Nanocrystalline A4B2O9 type niobate ceramic prepared through ultralow-temperature sintering, and preparation method thereof

An A4B2O9 and niobate technology is applied in the field of ultra-low temperature sintering to prepare nanocrystalline A4B2O9 type niobate ceramics, which can solve the problems of high cost, high prices of tantalate and rare earth elements, reduce thermal conductivity, shorten sintering time, Avoid high porosity effects

Pending Publication Date: 2021-06-11

KUNMING UNIV OF SCI & TECH

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Problems solved by technology

[0004] The present invention intends to provide a method for preparing nanocrystalline A4B2O9 niobate ceramics by ultra-low temperature sintering, so as to solve the problem that the existing thermal barrier coatin...

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Abstract

The invention belongs to the technical field of inorganic nonmetal thermal barrier coating materials, and discloses a nanocrystalline A4B2O9 type niobate ceramic prepared through ultralow-temperature sintering, and a preparation method thereof. The structural formula of the ceramic is A4B2O9, A is one or more of Ni, Co, Mg, Ca, Sr, Ba or Zn, B is Nb1-XTaX, and X is larger than or equal to 0.5 and larger than or equal to 0. The preparation method comprises the following steps: respectively carrying out thermal insulation and thermal decomposition on A(OH)2, ACO3, niobium oxalate and tantalum oxalate to obtain AO powder, Nb2O5 powder and Ta2O5 powder; then grinding to obtain a nano-sized powder mixture with high reaction activity; and finally, sintering the mixture powder to obtain the blocky A4B2O9 type niobate ceramic. The preparation method solves the problem that the cost of preparing the thermal barrier coating material is high due to the fact that the raw materials tantalate and rare earth elements used by the existing rare earth tantalate thermal barrier coating material are high in price.

Technology Topic

Thermal insulationPowder mixture +4

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Examples

Experimental program(10)
Effect test(1)

Example Embodiment

[0041] Example 1:

[0042] Non-low temperature sintering prepared nanocrystalline A4B2O9 niobate ceramic, the ceramic structure of CO 4 NB 2 O 9. Its preparation method includes the following steps:

[0043] step one,

[0044] Coco 3 , Oxalate is 1-1.5 h at 450-950 ° C, and COO and NB having high degrees of reaction is obtained by thermal decomposition. 2 O 5. In the present embodiment, the temperature is preferably 720 ° C, and the holding time is preferably 1 h.

[0045] Step two,

[0046] Will COO, NB 2 O 5 The powder and purity of 99.99% alcohol were blocked into a high energy ball mill for grinding, the weight ratio of powder and alcohol was 1: 6-10, and the rotational speed at the time of grinding was 2200-3500 rpm, and the grinding time was 11-24h. After the grinding is completed, the powder was taken out, and the powder was charged at 65-80 ° C for 6-10 h, and the powder was dried to form a highly reactive powder mixture having a nanometer size. In this embodiment, the weight ratio of powder and alcohol is 1: 8, and the rotation speed at the time of polishing is preferably 2500 rpm, and the grinding time is preferably 11 h; the holding temperature is preferably 65 ° C, the holding time is preferably 10 h.

[0047] Step three,

[0048] The spray BN treatment is performed in the sintered graphite mold, and then the highly reactive powder mixture is placed into the graphite mold to perform discharge plasma sintering, the sintered temperature is 520-600 ° C, the holding time is 6-15 min, the pressure pressure is 100 -200MPa, forming CO 4 NB 2 O 9 Ceramic block. In the present embodiment, the sintering temperature is preferably 520 ° C, preferably 10 min, and the pressure pressure is preferably 100 MPa.

Example Embodiment

[0049] Example 2:

[0050] Example 2 and Example 1 Differences in that the structural formula of the A4B2O9 type cerium tantate ceramic in the present embodiment is Ni 4 NB 2 O 9 The preparation method is consistent with Example 1.

Example Embodiment

[0051] Example 3:

[0052] Embodiment 3 The difference from Embodiment 1 is that the structural formula of the A4B2O9 type citrate ceramic in this embodiment is Mg 4 NB 2 O 9 The preparation method is consistent with Example 1.

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PUM

Property	Measurement	Unit
Grain size	<= 150.0	nm
Average grain size	<= 150.0	nm
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Low thermal conductivity

Nanocrystalline A4B2O9 type niobate ceramic prepared through ultralow-temperature sintering, and preparation method thereof

AI-Extracted Technical Summary

Problems solved by technology

Abstract

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Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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