METHOD FOR PRODUCING ALKALI METAL NIOBATE PARTICLES, AND ALKALI METAL NIOBATE PARTICLES

• US 20120064344A1
• Filed: 04/05/2010
• Published: 03/15/2012
• Est. Priority Date: 04/09/2009
• Status: Active Grant

• Current Assignee: Fuji Ceramics Corporation, Sakai Chemical Industry Company Limited, Tohoku University National Universities Corporation
• Original Assignee: Fuji Ceramics Corporation, Sakai Chemical Industry Company Limited, Tohoku University National Universities Corporation
• Inventors: Muramatsu, Atsushi, Kanie, Kiyoshi, Terabe, Atsuki, Mizutani, Hideto, Sueda, Satoru, Okamoto, Yasuhiro, Takahashi, Hirofumi
• Granted Patent: US 8,771,618 B2
• Time in Patent Office: Days
• US Class Current: 428/402
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01D 1/02 Oxides
• CPC Class Codes: C01D 13/00 Compounds of sodium or potassium not provided for elsewhere
• CPC Class Codes: C01G 1/02 Oxides
• CPC Class Codes: C01G 33/00 Compounds of niobium
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/38 cube-like
• CPC Class Codes: C01P 2004/39 parallelepiped-like
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C04B 2235/3201 Alkali metal oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3255 Niobates or tantalates, e.g. silver niobate
• CPC Class Codes: C04B 2235/5292 Flakes, platelets or plates
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/656 characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 35/495 based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
• CPC Class Codes: H10N 30/097 by sintering
• CPC Class Codes: H10N 30/8542 : Alkali metal based oxides, e.g. lithium, sodium or potassium niobates
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]

Abstract

Disclosed are a method of producing fine particulate alkali metal niobate in a liquid phase system, wherein the size and shape of the particulate alkali metal niobate can be controlled; and fine particulate alkali metal niobate having a controlled shape and size. One of specifically disclosed is a method of producing a substantially rectangular cuboid particulate alkali metal niobate represented by MNbO₃ (1), wherein M represents one element selected from alkaline metals, including specific four steps. Another one of specifically disclosed is particulate alkali metal niobate represented by the formula (1) having a substantially rectangular cuboid shape, wherein the substantially rectangular cuboid shape has a longest side and a shortest side, the length of the longest side represented by an index L_max is 0.10 to 25 μm, and the length of the shortest side represented by an index L_min is 0.050 to 15 μm.

Claims

1. A method of producing particulate alkali metal niobate represented by

MNbO₃  

 

(1)

wherein M represents one element selected from alkaline metals, the particulate alkali metal niobate having a substantially rectangular cuboid shape,

the method comprising the steps of;

(a) mixing a niobium-containing solution with an alkaline solution having a concentration of 0.1 to 30 mol/L, to prepare a suspension;

(b) still standing the suspension at between 80°

C. and 150°

C. for 12 to 48 hours;

(c) performing solvothermal reaction of the suspension at between 150°

C. and 300°

C. for 1 to 12 hours; and

(d) separating the particulate alkali metal niobate from a reaction mixture.

2. The method according to claim 1,

wherein M in the formula (1) is Na, and the alkaline solution is NaOH.

3. The method according to claim 1,

wherein M in the formula (1) is K, and the alkaline solution is KOH.

4. The method according to claim 1,

wherein the niobium-containing solution includes:

niobium oxide and/or niobium halide;

a solvent selected from the group consisting of water, ethylene glycol, and polyethylene glycol; and

an acid.

8. A particulate alkali metal niobate represented by the formula (1):

MNbO₃  

 

(1)

wherein M represents one element selected from alkaline metals, the particulate alkali metal niobate having a substantially rectangular cuboid shape,

wherein the substantially rectangular cuboid shape has a longest side and a shortest side,

the length of the longest side represented by an index L_max is 0.10 to 25 μ

m, and

the length of the shortest side respresented b an index L_min is 0.050 to 15 μ

m,

wherein the particulate alkali metal niobate is prepared by the method according to claim 1.

5. Particulate alkali metal niobate represented by the formula (1):

MNbO₃  

 

(1)

wherein M represents one element selected from alkaline metals, the particulate alkali metal niobate having a substantially rectangular cuboid shape,

wherein the substantially rectangular cuboid shape has a longest side and a shortest side,

the length of the longest side represented by an index L_max is 0.10 to 25 μ

m, and

the length of the shortest side represented by an index L_min is 0.050 to 15 μ

m.

6. The particulate alkali metal niobate according to claim 5,

wherein the ratio of the L_max to the L_min, L_max/L_min, is within the range of 1 to 5.

7. The particulate alkali metal niobate according to claim 5,

wherein the M in the formula (1) is Na or K.

9. A piezoelectric ceramic material comprising the particulate alkali metal niobate according to claim 5.