Zirconium-hafnium oxide ceramic powder and preparation method thereof

Abstract

The invention discloses zirconium-hafnium oxide ceramic powder and a preparation method thereof.The preparation method of the zirconium-hafnium oxide ceramic powder comprises the following steps that a zirconium source, a hafnium source, yttrium oxide and water are heated and stirred, then cooled to the room temperature and filtered, and filtrate is collected; adding gamma-aminobutyric acid into the filtrate, and stirring to obtain a mixed solution; and drying the mixed solution by distillation, sintering at high temperature, grinding and sieving to obtain the zirconium-hafnium oxide powder. The zirconium-hafnium oxide ceramic powder has excellent high-temperature resistance through specific raw materials and a preparation process, positive ions can be chelated by adding gamma-aminobutyric acid, the dispersing performance and molecular distance of all the raw materials are improved, and the high-temperature resistance of the zirconium-hafnium oxide ceramic powder is improved. The finally prepared ceramic powder has better crystallinity and purity, specifically, the highest phase transition temperature of the ceramic powder can reach 1582 DEG C or above, then the application field is expanded, and market requirements are better met.

Description

Technical Field

[0001] The invention relates to the technical field of zirconium-hafnium ceramic materials, and in particular to zirconium-hafnium oxide ceramic powder and a preparation method thereof. Background Art

[0002] The world's proven zirconium resources are approximately 19 million tons. Zirconium oxide is usually produced by purifying zirconium ores. There are three crystal states of pure ZrO2 at normal pressure: monoclinic zirconia (m-ZrO2), tetragonal zirconia (t-ZrO2) and cubic zirconia (c-ZrO2). The three crystal forms exist in different temperature ranges and can be mutually transformed. The temperature of monoclinic zirconia (m-ZrO2) is less than 950℃; the temperature of tetragonal zirconia (t-ZrO2) is 1200-2370℃; and the temperature of cubic zirconia (c-ZrO2) is greater than 2370℃. The three crystal states have different physical and chemical properties. In practical applications, different types of stabilizers are usually added to obtain the required crystal shape and performance to make different types of zirconia ceramics, such as partially stabilized zirconia (PSZ). When the stabilizer is CaO, MgO, or Y2O3, it is expressed as Ca-PSZ, Mg-PSZ, Y-PSZ, etc.

[0003] At present, the phase transition temperature of zirconia ceramics is lower than 1200°C, which in turn affects its scope of use.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a zirconium-hafnium oxide ceramic powder and a preparation method thereof. The zirconium-hafnium oxide ceramic powder of the present invention has excellent high temperature resistance through specific raw materials and preparation process, and the specific phase change temperature is as high as above 1450°C.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0007] A first aspect of the present invention provides a method for preparing zirconium and hafnium oxide ceramic powders, the method for preparing zirconium and hafnium oxide ceramic powders comprising the following steps:

[0008] (a) heating and stirring a zirconium source, a hafnium source, yttrium oxide and water, cooling to room temperature, filtering and collecting a filtrate;

[0009] (b) adding γ-aminobutyric acid to the filtrate and stirring to obtain a mixed solution;

[0010] (c) The mixed solution is evaporated to dryness, sintered at high temperature, ground and sieved to obtain the zirconium-hafnium oxide powder.

[0011] Preferably, the zirconium source is zirconium nitrate.

[0012] Preferably, the hafnium source is hafnium nitrate.

[0013] Preferably, the molar ratio of the zirconium source to the hafnium source is 1:(0.5-1).

[0014] Preferably, the molar ratio of the yttrium oxide to the zirconium source is (2-3):50.

[0015] Preferably, the heating and stirring temperature is 75 to 90° C., and the time is 1.5 to 2.5 hours.

[0016] Preferably, the molar ratio of the γ-aminobutyric acid to the zirconium source is (8-10):1.

[0017] Preferably, the stirring treatment time is 1 to 2 hours.

[0018] Preferably, the high temperature sintering comprises: heating to 240-260° C. at a heating rate of 1-2° C. / s and keeping the temperature for 15-20 min, and then heating to 1250-1400° C. at a heating rate of 4-6° C. / s and keeping the temperature for 4-5 h.

[0019] A second aspect of the present invention provides a zirconium-hafnium oxide ceramic powder prepared by the above preparation method.

[0020] Compared with the prior art, the beneficial effects of the present invention include at least:

[0021] The zirconium-hafnium oxide ceramic powder of the present invention has excellent high temperature resistance through specific raw materials and preparation process. Among them, through the addition of γ-aminobutyric acid, chelation of cations can be achieved, and the dispersion performance and molecular distance of each raw material are improved, so that the finally prepared ceramic powder has better crystallinity and purity. Specifically, the phase transition temperature of the ceramic powder can reach above 1582°C, thereby expanding the application field and better meeting market demand. DETAILED DESCRIPTION

[0022] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0023] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0024] The embodiment of the present invention provides a method for preparing zirconium-hafnium oxide ceramic powder, and the method for preparing zirconium-hafnium oxide ceramic powder comprises the following steps:

[0025] (a) heating and stirring a zirconium source, a hafnium source, yttrium oxide and water, cooling to room temperature, filtering and collecting a filtrate;

[0026] (b) adding γ-aminobutyric acid to the filtrate and stirring to obtain a mixed solution;

[0027] (c) The mixed solution is evaporated to dryness, sintered at high temperature, ground and sieved to obtain the zirconium-hafnium oxide powder.

[0028] The zirconium-hafnium oxide ceramic powder of the present invention has excellent high temperature resistance through specific raw materials and preparation process. Among them, through the addition of γ-aminobutyric acid, chelation of cations can be achieved, and the dispersion performance and molecular distance of each raw material are improved, so that the finally prepared ceramic powder has better crystallinity and purity. Specifically, the phase transition temperature of the ceramic powder can reach above 1582°C, thereby expanding the application field and better meeting market demand.

[0029] In one embodiment, the zirconium source is zirconium nitrate.

[0030] In one embodiment, the hafnium source is hafnium nitrate.

[0031] In one embodiment, the molar ratio of the zirconium source to the hafnium source may be 1:(0.5-1), specifically 1:0.5, or 1:1.

[0032] In one embodiment, the molar ratio of the yttrium oxide to the zirconium source may be (2-3):50, specifically 1:25 or 3:50.

[0033] In one embodiment, the heating and stirring temperature may be 75 to 90° C., and the time may be 1.5 to 2.5 hours.

[0034] In one embodiment, the molar ratio of the γ-aminobutyric acid to the zirconium source may be any value in the range of (8-10):1.

[0035] In one embodiment, the stirring treatment time may be 1 to 2 hours.

[0036] In one embodiment, the high temperature sintering includes: heating to 240-260° C. at a heating rate of 1-2° C. / s and keeping the temperature for 15-20 min, and then heating to 1250-1400° C. at a heating rate of 4-6° C. / s and keeping the temperature for 4-5 h.

[0037] Another embodiment of the present invention provides a zirconium-hafnium oxide ceramic powder prepared by the above preparation method.

[0038] The technical solution of the present invention is further described in detail below through specific embodiments.

[0039] Example 1

[0040] This embodiment is a method for preparing zirconium and hafnium oxide ceramic powder, and the method for preparing zirconium and hafnium oxide ceramic powder comprises the following steps:

[0041] (a) heating zirconium nitrate, hafnium nitrate, yttrium oxide and water to 75° C. and stirring for 2.5 hours, then cooling to room temperature, filtering and collecting the filtrate, wherein the molar ratio of zirconium nitrate to hafnium nitrate is 1:0.5; and the molar ratio of yttrium oxide to zirconium nitrate is 2:50;

[0042] (b) adding γ-aminobutyric acid to the filtrate and stirring for 1 hour to obtain a mixed solution, wherein the molar ratio of γ-aminobutyric acid to zirconium nitrate is 10:1;

[0043] (c) evaporating the mixed solution to dryness, heating to 240° C. at a heating rate of 1° C. / s and keeping the temperature for 20 min, then heating to 1250° C. at a heating rate of 4° C. / s and keeping the temperature for 5 h, and grinding and sieving to obtain the zirconium-hafnium oxide powder.

[0044] Example 2

[0045] This embodiment is a method for preparing zirconium and hafnium oxide ceramic powder, and the method for preparing zirconium and hafnium oxide ceramic powder comprises the following steps:

[0046] (a) heating zirconium nitrate, hafnium nitrate, yttrium oxide and water to 90° C. and stirring for 1.5 hours, cooling to room temperature, filtering and collecting the filtrate, wherein the molar ratio of zirconium nitrate to hafnium nitrate is 1:1; the molar ratio of yttrium oxide to zirconium nitrate is 3:50;

[0047] (b) adding γ-aminobutyric acid to the filtrate and stirring for 2 hours to obtain a mixed solution, wherein the molar ratio of γ-aminobutyric acid to zirconium nitrate is 8:1;

[0048] (c) evaporating the mixed solution to dryness, heating to 260° C. at a heating rate of 2° C. / s and keeping the temperature for 15 min, then heating to 1400° C. at a heating rate of 6° C. / s and keeping the temperature for 4 h, and grinding and sieving to obtain the zirconium-hafnium oxide powder.

[0049] Example 3

[0050] This embodiment is a method for preparing zirconium and hafnium oxide ceramic powder, and the method for preparing zirconium and hafnium oxide ceramic powder comprises the following steps:

[0051] (a) heating zirconium nitrate, hafnium nitrate, yttrium oxide and water to 85° C. and stirring for 2 hours, then cooling to room temperature, filtering and collecting the filtrate, wherein the molar ratio of zirconium nitrate to hafnium nitrate is 1:0.8; the molar ratio of yttrium oxide to zirconium nitrate is 2.5:50;

[0052] (b) adding γ-aminobutyric acid to the filtrate and stirring for 1.5 hours to obtain a mixed solution, wherein the molar ratio of γ-aminobutyric acid to zirconium nitrate is 9:1;

[0053] (c) evaporating the mixed solution to dryness, heating to 250° C. at a heating rate of 2° C. / s and keeping the temperature for 20 min, then heating to 1350° C. at a heating rate of 5° C. / s and keeping the temperature for 5 h, and grinding and sieving to obtain the zirconium-hafnium oxide powder.

[0054] Example 4

[0055] This embodiment is a method for preparing zirconium and hafnium oxide ceramic powder, and the method for preparing zirconium and hafnium oxide ceramic powder comprises the following steps:

[0056] (a) heating zirconium nitrate, hafnium nitrate, yttrium oxide and water to 85° C. and stirring for 2 hours, then cooling to room temperature, filtering and collecting the filtrate, wherein the molar ratio of zirconium nitrate to hafnium nitrate is 1:0.8; the molar ratio of yttrium oxide to zirconium nitrate is 2.5:50;

[0057] (b) adding γ-aminobutyric acid to the filtrate and stirring for 1.5 hours to obtain a mixed solution, wherein the molar ratio of γ-aminobutyric acid to zirconium nitrate is 9:1;

[0058] (c) evaporating the mixed solution to dryness, heating to 1350° C. at 5° C. / s and keeping the temperature for 5 h, grinding and sieving to obtain the zirconium-hafnium oxide powder.

[0059] Example 5

[0060] This embodiment is a method for preparing zirconium and hafnium oxide ceramic powder, and the method for preparing zirconium and hafnium oxide ceramic powder comprises the following steps:

[0061] (a) heating zirconium nitrate, hafnium nitrate, yttrium oxide and water to 85° C. and stirring for 2 hours, then cooling to room temperature, filtering and collecting the filtrate, wherein the molar ratio of zirconium nitrate to hafnium nitrate is 1:0.8; the molar ratio of yttrium oxide to zirconium nitrate is 2.5:50;

[0062] (b) adding γ-aminobutyric acid to the filtrate and stirring for 1.5 hours to obtain a mixed solution, wherein the molar ratio of γ-aminobutyric acid to zirconium nitrate is 9:1;

[0063] (c) evaporating the mixed solution to dryness, heating to 250° C. at a heating rate of 5° C. / s and keeping the temperature for 20 min, then heating to 1350° C. at a heating rate of 5° C. / s and keeping the temperature for 5 h, and grinding and sieving to obtain the zirconium-hafnium oxide powder.

[0064] Comparative Example 1

[0065] This comparative example is a method for preparing zirconium and hafnium oxide ceramic powder, and the method for preparing zirconium and hafnium oxide ceramic powder comprises the following steps:

[0066] (a) heating zirconium nitrate, hafnium nitrate, yttrium oxide and water to 85° C. and stirring for 2 hours, then cooling to room temperature, filtering and collecting the filtrate, wherein the molar ratio of zirconium nitrate to hafnium nitrate is 1:0.8; the molar ratio of yttrium oxide to zirconium nitrate is 2.5:50;

[0067] (b) The filtrate is evaporated to dryness, heated to 250° C. at a heating rate of 2° C. / s and kept at this temperature for 20 min, then heated to 1350° C. at a heating rate of 5° C. / s and kept at this temperature for 5 h, and then ground and sieved to obtain the zirconium-hafnium oxide powder.

[0068] Experimental example

[0069] The zirconium-hafnium oxide powders prepared in Examples 1 to 5 and Comparative Example 1 were obtained respectively;

[0070] The phase transition temperatures of the zirconium-hafnium oxide powders prepared in Examples 1 to 5 and Comparative Example 1 were tested, and the test results are shown in Table 1.

[0071] Table 1

[0072] Group Phase transition temperature(℃) Example 1 1468 Example 2 1582 Example 3 1559 Example 4 1415 Example 5 1471 Comparative Example 1 1346

[0073] From Table 1, we can see that:

[0074] Compared with the comparative example, the zirconium-hafnium oxide ceramic powder prepared in the embodiment of the present application has a more excellent heat resistance temperature and a wider application field.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for preparing zirconium-hafnium oxide ceramic powder, characterized in that: The preparation method of the zirconium-hafnium oxide ceramic powder comprises the following steps: (a) heating and stirring a zirconium source, a hafnium source, yttrium oxide and water, cooling to room temperature, filtering and collecting a filtrate; (b) adding γ-aminobutyric acid to the filtrate and stirring to obtain a mixed solution; (c) The mixed solution is evaporated to dryness, sintered at high temperature, ground and sieved to obtain the zirconium-hafnium oxide powder.

2. The preparation method according to claim 1, characterized in that: The zirconium source is zirconium nitrate.

3. The preparation method according to claim 1, characterized in that: The hafnium source is hafnium nitrate.

4. The preparation method according to claim 1, characterized in that: The molar ratio of the zirconium source to the hafnium source is 1:(0.5-1).

5. The preparation method according to claim 1, characterized in that: The molar ratio of the yttrium oxide to the zirconium source is (2-3):

50.

6. The preparation method according to claim 1, characterized in that: The heating and stirring temperature is 75-90° C., and the time is 1.5-2.5 h.

7. The preparation method according to claim 1, characterized in that: The molar ratio of the gamma-aminobutyric acid to the zirconium source is (8-10):

1.

8. The preparation method according to claim 1, characterized in that: The stirring treatment time is 1 to 2 hours.

9. The preparation method according to claim 1, characterized in that: The high temperature sintering comprises: heating to 240-260° C. at a heating rate of 1-2° C. / s and keeping the temperature for 15-20 minutes, and then heating to 1250-1400° C. at a heating rate of 4-6° C. / s and keeping the temperature for 4-5 hours.

10. Zirconium-hafnium oxide ceramic powder prepared by the preparation method according to any one of claims 1 to 9.