CN108394929B - A kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof - Google Patents

A kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof Download PDF

Info

Publication number
CN108394929B
CN108394929B CN201810271616.0A CN201810271616A CN108394929B CN 108394929 B CN108394929 B CN 108394929B CN 201810271616 A CN201810271616 A CN 201810271616A CN 108394929 B CN108394929 B CN 108394929B
Authority
CN
China
Prior art keywords
zinc oxide
thermal conductivity
preparation
pressure
cratered
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
CN201810271616.0A
Other languages
Chinese (zh)
Other versions
CN108394929A (en
Inventor
段波
李亚锋
李家良
余瑞
王洪涛
陈刚
翟鹏程
张清杰
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.)
Wuhan University of Technology WUT
Original Assignee
Wuhan University of Technology WUT
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 Wuhan University of Technology WUT filed Critical Wuhan University of Technology WUT
Priority to CN201810271616.0A priority Critical patent/CN108394929B/en
Publication of CN108394929A publication Critical patent/CN108394929A/en
Application granted granted Critical
Publication of CN108394929B publication Critical patent/CN108394929B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G9/00—Compounds of zinc
    • C01G9/02—Oxides; Hydroxides
    • C01G9/03—Processes of production using dry methods, e.g. vapour phase processes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

The invention belongs to field of thermoelectric material technique, disclose a kind of lower thermal conductivity zinc oxide and preparation method thereof with cratered hole pattern.The present invention is using four acicular type zinc oxide crystal whisker or micron order Zinc oxide powder as raw material, by carrying out high temperature and pressure sintering to Zinc oxide powder, remain unchanged zinc oxide grain object during sintering densification mutually, but significant change occurs for microscopic appearance, grain surface generates the pit-hole being largely evenly distributed, and the thermal conductivity of pure zinc oxide is greatly reduced, and be conducive to promote its stability, a new approaches are provided for the efficient preparation of lower thermal conductivity zinc oxide, are suitble to promote and apply.

Description

A kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof
Technical field
The invention belongs to field of electronic materials, and in particular to a kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof.
Background technique
Zinc oxide have the characteristics that anti-oxidant, high temperature resistant and it is pollution-free, non-toxic, preparation process is relatively easy, in High temperature thermoelectric application field has great application prospect, and is a kind of thermoelectric material of great potential.The thermal conductivity of pure zinc oxide It is very high, reach 40-50W/mK under normal temperature condition[1], it is 40 times of traditional bismuth telluride thermoelectric material or more.Therefore oxidation is reduced The thermal conductivity of Zinc material is the key that improve its thermoelectricity capability.
Currently, the method for commonly reducing the thermal conductivity of zinc oxide material is to adulterate other elements into zinc oxide to reduce Thermal conductivity, common member are known as: Al, Ni, Ga, Ti, Sb, Co etc., and synthesis and preparation process usually require relatively complicated change Reaction and the high temperature sintering of 1000-1400 degrees Celsius of tens hours are learned to realize；Preparation process complexity, the energy consumption being related to Height is unfavorable for promoting and applying.Therefore further exploring and reducing the new method of zinc oxide thermal conductivity is the emphasis studied at present.
Summary of the invention
Present invention is primarily aimed at providing a kind of simple, the efficient method for reducing zinc oxide thermal conductivity, by by oxygen Change zinc raw material and carry out high temperature and pressure sintering, substantially change zinc oxide grain surface microscopic topographic, to significantly reduce oxygen Change the thermal conductivity of Zinc material；This method strong operability, process is simple, and time-consuming is short, low energy consumption；Gained zinc oxide is sintered It can produce the pit-hole being largely evenly distributed in journey, the thermal conductivity of zinc oxide based material can be significantly reduced, be conducive to further improve Its thermoelectricity capability and stability.
To achieve the above object, the technical solution adopted by the present invention are as follows:
A kind of cratered hole lower thermal conductivity zinc oxide, it includes close-connected ZnO crystal grain, and the distribution of ZnO grain surface is cheated Hole.
In above scheme, the size of the ZnO crystal grain is 5-40 μm；Pit-hole is having a size of 0.2-2 μm.
A kind of preparation method of above-mentioned cratered hole lower thermal conductivity zinc oxide, includes the following steps:
1) using four acicular type zinc oxide crystal whisker or micron Zinc oxide powder as raw material；Powder raw material is pressed with tablet press machine Block obtains zinc oxide cold pressing block；
2) gained zinc oxide cold pressing block progress high temperature and pressure is sintered and cooled and is aoxidized up to cratered hole lower thermal conductivity Zinc.
In above scheme, the size of the micron Zinc oxide powder is 0.5-2 μm；In the four acicular type zinc oxide crystal whisker 0.7-1.4 μm of core diameter, 0.5-14 μm of spicule root diameter (RD), needle-shaped body length is 3-200 μm.
Preferably, the Zinc oxide powder is four acicular type zinc oxide crystal whisker, under high-temperature and high-pressure conditions, gained grain surface Equally distributed pit-hole is formed, the thermal conductivity of finally obtained densification zinc oxide product can realize whole reduction.
In above scheme, the pressure that the cold-press process uses is 150-250MPa, dwell time 4-5min.
In above scheme, in the high temperature and pressure sintering process, the pressure used is 1.5-2.5GPa, temperature 500- 900 DEG C, the heat-insulation pressure keeping time is 5-15min.
Preferably, the sintering temperature of the high temperature and pressure sintering process is 700-800 DEG C.
In above scheme, the high temperature and pressure sintering process uses cubic hydraulic press.
According to cratered hole lower thermal conductivity zinc oxide prepared by above scheme, its thermal conductivity can be reduced at a temperature of 850K 5.05W/mK, and there is high temperature resistant and steady performance, it can effectively widen the application field of zinc oxide based material.
The invention has the benefit that
1) the present invention provides a kind of preparation methods of zinc oxide with special appearance lower thermal conductivity, with four needle-shaped oxidations Zinc whisker or micron order Zinc oxide powder are raw material；By carrying out high temperature and pressure sintering to Zinc oxide powder, make zinc oxide grain Object mutually remains unchanged during sintering densification, but significant change occurs for microscopic appearance to significantly reduce its thermal conductivity, is low The preparation of thermal conductivity zinc oxide provides a new approaches, is conducive to further widen its answering in the fields such as thermoelectric material With；
2) the high temperature and pressure sintering process that the present invention uses can promote what the appearance of zinc oxide grain surface was largely evenly distributed The thermal conductivity of pit-hole, gained zinc oxide material significantly reduces, and high temperature resistant and performance stabilization, has important promotional value；
3) reaction condition of the present invention is simply easily achieved, high efficient and reliable, is suitble to promote and apply.
Detailed description of the invention
Fig. 1 is the XRD spectrum of 1~4 products therefrom of the embodiment of the present invention.
Fig. 2 is that the SEM of 1 products therefrom of the embodiment of the present invention schemes.
Fig. 3 is the thermal conductivity variation with temperature of embodiment 1,3,4 products therefrom and document report doping vario-property zinc oxide Curve.
Fig. 4 is that the SEM of 2 products therefrom of the embodiment of the present invention schemes.
Fig. 5 is that the SEM of 3 products therefrom of the embodiment of the present invention schemes.
Fig. 6 is that the SEM of 4 products therefrom of the embodiment of the present invention schemes.
Fig. 7 is the thermogravimetric map of 4 products therefrom of the embodiment of the present invention.
Fig. 8 is that the SEM of 5 products therefrom of the embodiment of the present invention schemes.
Specific embodiment
For a better understanding of the present invention, below with reference to the embodiment content that the present invention is furture elucidated, but it is of the invention Content is not limited solely to the following examples.
In following embodiment, the four acicular type zinc oxide crystal whisker of use is mentioned by Tangshan Jian Hua development in science and technology Co., Ltd For 0.7-1.4 μm of the centerbody diameter of whisker, 0.5-14 μm of spicule root diameter (RD), needle-shaped body length is 3-200 μm；It is average Partial size is provided for 1 micron of Zinc oxide powder by white sijna rice Science and Technology Ltd..
Embodiment 1
A kind of cratered hole lower thermal conductivity zinc oxide, preparation method include the following steps:
1) four acicular type zinc oxide crystal whisker is raw material, weighs 2.4g and is placed in diameter to be carried out in the mold of 13mm with tablet press machine Manual briquetting, the pressure for adjusting tablet press machine is 200MPa, and the dwell time is 4 minutes；Obtaining diameter is 13mm, with a thickness of 3.5mm Cold pressing block；
2) high temperature and pressure sintering is carried out to cold pressing block obtained by step 1) using TH-V cubic hydraulic press, wherein high temperature and pressure Sintering temperature is 800 DEG C, pressure 2GPa, and the heat-insulation pressure keeping time is 10 minutes；It takes out up to cratered hole lower thermal conductivity zinc oxide.
The present embodiment products therefrom is subjected to X-ray diffraction analysis (see Fig. 1), the results showed that, institute is sintered through high temperature and pressure Obtaining product is still single-phase ZnO.
Fig. 2 is the field emission scanning electron microscope figure of the present embodiment products therefrom；It can be observed that products therefrom is by partial size in figure It is formed for 20-40 μm of zinc oxide grain, and grain surface has a large amount of equally distributed pit-holes, pit-hole size is 0.5-2 μ m。
The curve that the present embodiment products therefrom thermal conductivity varies with temperature is shown in Fig. 3, the results showed that the thermal conductivity of products therefrom Doping vario-property zinc oxide (the Ref. of opposite traditional handicraft preparation；Effects of microstructure evolution on transport properties of thermoelectric nickel-doped zinc oxide,Journal of the European Ceramic Society, Volume 37, Issue 11,2017, Pages 3541-3550.) entirely testing It is greatly reduced in temperature range；Up to 5.05W/mK under the conditions of 850K temperature.
Embodiment 2
A kind of cratered hole lower thermal conductivity zinc oxide, preparation method include the following steps:
1) four acicular type zinc oxide crystal whisker is raw material, weighs 2.4g and is placed in diameter to be carried out in the mold of 13mm with tablet press machine Manual briquetting, the pressure for adjusting tablet press machine is 200MPa, and the dwell time is 4 minutes；Obtaining diameter is 13mm, with a thickness of 3.5mm's Cold pressing block；
2) high temperature and pressure sintering is carried out to cold pressing block obtained by step 1) using TH-V cubic hydraulic press, wherein high temperature and pressure Sintering temperature is 700 DEG C, pressure 2GPa, and the heat-insulation pressure keeping time is 10 minutes；It takes out up to cratered hole lower thermal conductivity zinc oxide.
The field emission scanning electron microscope figure of the present embodiment products therefrom is shown in Fig. 4, is observed that products therefrom by partial size in figure It is formed for 5~20 μm of zinc oxide grains, and a large amount of pit-holes are also distributed in grain surface.
Embodiment 3
A kind of cratered hole lower thermal conductivity zinc oxide, preparation method include the following steps:
1) four acicular type zinc oxide crystal whisker is raw material, weighs 2.4g and is placed in diameter to be carried out in the mold of 13mm with tablet press machine Manual briquetting, the pressure for adjusting tablet press machine is 200MPa, and the dwell time is 4 minutes；Obtaining diameter is 13mm, with a thickness of 3.5mm's Cold pressing block；
2) high temperature and pressure sintering is carried out to cold pressing block obtained by step 1) using TH-V cubic hydraulic press, wherein high temperature and pressure Sintering temperature is 600 DEG C, pressure 2GPa, and the heat-insulation pressure keeping time is 10 minutes；It takes out up to cratered hole lower thermal conductivity zinc oxide.
The field emission scanning electron microscope figure of the present embodiment products therefrom is shown in Fig. 5, is observed that products therefrom by partial size in figure It is formed for 5~20 μm of zinc oxide grains, and a large amount of pit-holes are distributed in grain surface.
The curve that the present embodiment products therefrom thermal conductivity varies with temperature is shown in Fig. 3, the results showed that the thermal conductivity of products therefrom It decreased significantly compared with the doping vario-property zinc oxide of traditional handicraft preparation.
Embodiment 4
A kind of cratered hole lower thermal conductivity zinc oxide, preparation method include the following steps:
1) four acicular type zinc oxide crystal whisker is raw material, weighs 2.4g and is placed in diameter to be carried out in the mold of 13mm with tablet press machine Manual briquetting, the pressure for adjusting tablet press machine is 200MPa, and the dwell time is 4 minutes；Obtaining diameter is 13mm, with a thickness of 3.5mm's Cold pressing block；
2) high temperature and pressure sintering is carried out to cold pressing block obtained by step 1) using TH-V cubic hydraulic press, wherein high temperature and pressure Sintering temperature is 500 DEG C, pressure 2GPa, and the heat-insulation pressure keeping time is 10 minutes；It takes out up to cratered hole lower thermal conductivity zinc oxide.
The field emission scanning electron microscope figure of the present embodiment products therefrom is shown in Fig. 6, is observed that products therefrom by partial size in figure It is formed for 3~10 μm of zinc oxide grains, and pit-hole is also distributed in grain surface.
The curve that the present embodiment products therefrom thermal conductivity varies with temperature is shown in Fig. 3, the results showed that the thermal conductivity of products therefrom There is entire lowering compared with the doping vario-property zinc oxide of traditional handicraft preparation.
The thermogravimetric analysis map of the present embodiment products therefrom is shown in Fig. 7, it can be seen that products therefrom is heated to 1000 DEG C substantially Massless changes (mass loss 0.32%, within the scope of test error), has excellent thermal stability.
Embodiment 5
A kind of cratered hole lower thermal conductivity zinc oxide, preparation method include the following steps:
1) Zinc oxide powder for being 1 micron using average grain diameter weighs 2.4g and is placed in the mold that diameter is 13mm as raw material Middle to carry out manual briquetting with tablet press machine, the pressure for adjusting tablet press machine is 200MPa, and the dwell time is 4 minutes；Then it will obtain Cold pressing block is placed in the molybdenum cup that diameter is 13mm, thickness is 4mm；
2) zinc oxide sample that above-mentioned cold pressing obtains is put into pyrophillite mold, and using TH-V cubic hydraulic press into The sintering of row high temperature and pressure, wherein high temperature and pressure sintering temperature is 800 DEG C, pressure 2GPa, and the heat-insulation pressure keeping time is 10 minutes；It takes Out up to cratered hole lower thermal conductivity zinc oxide.
Fig. 8 is the field emission scanning electron microscope figure of the present embodiment products therefrom, can be seen that crystal grain diameter also has obviously in figure Increase, and grain surface there are a large amount of pit-holes to generate；Its thermal conductivity is advantageously reduced, and expands it in the fields such as thermoelectric material Using.
Obviously, above-described embodiment is only intended to clearly illustrate made example, and is not the limitation to embodiment.It is right For those of ordinary skill in the art, can also make on the basis of the above description it is other it is various forms of variation or It changes.There is no necessity and possibility to exhaust all the enbodiments.And the obvious variation or change therefore amplified It moves within still in the protection scope of the invention.

Claims (5)

1. a kind of preparation method of cratered hole lower thermal conductivity zinc oxide, which comprises the steps of:
1) it using four acicular type zinc oxide crystal whisker or micron Zinc oxide powder as raw material, is cold-pressed, obtains zinc oxide cold pressing block；
2) gained zinc oxide cold pressing block progress high temperature and pressure is sintered and cooled up to the cratered hole lower thermal conductivity zinc oxide；It Including ZnO crystal grain interconnected, and ZnO grain surface is distributed pit-hole；The size of the ZnO crystal grain is 5-40 μm；Hole Hole size is 0.2-2 μm；
In the high temperature and pressure sintering process, for the pressure used for 1.5-2.5GPa, temperature is 500-900 DEG C, when heat-insulation pressure keeping Between be 5-15min.
2. preparation method according to claim 1, which is characterized in that the size of the micron Zinc oxide powder is 0.5-2 μ m。
3. preparation method according to claim 1, which is characterized in that the centerbody diameter of the four acicular type zinc oxide crystal whisker It is 0.7-1.4 μm, spicule root diameter (RD) is 0.5-14 μm, and needle-shaped body length is 3-200 μm.
4. preparation method according to claim 1, which is characterized in that the pressure that the cold-press process uses is 150- 250MPa, dwell time 4-5min.
5. preparation method according to claim 1, which is characterized in that the sintering temperature of the high temperature and pressure sintering process is 700-800℃。
CN201810271616.0A 2018-03-29 2018-03-29 A kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof Active CN108394929B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201810271616.0A CN108394929B (en) 2018-03-29 2018-03-29 A kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201810271616.0A CN108394929B (en) 2018-03-29 2018-03-29 A kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof

Publications (2)

Publication Number Publication Date
CN108394929A CN108394929A (en) 2018-08-14
CN108394929B true CN108394929B (en) 2019-11-26

Family

ID=63098923

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201810271616.0A Active CN108394929B (en) 2018-03-29 2018-03-29 A kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof

Country Status (1)

Country Link
CN (1) CN108394929B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109534385B (en) * 2018-11-06 2020-11-06 武汉理工大学 Nano-pore-rich silver sulfide and rapid preparation method thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2416110C1 (en) * 2010-03-15 2011-04-10 Федеральное государственное унитарное предприятие "Научно-исследовательский и технологический институт оптического материаловедения Всероссийского научного центра "Государственный оптический институт им. С.И. Вавилова" (ФГУП "НИТИОМ ВНЦ "ГОИ им. С.И. Вавилова") METHOD OF PRODUCING TRANSPARENT SCINTILLATION ZnO CERAMIC AND SCINTILLATOR
CN102774875A (en) * 2012-07-30 2012-11-14 西安理工大学 Preparation method of octahedral zinc oxide crystals with micrometer-nanometer pore micro structures
CN103950969A (en) * 2014-03-18 2014-07-30 清华大学 Preparation method of multistage porous metal oxide nano-material

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2416110C1 (en) * 2010-03-15 2011-04-10 Федеральное государственное унитарное предприятие "Научно-исследовательский и технологический институт оптического материаловедения Всероссийского научного центра "Государственный оптический институт им. С.И. Вавилова" (ФГУП "НИТИОМ ВНЦ "ГОИ им. С.И. Вавилова") METHOD OF PRODUCING TRANSPARENT SCINTILLATION ZnO CERAMIC AND SCINTILLATOR
CN102774875A (en) * 2012-07-30 2012-11-14 西安理工大学 Preparation method of octahedral zinc oxide crystals with micrometer-nanometer pore micro structures
CN103950969A (en) * 2014-03-18 2014-07-30 清华大学 Preparation method of multistage porous metal oxide nano-material

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Thermal Conductivity of Zinc Oxide: From Green to Sintered State;Tayo Olorunyolemi et al.;《 J. Am. Ceram. Soc.》;20020531;第85卷(第5期);第1249-1253页 *

Also Published As

Publication number Publication date
CN108394929A (en) 2018-08-14

Similar Documents

Publication Publication Date Title
CN108046774B (en) Preparation method of graphene ceramic composite material
CN106631008B (en) A kind of bulk does not split high density nano crystalline substance gadolinium zirconate ceramics and preparation method thereof
CN109734451A (en) A kind of high entropy ceramics of transition metal diboride and preparation method thereof
CN110204341A (en) One kind (Hf, Ta, Nb, Ti) B2High entropy ceramic powder and preparation method thereof
CN105293499A (en) Preparation method of B,N-codoped silicon carbide nano wave-absorbing material
CN110436930A (en) A kind of high-performance nano SiC ceramic and its preparation method and application
CN108394929B (en) A kind of cratered hole lower thermal conductivity zinc oxide and preparation method thereof
CN108326289A (en) A kind of method of modifying and Nano metal powder modification diamond of diamond
CN102924083B (en) Method for preparing zirconium carbide ceramic powder
Gallini et al. Synthesis and characterization of monazite-type Sr: LaPO4 prepared through coprecipitation
CN111848159A (en) Preparation method of yellow conductive zirconia ceramic
CN108149042A (en) A kind of cryogenic activating sintering preparation method of high-compactness molybdenum material
CN101070241A (en) Aluminium oxide silicon titanium carbonate/aluminium oxide lamina composite material and preparing method
Zhu et al. Enhanced average thermoelectric properties of n‑type Mg3Sb2 based materials by mixed-valence Ni doping
CN109554674A (en) A kind of preparation method of the bismuth telluride thermal electric film with heterojunction structure
CN105924175A (en) Fine-grained boron carbide ceramic and preparation method thereof
CN108690929A (en) The preparation method of interior raw type nano-particle reinforcement high-entropy alloy-base composite material
CN108300881A (en) A method of realizing the huge negative expansion of wide warm area in MnCoGe based alloys
CN111606711A (en) Polycrystal B4C-SiC double-layer composite material and preparation method thereof
CN108975918A (en) A kind of high tenacity high-temperature structural material MoSi2-Mo5Si3The preparation of composite ceramics
Katsuyama et al. Synthesis of NaxCo2O4 by the hydrothermal hot-pressing and its thermoelectric properties
CN104557042A (en) Cr2AlC/Al2O3 composite material and preparation method thereof
Huang et al. Sintering, microstructure and conductivity of La2NiO4+ δ ceramic
CN109266941A (en) Slab-shaped tungsten carbide-cobalt alloy and preparation method thereof
CN109087987A (en) A kind of α-MgAgSb base nano composite thermoelectric materials and preparation method thereof

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