the sum of the filler and the base material in the raw material of the high-temperature-resistant inorganic coating material is 50:100-60:100, the filler comprises flaky alumina, flaky chromium oxide and glass powder, and the base material comprises modified potassium silicate resin and sodium silicate. The solid content in the raw material of the high-temperature-resistant inorganic coating material is 70-75 wt%.

2. The high temperature resistant inorganic coating material of claim 1, wherein: The mass ratio of the filler to the base material in the raw material of the high-temperature-resistant inorganic coating material is 1:

1. The volume ratio of the filler to the sum of the filler and the base material in the raw material of the high-temperature-resistant inorganic coating material is 55:

100. The solid content in the raw material of the high-temperature-resistant inorganic coating material is 75 wt%.

3. The high temperature resistant inorganic coating material of claim 1, wherein, The preparation method of the modified potassium silicate resin comprises: mixing lithium silicate and magnesium silicate with potassium silicate resin at room temperature, and stirring at 500-1000 r / min to form a uniform and stable dispersion liquid, thereby obtaining the modified potassium silicate resin. The mass ratio of the lithium silicate, the magnesium silicate and the potassium silicate resin is 2-5:1-2:30-50.

4. The high temperature resistant inorganic coating material of claim 1, wherein: The purity of the flaky alumina is above 99 wt%, the flaky diameter is 20-50 μm, and the thickness is 3-10 nm. The purity of the flaky chromium oxide is above 99 wt%, the flaky diameter is 10-20 μm, and the thickness is 3-20 nm. The particle size of the glass powder is 10-50 μm.

5. The high temperature resistant inorganic coating material of claim 1, wherein: The silica sol comprises alkaline silica sol and / or neutral silica sol, and the anti-settling agent comprises fumed silica and / or bentonite.

6. The method of producing the high-temperature-resistant inorganic coating material according to any one of claims 1 to 5, characterized by, The preparation method comprises: The modified potassium silicate resin is prepared by modifying potassium silicate with lithium silicate and magnesium silicate. The sodium silicate, water and the modified potassium silicate resin are mixed, and then the flaky alumina, the flaky chromium oxide, the glass powder, the anti-settling agent and the silica sol are added and ultrasonically stirred and mixed to obtain a coating composition. The coating composition is uniformly coated on the surface of a concrete substrate, and is subjected to a curing treatment to form the high-temperature-resistant inorganic coating material.

7. The method of claim 6, wherein: The temperature of the curing treatment is 5-40 ℃.

8. A high temperature resistant inorganic coating, characterized in that, The high-temperature-resistant inorganic coating is prepared by the preparation method of any one of claims 6-7.

9. The high temperature resistant inorganic coating of claim 8, wherein: The thermal weight loss of the high-temperature-resistant inorganic coating is less than 2 wt% at 1000 ℃.

10. Use of the high-temperature-resistant inorganic coating material of any one of claims 1-5 or the high-temperature-resistant inorganic coating of any one of claims 8-9 in a chamber seal.

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