Method for enhancing performance of zinc aluminate ceramic by using metal oxide

Abstract

The invention belongs to the technical field of ceramic material preparation, and particularly relates to a method for enhancing the performance of zinc aluminate ceramic through metal oxide. Aiming at the problems of insufficient strength and the like of the zinc aluminate ceramic produced in the prior art, the zinc aluminate ceramic comprises the following raw materials: 40-65% of aluminum oxide, 30-55% of zinc oxide and 1-15% of metal oxide. The preparation process comprises the following steps: weighing aluminum oxide, zinc oxide and metal oxide according to a certain mass percentage, carrying out wet ball milling and mixing on the three kinds of powder by using absolute ethyl alcohol or deionized water, drying the ball-milled slurry, grinding the dried blocky powder by using a mortar, sieving, carrying out dry pressing on the sieved powder to form a green body, sintering the green body, and sintering the sintered green body to obtain the aluminum oxide-zinc oxide-metal oxide composite material. And cooling to obtain the zinc aluminate ceramic. The metal oxide is used as an additive, so that the mechanical property of the zinc aluminate ceramic is improved, and the application field of the zinc aluminate ceramic is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic material preparation, and in particular relates to a method for enhancing the performance of zinc aluminate ceramics with metal oxides. Background Art

[0002] Zinc aluminate ceramics (ZnAl2O4) as an important structural and functional ceramic material has received extensive attention and research in recent years. Zinc aluminate ceramics have high melting point, good thermal and chemical stability, low thermal expansion coefficient, good mechanical properties and corrosion resistance, which enable them to perform well under high temperature, high pressure and harsh environment.

[0003] In terms of electrical properties, zinc aluminate ceramics are widely used in electronic and electrical fields such as high-frequency circuits, capacitors and microwave devices due to their excellent electrical insulation and dielectric properties. In terms of mechanical properties, it has a certain hardness and wear resistance, and can remain stable in harsh environments, so it plays an important role in structural ceramics and abrasive applications. In terms of thermal properties, it exhibits good high temperature resistance and thermal shock stability, and is suitable for electronic devices and thermal barrier coatings in high temperature environments. In terms of chemical stability, it can resist acid and alkali corrosion and is suitable for chemical vessels and chemical reaction devices. In addition, zinc aluminate ceramics are also widely used in resistors, furnace refractory materials, optical glass and other fields.

[0004] At present, the preparation methods of zinc aluminate ceramics mainly include plasma sintering (SPS), microwave heating sintering, hot pressing sintering, and solid phase reaction sintering. Most of the zinc aluminate materials reported in the prior art are functional ceramics, such as a Chinese patent (publication number: CN109574650A) that proposes a preparation method for highly wave-transmitting porous zinc aluminate ceramics, while structural zinc aluminate ceramics are rarely reported due to poor structural performance. Summary of the invention

[0005] In view of the problem that zinc aluminate ceramics produced by the prior art have insufficient strength, the present invention proposes a method for enhancing the performance of zinc aluminate ceramics with metal oxides, and intends to use metal oxides (MO) to improve the performance of zinc aluminate ceramics. The method can promote the densification of zinc aluminate ceramics and improve their mechanical properties. The zinc aluminate ceramics prepared by the method make up for the lack of strength, improve the mechanical properties of zinc aluminate ceramics, and broaden their application fields. At the same time, the method is simple and easy to operate, has a low preparation cost, and has fewer process flows, and is suitable for mass production.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for enhancing the performance of zinc aluminate ceramics with metal oxides, using aluminum oxide and zinc oxide as raw materials and metal oxides as additives, comprising the following steps:

[0008] Step 1, weighing aluminum oxide, zinc oxide and metal oxide according to mass percentage;

[0009] Step 2, mixing the three powders and performing wet ball milling;

[0010] Step 3, drying the ball-milled slurry;

[0011] Step 4, grinding the dried bulk powder in a mortar and then sieving;

[0012] Step 5, dry-pressing the sieved powder into a green body;

[0013] Step 6, sintering the green body, and obtaining the zinc aluminate ceramic with enhanced performance after cooling.

[0014] Furthermore, in the step, the mass percentages of aluminum oxide, zinc oxide and metal oxide are 40-65%, 30-55% and 1-15% respectively.

[0015] Furthermore, the metal oxide is at least one of magnesium oxide, calcium oxide, titanium dioxide, tin oxide, and ferric oxide.

[0016] The aluminum oxide includes chemically pure aluminum oxide, activated aluminum oxide, calcined aluminum oxide, nano aluminum oxide, etc.; the zinc oxide includes chemically pure zinc oxide, activated zinc oxide, industrial grade zinc oxide, nano zinc oxide, etc.

[0017] Furthermore, the wet ball milling in step 2 is specifically as follows: ball milling is performed in anhydrous ethanol or deionized water which is 30-50% of the total mass of the aluminum oxide, zinc oxide and metal oxide, the ball milling medium is agate beads, the ball milling speed is 300-500 r / min, and the ball milling time is 2-5 h.

[0018] Furthermore, the drying temperature in step 3 is 60-100°C.

[0019] Furthermore, in step 4, a 60-mesh sieve is used for screening.

[0020] Furthermore, in step 5, the pressure of dry pressing is 20-60 MPa, and the holding time is 30-60 s.

[0021] Furthermore, in step 6, the sintering temperature is 1300-1700° C., the heating rate is 3-5° C. / min, and the holding time is 2-5 h.

[0022] The invention also provides a zinc aluminate ceramic prepared by the method.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The invention adopts aluminum oxide and zinc oxide as raw materials, MO as an additive, and adopts a solid phase reaction sintering method to successfully prepare zinc aluminate ceramics with good performance. The preparation process is simple and easy to operate, and it is easy to achieve large-scale production. The preparation scheme can improve the mechanical properties of zinc aluminate ceramics and expand the application field of zinc aluminate ceramics. DETAILED DESCRIPTION

[0025] In order to further illustrate the technical solution of the present invention, the present invention is further described below through embodiments.

[0026] The raw materials of the present invention are: aluminum oxide, zinc oxide, and MO. The aluminum oxide includes chemically pure aluminum oxide, activated aluminum oxide, calcined aluminum oxide, nano aluminum oxide, etc., and the addition amount of aluminum oxide is 40-65%; the zinc oxide includes chemically pure zinc oxide, activated zinc oxide, industrial-grade zinc oxide, nano zinc oxide, etc., and the addition amount of zinc oxide is 30-55%; the metal oxide (MO) includes magnesium oxide, calcium oxide, titanium dioxide, tin oxide, ferric oxide, etc., and the addition amount of MO is 1-15%.

[0027] Example 1

[0028] The method for enhancing the performance of zinc aluminate ceramics with metal oxides comprises the following steps:

[0029] (1) Weigh 45% aluminum oxide, 54% zinc oxide, and 1% ferric oxide by mass.

[0030] (2) The three powders were weighed and wet-milled in deionized water (50% of the total mass of the three powders). The milling medium was agate beads, the milling speed was 300 r / min, and the milling time was 5 h.

[0031] (3) The ball-milled slurry was placed in an oven and dried at 100°C.

[0032] (4) The dried bulk powder is ground into powder in a mortar and sieved through a 60-mesh sieve to obtain a precursor powder.

[0033] (5) The precursor powder is dry-pressed into a green body with a molding pressure of 20 MPa and a holding time of 60 s.

[0034] (6) The green body is placed in a silicon-molybdenum rod box furnace and sintered at 1350° C. for 3 h at a heating rate of 5° C. / min to obtain zinc aluminate ceramics with enhanced performance.

[0035] Example 2

[0036] The method for enhancing the performance of zinc aluminate ceramics with metal oxides comprises the following steps:

[0037] (1) Weigh 50% aluminum oxide, 45% zinc oxide, and 5% magnesium oxide by mass.

[0038] (2) Weigh the powders and perform wet ball milling in deionized water (40% of the total mass of the three powders). The ball milling medium is agate beads, the ball milling speed is 400 r / min, and the ball milling time is 4 h.

[0039] (3) The ball-milled slurry was placed in an oven and dried at 90°C.

[0040] (4) The dried bulk powder is ground into powder in a mortar and sieved through a 60-mesh sieve to obtain a precursor powder.

[0041] (5) The precursor powder is dry-pressed into a green body with a molding pressure of 30 MPa and a holding time of 50 s.

[0042] (6) The green body is placed in a silicon-molybdenum rod box furnace and sintered at 1400° C. for 4 h at a heating rate of 4° C. / min to obtain zinc aluminate ceramics with enhanced performance.

[0043] Example 3

[0044] The method for enhancing the performance of zinc aluminate ceramics with metal oxides comprises the following steps:

[0045] (1) Weigh 50% aluminum oxide, 40% zinc oxide, and 10% calcium oxide by mass.

[0046] (2) The three powders were weighed and wet-milled in anhydrous ethanol (50% of the total mass of the three powders), with agate beads as the milling medium, a milling speed of 500 r / min, and a milling time of 3 h.

[0047] (3) The ball-milled slurry was first dried naturally in the laboratory for 8 h and then placed in an oven to dry at 60 °C.

[0048] (4) The dried bulk powder is ground into powder in a mortar and sieved through a 60-mesh sieve to obtain a precursor powder.

[0049] (5) The precursor powder is dry-pressed into a green body with a molding pressure of 40 MPa and a holding time of 40 s.

[0050] (6) The green body is placed in a silicon-molybdenum rod box furnace and calcined at 1500° C. for 3 h at a heating rate of 3° C. / min to obtain zinc aluminate ceramics with enhanced performance.

[0051] Example 4

[0052] The method for enhancing the performance of zinc aluminate ceramics with metal oxides comprises the following steps:

[0053] (1) Weigh 48% aluminum oxide, 39% zinc oxide, and 13% titanium dioxide by mass.

[0054] (2) The three powders were weighed and wet-milled in 50% deionized water (50% of the total mass of the three powders). The milling medium was agate beads. The milling speed was 400 r / min and the milling time was 2 h.

[0055] (3) The ball-milled slurry was placed in an oven and dried at 80°C.

[0056] (4) The dried bulk powder is ground into powder in a mortar and sieved through a 60-mesh sieve to obtain a precursor powder.

[0057] (5) The precursor powder is dry-pressed into a green body with a molding pressure of 50 MPa and a holding time of 30 s.

[0058] (6) The green body is placed in a rotary kiln and calcined at 1600° C. for 2 h at a heating rate of 5° C. / min to obtain zinc aluminate ceramics with enhanced performance.

[0059] Comparison example:

[0060] (1) Weigh 56% aluminum oxide and 44% zinc oxide by mass.

[0061] (2) The two powders were weighed and wet-milled in deionized water (50% of the total mass of the two powders), with agate beads as the milling medium, a milling speed of 400 r / min, and a milling time of 4 h.

[0062] (3) The ball-milled slurry was placed in an oven and dried at 90°C.

[0063] (4) The dried bulk powder is ground into powder in a mortar and sieved through a 60-mesh sieve to obtain a precursor powder.

[0064] (5) The precursor powder is dry-pressed into a green body with a molding pressure of 40 MPa and a holding time of 40 s.

[0065] (6) The green body is placed in a silicon-molybdenum rod box furnace and calcined at 1550° C. for 3 h to obtain zinc aluminate ceramics. The heating rate is 5° C. / min.

[0066] Table 1 shows the properties of zinc aluminate ceramics of Examples 1 to 4 and the control example (without adding metal oxide).

[0067] Table 1 Comparison of zinc aluminate ceramic properties of Examples 1-4 and Control Example

[0068]

[0069] It can be seen from Table 1 that the performance of zinc aluminate ceramics is greatly improved after adding metal oxide additives. Compared with the control examples, the flexural strength of the four examples listed is at least 3 times higher, the compressive strength is at least 2 times higher, the hardness is more than doubled, the water absorption rate and porosity are greatly reduced, and the volume density is at least increased by 60%, indicating that the addition of metal oxides can greatly improve the density and strength of zinc aluminate ceramics.

[0070] The above shows and describes the main features and advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0071] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for enhancing the performance of zinc aluminate ceramics with metal oxides, characterized in that: Using aluminum oxide and zinc oxide as raw materials and metal oxide as additives, the method includes the following steps: Step 1, weighing aluminum oxide, zinc oxide and metal oxide according to mass percentage; Step 2, mixing the three powders and performing wet ball milling; Step 3, drying the ball-milled slurry; Step 4, grinding the dried bulk powder in a mortar and then sieving; Step 5, forming the sieved powder into a green body by dry pressing; Step 6, sintering the green body, and obtaining the zinc aluminate ceramic with enhanced performance after cooling.

2. The method for enhancing the performance of zinc aluminate ceramics with metal oxides according to claim 1, characterized in that: In the steps, the mass percentages of aluminum oxide, zinc oxide and metal oxide are 40-65%, 30-55% and 1-15% respectively.

3. The method for enhancing the performance of zinc aluminate ceramics with metal oxides according to claim 2, characterized in that: The metal oxide is at least one of magnesium oxide, calcium oxide, titanium dioxide, tin oxide and ferric oxide.

4. The method for enhancing the performance of zinc aluminate ceramics with metal oxides according to claim 1, characterized in that: The wet ball milling in step 2 is specifically as follows: ball milling is performed in anhydrous ethanol or deionized water which is 30-50% of the total mass of aluminum oxide, zinc oxide and metal oxide, the ball milling medium is agate beads, the ball milling speed is 300-500 r / min, and the ball milling time is 2-5 hours.

5. The method for enhancing the performance of zinc aluminate ceramics with metal oxides according to claim 1, characterized in that: The drying temperature in step 3 is 60-100°C.

6. The method for enhancing the performance of zinc aluminate ceramics with metal oxides according to claim 1, characterized in that: In step 4, a 60-mesh sieve is used for screening.

7. The method for enhancing the performance of zinc aluminate ceramics with metal oxides according to claim 1, characterized in that: The pressure of the dry pressing in step 5 is 20-60 MPa, and the holding time is 30-60 s.

8. The method for enhancing the performance of zinc aluminate ceramics with metal oxides according to claim 1, characterized in that: In step 6, the sintering temperature is 1300-1700° C., the heating rate is 3-5° C. / min, and the holding time is 2-5 hours.

9. Zinc aluminate ceramics obtained by the method according to any one of claims 1 to 8.

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