High-temperature-resistant, wear-resistant and corrosion-resistant coating material for inner wall of rotary kiln and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant, wear-resistant and corrosion-resistant coating material for the inner wall of a rotary kiln and a preparation method of the coating material. The coating material is prepared from modified polysilazane resin, nano ceramic, chromic oxide powder, chopped fibers, a thickening agent and a curing agent. The modified polysilazane resin is prepared by blending the functionalized graphene and the polysilazane resin; the functionalized graphene is prepared by reacting modified siloxane with graphene oxide; the modified siloxane has a structure as shown in a formula A in the specification. The polysilazane resin with excellent high-temperature resistance and the functionalized graphene with excellent corrosion resistance and wear resistance are blended and modified to prepare the modified polysilazane resin as a functional component, so that the prepared ceramic coating has excellent wear resistance and high-temperature resistance; and the composite material has excellent binding force and corrosion resistance, and can be widely applied to the fields of lithium batteries and rotary kilns. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the technical field of ceramic coating materials, and in particular to a high-temperature-resistant, wear-resistant, and corrosion-resistant coating material for the inner wall of a rotary kiln and a preparation method thereof. Background Art

[0002] my country's coatings industry has a long history, and its production and consumption are both in the world's leading position. It has broad development prospects and is gradually becoming a new growth point for the national economy. Since the 1990s, some units and enterprises engaged in coating production and research and development in my country have begun to focus on using sol-gel technology to develop inorganic / organic composite coatings, nano-superconducting powder materials, high-temperature corrosion-resistant coatings, etc. Ceramic coatings are also one of them.

[0003] There is no strict definition of ceramic coatings. Generally speaking, any coating that has ceramic-like properties after curing, especially high hardness and high wear resistance, can be called ceramic coatings. According to the film-forming resin, there are three main types of common ceramic coatings: inorganic ceramic coatings, epoxy ceramic coatings, and silicone ceramic coatings. Inorganic ceramic coatings are made from inorganic binders such as aluminum dihydrogen phosphate, potassium silicate, and feldspar, and can be used to protect carbon steel, stainless steel, and various alloy substrates.

[0004] Ceramic materials are widely used due to their water resistance and corrosion resistance. In the lithium battery production chain, ceramic materials also play an important role. In the lithium battery industry, ceramic materials can be used as electrode, diaphragm materials, packaging materials, and can also be used as auxiliary materials in the production process. For example, ceramic coatings are used to repair and protect the inner wall surface of large equipment and rotary kilns in the lithium battery industry.

[0005] However, faced with the rapid development of the lithium battery industry and rotary kiln equipment, the ceramic materials in the existing technology can no longer meet the production needs of industry manufacturers. On the one hand, the serious wear and tear on the surface of the equipment will greatly delay production efficiency. On the other hand, the lithium battery industry equipment and rotary kilns are easily damaged in high temperature environments for a long time, which will increase the production costs of enterprises.

[0006] Polysilazane resin is an inorganic polymer with silicon-nitrogen bonds as repeating units in the main chain of the molecule. The side chain contains Si-H active groups. It can self-cure in moisture at room temperature or cure quickly by high-temperature baking. After high-temperature baking at 400-500℃, the coating can be ceramicized to form a Si-N\Si-O ceramic coating, and the high-temperature resistance is increased to above 1500℃.

[0007] Polysilazane resins are widely used in aerospace, electronics, nuclear power, shipbuilding, chemical industry, automobile and other fields due to their excellent performance. However, for environments that require both high temperature resistance and wear and corrosion resistance, polysilazane resin coatings alone cannot fully meet the requirements.

[0008] Therefore, there is an urgent need for a high-temperature, wear-resistant and corrosion-resistant coating material for the inner wall of a rotary kiln that has both excellent high-temperature resistance and excellent wear and corrosion resistance. Summary of the invention

[0009] Purpose of the invention: In view of the defects of the prior art, the purpose of the present invention is to provide a high-temperature, wear-resistant and corrosion-resistant coating material for the inner wall of a rotary kiln with excellent wear resistance, high-temperature resistance and corrosion resistance and a preparation method thereof.

[0010] Technical solution: A high temperature, wear and corrosion resistant coating material for the inner wall of a rotary kiln, comprising modified polysilazane resin, nano-ceramics, chromium oxide powder, chopped fibers, a thickener and a curing agent; The modified polysilazane resin is prepared by blending functionalized graphene with polysilazane resin; The functionalized graphene is prepared by reacting modified siloxane with graphene oxide; The modified siloxane has a structure as shown in the following formula A: .

[0011] Furthermore, the modified siloxane is prepared by the following steps: in a reactor, bis(3-trimethoxysilylpropyl)-N-methylamine, 5-bromo-1-pentanol and a solvent are added, stirred and mixed evenly, heated to 80-90° C. under nitrogen protection, kept warm for 6-8 hours, removed the solvent, and obtained the modified siloxane after recrystallization.

[0012] Furthermore, the mass ratio of the bis(3-trimethoxysilylpropyl)-N-methylamine to 5-bromo-1-pentanol is 1.5-2:1.

[0013] Furthermore, the modified polysilazane resin is prepared by the following steps: (1) ultrasonically dispersing graphene oxide in N,N-dimethylformamide to obtain a graphene dispersion; (2) Add graphene dispersion and modified siloxane into the reactor, add hydrazine hydrate after ultrasonic treatment for 0.5-1 hour, stir evenly and transfer to the reactor; (3) heating the reactor to 100-110° C. and reacting for 2-3 hours, then filtering, washing, and drying to obtain functionalized graphene; (4) Add functionalized graphene and polysilazane resin into a reactor, heat to 70-80° C., mix well, add silane coupling agent, heat to 120-130° C., keep warm for 2-3 hours, and cool to obtain the modified polysilazane resin.

[0014] Furthermore, the silane coupling agent is selected from one of KH560 and KH550.

[0015] Furthermore, the mass ratio of the graphene oxide to the modified siloxane is 1:1.5-2; the mass ratio of the functionalized graphene to the polysilazane resin is 1:5-7.

[0016] Furthermore, the chopped fibers are selected from at least one of chopped quartz fibers, carbon fibers, silicon carbide fibers, and alumina fibers with a length of 1-5 mm; the thickener is fumed silica; the curing agent is selected from at least one of diethylenetriamine, ethylenediamine, hexamethylenediamine, triethylenetetramine, diethylaminopropylamine, polyetheramine, and isophoronediamine; and the nanoceramics are selected from one of alumina, silicon oxide, zirconium oxide, silicon carbide, boron carbide, tungsten carbide, titanium carbide, silicon nitride, or boron nitride.

[0017] Furthermore, based on the total mass fraction being 100%, the mass percentage of each component is: Modified polysilazane resin 30-35% Chromium oxide powder 3-5% Short-cut fiber 5-10% Thickener 3-5% Curing agent 1.5-2% The balance is nano-ceramics.

[0018] The method for preparing any of the above-mentioned high-temperature, wear-resistant and corrosion-resistant coating materials for the inner wall of a rotary kiln comprises the following steps: in a reactor, adding modified polysilazane resin, nano-ceramics, chromium oxide powder and chopped fibers in proportion, stirring for 20-30 minutes at 3500-5000 r / min and 45-65°C and then cooling, adding a thickener and a curing agent, and stirring evenly to obtain the high-temperature, wear-resistant and corrosion-resistant coating material for the inner wall of the rotary kiln.

[0019] Application of any of the above-mentioned high temperature resistant, wear resistant and corrosion resistant coating materials for the inner wall of a rotary kiln in the field of lithium batteries and rotary kilns.

[0020] Beneficial effects: (1) The high temperature resistant, wear resistant and corrosion resistant coating material for the inner wall of a rotary kiln provided by the present invention comprises a modified polysilazane resin, nano-ceramics, chromium oxide powder, chopped fibers, a thickener and a curing agent. The modified polysilazane resin is prepared by blending and modifying a polysilazane resin having excellent high temperature resistance with a functionalized graphene having excellent corrosion resistance and wear resistance to form a modified polysilazane resin as a functional component. The prepared ceramic coating has excellent wear resistance and high temperature resistance, as well as excellent bonding strength and corrosion resistance, and can be widely used in the fields of lithium batteries and rotary kilns.

[0021] (2) In the high temperature resistant, wear resistant and corrosion resistant coating material for the inner wall of the rotary kiln provided by the present invention, the modified polysilazane resin is prepared by blending and modifying the functionalized graphene and the polysilazane resin under the action of a silane coupling agent. The polysilazane resin with excellent high temperature resistance is modified based on the functionalized graphene with a high specific surface area. This can not only effectively improve the mechanical properties of the polysilazane resin such as Young's modulus, strength and toughness, but also its excellent chemical stability can significantly improve its corrosion resistance and further enhance its high temperature resistance, thereby improving the high temperature resistance and mechanical properties of the ceramic coating after curing.

[0022] (3) In the high temperature, wear-resistant and corrosion-resistant coating material for the inner wall of the rotary kiln provided by the present invention, the Si-H active groups of the polysilazane resin and the oxygen-containing groups on the surface of the functionalized graphene are effectively grafted onto the surface of the polysilazane resin under the action of the silane coupling agent, thereby realizing the chemical modification of the polysilazane resin by the functionalized graphene, and the performance of both can be exerted effectively and durably.

[0023] (4) In the high temperature resistant, wear resistant and corrosion resistant coating material for the inner wall of the rotary kiln provided by the present invention, the modified siloxane has a multi-branched silicon oxygen structure and a quaternary ammonium structure. On the one hand, it can improve the repellency and dispersibility between graphene oxides, thereby avoiding the agglomeration of graphene oxide and affecting the material properties; on the other hand, after the material is cured, a network structure can be formed through the mutual cross-linking of siloxanes and evenly distributed in the coating structure, which can significantly improve the wear resistance and corrosion resistance of the ceramic coating.

[0024] (5) The high temperature, wear-resistant and corrosion-resistant coating material for the inner wall of the rotary kiln provided by the present invention is made into an epoxy ceramic coating by modified polysilazane resin, nano-ceramics, chromium oxide powder, chopped fibers and curing components. It can have excellent bonding ability with the substrate by high temperature baking and curing during use, and the formed coating has excellent mechanical properties, wear resistance and high temperature resistance. DETAILED DESCRIPTION

[0025] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0026] Polysilazane resin was purchased from Hubei Xinyuhong Biomedical Technology Co., Ltd.; nanoceramics were titanium carbide powder purchased from Hebei Ruihuang Metal Materials Co., Ltd.; chromium oxide powder was ceramic chromium oxide purchased from Nangong Jiuxin New Materials Technology Co., Ltd.; commercially available ceramic coatings were epoxy ceramic anti-corrosion coatings purchased from Dacheng County Chongyou Construction Engineering Co., Ltd.; and the remaining reagents and equipment were conventional reagents and equipment in this technical field.

[0027] Preparation of modified siloxane The modified siloxane was prepared by the following steps: In a reactor, 3 g of bis(3-trimethoxysilylpropyl)-N-methylamine, 2 g of 5-bromo-1-pentanol and 50 mL of N,N-dimethylformamide were added, and the mixture was stirred and mixed evenly. Under nitrogen protection, the temperature was raised to 80° C. and kept for reaction for 6 hours, and then the solvent was removed and the modified siloxane was obtained after recrystallization; Mass spectrometry data of modified siloxane: The product was analyzed by LC-MS, and the m / z of the product was 442.27 (100.0%), 443.31 (31.9%), 444.28 (11.7%), and 445.30 (2.3%).

[0028] Preparation of modified polysilazane resin-1 The modified polysilazane resin-1 was prepared by the following steps: (1) Ultrasonic dispersion of 0.1 g of graphene oxide in 100 mL of N,N-dimethylformamide to prepare a graphene dispersion; (2) Add the graphene dispersion prepared in step (1) and 0.2 g of modified siloxane into the reactor, add 1.5 mL of hydrazine hydrate after ultrasonic treatment for 1 hour, stir evenly and transfer to the reactor; (3) heating the reactor to 100°C for 2 hours, filtering, washing, and drying to obtain functionalized graphene; (4) In a reactor, 0.5 g of functionalized graphene and 3 g of polysilazane resin were added, heated to 70° C. and mixed evenly, and then 0.1 g of KH560 was added. The temperature was raised to 120° C. and kept for reaction for 3 hours, and then cooled to obtain the modified polysilazane resin.

[0029] Preparation of modified polysilazane resin-2 The preparation method is basically the same as that of modified polysilazane resin-1, except that steps (1) to (3) are not performed, and in step (4), the functionalized graphene is replaced by an equal amount of graphene oxide.

[0030] Preparation of modified polysilazane resin-3 The preparation method is basically the same as that of modified polysilazane resin-1, except that the modified siloxane in step (2) is replaced by an equal amount of hydroxymethyltriethoxysilane.

[0031] Example 1 The high temperature, wear-resistant and corrosion-resistant coating material for the inner wall of the rotary kiln is prepared by the following steps: In the reactor, modified polysilazane resin-1, zirconium oxide, chromium oxide powder and chopped quartz fiber are added in proportion, stirred at 4000 r / min and 60° C. for 30 minutes and then cooled, fumed silica and diethylenetriamine are added, and stirred evenly to obtain the high-temperature, wear-resistant and corrosion-resistant coating material for the inner wall of the rotary kiln.

[0032] Taking the total mass fraction as 100%, the mass percentage of each component is: Modified polysilazane resin-1 35% Chromium oxide powder 5% Chopped quartz fiber 5% Fumed silica 3% Diethylenetriamine 2% The balance is zirconium oxide.

[0033] Example 2 The same as Example 1, except that, based on the total mass fraction being 100%, the components and their mass percentages are as follows: Modified polysilazane resin-1 30% Chromium oxide powder 3% Silicon carbide fiber 8% Fumed silica 5% Ethylenediamine 2% The balance is silicon carbide.

[0034] Example 3 The same as Example 1, except that, based on the total mass fraction being 100%, the components and their mass percentages are as follows: Modified polysilazane resin-1 35% Chromium oxide powder 4% Alumina fiber 10% Fumed silica 4% Triethylenetetramine 1.5% The balance is alumina.

[0035] Comparative Example 1 Commercially available ceramic coatings.

[0036] Comparative Example 2 The process is basically the same as Example 1, except that the modified polysilazane resin-1 is replaced by an equal amount of polysilazane resin.

[0037] Comparative Example 3 The process is basically the same as Example 1, except that the modified polysilazane resin-1 is replaced by an equal amount of modified polysilazane resin-2.

[0038] Comparative Example 4 The process is basically the same as Example 1, except that the modified polysilazane resin-1 is replaced by an equal amount of modified polysilazane resin-3.

[0039] Performance Testing The products of Examples 1-3 and Comparative Examples 1-4 were coated on the surface of the substrate respectively, and then baked and cured at 450° C. to form ceramic coatings of the same specifications.

[0040] Hardness test: The hardness of the coatings obtained in the above-mentioned Examples 1-3 and Comparative Examples 1-4 was tested by a Shore hardness tester.

[0041] Corrosion resistance test: According to GB / T 1771-1991, Determination of neutral salt spray resistance of paints and varnishes, the neutral salt spray resistance time of the coatings prepared in Examples 1-3 and Comparative Examples 1-4 was tested.

[0042] High temperature resistance test: the materials of the coatings prepared in the above Examples 1-3 and Comparative Examples 1-4 were placed in a resistance furnace and burned at 1200° C., and the time when bulging, cracking or peeling of the coatings appeared was recorded; The materials of the coatings prepared in the above Examples 1-3 and Comparative Examples 1-4 were respectively placed in a resistance furnace and burned at 1000° C., and the temperature was increased at 10° C. / min, and the temperature at which bulging, cracking or peeling of the coatings occurred was recorded.

[0043] Wear resistance test: The coatings prepared in the above Examples 1-3 and Comparative Examples 1-4 were tested for wear resistance at room temperature using an abrasion tester (test conditions: grinding wheel CS-10, load force 500 g, 500 cycles), and the wear amount of the coatings was recorded respectively.

[0044] The test results are shown in the following table: According to the comparison of the test results of Examples 1-3 with those of Comparative Example 1, the high-temperature, wear-resistant and corrosion-resistant coating material for the inner wall of the rotary kiln provided by the present invention has better mechanical strength and high-temperature resistance than the coating made of ceramic coating in the prior art, and has strong wear resistance and corrosion resistance, and can be widely used in the fields of lithium batteries and rotary kilns.

[0045] According to the comparison of the test results of Examples 1-3 and Comparative Examples 2-4, it can be seen that by adding functionalized graphene-modified polysilazane resin to the high-temperature resistant, wear-resistant and corrosion-resistant coating material for the inner wall of the rotary kiln provided by the present invention, the mechanical strength and high-temperature resistance of the coating can be further improved, and the corrosion resistance and wear resistance of the coating can be significantly improved.

[0046] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A high temperature, wear-resistant and corrosion-resistant coating material for the inner wall of a rotary kiln, characterized in that: It contains modified polysilazane resin, nano-ceramics, chromium oxide powder, chopped fibers, thickener and curing agent; The modified polysilazane resin is prepared by blending functionalized graphene with polysilazane resin; The functionalized graphene is prepared by reacting modified siloxane with graphene oxide; The modified siloxane has a structure as shown in the following formula A: 。 2. The high temperature, wear and corrosion resistant coating material for the inner wall of a rotary kiln according to claim 1, characterized in that: The modified siloxane is prepared by the following steps: adding bis(3-trimethoxysilylpropyl)-N-methylamine, 5-bromo-1-pentanol and a solvent into a reactor, stirring and mixing them uniformly, heating to 80-90° C. under nitrogen protection and keeping the temperature for 6-8 hours, removing the solvent, and obtaining the modified siloxane after recrystallization.

3. The high temperature, wear and corrosion resistant coating material for the inner wall of a rotary kiln according to claim 2, characterized in that: The mass ratio of the bis(3-trimethoxysilylpropyl)-N-methylamine to 5-bromo-1-pentanol is 1.5-2:

1.

4. The high temperature, wear and corrosion resistant coating material for the inner wall of a rotary kiln according to claim 1, characterized in that: The modified polysilazane resin is prepared by the following steps: (1) ultrasonically dispersing graphene oxide in N,N-dimethylformamide to obtain a graphene dispersion; (2) Add graphene dispersion and modified siloxane into the reactor, add hydrazine hydrate after ultrasonic treatment for 0.5-1 hour, stir evenly and transfer to the reactor; (3) heating the reactor to 100-110° C. for 2-3 hours, filtering, washing, and drying to obtain functionalized graphene; (4) Add functionalized graphene and polysilazane resin into a reactor, heat to 70-80° C., mix well, add silane coupling agent, heat to 120-130° C., keep warm for 2-3 hours, and cool to obtain the modified polysilazane resin.

5. The high temperature, wear and corrosion resistant coating material for the inner wall of a rotary kiln according to claim 4, characterized in that: The silane coupling agent is selected from one of KH560 and KH550.

6. The high temperature, wear and corrosion resistant coating material for the inner wall of a rotary kiln according to claim 4, characterized in that: The mass ratio of the graphene oxide to the modified siloxane is 1:1.5-2; the mass ratio of the functionalized graphene to the polysilazane resin is 1:5-7.

7. The high temperature, wear and corrosion resistant coating material for the inner wall of a rotary kiln according to claim 1, characterized in that: The chopped fibers are selected from at least one of chopped quartz fibers, carbon fibers, silicon carbide fibers, and alumina fibers with a length of 1-5 mm; the thickener is fumed silica; the curing agent is selected from at least one of diethylenetriamine, ethylenediamine, hexamethylenediamine, triethylenetetramine, diethylaminopropylamine, polyetheramine, and isophoronediamine; and the nanoceramics are selected from one of alumina, silicon oxide, zirconium oxide, silicon carbide, boron carbide, tungsten carbide, titanium carbide, silicon nitride, or boron nitride.

8. The high temperature, wear and corrosion resistant coating material for the inner wall of a rotary kiln according to claim 1, characterized in that: Taking the total mass fraction as 100%, the mass percentage of each component is: Modified polysilazane resin 30-35% Chromium oxide powder 3-5% Short-cut fiber 5-10% Thickener 3-5% Curing agent 1.5-2% The balance is nano-ceramics.

9. The method for preparing the high temperature resistant, wear resistant and corrosion resistant coating material for the inner wall of a rotary kiln according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: adding modified polysilazane resin, nano-ceramics, chromium oxide powder and chopped fibers in proportion into a reactor, stirring for 20-30 minutes at 3500-5000 r / min and 45-65° C., cooling, adding a thickener and a curing agent, and stirring evenly to obtain the high-temperature, wear-resistant and corrosion-resistant coating material for the inner wall of the rotary kiln.

10. Application of the high temperature resistant, wear resistant and corrosion resistant coating material for the inner wall of a rotary kiln according to any one of claims 1 to 8 in the field of lithium batteries and rotary kilns.

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