Method for preparing inner electrode of ceramic capacitor through copper-doped carburizing and cofiring of electronic ceramic

Abstract

The invention discloses a method for preparing an inner electrode of a ceramic capacitor by copper-doped carburizing and cofiring of electronic ceramic, which comprises the following steps of: 1, mixing 0.5-30wt% of copper source powder and electronic ceramic powder to prepare a sample, and sintering by a traditional solid-phase method; step 2, wrapping the sintered electronic ceramic chip with graphite paper and then clamping the electronic ceramic chip between carbon felts; 3, the electronic ceramic chip and the carbon felt are closely placed in a closed air pressure box, and vacuumizing is conducted till the air pressure needs to be lower than-0.095 MPa; step 4, applying current to the carbon felt to enable the carbon felt to generate Joule heat, rapidly raising the temperature to 1100-1300 DEG C at a temperature raising rate of 40-60 DEG C / min, keeping the temperature for 10-180 seconds, then turning off a power supply, and after the electronic ceramic chip is cooled, removing vacuum; through a vacuum carbon reduction cofiring process, rapid Joule heating of the graphite felt is combined with a vacuum environment, and reduction and carbon infiltration of a copper source are completed within an extremely short heat preservation time (10-180 seconds), so that the energy consumption and time cost of electrode preparation are greatly reduced, and the structural integrity of a ceramic matrix is ensured.

Description

Technical Field

[0001] This invention belongs to the field of ceramic capacitor technology, and relates to a method for preparing internal electrodes of ceramic capacitors, specifically a method for preparing internal electrodes of ceramic capacitors by copper doping, carburizing and co-firing electronic ceramics. Background Technology

[0002] In the field of electronic components such as ceramic capacitors, the fabrication process of electrode materials directly affects the conductivity, adhesion strength, and overall reliability of the devices. Traditional electrodes are mostly formed by external coating or electroplating, which often suffers from problems such as insufficient adhesion, high interfacial contact resistance, complex processes, and environmental pollution. With the development of multilayer ceramic devices towards miniaturization and high integration, internal electrode technology has gradually gained attention. However, most existing internal electrode fabrication methods rely on high-temperature, long-time sintering, which is not only energy-intensive and inefficient but also prone to causing abnormal grain growth in the ceramic matrix or oxidation and diffusion of electrode components, thereby impairing the electrical properties and structural stability of the material. Therefore, developing a co-firing method that can effectively bond electrode materials to the ceramic matrix under low-temperature, short-time conditions and precisely control the electrode composition has become an important direction for technological improvement in this field. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing internal electrodes of ceramic capacitors by copper doping and carburizing co-firing of electronic ceramics. This method achieves the reduction of copper source inside the ceramic and electrode formation in a very short time, and is simple, energy-saving and efficient.

[0004] To achieve the above objectives, the present invention employs the following technical solution: A method for preparing the internal electrode of a ceramic capacitor by copper doping and carburizing co-firing of electronic ceramics includes the following steps: Step 1: Mix 0.5-30wt% copper source powder with 70-99.5wt% electronic ceramic powder to prepare a sample, and then sinter it using the traditional solid-state method. Step 2: Wrap the sintered electronic ceramic sheet sample with graphite paper and sandwich it between carbon felts. Step 3: Place the electronic ceramic sheet sample and carbon felt tightly in a sealed pressure chamber and evacuate until the pressure is below -0.095 MPa; Step 4: Apply an electric current to the sample to generate Joule heating, rapidly heating it to 1100-1300℃ at a heating rate of 40-60℃ / min. Hold the temperature for 10-180s, then turn off the power. After the electronic ceramic sheet cools down, remove the vacuum.

[0005] The present invention also has the following technical features: Preferably, the sintering temperature of the traditional solid-state sintering method described in step one is 1180-1350℃, and the holding time is 4-8h.

[0006] Preferably, the copper source powder mentioned in step one includes any one of copper oxide powder, cuprous oxide, or copper powder.

[0007] Preferably, the carbon felt in step two has a thickness of 5-10 mm and a width of 1.5-2 times the diameter of the ceramic sheet.

[0008] Preferably, the current intensity in step four is 17-24A.

[0009] Compared with the prior art, the present invention has the following technical effects: This invention combines rapid Joule heating of graphite felt with a vacuum carbon reduction co-firing process, completing the reduction of the copper source and carbon infiltration within an extremely short holding time (10-180 seconds), significantly reducing the energy consumption and time cost of electrode preparation. It effectively avoids abnormal ceramic grain growth and excessive oxidation of copper components caused by traditional long-term high-temperature sintering, ensuring the structural integrity of the ceramic matrix. At the same time, by controlling the reaction time and temperature, controllable multi-component or single-component products from copper oxide and cuprous oxide to copper can be generated in situ inside the ceramic, realizing flexible control of electrode composition and structure. This provides an efficient, environmentally friendly, and simple new approach for the preparation of internal electrodes for high-performance, high-reliability multilayer ceramic electronic components. Attached Figure Description

[0010] Figure 1 This is a comparison image of the surface of the electronic ceramic sample before and after vacuum carbon reduction according to the present invention. Detailed Implementation

[0011] The following detailed explanation of the specific content of the present invention is provided in conjunction with embodiments. These descriptions are intended to explain the present invention and not to limit it.

[0012] Example 1 This embodiment provides a method for preparing the internal electrode of a ceramic capacitor by copper-doped carburizing and co-firing electronic ceramics, using copper oxide as the copper source and barium titanate as the electronic ceramic material. The specific preparation method includes the following steps: Step 1: Mix 15wt% copper oxide powder with electronic ceramic powder to prepare a sample, and then perform solid-state sintering at 1200℃ for 6 hours. Step 2: Wrap the sintered electronic ceramic sheet with graphite paper and sandwich it between carbon felts. The carbon felt is 6mm thick and 1.8 times the diameter of the ceramic sheet. Step 3: Place the electronic ceramic sheet and carbon felt tightly in a sealed pressure chamber and evacuate until the pressure is below -0.095 MPa; Step 4: Apply a 20A current to the sample to generate Joule heating, rapidly heat it to 1100 ℃ at a heating rate of 40℃ / min, hold it at that temperature for 60s, then turn off the power and remove the vacuum after the electronic ceramic sheet has cooled down.

[0013] Figure 1 The changes in surface morphology of the sample before and after treatment in Example 1 show that a uniform conductive phase is formed on the surface after co-firing.

[0014] Example 2 This embodiment provides a method for preparing the internal electrode of a ceramic capacitor by copper-doped carburizing and co-firing electronic ceramics. Cuprous oxide is used as the copper source, and strontium titanate is used as the electronic ceramic material. The specific preparation method includes the following steps: Step 1: Mix 30wt% cuprous oxide powder with electronic ceramic powder to prepare a sample, and then perform solid-state sintering at 1180℃ for 8 hours. Step 2: Wrap the sintered electronic ceramic sheet with graphite paper and sandwich it between carbon felts. The carbon felt is 5mm thick and 1.5 times the diameter of the ceramic sheet. Step 3: Place the electronic ceramic sheet and carbon felt tightly in a sealed pressure chamber and evacuate until the pressure is below -0.095 MPa; Step 4: Apply a 24A current to the sample to generate Joule heating and rapidly heat it to 1300℃ at a heating rate of 60℃ / min. Hold the temperature for 10 seconds, then turn off the power. After the electronic ceramic sheet cools down, remove the vacuum.

[0015] Example 3 This embodiment provides a method for preparing the internal electrode of a ceramic capacitor by copper-doped carburizing and co-firing electronic ceramics. Copper powder is used as the copper source, and alumina ceramic is used as the electronic ceramic material. The specific preparation method includes the following steps: Step 1: Mix 0.5wt% copper powder with electronic ceramic powder to prepare a sample, and then perform solid-state sintering at 1350℃ for 4 hours. Step 2: Wrap the sintered electronic ceramic sheet with graphite paper and sandwich it between carbon felts. The carbon felt is 10mm thick and twice the diameter of the ceramic sheet. Step 3: Place the electronic ceramic sheet and carbon felt tightly in a sealed pressure chamber and evacuate until the pressure is below -0.095 MPa; Step 4: Apply a 17A current to the sample to generate Joule heating, rapidly heat it to 1200℃ at a heating rate of 40℃ / min, hold it at that temperature for 180s, then turn off the power and remove the vacuum after the electronic ceramic sheet has cooled down.

[0016] The above-described specific embodiments are merely illustrative explanations of the present invention and do not constitute any limitation on the scope of protection of the present invention. Those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing the internal electrode of a ceramic capacitor by copper doping, carburizing, and co-firing, characterized in that, Includes the following steps: Step 1: Mix 0.5-30wt% copper source powder with 70-99.5wt% electronic ceramic powder to prepare a sample, and then sinter it using the traditional solid-state method. Step 2: Wrap the sintered electronic ceramic sheet with graphite paper and sandwich it between carbon felts; Step 3: Place the electronic ceramic sheet and carbon felt tightly in a sealed pressure chamber and evacuate until the pressure is below -0.095 MPa; Step 4: Apply an electric current to the carbon felt to generate Joule heating, rapidly heating it to 1100-1300℃ at a heating rate of 40-60℃ / min. Hold the temperature for 10-180 seconds, then turn off the power. After the electronic ceramic sheet cools down, remove the vacuum.

2. The method for preparing the internal electrode of a ceramic capacitor by copper doping and carburizing co-firing of electronic ceramics as described in claim 1, characterized in that, The sintering temperature of the traditional solid-state sintering method described in step one is 1180-1350℃, and the holding time is 4-8h.

3. The method for preparing the internal electrode of a ceramic capacitor by copper doping and carburizing co-firing of electronic ceramics as described in claim 1, characterized in that, The copper source powder mentioned in step one includes any one of copper oxide powder, cuprous oxide, or copper powder.

4. The method for preparing the internal electrode of a ceramic capacitor by copper doping, carburizing, and co-firing as described in claim 1, characterized in that, The carbon felt mentioned in step two has a thickness of 5-10 mm and a width that is 1.5-2 times the diameter of the ceramic sheet.

5. The method for preparing the internal electrode of a ceramic capacitor by copper doping and carburizing co-firing of electronic ceramics as described in claim 1, characterized in that, The current intensity mentioned in step four is 17-24A.

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