Acoustically active nano-structured metal oxides

Patent metadata

Field	Value
Publication number	US-2020112785-A1
Application number	US-201816624471-A
Country	US
Kind code	A1
Filing date	Jun 12, 2018
Priority date	Jun 23, 2017
Publication date	Apr 9, 2020
Grant date	—

Abstract

Acoustically active articles having a composition including a nano-structured metal oxide are provided. The nano-structured metal oxide has the formula M1xM2yOz, where M1 is selected from the group consisting of alkali metals, alkaline earth metals, and combinations thereof, M2 is a transition metal or post-transition metal, and M2 has an atomic number no greater than 78. The articles can lower a resonant frequency of a cavity by no less than 50 Hz when the cavity is filled with the article and the resonant frequency is in a range from about 50 Hz to about 1500 Hz.

First claim

1 . An acoustically active article having a composition comprising:
a nano-structured metal oxide having the formula M1 x M2 y O z , wherein M1 is selected from the group consisting of alkali metals, alkaline earth metals, and combinations thereof, M2 is a transition metal or post-transition metal, and M2 has an atomic number no greater than 78, and x is a number in the range 0≤x≤2, y is a number in the range 0.4≤y≤1.2, z is a number selected such that the nano-structured metal oxide is electrically neutral, and wherein the article is capable of lowering a resonant frequency of a cavity by no less than 50 Hz when the cavity is filled with the article and the resonant frequency of the cavity is in a range from about 50 Hz to about 1500 Hz.

2 . The article of claim 1 , wherein M1 includes at least one of Na, Ca, Li, and K.

3 . The article of claim 1 , wherein M2 includes at least one of Co and Mn.

4 . The article of claim 1 , wherein the nano-structured metal oxide comprises one or more of Na—Mn—O, K—Co—O, Ca—Mn—O, Li—Co—O, Na—Co—O, Ca—Co—O, Li—Mn—O, combinations thereof.

5 . The article of claim 1 , wherein the nano-structured metal oxide is present in the form of particles or flakes.

6 . The article of claim 5 , wherein the particles or flakes have a dimension in the range of 50 nm to 50 microns.

7 . The article of claim 1 , wherein the article has a pore volume no greater than 0.5 ml/g.

8 . The article of claim 7 , wherein the article has a pore volume in the range of 0.005 ml/g and 0.5 ml/g.

9 . The article of claim 1 , wherein the article has a surface area per unit weight no greater than 10 m 2 /g.

10 . The article of claim 1 , wherein the article has a surface area per unit weight in the range from 1.0 m 2 /g to 5 m 2 /g.

11 . The article of claim 1 , wherein the article includes about 4 wt % to about 12 wt % matrix material to distribute the nano-structured metal oxide.

12 . The article of claim 1 , wherein the article comprises about 50 wt % to about 100 wt % of the nano-structured metal oxide.

13 . The article of claim 12 , wherein the article comprises about 0 wt % to about 50 wt % of a filler or binder.

14 . A method of enhancing the performance of an acoustic device, the method comprising:
providing an acoustic device having a cavity; and providing the article of claim 1 to at least partially fill the cavity.

15 . The method of claim 14 , wherein the article is provided in the form of a film, a foam, or a fiber mat.

16 . The method of claim 14 , wherein the cavity has a volume from 0.1 cm 3 to 1000 cm 3 .

17 . The method of claim 14 , wherein the acoustic device comprises a speaker or a microphone.

18 . A method of making the article of claim 1 , the method further comprising loading the nano-structured metal oxide with a filler or binder material.

Assignees

• 3M Innovative Properties Co

Inventors

• Aksit Mahmut
• Stolzenburg Fabian

Classifications

• C01P2006/12

  Surface area · CPC title

• C01G45/1214

  containing alkali metals · CPC title

• C01G51/66

  containing alkaline earth metals, e.g. SrCoO3 · CPC title

• C01G51/42 Primary

  containing alkali metals, e.g. LiCoO2 · CPC title

• C01P2006/14

  Pore volume · CPC title