A method for preparing thermally sprayed chromium oxide composite ceramic powder

Abstract

The present invention discloses a method for preparing a thermally sprayed chromium oxide composite ceramic powder. The chromium oxide composite ceramic powder is composed of the following components, by weight: 400-750 kg of chromium oxide, 250-600 kg of titanium oxide, and 2-4.0% of the raw material weight in a neutral silica sol. The present invention uses silica sol as a silicon oxide source and a granulation binder, and produces a Cr2O3-5%SiO2-3%TiO2 composite powder through spray granulation and high-temperature sintering. The original particle size of silicon oxide in the silica sol is 14 nanometers, which can be effectively adsorbed and evenly coated on the surfaces of chromium oxide and titanium oxide, reducing the sintering temperature, lowering the coating porosity, and significantly improving the hardness and toughness. During the plasma spraying process, the reaction between chromium oxide and oxygen is effectively isolated to produce hexavalent chromium.

Description

Technical Field

[0001] The present invention belongs to the field of thermal spraying technology and material processing, and more specifically, relates to a method for preparing thermally sprayed chromium oxide composite ceramic powder. Background Art

[0002] With the further development of modern industrial technology, material performance and functional requirements are facing increasingly stringent challenges. As a key carrier of material properties and functions, the modification and protection of material surfaces using thermal spray technology has become a key development direction attracting much attention in today's equipment manufacturing field. Faced with increasingly complex wear and corrosion-resistant operating conditions, single metal or ceramic thermal spray coatings are no longer sufficient. Composite powders can produce extremely wear-resistant ceramic coatings for applications such as pump liners, pump shafts, and other rotating components within housings. Unlike many other ceramic powders, this coating does not require the sophisticated spraying techniques required, allowing for the creation of a uniform, high-hardness coating. This type of coating combines the properties of both alumina and titanium dioxide coatings, but is denser, harder, and stronger, while also exhibiting better intergranular bonding with the substrate.

[0003] Ceramic powder is a widely used plasma spray powder. The current mainstream production process uses sintered chromium oxide and titanium dioxide as raw materials and adopts the electric fusion crushing method. The raw material cost is high and the composition is uneven. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for preparing thermally sprayed chromium oxide composite ceramic powder.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a thermally sprayed chromium oxide composite ceramic powder, wherein the chromium oxide composite ceramic powder is composed of the following components, by weight: 400-750 kg of chromium oxide, 250-600 kg of titanium oxide, and 2-4.0% by weight of neutral silica sol, comprising the following steps:

[0006] S1. Place the raw materials of chromium oxide and titanium oxide in a mill to prepare pulp at room temperature, grind and mix for 150-280 minutes to obtain product A;

[0007] S2. Place the product A prepared in S1 into a blender, add 2-4.0% of the weight of the raw material neutral silica sol, and continue stirring for 20-30 minutes to obtain product B;

[0008] S3, placing the product B prepared in S2 into a spray granulator for spray granulation to obtain a product C of 1-3 mm;

[0009] S4, placing the product C prepared in S3 into an electric arc furnace for sintering to obtain product D;

[0010] S5. The product D prepared in S4 is subjected to a magnetic separator to remove free iron introduced from the grinding mill, thereby obtaining a finished chromium oxide composite ceramic powder.

[0011] Preferably, the particle size of the chromium oxide is 0.1-5 mm, and the particle size of the titanium oxide is 0.2-3 mm.

[0012] Preferably, the mill in S1 is a stirred ball mill or a sand mill.

[0013] Preferably, the chromium oxide composite ceramic powder is composed of the following components, by weight: 400 kg of chromium oxide, 600 kg of titanium oxide, and 0.2 kg of neutral silica sol.

[0014] Preferably, the chromium oxide composite ceramic powder is composed of the following components, by weight: 750 kg of chromium oxide, 250 kg of titanium oxide, and 0.4 kg of neutral silica sol.

[0015] Preferably, the chromium oxide composite ceramic powder is composed of the following components, by weight: 575 kg of chromium oxide, 425 kg of titanium oxide, and 0.3 kg of neutral silica sol.

[0016] The technical effects and advantages of the present invention are as follows: the present invention uses silica sol as a silicon oxide source and a granulation binder, and produces a Cr2O3-5%SiO23%TiO2 composite powder after spray granulation and high-temperature sintering. The original particle size of silicon oxide in the silica sol is 14 nanometers, which can be effectively adsorbed and evenly coated on the surface of chromium oxide and titanium oxide, thereby reducing the sintering temperature, lowering the porosity of the coating, and significantly improving the hardness and toughness. During the plasma spraying process, the reaction between chromium oxide and oxygen to produce hexavalent chromium is effectively isolated. In summary, the CT powder prepared by this method has low production cost, good product quality, and large production volume. The prepared composite coating has good weather resistance, high bonding strength, and a dense coating, laying the foundation for the wider application of plasma sprayed CT coatings. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] The invention discloses a preparation method of thermal spraying chromium oxide composite ceramic powder. The chromium oxide composite ceramic powder is composed of the following components by weight: 400-750 kg of chromium oxide, 250-600 kg of titanium oxide and 2-4.0% of the weight of the raw materials in neutral silica sol.

[0019] Example 1

[0020] 1) Place 400 kg of chromium oxide with a particle size of 0.1-5 mm and 600 kg of titanium oxide with a particle size of 0.1-5 mm in a stirring ball mill or a sand mill to prepare a slurry at room temperature, grind and mix for 150 minutes to obtain Product A;

[0021] 2) Place product A prepared in S1 into a blender, add 0.2 kg of neutral silica sol, and continue stirring for 20 minutes to obtain product B;

[0022] 3) Place the product B prepared in S2 into a spray granulator for spray granulation to obtain a product C with a diameter of 1-3 mm;

[0023] 4) placing the product C obtained in S3 into an electric arc furnace for sintering to obtain product D;

[0024] 5) The product D prepared in S4 is subjected to a magnetic separator to remove the free iron introduced by the mill, thereby obtaining a finished chromium oxide composite ceramic powder.

[0025] This invention uses silica sol as the silicon oxide source and granulation binder, and then produces a Cr2O3-5% SiO2-3% TiO2 composite powder through spray granulation and high-temperature sintering. The original particle size of the silicon oxide in the silica sol is 14 nanometers, which can effectively adsorb and evenly coat the surfaces of chromium oxide and titanium oxide. This reduces the sintering temperature, lowers the coating porosity, and controls the coating porosity range to 6.02-8.6 cm². Hardness and toughness are significantly improved. During the plasma spraying process, the reaction between chromium oxide and oxygen to produce hexavalent chromium is effectively isolated.

[0026] Example 2

[0027] 1) Place 750 kg of chromium oxide with a particle size of 0.1-5 mm and 250 kg of titanium oxide with a particle size of 0.1-5 mm in a stirring ball mill or a sand mill to prepare a pulp at room temperature, grind and mix for 280 minutes to obtain product A;

[0028] 2) Place product A prepared in S1 into a blender, add 0.4 kg of neutral silica sol, and continue stirring for 30 minutes to obtain product B;

[0029] 3) Place the product B prepared in S2 into a spray granulator for spray granulation to obtain a product C with a diameter of 1-3 mm;

[0030] 4) placing the product C obtained in S3 into an electric arc furnace for sintering to obtain product D;

[0031] 5) The product D prepared in S4 is subjected to a magnetic separator to remove the free iron introduced by the mill, thereby obtaining a finished chromium oxide composite ceramic powder.

[0032] This invention uses silica sol as the silicon oxide source and granulation binder, and then produces a Cr2O3-5% SiO2-3% TiO2 composite powder through spray granulation and high-temperature sintering. The original particle size of the silicon oxide in the silica sol is 14 nanometers, which can effectively adsorb and evenly coat the surfaces of chromium oxide and titanium oxide. This reduces the sintering temperature, lowers the coating porosity, and controls the coating porosity range to 6.0-8.0 cm². Hardness and toughness are significantly improved. During the plasma spraying process, the reaction between chromium oxide and oxygen to produce hexavalent chromium is effectively isolated.

[0033] Example 3

[0034] 1) Place 575 kg of chromium oxide with a particle size of 0.1-5 mm and 425 kg of titanium oxide with a particle size of 0.1-5 mm in a stirring ball mill or a sand mill to prepare a pulp, grind and mix for 200 minutes to obtain Product A;

[0035] 2) Place product A prepared in S1 into a blender, add 0.4 kg of neutral silica sol, and continue stirring for 25 minutes to obtain product B;

[0036] 3) Place the product B prepared in S2 into a spray granulator for spray granulation to obtain a product C with a diameter of 1-3 mm;

[0037] 4) placing the product C obtained in S3 into an electric arc furnace for sintering to obtain product D;

[0038] 5) The product D prepared in S4 is subjected to a magnetic separator to remove the free iron introduced by the mill, thereby obtaining a finished chromium oxide composite ceramic powder.

[0039] This invention uses silica sol as the silicon oxide source and granulation binder, and then produces a Cr2O3-5% SiO2-3% TiO2 composite powder through spray granulation and high-temperature sintering. The original particle size of the silicon oxide in the silica sol is 14 nanometers, which can effectively adsorb and evenly coat the surfaces of chromium oxide and titanium oxide. This reduces the sintering temperature, lowers the coating porosity, and controls the coating porosity range to 5.8-7.6 cm². Hardness and toughness are significantly improved. During the plasma spraying process, the reaction between chromium oxide and oxygen to produce hexavalent chromium is effectively isolated.

[0040] In summary, the technical effects and advantages of the present invention are as follows: the present invention uses silica sol as a silicon oxide source and a granulation binder, and produces a Cr2O3-5%SiO23%TiO2 composite powder after spray granulation and high-temperature sintering. The original particle size of silicon oxide in the silica sol is 14 nanometers, which can be effectively adsorbed and evenly coated on the surface of chromium oxide and titanium oxide, thereby reducing the sintering temperature, lowering the porosity of the coating, and significantly improving the hardness and toughness. During the plasma spraying process, the reaction between chromium oxide and oxygen to produce hexavalent chromium is effectively isolated. In summary, the CT powder prepared by this method has low production cost, good product quality, and large production volume. The prepared composite coating has good weather resistance, high bonding strength, and a dense coating, laying the foundation for the wider application of plasma sprayed CT coatings.

[0041] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a thermally sprayed chromium oxide composite ceramic powder, the chromium oxide composite ceramic powder comprising the following components, by weight: 400-750 kg of chromium oxide, 250-600 kg of titanium oxide, and 2-4.0% by weight of neutral silica sol, characterized in that: The silica sol is used as a silicon oxide source and a granulation binder. The original particle size of silicon oxide in the silica sol is 14 nanometers, which can be effectively adsorbed and evenly coated on the surface of chromium oxide and titanium oxide. The preparation method includes the following steps: S1. Place the raw materials of chromium oxide and titanium oxide in a mill to prepare pulp at room temperature, grind and mix for 150-280 minutes, wherein the particle size of the chromium oxide is 0.1-5 mm, and the particle size of the titanium oxide is 0.2-3 mm, to obtain product A; S2. Place the product A prepared in S1 into a blender, add 2-4.0% of the weight of the raw material of neutral silica sol, and continue stirring for 20-30 minutes to obtain product B; S3, placing the product B prepared in S2 into a spray granulator for spray granulation to obtain a product C of 1-3 mm; S4, placing the product C prepared in S3 into an electric arc furnace for sintering to obtain product D; S5. The product D prepared in S4 is subjected to a magnetic separator to remove free iron introduced from the grinding mill, thereby obtaining a finished chromium oxide composite ceramic powder.