Preparation method of electrical grade magnesium oxide capable of slowing down current leakage

Abstract

The invention relates to a preparation method of electrical-grade magnesium oxide for slowing down current leakage, belongs to the technical field of electrical-grade magnesium oxide, and solves the problems of poor insulativity, relatively high electrical leakage and the like in the actual use process of electrical-grade magnesium oxide. Comprising the following steps: step 1, weighing nano calcium oxide and lanthanide series metal oxide, putting the nano calcium oxide and the lanthanide series metal oxide into a quartz crucible, and uniformly mixing to obtain a primary mixed oxide auxiliary agent; 2, heating the mixed oxide auxiliary agent obtained in the step 1 in a muffle furnace, cooling to room temperature under a drying condition to obtain white powder, and grinding to obtain an oxide auxiliary agent; 3, absorbing ethyl acetate (EA), hydrogen-containing silicone oil and polycyclic aromatic hydrocarbon (D30), putting into a centrifugal tube, and uniformly mixing to obtain a liquid film coating auxiliary agent; the method has the advantages that the current leakage of the electrical-grade magnesium oxide with poor insulativity can be slowed down by adding the metal oxide aid under the condition that the original properties of the electrical-grade magnesium oxide are not changed. The method is simple, convenient and obvious in effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical-grade magnesium oxide, and particularly relates to a preparation method of electrical-grade magnesium oxide for reducing current leakage. Background Art

[0002] As an inorganic material with high insulation performance, magnesium oxide is in the form of white crystalline powder at room temperature, and its natural form is mainly magnesite deposits. This substance is not only the core raw material for the smelting of metallic magnesium, but also an important high-temperature insulation material in modern industry. With the improvement of the living standards of urban and rural residents, the popularity of household electric heating appliances such as electric water heaters and rice cookers has been continuously increasing, directly driving the market demand for electrical-grade magnesium oxide. Currently, the electrical leakage of electrical-grade magnesium oxide is relatively high, and its high-temperature stability is insufficient, resulting in a shortening of the insulation life by more than 40%. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a preparation method of electrical-grade magnesium oxide for reducing current leakage, solving the technical problems such as poor insulation and high electrical leakage of current electrical-grade magnesium oxide during actual use.

[0004] To solve the above problems, the technical solution of the present invention is: a preparation method of electrical-grade magnesium oxide for reducing current leakage, comprising the following steps:

[0005] Step 1: Weigh nano-calcium oxide and lanthanide metal oxides into a quartz crucible and mix them evenly to obtain a preliminary mixed oxide additive;

[0006] Step 2: Place the mixed oxide additive obtained in Step 1 in a muffle furnace at 800°C - 850°C and continuously heat it for 8h - 10h, then cool it to room temperature under dry conditions to obtain a white powder, and grind it to obtain an oxide additive;

[0007] Step 3: Prepare a liquid film-forming additive, suck ethyl acetate (EA), hydrogen-containing silicone oil, and polycyclic aromatic hydrocarbon (D30) into a centrifuge tube and mix them evenly to obtain a liquid film-forming additive;

[0008] Step 4: Weigh magnesium oxide powder and the oxide additive in Step 2, then add them to a mixer and stir well; then add the liquid film-forming additive in Step 3 and continue stirring; after mixing evenly, add gaseous silicon and continue stirring to obtain electrical-grade magnesium oxide.

[0009] Preferably, the doping ratio of nano-calcium oxide and lanthanide metal oxides is both 0.5%.

[0010] Preferably, the lanthanide metal oxide is La2O3, Sm2O3 or Eu2O3.

[0011] Preferably, in step three, the ratio of ethyl acetate (EA), hydrogen-containing silicone oil, and polycyclic aromatic hydrocarbon (D30) is 2:7:1.

[0012] Preferably, in step one, the nano calcium oxide is 10 g ± 0.2 g, and the lanthanide metal oxide is 10 g ± 0.2 g; in step three, the ethyl acetate (EA) is 2 mL ± 0.2 mL, the hydrogen-containing silicone oil is 7 mL ± 0.2 mL, and the polycyclic aromatic hydrocarbon (D30) is 1 mL ± 0.05 mL; in step four, the magnesium oxide powder is 198 g ± 0.5 g, the oxide additive is 2 g ± 0.2 g, the liquid film-forming additive is 1 mL ± 0.05 mL, and the fumed silica is 0.7 g ± 0.2 g.

[0013] Preferably, the stirring time in step four is 20 minutes - 30 minutes each time, and the stirring speed is 40 r / min each time.

[0014] Preferably, the purity of the nano calcium oxide is 98%, and the density of the nano calcium oxide is 3.3 g / mL.

[0015] Preferably, the method for determining the doping ratio of nano calcium oxide and lanthanide metal oxide is as follows:

[0016] Step one: Determine the addition ratio of the metal oxide;

[0017] Calculated based on the proportion of 200 g of finished magnesium oxide, magnesium oxide materials containing calcium oxide with proportion gradients of 0, 0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.50%, 1.75%, and 2.00% are prepared respectively. By measuring the leakage current and peak current of the corresponding electrical grade magnesium oxide and observing whether the magnesium oxide powder turns black after power-on, it is finally concluded that when the calcium oxide content is 1%, the leakage current and peak current are the best;

[0018] Step two: Determine the types of metal oxide fillers;

[0019] Calculated based on the proportion of 200 g of finished magnesium oxide, a total of 9 metal oxides, namely transition metals and lanthanide metals ZnO, Al2O3, CaO, ZrO2, La2O3, CeO2, Sm2O3, Eu2O3, and Gd2O3, are used as fillers for magnesium oxide respectively, and the oxide addition ratio is 1% for all; by comparing the peak current of the electrical grade magnesium oxide with different fillers and whether the magnesium powder turns black, finally, these four metal oxides, CaO, La2O3, Sm2O3, and Eu2O3, are selected as fillers;

[0020] Step three: Optimize the mixing ratio of the metal oxide fillers;

[0021] Mixing and doping CaO with three other lanthanide oxides La2O3, Sm2O3, and Eu2O3; the doping ratios of CaO to the three lanthanide oxides range from 0.1%:0.9% to 0.9%:0.1% in 9 gradients. It is found that when the doping ratio of CaO to the three lanthanide oxides is 0.5%:0.5%, both the leakage current and peak current of magnesium oxide are the smallest. The conclusion is that the optimal doping ratio of CaO to the three lanthanide oxides is 0.5%.

[0022] Among them, D30 is a kind of polycyclic aromatic hydrocarbon.

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

[0024] A preparation method of an electrician-grade magnesium oxide for slowing down current leakage according to the present invention uses calcium oxide as the main body of the auxiliary filler. By adding three lanthanide metal oxides, lanthanum, samarium, and europium, and uniformly mixing them by the melting method, an oxide auxiliary is obtained. Adding the oxide auxiliary during the magnesium oxide film coating process can significantly reduce the leakage current and peak current of the electrician-grade magnesium oxide, and it does not turn black under the condition of dry burning for 2 hours. The electrician-grade magnesium oxide developed with this oxide auxiliary has the advantages of high insulation, high voltage resistance, low heat generation, non-moisture return, and easy storage during use, which has enlightenment significance for the development of insulation magnesium oxide series products and has good market development potential. Description of the Drawings

[0025] Figure 1 It is the optimization diagram of the proportion of calcium oxide as the filler. Detailed Embodiments

[0026] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0027] Embodiment 1: This embodiment provides a preparation method of an electrician-grade magnesium oxide for slowing down current leakage, including the following steps:

[0028] Step 1: Accurately weigh 10g ± 0.2g of nano-calcium oxide and 10g ± 0.2g of lanthanide metal oxide into a quartz crucible and mix them evenly to obtain a preliminary oxide auxiliary; the purity of the nano-calcium oxide is 98%, the density of the nano-calcium oxide is 3.3g / mL, and the lanthanide metal oxides are La2O3, Sm2O3, Eu2O3, etc.;

[0029] Step 2: Place the mixed oxide auxiliary obtained in Step 1 in a muffle furnace at 800°C - 850°C and continuously heat it for 8h - 10h, and cool it to room temperature under dry conditions to obtain a white powder. After grinding, an oxide auxiliary is obtained;

[0030] Step 3: Configure the liquid film coating aid. Use a pipette to accurately aspirate 2 mL ± 0.2 mL of ethyl acetate (EA), 7 mL ± 0.2 mL of hydrogen-containing silicone oil, and 1 mL ± 0.05 mL of polycyclic aromatic hydrocarbon (D30) into a 15 mL centrifuge tube and mix evenly.

[0031] Step 4: Accurately weigh 198 g ± 0.5 g of magnesium oxide powder and 2 g ± 0.2 g of the oxide aid in Step 1, add them to a 1 L mixer and stir well for about 30 minutes; then add 1 mL ± 0.05 mL of the liquid film coating aid in Step 3 to the mixer and continue stirring for 30 minutes; after the liquid film coating aid is mixed evenly, add 0.7 g ± 0.2 g of fumed silica to the mixer and continue stirring for 30 minutes to obtain high-insulation electrical-grade magnesium oxide.

[0032] The advantage of the preparation method adopted in this embodiment is that for electrical-grade magnesium oxide with poor insulation, without changing its original properties, the current leakage can be reduced by adding metal oxide aids. This method is simple, convenient and effective.

[0033] Example 2: This example provides a method for preparing electrical-grade magnesium oxide to slow down current leakage, including the following steps:

[0034] Step 1: Determine the proportion of lanthanide metal oxides in magnesium oxide.

[0035] Calculated based on the proportion of 200 g of finished magnesium oxide, accurately weigh a total of 2 g of CaO and lanthanide metal oxide (LMO). The lanthanide metal oxide is La2O3, Sm2O3 or Eu2O3. Among them, the proportions of CaO:LMO are 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1 respectively to configure 9 different proportions of lanthanide metal oxide additives. Mix the additives evenly and add them to a muffle furnace at 800 °C and heat for 8 h. After cooling, put them into a self-sealing bag and mark and seal.

[0036] Step 2: Mix magnesium oxide and lanthanide metal oxide evenly.

[0037] Weigh 198 g of magnesium oxide raw material and the previously configured 2 g of lanthanide metal oxide additive and add them to a 1 L mixer and stir at a speed of 40 r / min for 20 min.

[0038] Step 3: Configure the liquid film coating aid.

[0039] Adopt the blending scheme of ethyl acetate (EA), hydrogen-containing silicone oil, and D30 (polycyclic aromatic hydrocarbon) to configure the liquid film coating aid. The proportions of the three are 2:7:1 respectively. To prevent the occurrence of silicone oil ring-opening polymerization reaction, the aid is prepared and used immediately.

[0040] Step 4: Coat magnesium oxide with a film.

[0041] After the magnesium oxide and lanthanide metal oxide in the mixer in Step 2 are mixed evenly, add the liquid film coating assistant prepared in Step 3, and then continue to turn on the mixer switch and stir at a speed of 40 r / min for another 20 min.

[0042] Step 5: Gas-phase silicon adsorption;

[0043] After the magnesium oxide in the mixer in Step 4 is completely coated, add 0.7 g of gas-phase silicon to adsorb the excess silicone oil assistant, and continue to stir at a speed of 40 r / min for 20 min.

[0044] Due to their unique electronic structures and chemical properties, lanthanide metal oxides have a wide range of applications in materials science. In terms of insulation performance, lanthanide metal oxides usually have good electrical insulation, which makes them potentially valuable as insulating materials in electrical-grade magnesium oxide. The principle is that lanthanide metal oxides may have a specific electronic structure, resulting in a relatively large band gap in their energy band structure. This band gap prevents the transition of electrons, thus making the material exhibit insulation. In addition, in lanthanide metal oxides, a dense oxide film can be rapidly formed on the surface, and this oxide film is impermeable to almost all media, thus providing excellent insulation performance.

[0045] The present invention has the following advantages compared with the prior art:

[0046] The addition of calcium oxide can improve the thermodynamic stability of the magnesium oxide-based material. This improvement in stability helps to reduce the electrical leakage of the material at high temperatures because compounds with high thermodynamic stability are less likely to undergo electrochemical reactions, thereby reducing the conductivity and electrical leakage. The addition of calcium oxide can also play a modifying role, changing the surface properties of the material, reducing the migration of electrons, and thus reducing electrical leakage; in addition, it can also inhibit the blackening of the magnesium oxide powder after organic modification when it is electrified. The double-metal doping can reduce the sintering temperature, which helps to reduce the defects in the material, thereby reducing the electronic conductivity and electrical leakage. The doping of calcium oxide can effectively inhibit the valence state transition of lanthanide metals, thereby reducing the electronic conductivity. This is because the transition of lanthanide metals from trivalent to divalent will lead to a smaller band gap of the material, increasing the electronic conductivity, while the doping of calcium oxide is conducive to maintaining a relatively large band gap, thus inhibiting the electronic conductivity.

[0047] In a method for preparing electrical-grade magnesium oxide for reducing current leakage according to this embodiment, ordinary electrical-grade magnesium oxide is selected as the core raw material. With the help of the advanced shaping technology of a spherical machine, the originally irregular magnesium oxide crystal particles are processed into regular shapes such as circular or quasi-circular. This optimization of the particle shape greatly improves the fluidity of the magnesium oxide powder, enabling it to be arranged more evenly and tightly during the subsequent filling process. As a result, the filling density of the finished product is significantly increased, thereby effectively enhancing the voltage resistance performance of the product.

[0048] In a method for preparing electrical-grade magnesium oxide for reducing current leakage according to this embodiment, organic impurities and crystal water in the magnesium oxide are removed through high-temperature heat treatment to improve the material purity and stability; then, the atomization technology is used to evenly coat the surface of the ultrasonic-stirred organic silicone oil to form a dense moisture-proof layer, enhancing its hydrophobicity and high-temperature resistance, and significantly improving the moisture-proof and high-temperature resistance of the magnesium oxide.

[0049] In a method for preparing electrical-grade magnesium oxide for reducing current leakage according to this embodiment, through the plasma pulse high-voltage demagnetization treatment process, the ferromagnetic oxides in the fused magnesia are demagnetized, thereby significantly reducing the content of ferromagnetic substances.

[0050] In a method for preparing electrical-grade magnesium oxide for reducing current leakage according to this embodiment, the experimental scheme aims to improve the insulation performance of magnesium oxide, such as reducing electrical leakage and peak current, by changing the proportion of lanthanide metal oxides and adding film-forming aids. By adsorbing the excess silicone oil aids with gaseous silicon, the residual silicone oil can be reduced, and the purity and performance of the product can be improved.

[0051] The method for optimizing and determining the proportion of metal oxides is as follows:

[0052] I. Determine the addition proportion of metal oxides, taking calcium oxide as an example; calculated based on the proportion of 200 g of finished magnesium oxide, prepare magnesium oxide materials containing calcium oxide with proportion gradients of 0, 0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.50%, 1.75%, and 2.00% respectively. By measuring the leakage current and peak current of the corresponding electrical-grade magnesium oxide, and observing whether the magnesium oxide powder turns black after power-on, it is finally obtained that when the calcium oxide content is 1%, the leakage current and peak current are the best, as shown in Table 1 and Figure 1 shown.

[0053] II. Determine the types of metal oxide fillers; Calculated based on the proportion of 200 g of finished magnesium oxide, a total of 9 metal oxides, namely transition metals and lanthanide metals ZnO, Al2O3, CaO, ZrO2, La2O3, CeO2, Sm2O3, Eu2O3, and Gd2O3, are used as fillers for magnesium oxide, and the addition ratio of the oxides is 1%. Table 2 selects four metal oxides, namely CaO, La2O3, Sm2O3, and Eu2O3, as fillers by comparing the peak current of electrical-grade magnesium oxide with different fillers and whether the magnesium powder turns black. The leakage currents of all four are below 0.2 mA, and there is no carbonization, that is, no blackening.

[0054] III. Optimize the mixing ratio of metal oxide fillers; The above optimization shows that the four metal oxides CaO, La2O3, Sm2O3, and Eu2O3 all perform well in the leakage current test. To reduce costs, CaO is mixed and doped with the other three lanthanide oxides La2O3, Sm2O3, and Eu2O3. The doping ratio of CaO to the three lanthanide oxides ranges from 0.1%:0.9% to 0.9%:0.1%, a total of 9 gradients. It can be found from Table 3 that when the doping ratio of CaO to the lanthanide oxide Eu2O3 is 0.5%:0.5%, both its leakage current and peak current are the smallest. Finally, it is concluded that the optimal doping ratio of CaO to the three lanthanide oxides is 0.5%. The filler ratios and electrical properties of CaO and the three lanthanide oxides are shown in Tables 4.1 - 4.5.

[0055] Table 1 shows the optimization of the proportion of calcium oxide filler.

[0056]

[0057]

[0058] Table 1

[0059] Table 2 shows the optimization of the proportion of metal oxide fillers.

[0060] Proportion of metal oxide (1%) Leakage current (mA) Peak current (mA) Whether it turns black ZnO 0.381 Overload Yes <![CDATA[Al2O3]]> 1.073 Overload Yes CaO 0.261 0.425 No <![CDATA[ZrO2]]> 0.607 0.796 Yes <![CDATA[La2O3]]> 0.204 0.383 No <![CDATA[CeO2]]> 0.807 0.847 Yes <![CDATA[Sm2O3]]> 0.173 0.328 No <![CDATA[Eu2O3]]> 0.184 0.359 No <![CDATA[Gd2O3]]> 0.532 Overload Yes

[0061] Table 2

[0062] Table 3 shows the optimization of the mixing and doping ratio of lanthanide metal oxide (Eu2O3) and calcium oxide.

[0063] <![CDATA[Proportion of Eu2O3]]> Proportion of calcium oxide Leakage current (mA) Peak current (mA) Whether it turns black 0.1％ 0.9％ 0.172 0.362 No 0.2％ 0.8％ 0.169 0.307 No 0.3％ 0.7％ 0.158 0.251 No 0.4％ 0.6％ 0.163 0.247 No 0.5％ 0.5％ 0.157 0.205 No 0.6％ 0.4％ 0.168 0.335 No 0.7％ 0.3％ 0.172 0.335 No 0.8％ 0.2％ 0.174 0.364 No 0.9％ 0.1％ 0.182 0.437 No

[0064] Table 3

[0065] Table 4.1 shows the optimization comparison of the mixed fillers of lanthanide metal oxides (La2O3, Sm2O3, Eu2O3) and calcium oxide (the first group).

[0066]

[0067] Table 4.1

[0068] Table 4.2 shows the optimization comparison of the mixed fillers of lanthanide metal oxides (La2O3, Sm2O3, Eu2O3) and calcium oxide (the second group).

[0069]

[0070] Table 4.2

[0071] Table 4.3 shows the optimization comparison of the mixed fillers of lanthanide metal oxides (La2O3, Sm2O3, Eu2O3) and calcium oxide (the third group).

[0072]

[0073] Table 4.3

[0074] Table 4.4 shows the optimization comparison of the mixed fillers of lanthanide metal oxides (La2O3, Sm2O3, Eu2O3) and calcium oxide (the fourth group).

[0075]

[0076] Table 4.4

[0077] Table 4.5 shows the optimization comparison of the mixed fillers of lanthanide metal oxides (La2O3, Sm2O3, Eu2O3) and calcium oxide (the fifth group).

[0078]

[0079] Table 4.5

[0080] From Table 1 and Figure 1It can be seen from [the relevant content] that within the range of 0-2% of the proportion of the filler calcium oxide, the leakage current of the magnesium oxide powder is in the mA order of magnitude, and its peak current is slightly greater than its leakage current. It can be found that the leakage current of the magnesium oxide powder first decreases and then increases with the increase of the proportion of the filler calcium oxide. The minimum leakage current is reached when the proportion of calcium oxide is 1%. Compared with the magnesium oxide prepared by the conventional process, the leakage current is reduced by more than 70%, and the heating tube does not turn black after being powered on. For the comparative analysis of the data in Table 2, it can be clearly seen that in addition to the calcium oxide filler, there are three fillers, lanthanum oxide, samarium oxide, and europium oxide, which all have good effects in reducing the leakage current, and the reduction of their peak current is particularly obvious. This is because the addition of lanthanide metal oxides can reduce the sintering temperature and increase the grain boundary conductivity, thereby reducing the electrical leakage. Table 3 shows the optimization of the mixing and doping ratio of lanthanum oxide and calcium oxide. It can be seen that when the ratios of lanthanum oxide and calcium oxide are both 0.5%, the leakage current is the lowest and the peak current of this type of magnesium oxide is about 0.2 mA. Tables 4.1 to 4.5 compare the doping of several lanthanide metal oxides with calcium oxide. It can be seen that the leakage current and peak current of the magnesium oxide powder containing three lanthanide metal oxide fillers reach the minimum. This may be because double and multi-doped oxides can further optimize the lattice structure, increase oxygen vacancies, reduce the ionic conductivity, and thus reduce the electrical leakage.

Claims

1. A preparation method of electrical grade magnesium oxide for reducing current leakage, characterized in that, It includes the following steps: Step 1: Weigh nano-calcium oxide and lanthanide metal oxide into a quartz crucible and mix them evenly to obtain a preliminary mixed oxide additive; Step 2: Place the mixed oxide additive obtained in Step 1 in a muffle furnace at 800 °C - 850 °C and continuously heat it for 8 h - 10 h, then cool it to room temperature under dry conditions to obtain a white powder, and grind it to obtain the oxide additive; Step 3: Prepare a liquid film-forming additive. Pipette ethyl acetate (EA), hydrogen-containing silicone oil, and polycyclic aromatic hydrocarbon (D30) into a centrifuge tube and mix them evenly to obtain the liquid film-forming additive; Step 4: Weigh magnesium oxide powder and the oxide additive in Step 2, then add them to a mixer and stir well; subsequently, add the liquid film-forming additive in Step 3 and continue stirring; after mixing evenly, add fumed silica and continue stirring to obtain electrical-grade magnesium oxide.

2. The preparation method of an electrical-grade magnesium oxide for reducing current leakage according to claim 1, characterized in that, The doping ratios of nano-calcium oxide and lanthanide metal oxide are both 0.5%.

3. The preparation method of an electrical-grade magnesium oxide for reducing current leakage according to claim 1, characterized in that, The lanthanide metal oxide is La2O3, Sm2O3, or Eu2O3.

4. The preparation method of an electrical grade magnesium oxide for reducing current leakage according to claim 1, characterized in that, In Step 3, the ratio of ethyl acetate (EA), hydrogen-containing silicone oil, and polycyclic aromatic hydrocarbon (D30) is 2:7:

1.

5. The preparation method of an electrical-grade magnesium oxide for reducing current leakage according to claim 1, characterized in that, In Step 1, the nano-calcium oxide is 10 g ± 0.2 g, and the lanthanide metal oxide is 10 g ± 0.2 g; in Step 3, the ethyl acetate (EA) is 2 mL ± 0.2 mL, the hydrogen-containing silicone oil is 7 mL ± 0.2 mL, and the polycyclic aromatic hydrocarbon (D30) is 1 mL ± 0.05 mL; in Step 4, the magnesium oxide powder is 198 g ± 0.5 g, the oxide additive is 2 g ± 0.2 g, the liquid film-forming additive is 1 mL ± 0.05 mL, and the fumed silica is 0.7 g ± 0.2 g.

6. The preparation method of an electrical-grade magnesium oxide for reducing current leakage according to claim 1, characterized in that, The stirring time for the three times in Step 4 is 20 minutes - 30 minutes, and the stirring speed is 40 r / min.

7. The preparation method of an electrical-grade magnesium oxide for reducing current leakage according to claim 1, characterized in that, The purity of nano-calcium oxide is 98%, and the density of nano-calcium oxide is 3.3 g / mL.

8. The preparation method of an electrical grade magnesium oxide for reducing current leakage according to claim 2, characterized in that, The method for determining the doping ratio of nano-calcium oxide and lanthanide metal oxide is as follows: Step 1: Determine the addition ratio of the metal oxide; Calculated based on the ratio of 200 g of the finished magnesium oxide, prepare magnesium oxide materials containing calcium oxide with proportion gradients of 0, 0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.50%, 1.75%, and 2.00% respectively. By measuring the leakage current and peak current of the corresponding electrical-grade magnesium oxide and observing whether the magnesium oxide powder turns black after electrification, it is finally concluded that when the calcium oxide content is 1%, the leakage current and peak current are the best; Step 2: Determine the type of the metal oxide filler; Calculated based on the ratio of 200 g of the finished magnesium oxide, use 9 metal oxides including transition metals and lanthanide metals ZnO, Al2O3, CaO, ZrO2, La2O3, CeO2, Sm2O3, Eu2O3, and Gd2O3 as the fillers of magnesium oxide respectively, and the oxide addition ratio is 1%; by comparing the peak current of the electrical-grade magnesium oxide with different fillers and whether the magnesium powder turns black, finally select these four metal oxides CaO, La2O3, Sm2O3, and Eu2O3 as the fillers; Step 3: Optimize the mixing ratio of the metal oxide fillers; Mix and dope CaO with three other lanthanide oxides La2O3, Sm2O3, and Eu2O3; the doping ratios of CaO to the three lanthanide oxides range from 0.1%:0.9% to 0.9%:0.1%, with a total of 9 gradients. It is found that when the doping ratio of CaO to the three lanthanide oxides is 0.5%:0.5%, both the leakage current and the peak current of magnesium oxide are the smallest. The conclusion is drawn that the optimal doping ratio of CaO to the three lanthanide oxides is 0.5% for all of them.

Images