Method for controlling oxygen partial pressure and properties during sintering of barium titanate ceramics using coconut shell

Abstract

This invention discloses a method for controlling the oxygen partial pressure and performance of barium titanate ceramics during sintering using coconut shells, comprising the following steps: Step 1: Select coconut shells, clean them, remove the fibers, and dehydrate and dry them using a high-temperature forced-air drying oven; Step 2: Crush the dried coconut shells into small pieces, place them in a crucible, and carbonize them at high temperature in a muffle furnace; Step 3: Take out the high-temperature carbonized coconut shell char, grind it, and sieve it; Step 4: Weigh the coconut shell char and barium titanate powder at a mass ratio of 2~6:100, and then grind them to fully mix the coconut shell char and barium titanate powder; Step 5: Add a binder to the mixed powder, grind it thoroughly, and then press the powder into sheets to obtain a green body of fully mixed coconut shell char and barium titanate; Step 6: Place the pressed green body into a muffle furnace and sinter it at high temperature; Step 7: Obtain the coconut shell char mixed barium titanate ceramic.

Description

Technical Field

[0001] This invention belongs to the field of functional ceramics technology, specifically relating to a method for controlling the oxygen partial pressure and performance of barium titanate ceramics during sintering using coconut shells. Background Technology

[0002] Barium titanate-based composite ceramics are one of the essential materials in the electronics industry, and the oxygen partial pressure during sintering has a decisive impact on their performance. Currently, the main methods to address this issue are: 1. Sintering with a specific gas; 2. Using volatile compounds. However, these two methods have the following problems: 1. The specific gas used is expensive, the gas itself is not environmentally friendly or economical, and it easily causes air pollution. Furthermore, excessively high concentrations of the gas during the process can react with certain components in the composite material to generate impurities, affecting the overall material performance; 2. Introducing volatile compounds is expensive, which is not conducive to large-scale production, and the compounds easily release into the air after vaporization, causing pollution; 3. Regardless of whether a gas is used or a volatile compound is introduced, due to the density of the ceramic blank itself, the interaction with the ceramic is mostly limited to the surface and cannot penetrate deep into the ceramic interior, making it difficult to achieve overall oxygen partial pressure control.

[0003] Coconut shell is the endocarp of the coconut palm, a plant in the palm family. It is widely distributed and produced in large quantities in tropical and subtropical regions such as Hainan. Coconut shell itself is a natural fuel that can be converted into char at high temperatures. The main component of char is porous carbonaceous material.

[0004] Previous studies have extensively explored the composite composition of barium titanate and carbon-containing materials, with some indicating that carbon-containing materials can carburize into the barium titanate. In these studies, this carburization primarily occurs at the interface between the barium titanate and the carbon-containing material, resulting in surface composites of the two materials. These studies often aim to improve the performance of the composite, thus focusing on the interaction between the two materials in their analysis of performance and improvement mechanisms. However, these studies cannot directly control the oxygen partial pressure and properties of barium titanate ceramics during sintering using carbon-containing materials. Firstly, because the composite is a direct surface process, even if carbon combustion occurs during heat treatment, it remains only on the surface of the barium titanate base material, altering only the surface atmosphere. Direct control over the internal atmosphere of the barium titanate ceramic is impossible, a limitation of these studies. Secondly, if the oxygen partial pressure and performance of barium titanate ceramics are to be controlled simply, then the interaction between carbon and the barium titanate base material must be eliminated, and carbon must only play the role of controlling the combustion atmosphere. Previous studies on this type of research have mostly relied on the interaction between barium titanate and carbon-containing materials. Therefore, the performance mechanism cannot achieve simple atmosphere control. This is another shortcoming of this type of research in controlling the oxygen partial pressure and performance of barium titanate ceramics during sintering. Therefore, developing a method for controlling the oxygen partial pressure and performance of barium titanate ceramics during sintering has great market potential. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for controlling the oxygen partial pressure and properties of barium titanate ceramics during sintering using coconut shells.

[0006] To solve the technical problem, the technical solution of this invention is: a method for controlling the oxygen partial pressure and properties of barium titanate ceramics during sintering using coconut shells, comprising the following steps:

[0007] Step 1: Select coconut shells, wash them, remove the fibers, and dehydrate and dry them using a high-temperature forced-air drying oven;

[0008] Step 2: Crush the dried coconut shells into small pieces, put them into a crucible, and carbonize them at high temperature in a muffle furnace;

[0009] Step 3: Take out the coconut shell charcoal after high-temperature carbonization, grind it, and sieve it;

[0010] Step 4: Weigh the coconut shell charcoal and barium titanate powder at a mass ratio of 2~6:100. Adjust the mass ratio of coconut shell charcoal to barium titanate powder to control the performance of barium titanate ceramics. Then grind to fully mix the coconut shell charcoal and barium titanate powder.

[0011] Step 5: Add binder to the mixed powder, grind thoroughly, and then compress the powder into tablets to obtain a raw blank in which coconut shell carbon and barium titanate are fully mixed.

[0012] Step 6: Place the compressed green blank into a muffle furnace and sinter it at a high temperature;

[0013] Step 7: Obtain coconut shell carbon mixed barium titanate ceramic.

[0014] Preferably, in step 1, the coconut shells selected are from old coconuts with thick and hard shells, and the fibers on them are removed. The coconuts are then dehydrated and dried in a high-temperature forced-air drying oven at 120°C for 1.5 to 3 hours.

[0015] Preferably, the highest temperature for high-temperature carbonization in step 2 is 900℃, the holding time is 2-3 hours, and the maximum heating rate is 5℃ / min.

[0016] Preferably, the specific process of the high-temperature carbonization is as follows: the temperature is raised from 20°C to 200°C in 36 minutes, then raised from 200°C to 600°C in 80 minutes, then raised from 600°C to 900°C in 60 minutes, held at 900°C for 120 minutes, then cooled from 900°C to 500°C in 60 minutes, and finally cooled down with the furnace.

[0017] Preferably, in step 3, a 150-mesh sieve is used for sieving.

[0018] Preferably, in step 4, the mass ratio of coconut shell charcoal to barium titanate powder is 2~4:100.

[0019] Preferably, in step 4, adjusting the mass ratio of coconut shell charcoal to barium titanate powder to control the performance of barium titanate ceramics specifically involves the following: when the mass ratio of coconut shell charcoal to barium titanate powder is close to 2:100, the dielectric loss of the barium titanate ceramic is the lowest at the same frequency, and the dielectric constant is the highest at the same frequency; when the mass ratio of coconut shell charcoal to barium titanate powder is close to 6:100, the dielectric loss of the barium titanate ceramic is the highest at the same frequency, and the dielectric constant is the lowest at the same frequency.

[0020] Preferably, in step 5, the binder is a PVA solution, and the weight ratio of powder to binder is 100:5~10.

[0021] Preferably, the maximum sintering temperature in step 6 is 1275℃, the holding time is 2-4 hours, and the maximum heating rate is 5℃ / min.

[0022] Preferably, the sintering process is as follows: the temperature is raised from 20°C to 200°C after 30 minutes, then raised to 600°C after 80 minutes, held at 600°C for 30 minutes, then raised to 1225°C after 125 minutes, then raised to 1275°C after 50 minutes, held at 1275°C for 120 minutes, then lowered to 500°C after 60 minutes, and finally cooled down with the furnace.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] (1) This invention uses coconut shell as raw material for processing, and uses coconut shell carbon to mix with barium titanate to control the oxygen partial pressure during the sintering process. This can significantly reduce the raw material cost in oxygen partial pressure control during barium titanate ceramic sintering; ensure that there is no environmental pollution in oxygen partial pressure control during barium titanate ceramic sintering; avoid the generation of impurities in oxygen partial pressure control during barium titanate ceramic sintering; and achieve overall external and internal control of oxygen partial pressure control during barium titanate ceramic sintering.

[0025] (2) In this invention, coconut shell is calcined into charcoal and then fully mixed with barium titanate. Under high-temperature sintering conditions, the charcoal can be burned inside the barium titanate ceramic, which will consume oxygen and generate carbon dioxide. At the same time, a local relatively closed environment is formed by the sealing of external experimental equipment, so that an oxygen-carbon dioxide atmosphere can be formed locally. In addition, since the coconut shell charcoal and barium titanate powder are fully mixed, this atmosphere will exist in the entire interior and outer surface of the ceramic, thereby achieving overall control of the oxygen partial pressure both inside and outside. By adjusting the mixing ratio of coconut shell charcoal and barium titanate, the oxygen partial pressure during sintering can be regulated.

[0026] (3) The raw material used in this invention, coconut shell, has a large output, which can significantly reduce the cost of raw materials; the naturalness of coconut shell can solve the environmental pollution problem of specific gases or high-temperature volatile compounds; coconut shell char itself does not contain other components, which can solve the problem of impurity generation caused by the atmosphere; the full mixing of coconut shell char and barium titanate powder can ensure that this oxygen partial pressure control is not only on the surface, but can penetrate into the interior of the ceramic, so as to achieve overall oxygen partial pressure control of the exterior and interior.

[0027] (4) This invention mixes calcined coconut shell charcoal with barium titanate and controls the oxygen partial pressure during sintering, thus avoiding the problems of high cost, environmental pollution, easy generation of impurities, and difficulty in penetrating the interior of ceramics that exist in previous methods. Attached Figure Description

[0028] Figure 1 The process flow diagram of the method for controlling oxygen partial pressure and performance of barium titanate ceramics during sintering using coconut shells in this invention;

[0029] Figure 2 XRD pattern of barium titanate ceramic sintered in Example 5 of this invention;

[0030] Figure 3 The dielectric loss-frequency spectrum of the barium titanate ceramic sintered in Example 5 of this invention;

[0031] Figure 4 The dielectric constant-frequency spectrum of the barium titanate ceramic sintered in Example 5 of this invention. Detailed Implementation

[0032] The specific implementation of the present invention is described below with reference to embodiments:

[0033] Example 1

[0034] like Figure 1 As shown, this invention discloses a method for controlling the oxygen partial pressure and properties of barium titanate ceramics during sintering using coconut shells, comprising the following steps:

[0035] Step 1: Select coconut shells, wash them, remove the fibers, and dehydrate and dry them using a high-temperature forced-air drying oven;

[0036] Step 2: Crush the dried coconut shells into small pieces, put them into a crucible, and carbonize them at high temperature in a muffle furnace;

[0037] Step 3: Take out the coconut shell charcoal after high-temperature carbonization, grind it, and sieve it;

[0038] Step 4: Weigh the coconut shell charcoal and barium titanate powder at a mass ratio of 2~6:100. Adjust the mass ratio of coconut shell charcoal to barium titanate powder to control the performance of barium titanate ceramics. Then grind to fully mix the coconut shell charcoal and barium titanate powder.

[0039] Step 5: Add binder to the mixed powder, grind thoroughly, and then compress the powder into tablets to obtain a raw blank in which coconut shell carbon and barium titanate are fully mixed.

[0040] Step 6: Place the compressed green blank into a muffle furnace and sinter it at a high temperature;

[0041] Step 7: Obtain coconut shell carbon mixed barium titanate ceramic.

[0042] This invention can significantly reduce raw material costs, improve environmental friendliness, solve impurity generation, and achieve overall control of external and internal factors in the oxygen partial pressure control of barium titanate ceramic sintering, thus solving the problems existing in the current methods.

[0043] Example 2

[0044] Preferably, in step 1, the coconut shells selected are from old coconuts with thick and hard shells, and the fibers on them are removed. The coconuts are then dehydrated and dried in a high-temperature forced-air drying oven at 120°C for 1.5 to 3 hours.

[0045] Coconut shells are used as raw materials for processing. Coconut shell charcoal is mixed with barium titanate to control the oxygen partial pressure during the sintering process.

[0046] Coconut shells are abundant, low-cost, natural, and environmentally friendly, and the product of this method is also carbon dioxide. This invention utilizes the principle that coconut shell charcoal absorbs oxygen from a closed environment and generates carbon dioxide during combustion and oxidation, thereby creating a local oxygen-carbon dioxide atmosphere. Because the coconut shell charcoal and barium titanate powder are fully mixed, the oxygen partial pressure during the sintering of barium titanate ceramics is controlled both externally and internally.

[0047] Preferably, the highest temperature for high-temperature carbonization in step 2 is 900℃, the holding time is 2-3 hours, and the maximum heating rate is 5℃ / min.

[0048] Preferably, the specific process of the high-temperature carbonization is as follows: the temperature is raised from 20°C to 200°C in 36 minutes, then raised from 200°C to 600°C in 80 minutes, then raised from 600°C to 900°C in 60 minutes, held at 900°C for 120 minutes, then cooled from 900°C to 500°C in 60 minutes, and finally cooled down with the furnace.

[0049] Example 3

[0050] Preferably, in step 3, a 150-mesh sieve is used for sieving.

[0051] Preferably, in step 4, the mass ratio of coconut shell charcoal to barium titanate powder is 2~4:100.

[0052] Preferably, in step 4, adjusting the mass ratio of coconut shell charcoal to barium titanate powder to control the performance of barium titanate ceramics specifically involves the following: when the mass ratio of coconut shell charcoal to barium titanate powder is close to 2:100, the dielectric loss of the barium titanate ceramic is the lowest at the same frequency, and the dielectric constant is the highest at the same frequency; when the mass ratio of coconut shell charcoal to barium titanate powder is close to 6:100, the dielectric loss of the barium titanate ceramic is the highest at the same frequency, and the dielectric constant is the lowest at the same frequency.

[0053] Example 4

[0054] Preferably, in step 5, the binder is a PVA solution, and the weight ratio of powder to binder is 100:5~10.

[0055] Preferably, the maximum sintering temperature in step 6 is 1275℃, the holding time is 2-4 hours, and the maximum heating rate is 5℃ / min.

[0056] Preferably, the sintering process is as follows: the temperature is raised from 20°C to 200°C after 30 minutes, then raised to 600°C after 80 minutes, held at 600°C for 30 minutes, then raised to 1225°C after 125 minutes, then raised to 1275°C after 50 minutes, held at 1275°C for 120 minutes, then lowered to 500°C after 60 minutes, and finally cooled down with the furnace.

[0057] Example 5

[0058] like Figure 1 As shown, the first step is to select and clean the coconut shells. Select the thicker and harder old coconut shells, clean them, remove the fibers until the surface is smooth, and use a high-temperature drying oven set to 120°C to dehydrate and dry for 2 hours.

[0059] Step 2: Coconut shell crushing and high-temperature carbonization; The dried coconut shells are crushed into small pieces, placed in a crucible, and carbonized at high temperature in a muffle furnace. The maximum temperature is 900℃, and the holding time is 2 hours. The maximum heating rate is 5℃ / min. The specific process is as follows: 20℃—36min—200℃—80min—600℃—60min—900℃—120min—900℃—60min—500℃—cooling down with the furnace;

[0060] Step 3: Grind and sieve the carbonized coconut shells; take out the high-temperature carbonized coconut shell charcoal, grind it, and sieve it through a 150-mesh sieve to ensure that the size of the coconut shell charcoal is small enough.

[0061] Step 4: Mix and grind coconut shell charcoal and barium titanate powder in a certain proportion; weigh coconut shell charcoal and barium titanate powder at a mass ratio of 2%, 4% and 6% respectively, and grind them to make them fully mixed.

[0062] Step 5: Powder tableting after mixing; PVA solution is added to the mixed powder as a binder, and after thorough grinding, the powder is tableted to obtain a preform of coconut shell carbon and barium titanate that is fully mixed. Each preform weighs between 0.36 and 0.37 g.

[0063] Step 6: Sintering; The pressed green blank is placed in a muffle furnace and sintered at a high temperature of 1275℃ for 2 hours. The maximum heating rate is 5℃ / min. The specific process is as follows: 20℃—30min—200℃—80min—600℃—30min—600℃—125min—1225℃—50min—1275℃—120min—1275℃—60min—500℃—cooling down with the furnace.

[0064] Step 7: Conduct various performance tests on the sintered coconut shell carbon-doped barium titanate ceramic.

[0065] Comparative example:

[0066] To make a performance comparison, another set of pure barium titanate ceramics was prepared, with the process conditions remaining the same as those above.

[0067] like Figure 2 The image shows the XRD pattern of sintered barium titanate ceramics. The barium titanate sintered using the method of this invention exhibited the original tetragonal perovskite structure (JCPDS.05-0626) of barium titanate at mixing mass ratios of 2%, 4%, and 6% coconut shell carbon, without the appearance of a second phase. This indicates that the coconut shell carbon did not introduce impurities during the oxygen partial pressure control of barium titanate sintering, and that all carbon elements were burned and volatilized during the process.

[0068] Barium titanate, as a crucial foundational material for practical electronic components, is paramount in enhancing its industrial application value. For barium titanate with industrial application value, performance stability is the most critical performance indicator. Dielectric loss is a vital metric for evaluating the performance stability of electronic components. During operation, electrical energy is converted into heat, causing the dielectric temperature to rise. Excessive dielectric loss leads to excessively high dielectric temperatures, accelerating thermal decomposition and aging, potentially resulting in complete performance failure. Therefore, to adapt to different operating frequencies and temperatures, it is essential to reduce dielectric loss while maintaining a sufficient dielectric constant. This is crucial for the stable operation of electronic components and circuits.

[0069] like Figure 3 The figure shows the dielectric loss-frequency spectrum of sintered barium titanate ceramics. Barium titanate sintered using the method of this invention exhibited significant reductions in dielectric loss at mixing mass ratios of 2%, 4%, and 6% coconut shell carbon. The sample with a 2% mixing mass ratio showed the lowest dielectric loss, while the samples with 4% and 6% mixing mass ratios showed slightly higher dielectric losses. This indicates that coconut shell carbon can significantly improve the performance stability of barium titanate sintering by controlling the oxygen partial pressure. Furthermore, this demonstrates that the coconut shell carbon was indeed completely burned and volatilized during the experiment. A significant cause of dielectric loss is the conductive ions in barium titanate ceramics; these ions increase the leakage current density within the ceramic, leading to increased dielectric loss. Carbon has better conductivity than barium titanate; if carbon remains in the barium titanate, it will inevitably cause an increase in leakage current density and dielectric loss. Figure 3It is evident that the dielectric loss of barium titanate mixed with coconut shell char is significantly reduced, which fully demonstrates that the coconut shell char was indeed completely burned and volatilized during the experiment. This strongly proves that the change in dielectric properties caused by this process is due to the control of oxygen partial pressure caused by the combustion of coconut shell char during barium titanate sintering.

[0070] The proof that this invention controls oxygen partial pressure deep into the ceramic interior is as follows:

[0071] 1. The coconut shell charcoal has been fully mixed with the barium titanate ceramic. Then, the mixed powder is pressed into tablets, and the coconut shell charcoal will be fully distributed in the ceramic blank obtained by pressing.

[0072] 2. During the sintering of the bisque, the coconut shell char distributed within the bisque is fully combusted and completely converted into gas, which allows for oxygen partial pressure control to penetrate deep into the ceramic interior.

[0073] In Example 5, we described in detail the sample preparation process, including the mixing of coconut shell char and barium titanate, re-pressing, and re-sintering. We also explained the experimental data. A comparison of the experimental data from Example 5 and the comparative examples shows that the coconut shell char was fully combusted and converted into gas during sintering. On the one hand, XRD crystal structure analysis indicates that no coconut shell char residue remains. On the other hand, the general reduction in dielectric loss of the mixed coconut shell char samples demonstrates that carbon residue does not increase dielectric loss, proving that carbon has been completely removed.

[0074] Therefore, the reason for the performance change in this process can be determined to be the control of oxygen partial pressure by the coconut shell carbon that penetrates deep into the ceramic. Thus, it can be proved that coconut shell carbon can not only control the atmosphere on the surface of barium titanate ceramic, but also directly control the atmosphere inside the barium titanate ceramic.

[0075] In addition, such as Figure 4 As shown, the dielectric constant-frequency spectrum of sintered barium titanate ceramics reveals that barium titanate sintered using the method of this invention exhibits a decrease in relative dielectric constant at mixing mass ratios of 2%, 4%, and 6% coconut shell carbon. All three mixing mass ratios show a decrease compared to pure barium titanate, with the 2% mixing mass ratio showing the smallest decrease, while the 4% and 6% mixing mass ratios show a further decreasing trend in dielectric constant. However, it is important to note that the frequency stability of the dielectric constant is enhanced compared to pure barium titanate. Specifically, the amplitude of the change in dielectric constant at both high and low frequencies is reduced. Combining these two aspects, this further demonstrates that coconut shell carbon can significantly improve the performance stability of barium titanate sintering by controlling the oxygen partial pressure.

[0076] In summary, this invention utilizes coconut shell carbon to control the oxygen partial pressure during the sintering of barium titanate without introducing impurities, and plays an important role in improving performance stability. This proves that this invention can achieve the expected results.

[0077] The working principle of this invention is as follows:

[0078] This invention uses coconut shells as raw materials, which are carbonized at high temperatures to obtain coconut shell charcoal. The coconut shell charcoal is then mixed with barium titanate powder to control the oxygen partial pressure during sintering. Since barium titanate has a high sintering temperature, generally in the range of 1200℃ to 1300℃, the coconut shell charcoal has already undergone high-temperature combustion and oxidation. In the experiment, a relatively closed environment can be constructed by sealing external experimental equipment. During the combustion and oxidation process of the coconut shell charcoal, it will inevitably absorb oxygen from the closed environment and generate carbon dioxide, thus creating a local oxygen-carbon dioxide atmosphere. In addition, since the coconut shell charcoal and barium titanate powder are fully mixed, this atmosphere exists throughout the entire interior and outer surface of the ceramic, thereby achieving overall control of the oxygen partial pressure both externally and internally.

[0079] This invention uses coconut shells as raw material for processing, and mixes coconut shell charcoal with barium titanate to control the oxygen partial pressure during sintering. This significantly reduces the raw material cost for oxygen partial pressure control in barium titanate ceramic sintering; ensures no environmental pollution during oxygen partial pressure control; avoids impurity generation during oxygen partial pressure control; and achieves comprehensive external and internal control of oxygen partial pressure during barium titanate ceramic sintering.

[0080] This invention involves calcining coconut shells into charcoal, which is then thoroughly mixed with barium titanate. Under high-temperature sintering conditions, the charcoal penetrates the interior of the barium titanate. As the temperature continues to rise, the charcoal burns, consuming oxygen and generating carbon dioxide. Simultaneously, a relatively enclosed environment is created through the sealing of external experimental equipment, thus forming an oxygen-carbon dioxide atmosphere locally. Furthermore, because the coconut shell charcoal and barium titanate powder are thoroughly mixed, this atmosphere exists throughout the entire interior and outer surface of the ceramic, thereby achieving overall control of the oxygen partial pressure both externally and internally. By adjusting the mixing ratio of coconut shell charcoal and barium titanate, the oxygen partial pressure during sintering can be regulated.

[0081] The raw material used in this invention, coconut shell, has a large yield, which can significantly reduce raw material costs. The natural nature of coconut shell can solve the environmental pollution problem of specific gases or high-temperature volatile compounds. Coconut shell charcoal itself does not contain other components, which can solve the problem of impurity generation caused by the atmosphere. The thorough mixing of coconut shell charcoal and barium titanate powder can ensure that this oxygen partial pressure control is not only limited to the surface, but also penetrates into the interior of the ceramic, achieving overall oxygen partial pressure control both externally and internally.

[0082] This invention avoids the problems of high cost, environmental pollution, easy generation of impurities, and difficulty in penetrating the interior of ceramics that exist in previous methods by mixing calcined coconut shell charcoal with barium titanate and controlling the oxygen partial pressure during sintering.

[0083] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

[0084] Many other changes and modifications can be made without departing from the concept and scope of this invention. It should be understood that this invention is not limited to the specific embodiments, and the scope of this invention is defined by the appended claims.

Claims

1. A method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells, characterized in that... Includes the following steps: Step 1: Select coconut shells, wash them, remove the fibers, and dehydrate and dry them using a high-temperature forced-air drying oven; Step 2: Crush the dried coconut shells into small pieces, put them into a crucible, and carbonize them at high temperature in a muffle furnace; Step 3: Take out the coconut shell charcoal after high-temperature carbonization, grind it, and sieve it; Step 4: Weigh coconut shell charcoal and barium titanate powder at a mass ratio of 2-6:

100. Adjusting the mass ratio of coconut shell charcoal to barium titanate powder controls the performance of barium titanate ceramics. When the mass ratio of coconut shell charcoal to barium titanate powder is close to 2:100, the dielectric loss of barium titanate ceramics is the lowest at the same frequency, and the dielectric constant is the highest at the same frequency. When the mass ratio of coconut shell charcoal to barium titanate powder is close to 6:100, the dielectric loss of barium titanate ceramics is the highest at the same frequency, and the dielectric constant is the lowest at the same frequency. Then grind to fully mix the coconut shell charcoal and barium titanate powder. The thorough mixing of coconut shell charcoal and barium titanate powder achieves overall control of oxygen partial pressure during the sintering of barium titanate ceramics, both externally and internally. Step 5: Add binder to the mixed powder, grind thoroughly, and then compress the powder into tablets to obtain a raw blank in which coconut shell carbon and barium titanate are fully mixed. Step 6: Place the compressed green blank into a muffle furnace and sinter it at a high temperature; Step 7: Obtain coconut shell carbon mixed barium titanate ceramic.

2. The method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells according to claim 1, characterized in that: In step 1, select old coconut shells that are thick and hard, remove the fibers, and dehydrate and dry them in a high-temperature forced-air drying oven set at 120°C for 1.5 to 3 hours.

3. The method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells according to claim 1, characterized in that: The highest temperature for high-temperature carbonization in step 2 is 900℃, and the holding time is 2-3 hours, with a maximum heating rate of 5℃ / min.

4. The method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells according to claim 3, characterized in that, The specific process of high-temperature carbonization is as follows: the temperature is raised from 20°C to 200°C in 36 minutes, then raised to 600°C in 80 minutes, then raised to 900°C in 60 minutes, held at 900°C for 120 minutes, then cooled to 500°C in 60 minutes, and finally cooled down with the furnace.

5. The method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells according to claim 3, characterized in that: In step 3, sieving is performed using a 150-mesh sieve.

6. The method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells according to claim 3, characterized in that: In step 4, the mass ratio of coconut shell charcoal to barium titanate powder is 2~4:

100.

7. The method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells according to claim 1, characterized in that: In step 5, the binder is a PVA solution, and the weight ratio of powder to binder is 100:5~10.

8. The method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells according to claim 1, characterized in that: The highest temperature for sintering in step 6 is 1275℃, and the holding time is 2-4 hours, with a maximum heating rate of 5℃ / min.

9. The method for controlling oxygen partial pressure and properties during the sintering of barium titanate ceramics using coconut shells according to claim 8, characterized in that, The specific sintering process is as follows: the temperature is raised from 20°C to 200°C after 30 minutes, then raised to 600°C after 80 minutes, held at 600°C for 30 minutes, then raised to 1225°C after 125 minutes, then raised to 1275°C after 50 minutes, held at 1275°C for 120 minutes, then lowered to 500°C after 60 minutes, and finally cooled down with the furnace.

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