CN104557019B - Sintered at ultra low temperature temperature-stable microwave dielectric ceramic LiBiB2o5and preparation method thereof - Google Patents
Sintered at ultra low temperature temperature-stable microwave dielectric ceramic LiBiB2o5and preparation method thereof Download PDFInfo
- Publication number
- CN104557019B CN104557019B CN201410825331.9A CN201410825331A CN104557019B CN 104557019 B CN104557019 B CN 104557019B CN 201410825331 A CN201410825331 A CN 201410825331A CN 104557019 B CN104557019 B CN 104557019B
- Authority
- CN
- China
- Prior art keywords
- hours
- temperature
- dielectric ceramic
- microwave
- powder
- 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
Links
- 239000000919 ceramic Substances 0.000 title claims abstract description 20
- 238000002360 preparation method Methods 0.000 title claims abstract description 8
- 239000000843 powder Substances 0.000 claims abstract description 9
- 239000000203 mixture Substances 0.000 claims abstract description 7
- 239000004372 Polyvinyl alcohol Substances 0.000 claims abstract description 6
- 238000000498 ball milling Methods 0.000 claims abstract description 6
- 239000011230 binding agent Substances 0.000 claims abstract description 6
- 229920002451 polyvinyl alcohol Polymers 0.000 claims abstract description 6
- 229940068984 polyvinyl alcohol Drugs 0.000 claims abstract description 6
- 235000019422 polyvinyl alcohol Nutrition 0.000 claims abstract description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical group CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 3
- WMWLMWRWZQELOS-UHFFFAOYSA-N bismuth(III) oxide Inorganic materials O=[Bi]O[Bi]=O WMWLMWRWZQELOS-UHFFFAOYSA-N 0.000 claims abstract description 3
- 229960000935 dehydrated alcohol Drugs 0.000 claims abstract description 3
- 238000001035 drying Methods 0.000 claims abstract description 3
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims abstract description 3
- 229910052808 lithium carbonate Inorganic materials 0.000 claims abstract description 3
- 238000000465 moulding Methods 0.000 claims abstract description 3
- 239000002994 raw material Substances 0.000 claims abstract description 3
- 239000000126 substance Substances 0.000 claims description 3
- 238000005245 sintering Methods 0.000 abstract description 5
- 239000000463 material Substances 0.000 description 10
- 229910010293 ceramic material Inorganic materials 0.000 description 9
- 238000004891 communication Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 5
- 239000011521 glass Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 239000002131 composite material Substances 0.000 description 2
- 238000009766 low-temperature sintering Methods 0.000 description 2
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Inorganic materials O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 description 2
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 2
- 229910000906 Bronze Inorganic materials 0.000 description 1
- 229910026161 MgAl2O4 Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910010252 TiO3 Inorganic materials 0.000 description 1
- 229910003080 TiO4 Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000010974 bronze Substances 0.000 description 1
- 239000003985 ceramic capacitor Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 238000011982 device technology Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229910052839 forsterite Inorganic materials 0.000 description 1
- 239000002241 glass-ceramic Substances 0.000 description 1
- 230000001965 increasing effect Effects 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 208000030208 low-grade fever Diseases 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- XHGGEBRKUWZHEK-UHFFFAOYSA-L tellurate Chemical compound [O-][Te]([O-])(=O)=O XHGGEBRKUWZHEK-UHFFFAOYSA-L 0.000 description 1
- 230000035922 thirst Effects 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Landscapes
- Inorganic Insulating Materials (AREA)
- Compositions Of Oxide Ceramics (AREA)
Abstract
The invention discloses the temperature-stable ultralow dielectric microwave dielectric ceramic LiBiB of a kind of sintered at ultra low temperature2O5And preparation method thereof.(1) be 99.9%(percentage by weight by purity) more than Li2CO3、Bi2O3And H3BO3Starting powder press LiBiB2O5Composition weigh dispensing；(2) by step (1) raw material wet ball-milling mix 12 hours, ball-milling medium is dehydrated alcohol, after drying in 550 DEG C of air atmosphere pre-burning 6 hours；(3) after adding binding agent pelletize in the powder that step (2) prepares, re-compacted molding, finally sinter 4 hours in 600 ~ 650 DEG C of air atmosphere；Described binding agent uses mass concentration to be the poly-vinyl alcohol solution of 5%, and the addition of polyvinyl alcohol accounts for the 3% of powder gross mass.Ceramic post sintering prepared by the present invention is good, and dielectric constant reaches 8.7～9.1, and its quality factor q f value is up to 95000 134000GHz, and temperature coefficient of resonance frequency is little, industrially has great using value.
Description
Technical field
The present invention relates to dielectric ceramic material, particularly relate to for manufacturing ceramic substrate, the resonance that microwave frequency uses
Dielectric ceramic materials of microwave device such as device and wave filter and preparation method thereof.
Background technology
Microwave dielectric ceramic refers to be applied in microwave frequency band (mainly UHF and SHF frequency range) circuit as dielectric material
And complete the pottery of one or more functions, modern communication is widely used as resonator, wave filter, dielectric substrate and medium
The components and parts such as wave circuit, are the key foundation materials of modern communication technology, in portable mobile phone, automobile telephone, nothing
The aspect such as rope phone, television satellite accepter and military radar has highly important application, small-sized at modern communication instrument
Change, integrated during just playing increasing effect.
It is applied to the dielectric ceramic of microwave frequency band, should meet the requirement of following dielectric property: (1) seriation DIELECTRIC CONSTANT εr
To adapt to different frequency and the requirement of different application occasion;(2) high quality factor q value or low dielectric loss tan δ are to reduce
Noise, typically requires Qf >=3000 GHz;(3) the temperature coefficient τ of resonant frequencyƒThe least to ensure what device had had
Heat stability, general requirement-10 ppm/DEG C≤τƒ≤+10 ppm/℃.Just have tried to from late 1930s in the world
Dielectric substance is applied to microwave technology, and prepares TiO2Microwave dielectric filter, but its temperature coefficient of resonance frequency τƒ
Too greatly cannot be practical.Since the seventies in last century, the large-scale development to medium ceramic material, root are started
According to relative dielectric constant εrSize from use frequency range different, generally can will have been developed that and developing microwave-medium pottery
Porcelain is divided into 4 classes.
(1) ultralow dielectric microwave dielectric ceramic, main representative is Al2O3-TiO2、Y2BaCuO5、MgAl2O4With
Mg2SiO4Deng, its εr≤ 20, quality factor q × f >=50000GHz, τƒ≤10 ppm/°C.It is mainly used in microwave base plate and height
End microwave device.
(2) low εrWith the microwave dielectric ceramic of high q-factor, mainly BaO-MgO-Ta2O5, BaO-ZnO-Ta2O5Or BaO-
MgO-Nb2O5,BaO-ZnO-Nb2O5System or the hybrid system MWDC material between them.Its εr=20～35, Q=(1～2) ×
104(under the GHz of f >=10), τƒ≈0.As medium in the microwave communication equipments such as the direct broadcasting satellite being mainly used in f >=8 GHz
Resonating device.
(3) medium εrWith the microwave dielectric ceramic of Q-value, it is mainly with BaTi4O9、Ba2Ti9O20(Zr, Sn) TiO4Etc. for
The MWDC material of base, its εr=35 ~ 45, Q=(6～9) × 103(under f=3～-4GHz), τƒ≤5 ppm/°C.It is mainly used in 4
～8 in microwave military radar in GHz frequency range and communication system as dielectric resonance device.
(4) high εrAnd the microwave dielectric ceramic that Q-value is relatively low, in being mainly used in 0.8～4GHz frequency range, civilian movement is led to
News system, this is also the emphasis of microwave dielectric ceramic research.Since the eighties, Kolar, Kato et al. in succession find and have studied
Perovskite-like tungsten bronze type BaO Ln2O3—TiO2Series (Ln=La, Sm, Nd or Pr etc. are called for short BLT system), composite perofskite
Structure C aO Li2O—Ln2O3—TiO2Series, lead base series material, Ca1-xLn2x/3TiO3It is contour εrMicrowave dielectric ceramic,
The wherein BaO Nd of BLT system2O3—TiO2Material dielectric constant reaches 90, lead base series (Pb, Ca) ZrO3Dielectric constant reaches
To 105.
The sintering temperature of the above material system is generally greater than 1300 ° of C, it is impossible to directly with low-cost Ag and Cu
Formation multilayer ceramic capacitor is burnt altogether at low-melting-point metal electrode.In recent years, along with LTCC Technology (Low
Temperature Co-fired Ceramics, LTCC) development and the requirement of microwave multilayer device development, both domestic and external grind
Study carefully personnel to have carried out exploring widely and studying to some low grade fever's system materials, mainly use devitrified glass or glass-ceramic
Composite system, has of a relatively high dielectric loss mutually because of low-melting glass, and the existence of glass phase substantially increases material
Dielectric loss.Therefore the emphasis that the low fired microwave dielectric ceramic material without glass phase is current research is developed.
Explore novel with exploitation can be during low fired microwave dielectric ceramic materials, the Li base that intrinsic sintering temperature is low
The material systems such as compound, Bi based compound, tungstates architecture compound and tellurate architecture compound get the attention with
Research, but due to three performance indications (ε of microwave dielectric ceramicrWith Q f and τfBetween) be mutually restriction relation (see
Document: the restricting relation between microwave dielectric ceramic materials dielectric properties, Zhu Jianhua, Liang Fei, Wang little Hong, Lv Wenzhong, electronic component
With material, phase March the 3rd in 2005), meet three performance requirements and the single-phase microwave-medium ceramics of low temperature sintering is considerably less,
Their temperature coefficient of resonance frequency is the most excessive or quality factor are on the low side and cannot production application.At present microwave is situated between
The research major part of matter pottery is the summary of experience drawn by great many of experiments, does not but have complete theory to illustrate that microcosmic is tied
Structure and the relation of dielectric properties, the most also cannot predict its temperature coefficient of resonance frequency from the composition of compound with structure
With microwave dielectric properties such as quality factor, explore and develop and low-temperature sintering can have again near-zero resonance frequency temperature coefficient (-10
ppm /℃≤τƒ≤+10 ppm/ DEG C) it is that those skilled in the art thirst for always with the microwave dielectric ceramic of higher figure of merit
Solve but be difficult to the difficult problem succeeded all the time.
Summary of the invention
It is an object of the invention to provide temperature-stable and the low-loss ultralow dielectric microwave of a kind of sintered at ultra low temperature
Dielectric ceramic material and preparation method thereof.
The chemical composition of the microwave dielectric ceramic material of the present invention is LiBiB2O5。
The preparation method step of this microwave dielectric ceramic material is:
(1) be 99.9%(percentage by weight by purity) more than Li2CO3、Bi2O3And H3BO3Starting powder press
LiBiB2O5Composition weigh dispensing.
(2) being mixed 12 hours by step (1) raw material wet ball-milling, ball-milling medium is dehydrated alcohol, big at 550 DEG C after drying
Pre-burning 6 hours in gas atmosphere.
(3), after adding binding agent pelletize in the powder that step (2) prepares, re-compacted molding, finally at 600 ~ 650 DEG C
Air atmosphere sinters 4 hours；Described binding agent uses mass concentration to be the poly-vinyl alcohol solution of 5%, polyvinyl alcohol addition
Account for the 3% of powder gross mass.
Advantages of the present invention: LiBiB2O5Ceramic sintering temperature is less than 650 DEG C, and dielectric constant reaches 8.7～9.1, its resonance
The temperature coefficient τ of frequencyƒLittle, temperature stability is good；Quality factor q f value is up to 95000-134000GHz, can be widely used for each
The manufacture of the microwave devices such as kind of medium substrate, resonator and wave filter, can meet low temperature co-fired technology and microwave multilayer device
Technology needs, and industrially has great using value.
Detailed description of the invention
Embodiment:
Table 1 shows 3 specific embodiments and the microwave dielectric property thereof of the different sintering temperatures constituting the present invention.Its system
Preparation Method as it has been described above, carry out the evaluation of microwave dielectric property by cylindrical dielectric resonator method.
This pottery can be widely used for the manufacture of the microwave devices such as various medium substrate, resonator and wave filter, can meet shifting
The technology of the systems such as dynamic communication and satellite communication needs.
Table 1:
Claims (1)
1. the temperature-stable ultralow dielectric microwave dielectric ceramic of a sintered at ultra low temperature, it is characterised in that described microwave is situated between
The chemical composition of electroceramics is: LiBiB2O5；
The preparation method of described microwave dielectric ceramic concretely comprises the following steps:
(1) be 99.9%(percentage by weight by purity) more than Li2CO3、Bi2O3And H3BO3Starting powder press LiBiB2O5's
Composition weighs dispensing；
(2) being mixed 12 hours by step (1) raw material wet ball-milling, ball-milling medium is dehydrated alcohol, at 550 DEG C of air gas after drying
Pre-burning 6 hours in atmosphere；
(3), after adding binding agent pelletize in the powder that step (2) prepares, re-compacted molding, finally at 600 ~ 650 DEG C of air
Atmosphere sinters 4 hours；Described binding agent uses mass concentration to be the poly-vinyl alcohol solution of 5%, and polyvinyl alcohol addition accounts for powder
The 3% of end gross mass.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410825331.9A CN104557019B (en) | 2014-12-27 | 2014-12-27 | Sintered at ultra low temperature temperature-stable microwave dielectric ceramic LiBiB2o5and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410825331.9A CN104557019B (en) | 2014-12-27 | 2014-12-27 | Sintered at ultra low temperature temperature-stable microwave dielectric ceramic LiBiB2o5and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104557019A CN104557019A (en) | 2015-04-29 |
| CN104557019B true CN104557019B (en) | 2016-09-28 |
Family
ID=53074206
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410825331.9A Active CN104557019B (en) | 2014-12-27 | 2014-12-27 | Sintered at ultra low temperature temperature-stable microwave dielectric ceramic LiBiB2o5and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104557019B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105439553A (en) * | 2015-12-19 | 2016-03-30 | 桂林理工大学 | Temperature-stable microwave dielectric ceramic Bi4MgB2O10 with low dielectric constant and preparation method thereof |
| CN106927828A (en) * | 2017-03-24 | 2017-07-07 | 桂林理工大学 | A kind of temperature-stable indate microwave dielectric ceramic |
| CN106927811A (en) * | 2017-03-24 | 2017-07-07 | 桂林理工大学 | A kind of indate high quality factor ultralow dielectric microwave dielectric ceramic |
| CN106917140B (en) * | 2017-03-26 | 2019-10-15 | 中国科学院新疆理化技术研究所 | Boronic acid compound lithium sodium birefringece crystal and preparation method and purposes |
| CN106830924A (en) * | 2017-03-27 | 2017-06-13 | 桂林理工大学 | A kind of low-loss gallate ultralow dielectric microwave dielectric ceramic |
| CN108395234A (en) * | 2018-02-05 | 2018-08-14 | 桂林理工大学 | Sintered at ultra low temperature, ultralow dielectric microwave dielectric material and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102320825A (en) * | 2011-08-16 | 2012-01-18 | 广西新未来信息产业股份有限公司 | Low-temperature sintered microwave dielectric ceramic and sintering method thereof |
| CN103922723A (en) * | 2014-04-06 | 2014-07-16 | 桂林理工大学 | Ultralow temperature sintered microwave dielectric ceramic Li3V3Bi2O12 and preparation method thereof |
-
2014
- 2014-12-27 CN CN201410825331.9A patent/CN104557019B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102320825A (en) * | 2011-08-16 | 2012-01-18 | 广西新未来信息产业股份有限公司 | Low-temperature sintered microwave dielectric ceramic and sintering method thereof |
| CN103922723A (en) * | 2014-04-06 | 2014-07-16 | 桂林理工大学 | Ultralow temperature sintered microwave dielectric ceramic Li3V3Bi2O12 and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104557019A (en) | 2015-04-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104628369B (en) | A kind of ultralow dielectric temperature-stable microwave dielectric ceramic Li2mg4si4o13 | |
| CN104557019B (en) | Sintered at ultra low temperature temperature-stable microwave dielectric ceramic LiBiB2o5and preparation method thereof | |
| CN106187160A (en) | Low-loss temperature-stabilized microwave dielectric ceramic LiGaSn3o8 | |
| CN104671783B (en) | Low-loss temperature stabilized microwave dielectric ceramic LiMg3NbWO9 | |
| CN106116550A (en) | A kind of silicate Li2siO3application as temperature-stable high quality factor microwave dielectric ceramic | |
| CN104628384B (en) | Low-loss temperature-stabilized medium dielectric constant microwave medium microwave dielectric ceramic LiBi2nbO6 | |
| CN104446433B (en) | Temperature-stable ultralow dielectric microwave dielectric ceramic Li3al2p3o12 | |
| CN104446474B (en) | The microwave-medium ceramics NdBiWO of temperature coefficient of resonance frequency nearly zero6 | |
| CN104446473B (en) | A kind of temperature-stable ultra-low loss microwave dielectric ceramic and preparation method thereof | |
| CN106116522A (en) | Temperature-stable ultralow dielectric microwave dielectric ceramic Mg3li2b2o7and preparation method thereof | |
| CN104478429B (en) | Temperature-stable ultralow dielectric microwave dielectric ceramic Li2znO2and preparation method thereof | |
| CN106082995A (en) | High quality factor temperature-stable microwave dielectric ceramic Ba2liB5o10and preparation method thereof | |
| CN104557014B (en) | A kind of ultralow dielectric microwave dielectric ceramic of temperature coefficient of resonance frequency nearly zero and preparation method thereof | |
| CN104557020B (en) | A kind of sintered at ultra low temperature ultralow dielectric microwave dielectric ceramic and preparation method thereof | |
| CN105948729A (en) | Temperature-stable ultralow-dielectric-constant microwave dielectric ceramic LiBSiO4 | |
| CN106220146A (en) | Temperature-stable ultralow dielectric microwave dielectric ceramic LiGa3ge2o9 | |
| CN105967667A (en) | Application of LiInSiO4 as low-loss stable-temperature microwave dielectric ceramic | |
| CN106116525A (en) | High quality factor temperature-stable microwave dielectric ceramic LiGaGe3o8 | |
| CN106242556A (en) | A kind of low-loss temperature-stabilized microwave dielectric ceramic LiBSn2o6 | |
| CN104446375B (en) | Temperature-stable ultralow dielectric microwave dielectric ceramic BaLa0.8nd1.2b10o19 | |
| CN106116523A (en) | A kind of germanate LiBGeO4application as temperature-stable microwave dielectric ceramic | |
| CN106083031A (en) | Low temperature sintering temperature-stable microwave dielectric ceramic Li2cu3ti4o12and preparation method thereof | |
| CN106116563A (en) | Low temperature sintering temperature-stable microwave dielectric ceramic Li4cu3ti4o13and preparation method thereof | |
| CN106242528A (en) | High quality factor temperature-stable microwave dielectric ceramic Li2znGe2o6 | |
| CN106187158A (en) | High quality factor temperature-stable ultralow dielectric microwave dielectric ceramic Li2mgSnO4 |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20201210 Address after: No. 10, Yingbin Avenue, Dongtai Development Zone, Yancheng City, Jiangsu Province Patentee after: Jiangsu Chuangqi Testing Technology Co.,Ltd. Address before: 541004 the Guangxi Zhuang Autonomous Region Guilin Construction Road No. 12 Patentee before: GUILIN University OF TECHNOLOGY |
|
| TR01 | Transfer of patent right | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Application publication date: 20150429 Assignee: DONGTAI GAOKE TECHNOLOGY INNOVATION PARK Co.,Ltd. Assignor: Jiangsu Chuangqi Testing Technology Co.,Ltd. Contract record no.: X2023980048819 Denomination of invention: Ultra low temperature sintering temperature stable microwave dielectric ceramic LiBiB2O5and its preparation method Granted publication date: 20160928 License type: Common License Record date: 20231202 |
|
| EE01 | Entry into force of recordation of patent licensing contract |