Oxidation-induced shape memory fiber and preparation method and application thereof

Patent metadata

Field	Value
Publication number	US-2022017425-A1
Application number	US-202117488369-A
Country	US
Kind code	A1
Filing date	Sep 29, 2021
Priority date	Jan 9, 2020
Publication date	Jan 20, 2022
Grant date	—

Abstract

The present disclosure relates to an oxidation-induced shape memory fiber comprising a tension-bearing core material and/or a tension-bearing core material coated with an antioxidative coating, and an oxidizable pressure-bearing coating. The oxidizable pressure-bearing coating is coated outside the tension-bearing core material and/or the tension-bearing core material coated with an antioxidative coating; the oxidizable pressure-bearing coating is in compressive stress state and/or the tension-bearing core material coated with an antioxidative coating and the oxidizable pressure-bearing coating are in tension-compression balance state. The disclosure also relates to preparation and application thereof, the preparation is: reserving anchoring end, exerting tension force on tension-bearing core material and/or tension-bearing core material coated with an antioxidative coating, followed by coating oxidizable pressure-bearing coating thereon. The oxidation-induced shape memory fiber is applicable to high temperature oxidation environment.

First claim

What is claimed is:

1 . An oxidation-induced shape memory fiber, characterized in that
the oxidation-induced shape memory fiber comprises a tension-bearing core material and an oxidizable pressure-bearing coating, the oxidizable pressure-bearing coating is coated outside of the tension-bearing core material and the end of the tension-bearing core material is not coated with the oxidizable pressure-bearing coating; the end of the tension-bearing core material which is not coated with the oxidizable pressure-bearing coating is defined as an anchoring end; under the equivalent oxidation conditions and experimental situations, the oxidation speed of the oxidizable pressure-bearing coating is bigger than the oxidation speed of the tension-bearing core material; the oxidizable pressure-bearing coating is in a compressive stress state along the length direction of the tension-bearing core material; and the tension-bearing core material and the oxidizable pressure-bearing coating are in a tension-compression balance state along the length direction of the tension-bearing core material.

2 . The oxidation-induced shape memory fiber according to claim 1 , characterized in that the tension-bearing core material is composed of an antioxidative material or a non-antioxidative material coated with an antioxidative material coating.

3 . The oxidation-induced shape memory fiber according to claim 1 , characterized in that an extremely oxidizable coating is arranged between the tension-bearing core material and the oxidizable pressure-bearing coating; the cross-section of the oxidation-induced shape memory fiber is the tension-bearing core material, the extremely oxidizable coating and the oxidizable pressure-bearing coating from inside to the outside in succession, under the equivalent oxidation conditions and experimental situations, the antioxidative ability of the three materials, namely tension-bearing core material, the oxidizable pressure-bearing coating and the extremely oxidizable coating, decreases successively while the cross-section oxidation loss rate increases successively; the oxidizable pressure-bearing coating is in a compressive stress state along the length direction of the tension-bearing core material; and the tension-bearing core material and the oxidizable pressure-bearing coating are in a tension-compression balance state along the length direction of the tension-bearing core material.

4 . The oxidation-induced shape memory fiber according to claim 1 , characterized in that the outer surface of the end or other positions of the memory fiber is coated with a second antioxidative coating; the sections where the surface of the end or other positions of the memory fiber is coated with the second antioxidative coating are defined as reinforced anchoring ends.

5 . The oxidation-induced shape memory fiber according to claim 1 , characterized in that the oxidation environment includes at least one of gas oxidation and liquid oxidation;
the core material is chosen from at least one of C, SiC, B 4 C and metal fiber; the antioxidative coating is chosen from at least one of SiC, B 4 C, ZrC, TiC, HfC, TaC, NbC, Si 3 N 4 , BN, AN, TaN, CrSi 2 , MoSi 2 , TaSi 2 , WSi 2 , HfSi 2 , Nb 5 Si 3 , V 5 Si 3 , CrB 2 , TiB 2 , ZrB 2 or the multiphase composite coating Hf—Ta—C and Hf—Si—C or is multilayer coated; the oxidizable pressure-bearing coating is chosen from a C coating and a carbon-rich coating.

6 . The oxidation-induced shape memory fiber according to claim 1 , characterized in that the anchoring end plays a role of anchoring within a matrix; the anchor type of the anchoring end is chosen from the anchoring type with an exposed end; the exposed length of the anchoring type with an exposed end is l′; the l′ meets the formula:

l
′

≥

d
⁢

σ

f
⁢
1

4
⁢

τ
¯

.

7 . A preparation method for the oxidation-induced shape memory fiber according to claim 1 , characterized in that
reserving an anchoring end, exerting tension force on the core material or the core material with an antioxidative coating; then preparing a layer of oxidizable pressure-bearing coating on the surface thereof; removing the tension force to obtain a sample; or reserving an anchoring end, exerting tension force on the core material or the core material with an antioxidative coating; then preparing a layer of oxidizable pressure-bearing coating on the surface thereof; removing the tension force, followed by coating a second antioxidative layer on a preset part of the oxidizable pressure-bearing coating; or reserving an anchoring end, exerting tension force on the core material or the core material with an antioxidative coating; then preparing a layer of extremely oxidizable coating on the surface thereof, followed by coating an oxidizable pressure-bearing coating outside thereof; removing the tension force to obtain a sample; the exerted tension force is 30% to 90% of the bearing force for the tension-bearing fiber or the tension-bearing fiber with the antioxidative coating.

8 . The preparation method for the oxidation-induced shape memory fiber according to claim 7 , characterized in that in the whole oxidation-induced shape memory fiber, in order to allow the prestressing force exerted on the outside by the memory fiber to reach the maximum, the optimal acquisition method is:
under the condition that the cross-sectional area of the oxidation-induced shape memory fiber is constant, the magnitude of the prestressing force storage for the memory fiber is closely related to the volume fraction V f of the tension-bearing fiber and the axial force F of the tension-bearing fiber is

F
=

σ
f
p

⁢

A
f

=

E
c

⁢

V
c

⁢

σ
o

⁢

A
f

E
c

Assignees

• Univ Qingdao Technology

Inventors

• Wang Ziguo
• Wang Sheng
• Sun Yuyan
• Liu Guibin
• Yu Qi
• Wan Xiaomei

Classifications

• C04B20/0068

  Composite fibres, e.g. fibres with a core and sheath of different material · CPC title

• C04B35/76

  Fibres, filaments, whiskers, platelets, or the like · CPC title

• C04B35/62873 Primary

  Carbon · CPC title

• C04B35/62868

  Boron nitride · CPC title

• C04B2235/9684

  Oxidation resistance · CPC title