Ceramic material based on potassium titanate whisker and preparation process thereof

Abstract

The invention discloses a potassium titanate whisker-based ceramic material and a preparation process thereof. The potassium titanate whisker-based ceramic material comprises the following components: potassium titanate whiskers, a sintering aid, silicate, silicon dioxide, an additive and silicon nitride powder. A proper titanium source and a proper potassium source are selected as initial raw materials; the preparation method comprises the following steps: mixing a titanium source and a potassium source according to a certain stoichiometric ratio, and fully grinding in equipment such as a ball mill; the ground mixed raw materials are put into a high-temperature furnace to be subjected to a sintering reaction, the sintering temperature is generally 600-1200 DEG C, a titanium source and a potassium source are subjected to a solid-phase reaction at the high temperature, and the potassium titanate whiskers are generated. According to the ceramic material based on the potassium titanate whiskers and the preparation process thereof, by adding the potassium titanate whisker material, when the ceramic material is damaged, the whiskers can absorb residual energy during crack expansion, so that the toughness and strength of the material can be effectively improved, and meanwhile, the fracture behavior of the material is changed, so that the material is converted from brittle fracture to ductile fracture.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic material preparation, in particular to a ceramic material based on potassium titanate whiskers and a preparation process thereof. Background Art

[0002] Ceramic materials refer to a type of inorganic non-metallic materials made from natural or synthetic compounds through forming and high-temperature sintering. They have excellent properties such as insulation, high hardness, low density, radiation resistance, and corrosion resistance. They are used in daily life, industrial fields, and electrical fields. Ceramic materials are diverse in types and excellent in performance, and are an indispensable type of material.

[0003] However, ceramic materials have low toughness and are prone to brittle fracture or surface cracks when subjected to external forces. When the thermal stress generated by a sudden temperature change in the ceramic material exceeds its strength, the material will crack, peel off or even break, and then fail. Therefore, there is an urgent need to provide a ceramic material based on potassium titanate whiskers and its preparation process to solve the above-mentioned problems. Summary of the invention

[0004] The purpose of the present invention is to provide a ceramic material based on potassium titanate whiskers and a preparation process thereof, so as to solve the problem that the ceramic material mentioned in the above background technology has low toughness and is prone to brittle fracture or surface cracks when subjected to external force. When the thermal stress generated by the ceramic material due to a sudden temperature change exceeds its strength, the material will crack, peel off or even break, and then fail.

[0005] To achieve the above object, the present invention provides the following technical solution: a ceramic material based on potassium titanate whiskers, comprising the following components:

[0006] Potassium titanate whiskers, sintering aids: yttrium oxide (Y2O3), silicates, silicon dioxide, additives: MgO, Fe2O3, silicon nitride powder.

[0007] The specific manufacturing process of the ceramic material based on potassium titanate whiskers is as follows:

[0008] 1. Preparation of Potassium Titanate Whiskers

[0009] Step 1: Prepare the ingredients

[0010] Selecting suitable titanium source (such as titanium dioxide) and potassium source (such as potassium carbonate) as starting materials, these raw materials need to have high purity to ensure the quality of the prepared potassium titanate whiskers;

[0011] Step 2: Mix and grind

[0012] The titanium source and the potassium source are mixed in a certain stoichiometric ratio, and then fully ground in a ball mill or other equipment. The purpose of grinding is to mix the raw materials evenly, reduce the particle size of the raw materials, and increase the contact area of ​​the reaction;

[0013] Step 3: High temperature sintering

[0014] The ground mixed raw materials are placed in a high-temperature furnace for sintering reaction. The sintering temperature is generally between 600-1200°C. At high temperature, the titanium source and the potassium source undergo a solid phase reaction to generate potassium titanate whiskers. During the sintering process, parameters such as the heating rate, holding time, and cooling rate need to be controlled to control the growth and quality of the whiskers.

[0015] 2. Preparation of Ceramic Materials

[0016] Step 1: Use silicon powder as raw material and perform preliminary nitridation in nitrogen at a high temperature of 1200°C, so that a portion of the silicon powder reacts with nitrogen to form silicon nitride. In this process, adding a certain proportion (such as 30% by mass) of silicon nitride powder as a diluent can improve the nitridation efficiency of the silicon powder;

[0017] Step 2: Add silicon nitride powder to auxiliary materials such as combustion aid and binder, mix them, and then perform ball milling. Ball milling can make the powder particle size more uniform, which helps to improve the quality and precision of molding.

[0018] Step 3: preparing an initial layered silicate, pickling the initial layered silicate to remove the iron element therein, and filling silicon dioxide between the layers of the pickled layered silicate;

[0019] Step 4: Mix the filled layered silicate with silicon nitride and a small amount of additives, and perform hot pressing and sintering at a pressure greater than 16 MPa and 1600-1700° C. to prepare a ceramic material;

[0020] Three: Post-processing:

[0021] (1) Grinding and polishing:

[0022] After sintering, grinding and polishing of silicon nitride ceramics can improve the dimensional accuracy and surface finish of the ceramics;

[0023] (2) Cleaning

[0024] Remove impurities on the surface of ceramics to ensure the cleanliness of ceramics;

[0025] (3) Surface treatment

[0026] Coating a layer of metal film, ceramic film or other materials on the surface of silicon nitride ceramics can change the chemical and physical properties of silicon nitride ceramics and improve their performance. For example, coating with fluorocarbon resin film can increase the corrosion resistance of silicon nitride ceramics; coating with titanium film can improve the biocompatibility of silicon nitride ceramics.

[0027] 4. Performance Optimization

[0028] (1) During the sintering process of silicon nitride ceramics, adding an appropriate amount of yttrium oxide (Y2O3) as a sintering aid can promote the sintering of silicon nitride particles and improve the density and strength of the ceramics;

[0029] (2) Performance improving additives:

[0030] During the sintering process of silicon nitride ceramics, adding potassium titanate whisker material can effectively improve the toughness and strength of the material, while changing the fracture behavior of the material from brittle fracture to ductile fracture.

[0031] Preferably, the purity of the titanium dioxide is generally required to be above 98%, and the purity of potassium carbonate should also reach analytical grade.

[0032] Preferably, the heating rate is generally controlled at 5-10° C. minutes, the holding time is controlled at about 5-10 hours, and the cooling rate also needs to be properly controlled to avoid whisker defects during the cooling process.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1) The potassium titanate whisker-based ceramic material and its preparation process, during the sintering process of silicon nitride ceramics, an appropriate amount of yttrium oxide (Y2O3) is added as a sintering aid to promote the sintering of silicon nitride particles and improve the density and strength of the ceramics;

[0035] 2) The potassium titanate whisker-based ceramic material and its preparation process, by adding potassium titanate whisker material, when the ceramic material is damaged, the whisker will absorb the remaining energy during crack expansion, which can effectively improve the toughness and strength of the material, and at the same time change the fracture behavior of the material, so that it changes from brittle fracture to ductile fracture;

[0036] 3) The ceramic material based on potassium titanate whiskers and its preparation process, by mixing and sintering the carbon dioxide-filled layered silicate with the ceramic raw material, obtains a ceramic material with improved thermal shock resistance and good mechanical strength;

[0037] 4) The potassium titanate whisker-based ceramic material and its preparation process, when preparing silicon nitride powder raw material, silicon powder is used as raw material, and preliminary nitridation is carried out in nitrogen at a high temperature of 1200°C, and an appropriate amount of silicon nitride powder is added as a diluent, so that the nitridation efficiency of silicon powder can be improved during the process of silicon powder reacting with nitrogen to generate silicon nitride. DETAILED DESCRIPTION

[0038] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The present invention provides the following technical solution: a ceramic material based on potassium titanate whiskers comprises the following components:

[0040] Potassium titanate whiskers, sintering aids: yttrium oxide (Y2O3), silicates, silicon dioxide, additives: MgO, Fe2O3, silicon nitride powder.

[0041] The specific production process of ceramic materials based on potassium titanate whiskers is as follows:

[0042] 1. Preparation of Potassium Titanate Whiskers

[0043] Step 1: Prepare the ingredients

[0044] Selecting suitable titanium source (such as titanium dioxide) and potassium source (such as potassium carbonate) as starting materials, these raw materials need to have high purity to ensure the quality of the prepared potassium titanate whiskers;

[0045] Step 2: Mix and grind

[0046] The titanium source and the potassium source are mixed in a certain stoichiometric ratio, and then fully ground in a ball mill or other equipment. The purpose of grinding is to mix the raw materials evenly, reduce the particle size of the raw materials, and increase the contact area of ​​the reaction;

[0047] Step 3: High temperature sintering

[0048] The ground mixed raw materials are placed in a high-temperature furnace for sintering reaction. The sintering temperature is generally between 600-1200°C. At high temperature, the titanium source and the potassium source undergo a solid phase reaction to generate potassium titanate whiskers. During the sintering process, parameters such as the heating rate, holding time, and cooling rate need to be controlled to control the growth and quality of the whiskers.

[0049] 2. Preparation of Ceramic Materials

[0050] Step 1: Use silicon powder as raw material and perform preliminary nitridation in nitrogen at a high temperature of 1200°C, so that a portion of the silicon powder reacts with nitrogen to form silicon nitride. In this process, adding a certain proportion (such as 30% by mass) of silicon nitride powder as a diluent can improve the nitridation efficiency of the silicon powder;

[0051] Step 2: Add silicon nitride powder to auxiliary materials such as combustion aid and binder, mix them, and then perform ball milling. Ball milling can make the powder particle size more uniform, which helps to improve the quality and precision of molding.

[0052] Step 3: preparing an initial layered silicate, pickling the initial layered silicate to remove the iron element therein, and filling silicon dioxide between the layers of the pickled layered silicate;

[0053] Step 4: Mix the filled layered silicate with silicon nitride and a small amount of additives, and perform hot pressing and sintering at a pressure greater than 16 MPa and 1600-1700° C. to prepare a ceramic material;

[0054] Three: Post-processing:

[0055] (1) Grinding and polishing:

[0056] After sintering, grinding and polishing of silicon nitride ceramics can improve the dimensional accuracy and surface finish of the ceramics;

[0057] (2) Cleaning

[0058] Remove impurities on the surface of ceramics to ensure the cleanliness of ceramics;

[0059] (3) Surface treatment

[0060] Coating a layer of metal film, ceramic film or other materials on the surface of silicon nitride ceramics can change the chemical and physical properties of silicon nitride ceramics and improve their performance. For example, coating with fluorocarbon resin film can increase the corrosion resistance of silicon nitride ceramics; coating with titanium film can improve the biocompatibility of silicon nitride ceramics.

[0061] 4. Performance Optimization

[0062] (1) During the sintering process of silicon nitride ceramics, adding an appropriate amount of yttrium oxide (Y2O3) as a sintering aid can promote the sintering of silicon nitride particles and improve the density and strength of the ceramics;

[0063] (2) Performance improving additives:

[0064] During the sintering process of silicon nitride ceramics, adding potassium titanate whisker material can effectively improve the toughness and strength of the material, while changing the fracture behavior of the material from brittle fracture to ductile fracture.

[0065] The purity of titanium dioxide is generally required to be above 98%, and the purity of potassium carbonate should also reach analytical grade.

[0066] The heating rate is generally controlled at 5-10℃ min, the holding time is controlled at about 5-10 hours, and the cooling rate also needs to be properly controlled to avoid whisker defects during the cooling process.

[0067] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0068] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to 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 protection scope of the present invention.

Claims

1. A ceramic material based on potassium titanate whiskers, characterized in that: Includes the following components: Potassium titanate whiskers, sintering aids: yttrium oxide (Y2O3), silicates, silicon dioxide, additives: MgO, Fe2O3, silicon nitride powder.

2. The process for preparing a ceramic material based on potassium titanate whiskers according to claim 1, characterized in that: The specific manufacturing process of the ceramic material based on potassium titanate whiskers is as follows:

1. Preparation of Potassium Titanate Whiskers Step 1: Prepare the ingredients Selecting suitable titanium source (such as titanium dioxide) and potassium source (such as potassium carbonate) as starting materials, these raw materials need to have high purity to ensure the quality of the prepared potassium titanate whiskers; Step 2: Mix and grind The titanium source and the potassium source are mixed in a certain stoichiometric ratio, and then fully ground in a ball mill or other equipment. The purpose of grinding is to mix the raw materials evenly, reduce the particle size of the raw materials, and increase the contact area of ​​the reaction; Step 3: High temperature sintering The ground mixed raw materials are placed in a high-temperature furnace for sintering reaction. The sintering temperature is generally between 600-1200°C. At high temperature, the titanium source and the potassium source undergo a solid phase reaction to generate potassium titanate whiskers. During the sintering process, parameters such as the heating rate, holding time, and cooling rate need to be controlled to control the growth and quality of the whiskers.

2. Preparation of Ceramic Materials Step 1: Use silicon powder as raw material and perform preliminary nitridation in nitrogen at a high temperature of 1200°C, so that a portion of the silicon powder reacts with nitrogen to form silicon nitride. In this process, adding a certain proportion (such as 30% by mass) of silicon nitride powder as a diluent can improve the nitridation efficiency of the silicon powder; Step 2: Add silicon nitride powder to auxiliary materials such as combustion aid and binder, mix them, and then perform ball milling. Ball milling can make the powder particle size more uniform, which helps to improve the quality and precision of molding. Step 3: preparing an initial layered silicate, pickling the initial layered silicate to remove the iron element therein, and filling silicon dioxide between the layers of the pickled layered silicate; Step 4: Mix the filled layered silicate with silicon nitride and a small amount of additives, and perform hot pressing and sintering at a pressure greater than 16 MPa and 1600-1700° C. to prepare a ceramic material; 3. Post-processing: (1) Grinding and polishing: After sintering, grinding and polishing of silicon nitride ceramics can improve the dimensional accuracy and surface finish of the ceramics; (2) Cleaning Remove impurities on the surface of ceramics to ensure the cleanliness of ceramics; (3) Surface treatment Coating a layer of metal film, ceramic film or other materials on the surface of silicon nitride ceramics can change the chemical and physical properties of silicon nitride ceramics and improve their performance. For example, coating with fluorocarbon resin film can increase the corrosion resistance of silicon nitride ceramics; coating with titanium film can improve the biocompatibility of silicon nitride ceramics.

4. Performance Optimization (1) During the sintering process of silicon nitride ceramics, adding an appropriate amount of yttrium oxide (Y2O3) as a sintering aid can promote the sintering of silicon nitride particles and improve the density and strength of the ceramics; (2) Performance improving additives: During the sintering process of silicon nitride ceramics, adding potassium titanate whisker material can effectively improve the toughness and strength of the material, while changing the fracture behavior of the material from brittle fracture to ductile fracture.

3. The process for preparing a ceramic material based on potassium titanate whiskers according to claim 2, characterized in that: The purity of the titanium dioxide is generally required to be above 98%, and the purity of potassium carbonate should also reach analytical grade.

4. The process for preparing a ceramic material based on potassium titanate whiskers according to claim 2, characterized in that: The heating rate is generally controlled at 5-10° C. minutes, the holding time is controlled at about 5-10 hours, and the cooling rate also needs to be properly controlled to avoid defects in the whiskers during the cooling process.