High-voltage direct-current relay ceramic and preparation method thereof

Abstract

The invention relates to the field of ceramic materials, in particular to high-voltage direct-current relay ceramic and a preparation method thereof.The high-voltage direct-current relay ceramic is prepared from aluminum oxide powder, a sintering aid and a binder; the binder is composed of a hydrogen-containing vinyl organic silicon resin monomer and a transition metal organic complex, and when the binder is applied to a new energy automobile, a high-voltage direct-current circuit in an electric automobile can be effectively controlled and protected, and safe use of a battery is ensured.

Description

Technical Field

[0001] The present invention relates to the field of ceramic materials, and specifically to a ceramic for high-voltage direct-current relays and a preparation method thereof. Background Art

[0002] Ceramic materials have good insulation performance, can withstand high voltages, have good chemical corrosion resistance and packaging reliability, and are less affected by corrosive media such as acids and alkalis. Therefore, high-voltage direct-current relays made of ceramic materials are gradually replacing epoxy resin high-voltage direct-current relays and are used in new energy vehicles. Binders play a crucial role in the forming process of ceramic materials. At present, polyvinyl alcohol or polyvinyl butyral is mostly used as the binder for ceramic materials, and there are few reports on the use of silicone resin as the binder for ceramic materials. Summary of the Invention

[0003] Object of the Invention: Aiming at the above technical problems, the present invention provides a ceramic for high-voltage direct-current relays and a preparation method thereof.

[0004] The technical solution adopted is as follows:

[0005] A ceramic for high-voltage direct-current relays is made of alumina powder, sintering aids and a binder;

[0006] The binder is composed of a hydrogen-containing vinyl silicone resin monomer and a transition metal organic complex.

[0007] Further, the mass ratio of the hydrogen-containing vinyl silicone resin monomer to the transition metal organic complex is 100:1-5.

[0008] Further, the mass ratio of the alumina powder, sintering aids and binder is 100:1-5:1-3.

[0009] Further, the sintering aids are composed of manganese dioxide, titanium dioxide, magnesium oxide and rare earth oxides.

[0010] Further, the mass ratio of manganese dioxide, titanium dioxide, magnesium oxide and rare earth oxides is 1-5:1-5:1-5:1-5.

[0011] Further, the rare earth oxide is lanthanum oxide.

[0012] Further, the preparation method of the hydrogen-containing vinyl silicone resin monomer is as follows:

[0013] Dissolve triethoxysilane and vinyltriethoxysilane in absolute ethanol, add hydrochloric acid aqueous solution, hydrolyze at 20-40 °C for 1-5 h, and then carry out vacuum distillation.

[0014] Furthermore, the transition metal organic complex is an iron organic complex.

[0015] Furthermore, the iron organic complex is hydrazinocarbonylferrocene, and the CAS number of triethoxysilane is 12153-28-5.

[0016] The present invention also provides a method for preparing high-voltage DC relay ceramics:

[0017] Using anhydrous ethanol as a ball milling aid, alumina powder and a sintering aid are mixed and ball milled, and then hydrogenated vinyl silicone resin monomer and transition metal organic complex are added. After sufficient stirring, the anhydrous ethanol is evaporated to obtain a mixed powder. The mixed powder is added into a mold and pressed into a green billet, and finally the green billet is sintered.

[0018] Furthermore, during sintering, the temperature is first raised to 250-300°C at a rate of 5-10°C / min, kept warm for 60-120 minutes, then raised to 600-650°C at a rate of 5-10°C / min, kept warm for 120-180 minutes, and finally raised to 1350-1400°C at a rate of 1-5°C / min, kept warm for 120-180 minutes.

[0019] It has the following beneficial effects:

[0020] The present invention provides a high-voltage DC relay ceramic. The sintering aid synergistically achieves low-temperature, high-density sintering and excellent mechanical properties of alumina through liquid phase activation, solid solution strengthening, grain boundary pinning and grain boundary stabilization. The hydrogenated vinyl silicone resin monomer is first cured with a low degree of crosslinking during the heating process, and then further undergoes a hydrosilylation reaction under the catalysis of a transition metal organic complex to further self-crosslink, thereby forming a three-dimensional network structure with an adhesive effect between the ceramic particles. The three-dimensional network structure plays a bridging role from the molding to the sintering of the ceramic, and gives the green body sufficient mechanical strength. During high-temperature sintering, it decomposes into silicon dioxide, which can fill the grain boundary gaps, significantly reducing the risk of pore generation, and has the advantages of low residual carbon content and low shrinkage. Compared with commercially available silicone resin adhesives, the adhesive component of the present invention has a higher improvement in the mechanical properties of the high-voltage DC relay ceramic and can effectively reduce the shrinkage rate during the sintering process. When used in new energy vehicles, it can effectively control and protect the high-voltage DC circuit in the electric vehicle and ensure the safe use of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a cross-sectional SEM image of the high-voltage DC relay ceramic prepared in Example 1;

[0022] Figure 2 This is the curing process of the hydrogenated vinyl silicone resin monomer in Example 1. DETAILED DESCRIPTION

[0023] For those without specific conditions noted in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase. Technologies not mentioned in the present invention refer to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel tests and adopt the same treatment steps and parameters.

[0024] Example 1:

[0025] A high-voltage DC relay ceramic is made of alumina powder, manganese dioxide, titanium dioxide, magnesium oxide, lanthanum oxide and binder with a mass ratio of 100:0.5:0.5:1:0.5:1;

[0026] The binder is composed of a hydrogen-containing vinyl silicone resin monomer and ferrocene hydrazidecarbonyl with a mass ratio of 100:1.

[0027] The preparation method of the hydrogen-containing vinyl silicone resin monomer is as follows:

[0028] Dissolve 82.2 g of triethoxysilane and 19 g of vinyltriethoxysilane in 150 ml of absolute ethanol, slowly drop 35.1 g of a pre-prepared 0.1 mol / L hydrochloric acid aqueous solution into the system, hydrolyze for 5 h under the condition of a 30 °C water bath after dropping, and then remove absolute ethanol and water by vacuum distillation.

[0029] The preparation method of the above high-voltage DC relay ceramic:

[0030] Using absolute ethanol as a ball-milling aid, add alumina powder, manganese dioxide, titanium dioxide, magnesium oxide, and lanthanum oxide into the ball-milling tank of a planetary ball mill and mix and ball-mill for 10 h, then add the hydrogen-containing vinyl silicone resin monomer and ferrocene hydrazidecarbonyl, fully stir and then remove absolute ethanol by vacuum evaporation to obtain a mixed powder. Add the mixed powder into a mold and press it into a green body at 50 MPa. Put the green body into a sintering furnace, first heat it to 300 °C at a rate of 10 °C / min in an air atmosphere, hold for 120 min, then heat it to 650 °C at a rate of 5 °C / min, hold for 180 min, and finally heat it to 1350 °C at a rate of 1 °C / min and hold for sintering for 180 min.

[0031] Example 2:

[0032] A high-voltage DC relay ceramic is made of alumina powder, manganese dioxide, titanium dioxide, magnesium oxide, lanthanum oxide and binder with a mass ratio of 100:0.5:0.5:1:0.5:2;

[0033] The binder is composed of a hydrogen-containing vinyl silicone resin monomer and ferrocene hydrazidecarbonyl with a mass ratio of 100:1.

[0034] The preparation method of the hydrogen-containing vinyl organosilicon resin monomer is as follows:

[0035] Dissolve 82.2 g of triethoxysilane and 19 g of vinyltriethoxysilane in 150 ml of absolute ethanol, slowly add 35.1 g of a pre-prepared 0.1 mol / L hydrochloric acid aqueous solution dropwise to the system, after dropping, hydrolyze at 30 °C in a water bath for 5 h, and then remove absolute ethanol and water by vacuum distillation.

[0036] The preparation method of the above-mentioned high-voltage DC relay ceramic:

[0037] Using absolute ethanol as a ball-milling aid, add alumina powder, manganese dioxide, titanium dioxide, magnesium oxide, and lanthanum oxide to the ball-milling tank of a planetary ball mill and mix and ball-mill for 10 h, then add the hydrogen-containing vinyl organosilicon resin monomer and hydrazinocarbonylferrocene, stir well and then remove absolute ethanol by vacuum distillation to obtain a mixed powder. Add the mixed powder to a mold and press it into a green body at 50 MPa. Put the green body into a sintering furnace, first heat it to 300 °C at a rate of 10 °C / min in an air atmosphere, hold for 120 min, then heat it to 650 °C at a rate of 5 °C / min, hold for 180 min, and finally heat it to 1350 °C at a rate of 1 °C / min and hold for sintering for 180 min. The cross-sectional SEM diagram is as Figure 1 shown, and it can be seen that the internal density is relatively high.

[0038] Example 3:

[0039] A high-voltage DC relay ceramic is made of alumina powder, manganese dioxide, titanium dioxide, magnesium oxide, lanthanum oxide and a binder with a mass ratio of 100:0.5:0.5:1:0.5:3;

[0040] The binder is composed of a hydrogen-containing vinyl organosilicon resin monomer and hydrazinocarbonylferrocene with a mass ratio of 100:1.

[0041] The preparation method of the hydrogen-containing vinyl organosilicon resin monomer is as follows:

[0042] Dissolve 82.2 g of triethoxysilane and 19 g of vinyltriethoxysilane in 150 ml of absolute ethanol, slowly add 35.1 g of a pre-prepared 0.1 mol / L hydrochloric acid aqueous solution dropwise to the system, after dropping, hydrolyze at 30 °C in a water bath for 5 h, and then remove absolute ethanol and water by vacuum distillation.

[0043] The preparation method of the above-mentioned high-voltage DC relay ceramic:

[0044] With anhydrous ethanol as a ball milling aid, alumina powder, manganese dioxide, titanium dioxide, magnesium oxide, and lanthanum oxide are added to the ball mill jar of a planetary ball mill and mixed and ball-milled for 10 hours. Then, hydrogenated vinyl silicone resin monomer and hydrazinocarbonylferrocene are added. After sufficient stirring, the anhydrous ethanol is evaporated under reduced pressure to obtain a mixed powder. The mixed powder is added to a mold and pressed into a green billet at 50 MPa. The green billet is placed in a sintering furnace, and the temperature is first increased to 300°C at a rate of 10°C / min in an air atmosphere, kept warm for 120 minutes, then increased to 650°C at a rate of 5°C / min, kept warm for 180 minutes, and finally increased to 1350°C at a rate of 1°C / min, kept warm for 180 minutes.

[0045] Comparative Example 1:

[0046] The method is basically the same as Example 1, except that HC-1801B solvent-based methylphenyl silicone resin (Zhejiang Hongxin Innovation Materials) is used instead of the binder.

[0047] Comparative Example 2:

[0048] The process is basically the same as Example 1, except that manganese dioxide is not added.

[0049] Comparative Example 3:

[0050] The process is basically the same as Example 1, except that titanium dioxide is not added.

[0051] Comparative Example 4:

[0052] The process is basically the same as Example 1, except that magnesium oxide is not added.

[0053] Comparative Example 5:

[0054] The process is basically the same as Example 1, except that lanthanum oxide is not added.

[0055] Performance Testing

[0056] Ceramic samples were prepared according to the methods of Examples 1-3 and Comparative Examples 1-5 of the present invention and then subjected to performance testing.

[0057] The bulk density of the sample was calculated using the Archimedes drainage method;

[0058] Use a vernier caliper to measure the length of the sample before and after sintering, and calculate the shrinkage according to the following formula:

[0059] Shrinkage = (L0-L1) / L0

[0060] Where L0 is the sum of the lengths of the green body in the x, y, and z directions before sintering; L1 is the sum of the lengths of the green body in the x, y, and z directions after sintering.

[0061] The flexural strength of the specimen was measured by the three-point bending method on a universal testing machine, with a span of 30 mm, a loading rate of 0.5 mm / min, a sample size of 3 mm × 4 mm × 35 mm. Five specimens were tested for each data, and then the average value was taken. The test results are shown in Table 1 below:

[0062] Table 1:

[0063] <![CDATA[Bulk density / (g / cm 3 )]]> Shrinkage rate / % Flexural strength / MPa Example 1 3.62 0.13 336.5 Example 2 3.65 0.11 350.3 Example 3 3.61 0.14 329.7 Comparative Example 1 3.28 2.67 266.4 Comparative Example 2 3.40 0.35 301.6 Comparative Example 3 3.37 0.62 284.3 Comparative Example 4 3.32 0.84 274.5 Comparative Example 5 3.55 0.47 305.6

[0064] As can be seen from Table 1 above, the mechanical properties of the high-voltage DC relay ceramics prepared by the method of the present invention are excellent, and the shrinkage rate during the sintering process is low. Moreover, as the amount of the binder increases, the mechanical properties show a trend of increasing first and then decreasing.

[0065] From the comparison between Example 1 and Comparative Example 1, it can be seen that compared with the commercially available silicone resin binder, the binder component of the present invention has a higher improvement in the mechanical properties of the high-voltage DC relay ceramics, and can effectively reduce the shrinkage rate during the sintering process;

[0066] From the comparison between Example 1 and Comparative Examples 2-4, it can be seen that the addition of manganese dioxide, titanium dioxide, magnesium oxide, and lanthanum oxide plays a positive role in improving the mechanical properties of the high-voltage DC relay ceramics and reducing the shrinkage rate during the sintering process.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-voltage DC relay ceramic, characterized in that It is made of alumina powder, sintering aids and a binder; The binder is composed of a hydrogen-containing vinyl silicone resin monomer and a transition metal organic complex.

2. The high-voltage DC relay ceramic according to claim 1, wherein The mass ratio of the hydrogen-containing vinyl silicone resin monomer to the transition metal organic complex is 100:1 - 5.

3. The high-voltage DC relay ceramic according to claim 1, wherein, The mass ratio of the alumina powder, sintering aids and binder is 100:1 - 5:1 - 3.

4. The high-voltage DC relay ceramic according to claim 1, wherein The sintering aids are composed of manganese dioxide, titanium dioxide, magnesium oxide and rare earth oxides.

5. The ceramic for high-voltage DC relay according to claim 4, wherein The mass ratio of the manganese dioxide, titanium dioxide, magnesium oxide and rare earth oxides is 1 - 5:1 - 5:1 - 5:1 - 5.

6. The high-voltage DC relay ceramic according to claim 5, wherein The preparation method of the hydrogen-containing vinyl silicone resin monomer is as follows: Dissolve triethoxysilane and vinyltriethoxysilane in absolute ethanol, add an aqueous hydrochloric acid solution, hydrolyze at 20 - 40°C for 1 - 5 h, and then perform vacuum distillation.

7. The ceramic for high-voltage DC relay according to claim 1, wherein The transition metal organic complex is an iron organic complex.

8. The high-voltage DC relay ceramic according to claim 7, characterized in that, The iron organic complex is hydrazinocarbonylferrocene.

9. A method for preparing a high-voltage DC relay ceramic as described in any one of claims 2-8, characterized in that, Using absolute ethanol as a ball milling aid, mix and ball mill the alumina powder and sintering aids, then add the hydrogen-containing vinyl silicone resin monomer and the transition metal organic complex, fully stir and heat to evaporate the absolute ethanol to obtain a mixed powder. Add the mixed powder into a mold to press into a green body, and finally sinter the green body.

10. The preparation method of the ceramic for a high-voltage DC relay according to claim 9, characterized in that, During sintering, first heat up at a rate of 5 - 10°C / min to 250 - 300°C, hold for 60 - 120 min, then heat up at a rate of 5 - 10°C / min to 600 - 650°C, hold for 120 - 180 min, and finally heat up at a rate of 1 - 5°C / min to 1350 - 1400°C, hold for 120 - 180 min.

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