CN111235538B - Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect - Google Patents

Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect Download PDF

Info

Publication number
CN111235538B
CN111235538B CN202010131263.1A CN202010131263A CN111235538B CN 111235538 B CN111235538 B CN 111235538B CN 202010131263 A CN202010131263 A CN 202010131263A CN 111235538 B CN111235538 B CN 111235538B
Authority
CN
China
Prior art keywords
shape memory
memory alloy
substrate
flexoelectric
composite material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010131263.1A
Other languages
Chinese (zh)
Other versions
CN111235538A (en
Inventor
王飞
郑志强
黄平
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xian Jiaotong University
Original Assignee
Xian Jiaotong University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xian Jiaotong University filed Critical Xian Jiaotong University
Priority to CN202010131263.1A priority Critical patent/CN111235538B/en
Publication of CN111235538A publication Critical patent/CN111235538A/en
Application granted granted Critical
Publication of CN111235538B publication Critical patent/CN111235538B/en
Priority to PCT/CN2021/087308 priority patent/WO2021170150A1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • C23C14/3457—Sputtering using other particles than noble gas ions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/02—Stamping using rigid devices or tools
    • B21D22/04—Stamping using rigid devices or tools for dimpling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D37/00—Tools as parts of machines covered by this subclass
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/02—Pretreatment of the material to be coated
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/08—Oxides
    • C23C14/086—Oxides of zinc, germanium, cadmium, indium, tin, thallium or bismuth

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Semiconductor Memories (AREA)
  • Micromachines (AREA)
  • Parts Printed On Printed Circuit Boards (AREA)

Abstract

The invention discloses a preparation method of a composite material with shape memory alloy induction adjustable flexoelectric effect. The composite material is characterized in that the shape memory alloy is used as a substrate, a flexible electric film is prepared on the surface of the substrate, and the temperature control deformation characteristic of the shape memory alloy is utilized to enable the flexible electric film to generate deformation (high strain gradient) so as to generate polarization and generate electric potential. The realization mode is as follows: firstly, carrying out indentation deformation treatment on the shape memory alloy by adopting a pressure head, then grinding and polishing an indentation layer, and preparing the flexoelectric film on the surface of the substrate by adopting a magnetron sputtering method. When the shape memory alloy substrate is heated, a large number of bulges (high strain gradient areas) appear on the surface of the substrate, a large number of areas with high strain gradients are correspondingly generated in the material of the flexoelectric thin film, and the flexoelectric thin film is polarized to generate electric potential. The composite structure is simple to prepare, has strong flexoelectric effect, can be produced in large scale, and is applied to the fields of energy capture, sensing and the like.

Description

Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect
Technical Field
The invention relates to the field of functional materials, and mainly relates to a preparation method of a composite material based on a shape memory alloy induction adjustable flexoelectric effect.
Background
The mechanical-electrical coupling refers to the mutual conversion between mechanical energy and electrical energy, and is highly regarded in the fields of micro-electro-mechanical systems and the like. Flexoelectric effect, a typical mechano-electric coupling effect, has been reported by Kogan since 1964, and has attracted extensive research interest in recent years. Flexoelectric effect means that strain gradients or inhomogeneous strain fields can locally disrupt the inversion symmetry, leading to electric polarization of the crystal, even a centrosymmetric crystal. It describes the electric polarization phenomenon induced by strain gradient (positive flexoelectric effect) and the mechanical deformation induced by electric field gradient (inverse flexoelectric effect), and has wide application in the fields of energy collection, sensors, drivers and the like. Hu et al, for example, produced the first automated power supply system driven by a nanogenerator through the flexoelectric effect, which could be wirelessly connected and used for long-distance data transmission.
A lot of research shows that the strain gradient is an important factor of the flexoelectric effect, and when the strain is the same, a material with a micro size (micro-nano scale) has a larger strain gradient, so that the flexoelectric effect is more obvious. However, the present research on the flexoelectric effect focuses on small-sized materials because it is very difficult to generate a high strain gradient in large-sized materials, so that the electric polarization generated by the flexoelectric effect is very limited. Composite materials similar to pyramid structures are prepared as in Zhu et al, with dimensions on the millimeter scale. Studies have shown that the material achieves strong flexoelectric properties, although the generation of high strain gradients is limited due to the large dimensions. Therefore, if a high strain gradient can be realized in a large-sized material, the flexoelectric effect is more obvious, and the application range is wider.
Disclosure of Invention
In order to solve the above problems, the present invention provides a method for preparing a composite material based on shape memory alloy-induced controllable flexoelectric effect, wherein the composite material can generate high strain gradient in a large-sized flexoelectric film, and further generate strong flexoelectric effect. The invention adopts the following technical scheme that:
a preparation method of a composite material based on a shape memory alloy induced flexoelectric effect is characterized by comprising the following steps: taking the shape memory alloy as a substrate, and preparing a flexoelectric film on the surface of the substrate after pre-deformation treatment to prepare the composite material with the double-layer structure.
The shape memory alloy substrate is made of nickel-titanium alloy.
The flexible electric film adopts a zinc oxide film.
The thickness of the zinc oxide film is 0.5-2 μm, and the thickness of the nickel-titanium shape memory alloy substrate is 0.1-1 mm.
The nickel-titanium shape memory alloy is subjected to pre-deformation treatment, namely a pressure head is used for deforming a shape memory alloy substrate, the load is 1000-3000N, and the load is kept for 30-90 s. Then used 400 in turn#、800#、1200#、1500#、2000#And (3) sanding the substrate, and polishing the surface of the substrate to a mirror surface effect by adopting a polishing agent with the particle size of 0.5 mu m and 0.25 mu m.
The preparation method of the zinc oxide flexible electric film adopts a magnetron sputtering method to prepare the zinc oxide flexible electric film on the surface of the polished substrate, zinc oxide is used as a target material, and argon and oxygen are used as sputtering gases.
The pressure head is a rectangular steel block with the shape of 1cm multiplied by 2cm, and a large number of semi-cylindrical protrusions are processed on one end face of the pressure head.
The length of the semi-cylindrical bulge is 1cm, and the radius of the semi-cylindrical bulge is 0.1mm-1 mm.
The invention has the following advantages:
1. the high strain gradient generated in the large-size flexoelectric film is realized so as to generate strong flexoelectric effect.
2. The flexural electrical property has adjustability, and can be adjusted through parameters such as the size of the zinc oxide film, the size of the pressure head protrusion and the like.
3. The composite material has simple preparation process.
4. The composite material based on the shape memory alloy induced flexoelectric effect prepared by the invention can be applied to the fields of energy collection, sensors and the like.
Drawings
FIG. 1: a schematic structural diagram of a shape memory alloy induced flexoelectric effect composite material;
FIG. 2: a structural design schematic diagram of the pressure head;
FIG. 3: testing the temperature control deformation of the composite material;
FIG. 4: and (5) performance test results of the shape memory alloy induced flexoelectric effect.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific examples, but the present invention is not limited thereto.
Referring to fig. 1, wherein 1 is zinc oxide flexoelectric thin film, 2 is nickel titanium shape memory alloy substrate; it can be seen from fig. 2 that the end face of the ram has a large number of parallel semi-cylindrical projections; in fig. 3, it can be seen that a large number of protrusions are generated on the surface of the shape memory alloy substrate after the pre-deformation treatment, and therefore a large number of protrusions are generated on the zinc oxide film; fig. 4 shows the results of flexural electrical property tests of the composite material. The abscissa is time and the ordinate is current. It can be seen from the figure that the composite material has obvious flexoelectric effect, and when the area of the sample is increased, the current is increased, which shows that the flexoelectric effect can be adjusted by controlling the size of the sample.
The invention relates to a preparation method of a composite material with shape memory alloy induced adjustable and controllable flexoelectric property, which comprises a double-layer structure formed by combining a nickel-titanium shape memory alloy substrate layer 2 and a zinc oxide flexoelectric film 1, and is shown in figure 1.
Firstly, a shape memory alloy substrate (10mm multiplied by 0.1mm) is subjected to pre-deformation treatment by using a pressure head, the appearance design of the pressure head is shown in figure 2, the surface is formed by a large number of semi-cylindrical bulges, the length of each bulge is 10mm, and the radius of each single bulge is 0.5 mm. 2000N is loaded on the shape memory alloy substrate through the pressure head, the load is kept for 60s, and the surface of the shape memory alloy substrate is deformed.
The indentation layers on the surface of the shape memory alloy substrate are sequentially used for 400#、800#、1200#、1500#、2000#The sand paper is used for polishing and flattening, and then a polishing agent with the grain diameter of 0.5 mu m and 0.25 mu m is used for polishing the surface of the substrate to a mirror surface effect.
Preparing zinc oxide flexible electric film on the surface of shape memory alloy by magnetron sputtering method, and vacuumizing the sputtering chamber to 3 × 10-4Pa, using zinc oxide targetsThe method comprises the following steps of taking argon and oxygen as sputtering gases, wherein the flow of the argon is 3sccm, the flow of the oxygen is 6sccm, the air pressure of a sputtering chamber is 0.5Pa, selecting a radio frequency power supply, preparing power is 50W, simultaneously applying bias voltage of 80V, and preparing for 1 hour and 4 hours respectively to prepare zinc oxide films with different thicknesses.
And attaching electrodes to the upper surface and the lower surface of the prepared sample, heating the sample, and measuring current signals by using a table type high-precision multimeter in the heating process. After heating, a large number of bulges are generated on the surface of the shape memory alloy substrate, and a large number of bulges corresponding to the prepared zinc oxide film are generated, as shown in figure 3.
In the heating process, as the nickel-titanium shape memory alloy substrate deforms, a large number of deformation regions with high strain gradient are also generated on the zinc oxide film, and the zinc oxide film is polarized to generate electric potential, so that obvious current is generated, as shown in figure 4. In FIG. 4, (a) and (b) are prepared areas of 0.5cm2And 1cm2The zinc oxide film sample of (a) shows that the current generated by the flexoelectric effect is higher when the film area is larger. This shows that the flexoelectric effect induced by the shape memory alloy can be regulated and controlled by the parameters such as the size of the flexoelectric film, the size of the indenter and the like.

Claims (4)

1. The preparation method of the composite material with shape memory alloy induction controllable flexoelectric effect is characterized in that: taking nickel-titanium shape memory alloy as a substrate (2), preparing a zinc oxide film (1) on the surface of the substrate after pre-deformation treatment, and preparing the composite material with a double-layer structure:
firstly, the nickel-titanium shape memory alloy is pre-deformed, namely, a pressure head is used for deforming the shape memory alloy substrate, the load is 1000-3000N, the load is kept for 30-90s, and then 400 is used in sequence#、800#、1200#、1500#、2000#Polishing the substrate surface to a mirror surface effect by adopting a polishing agent with the grain diameter of 0.5 mu m and 0.25 mu m;
preparing a zinc oxide film on the surface of the polished substrate by adopting a magnetron sputtering method, wherein zinc oxide is used as a target material, a radio frequency power supply is used as a power supply, and argon and oxygen are used as sputtering gases.
2. The method for preparing a composite material with shape memory alloy induced controllable flexoelectric effect according to claim 1, wherein the thickness of the zinc oxide film is 0.5 μm-2 μm, and the thickness of the nickel titanium shape memory alloy substrate is 0.1mm-1 mm.
3. The method according to claim 1, wherein the indenter has a rectangular steel block with a shape of 1cm x 2cm and a plurality of semi-cylindrical protrusions are formed on one end surface of the indenter.
4. The method for preparing a composite material with a shape memory alloy induced and controllable flexoelectric effect according to claim 3, wherein the length of the semi-cylindrical protrusion is 1cm, and the radius is 0.1mm-1 mm.
CN202010131263.1A 2020-02-28 2020-02-28 Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect Active CN111235538B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202010131263.1A CN111235538B (en) 2020-02-28 2020-02-28 Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect
PCT/CN2021/087308 WO2021170150A1 (en) 2020-02-28 2021-04-14 Method for using shape memory alloy to prepare composite material capable of inducing and regulating flexoelectric effect

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010131263.1A CN111235538B (en) 2020-02-28 2020-02-28 Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect

Publications (2)

Publication Number Publication Date
CN111235538A CN111235538A (en) 2020-06-05
CN111235538B true CN111235538B (en) 2021-03-16

Family

ID=70876678

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010131263.1A Active CN111235538B (en) 2020-02-28 2020-02-28 Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect

Country Status (2)

Country Link
CN (1) CN111235538B (en)
WO (1) WO2021170150A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111235538B (en) * 2020-02-28 2021-03-16 西安交通大学 Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect
CN113083638A (en) * 2021-03-16 2021-07-09 西安交通大学 Method for regulating and controlling hydrophobicity of shape memory alloy based on pre-deformation treatment
CN113930734A (en) * 2021-09-17 2022-01-14 中国地质大学（武汉） Preparation method of thermoelectric composite material based on 4D printing technology
CN115463965B (en) * 2022-08-29 2024-06-07 武汉大学 Gradient micro-nano structure Ti-TiZnXLayered composite material and method for producing the same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008005820A2 (en) * 2006-06-30 2008-01-10 The Penn State Research Foundation Piezoelectric composite based on flexoelectric charge separation
CN104570498A (en) * 2014-11-24 2015-04-29 深圳市华星光电技术有限公司 Flexible liquid crystal panel and manufacturing method thereof
EP3154099A1 (en) * 2015-10-09 2017-04-12 Institut Català de Nanociència i Nanotecnologia Flexoelectric device
CN109950045A (en) * 2019-03-19 2019-06-28 西安交通大学 A kind of flexure electroelectret and preparation method thereof with controllable class flexoelectric effect

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62229902A (en) * 1986-03-31 1987-10-08 富士電機株式会社 Gapless arrestor with abnormality detecting function
CN103046018B (en) * 2013-01-04 2014-08-20 中国石油大学(北京) Method for endowing film with large elastic strain by shape memory alloy
CN103045828B (en) * 2013-01-04 2014-05-14 中国石油大学(北京) Method for realizing tensile elastic strain of film with surface relief of shape memory alloy
CN111235538B (en) * 2020-02-28 2021-03-16 西安交通大学 Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008005820A2 (en) * 2006-06-30 2008-01-10 The Penn State Research Foundation Piezoelectric composite based on flexoelectric charge separation
CN104570498A (en) * 2014-11-24 2015-04-29 深圳市华星光电技术有限公司 Flexible liquid crystal panel and manufacturing method thereof
EP3154099A1 (en) * 2015-10-09 2017-04-12 Institut Català de Nanociència i Nanotecnologia Flexoelectric device
CN109950045A (en) * 2019-03-19 2019-06-28 西安交通大学 A kind of flexure electroelectret and preparation method thereof with controllable class flexoelectric effect

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
"Flexoelectric materials and their related applications:A focused review";Longlong Shu et al.;《Advanced Ceramics》;20190615;第153-173页 *
"Nnaoscale mechanical energy harvesting using piezoelectricity and flexoelectricity";Xu Liang et al.;《Smart Materials and Structures》;20170221;第1-17页 *
"Out-of-plane polarization in bent graphene-like Zinc Oxide and nanogenerator applications";Dan Tan et al.;《Advanced Functional Materials》;20191231;第1-8页 *
"镍钛合金表面锆膜磁控溅射制备与组织结构研究";吉宏林等;《稀有金属材料与工程》;20090215;第38卷(第2期);第295-298页 *

Also Published As

Publication number Publication date
WO2021170150A1 (en) 2021-09-02
CN111235538A (en) 2020-06-05

Similar Documents

Publication Publication Date Title
CN111235538B (en) Preparation method of shape memory alloy-induced composite material capable of regulating flexoelectric effect
Bruno et al. Properties of piezoceramic materials in high electric field actuator applications
Tang et al. Fabrication and analysis of high-performance piezoelectric MEMS generators
CN104529532B (en) Bend voltage electric material
Lin et al. Fabrication and electromechanical characterization of a piezoelectric structural fiber for multifunctional composites
Li et al. ZnO thin film piezoelectric micromachined microphone with symmetric composite vibrating diaphragm
Kim et al. Electro-mechanical behavior and direct piezoelectricity of cellulose electro-active paper
CN101456733B (en) Method for preparing potassium niobate sodium base leadless piezoelectric ceramic thin sheet
Bi et al. Tunable resonance frequency of magnetoelectric layered composites
Schäffner et al. Microstructured single-layer electrodes embedded in P (VDF-TrFE) for flexible and self-powered direction-sensitive strain sensors
CN101306948B (en) Novel ferroelectric-ferromagnetic thick film and method for preparing same
Yanaseko et al. Characterization of a metal-core piezoelectric ceramics fiber/aluminum composite
Kang et al. Investigation of mechanical energy harvesting cycles using ferroelectric/ferroelastic switching
Su et al. Routes to net shape electroceramic devices and thick films
Sasikala et al. The electro-mechanical performance of electro-active polymer based actuators fabricated using ultra thin metal electrode
Chen et al. A functional gradient ceramic monomorph actuator fabricated using electrophoretic deposition
Shen et al. Displacement and resonance behaviors of a piezoelectric diaphragm driven by a double-sided spiral electrode
CN101599340A (en) Direct magnetic coupling preparation method of magneto strictive multiplayer film
Kuts et al.  Magnetoelectric effect in three-layered gradient LiNbO3/Ni/Metglas composites
Sato et al. Fabrication and vibration suppression behavior of metal core-piezoelectric fibers in CFRP composite
KR20210007857A (en) Piezoelectric composite, method of manufacturing the same, and magnetoelectric laminate structure having the same
Shin et al. Preparation and properties of elastically coupled electro-magnetic elements with a bonding structure
Jungk et al. Length-scale-based hardening model for ultra-small volumes
Levy et al. PZN-PT single-crystal thin film monomorph actuator
Xiang et al. Electrostatic analysis of functionally graded piezoelectric cantilevers

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant