CN103601485A - Lithium-zinc titanate microwave medium ceramic material prepared by semi-chemical method and preparation method thereof - Google Patents

Abstract

The invention discloses a lithium-zinc titanate microwave medium ceramic material prepared by a semi-chemical method and a preparation method thereof, and relates to a ceramic composition with components as characteristics. The lithium-zinc titanate microwave medium ceramic material is composed of Li2ZnTi3O8 powder and xwt% of a sintering aid, wherein the sintering aid is one of low-melting-point oxides including B2O3, Bi2O3 and V2O5, and x is 0.25wt%-1.0wt%. A sol-gel method is firstly used to prepare Li2ZnTi3O8 powder, and then, Li2ZnTi3O8 and the sintering aid are mixed to prepare the lithium-zinc titanate microwave medium ceramic material through a solid-phase reaction method. The microwave medium ceramic material prepared by the preparation method disclosed by the invention has a sintering temperature not higher than 900 DEG C, a quality factor Q*f value of about 49760 GHz-60580 GHz, dielectric constant epsilon r of 24.69-26.83, and a resonant frequency temperature coefficient tau f of (-)21.48*10<-6>-15.68*10<-6>, and can be used for manufacturing microwave apparatuses such as a resonator, a microwave antenna and a microwave device.

Description

Lithium titanate zinc microwave dielectric ceramic materials prepared by a kind of half chemical method and preparation method thereof

Technical field

The invention belongs to electronic ceramics and manufacture field thereof, relate to and take the ceramic composition that composition is feature, be specifically related to lithium titanate zinc microwave dielectric ceramic materials prepared by a kind of half chemical method and preparation method thereof.

Background technology

Innovation along with technology such as modern communication, WLAN (wireless local area network), Global Positioning Systems, novel microwave device and the associated media pottery thereof of various microminiaturizations, high frequency, chip type are developed rapidly, the microwave-medium ceramics (low temperature co-fired ceramic, LTCC) burning altogether with low melting point base metal Cu, Ag or the Cu/Ag alloy of high conductivity becomes the main flow of microwave dielectric material development.

Microwave-medium ceramics is as the critical material of manufacturing these devices, and its performance index have determined the performance of micro-wave communication device and system to a great extent.And LTCC Technology (LTCC) realize just microwave device to high frequency, at a high speed, the important channel of lightweight, the future development such as slim, the sintering temperature of LTCC technical requirements microwave dielectric ceramic materials is lower than 1000 ℃, and with 961 ℃ of electrode materials Ag(fusing points) altogether burning there is not chemical reaction.The sintering temperature of most of microwave dielectric ceramic materials of research, mostly more than 1200 ℃, cannot be burnt at low temperatures altogether with metal electrode material at present.Therefore, the sintering temperature of reduction microwave-medium ceramics and exploitation sintering temperature microwave dielectric ceramic materials low, that dielectric properties are good have great practical value.

For reducing the sintering temperature of microwave-medium ceramics, the common burning of the electrodes such as realization and Ag, Cu, pure solid reaction process need to add the sintering temperature that a large amount of low melting point oxides or glass auxiliary agent reduce microwave dielectric ceramic materials conventionally.The introducing of a large amount of sintering aids often causes the obvious deterioration of ceramic microwave dielectric properties.Therefore, finding the sintering temperature that effective preparation method reduces microwave ceramic material system is more and more subject to people's attention.

Half chemical method adopts sol-gel technique in conjunction with solid reaction process.Ceramic powder narrow diameter distribution prepared by collosol and gel (sol-gel) technology, pattern is regular single, and median size is little, can reach Nano grade.Nano-powder is conducive to mass transfer diffusion in sintering process, reduces ceramic sintering temperature.By solid reaction process, mix micro-sintering agent, preparation technology is simple, and can further reduce sintering temperature, raising ceramic body density and microwave dielectric property.

Summary of the invention

For above-mentioned prior art, the object of the invention is to how to provide lithium titanate zinc microwave dielectric ceramic materials prepared by a kind of half chemical method and preparation method thereof, its technological process is simple, operation is easy to control, low production cost, and sintering temperature is low.

In order to solve the problems of the technologies described above, the present invention adopts following technical scheme:

A lithium titanate zinc microwave dielectric ceramic materials prepared by half chemical method, is characterized in that, by Li ₂znTi ₃o ₈powder+xwt% sintering agent forms, described Li ₂znTi ₃o ₈powder adopts sol-gel technique preparation, and sintering agent is low melting point oxide B ₂o ₃, Bi ₂o ₃, V ₂o ₅in a kind of, 0.25≤x≤1.0wt%, the mass percent that x is sintering agent.

The preparation method of lithium titanate zinc microwave dielectric ceramic materials prepared by described half chemical method, is characterized in that, first with sol-gel method, preparing lithium titanate zinc powder body is Li ₂znTi ₃o ₈powder, then by Li ₂znTi ₃o ₈powder and sintering agent mix employing solid reaction process and prepare lithium titanate zinc microwave-medium ceramics.

Described sol-gel method is prepared the processing step of lithium titanate zinc powder body, and it comprises the steps:

Step 1: at 60～80 ℃, by C ₁₆h ₃₆o ₄ti and methyl ethyl diketone by volume 5:1 mix, and add appropriate ethylene glycol monomethyl ether, after stirring, obtain C ₁₆h ₃₆o ₄ti solution;

Step 2: by LiNO ₃, Zn (NO ₃) ₂press Li:Zn mol ratio 2:1 and mix, the mixture of acquisition adds appropriate ethylene glycol to stir, and makes LiNO ₃, Zn (NO ₃) ₂dissolve completely, obtain the mixing solutions of lithium zinc;

Step 3: the lithium zinc mixing solutions by step 2 gained is poured into the C in step 1 ₁₆h ₃₆o ₄ti solution

In, add appropriate Glacial acetic acid, control the pH value of solution in 2～3 scopes, constant temperature stirs 3～5h, obtains colored transparent clear liquid; After still aging stable 12h, in 100 ℃ of dry 24h, obtain dry gel powder, pre-burning 4h in 800 ℃ of air atmospheres, obtains Li ₂znTi ₃o ₈powder is crossed 100 mesh sieves, stand-by.

Described solid reaction process is prepared lithium titanate zinc microwave-medium ceramics, comprises the steps:

Step 1: by the Li preparing ₂znTi ₃o ₈powder and B ₂o ₃, Bi ₂o ₃or V ₂o ₅in one or more sintering agents by proportioning, mix;

Step 2: by mixed Li ₂znTi ₃o ₈powder and sintering agent pack in ball grinder, add dehydrated alcohol and zirconia ball, mixed Li ₂znTi ₃o ₈the mass ratio of powder and sintering agent, anhydrous this alcoholic solvent of second, zirconia ball is 1:1.5:3, and mixing and ball milling 24h is dried, and crosses 100 mesh sieves and obtains ceramic powder;

Step 3: then add 5% polyvinyl alcohol water solution in ceramic powder, mix, dry, cross 100 mesh sieve granulations;

Step 4: the pressed by powder after granulation is become to cylindrical sample, and sintering 4h at 800～900 ℃ of temperature, obtains low sintering microwave dielectric ceramic materials.

Compared with prior art, the present invention has following beneficial effect:

One, the microwave-medium ceramics that prepared by the present invention, its sintering temperature low (≤900 ℃), microwave property is excellent, and quality factor q * f value is high is about 4.98～6.06 * 10 ⁴, high-frequency dielectric constant ε _rbe 24.69～26.83, frequency-temperature coefficient τ _flittle, can be used for the manufacture of the microwave devices such as resonator, microwave antenna, wave filter.

Two, first with sol-gel method, to prepare lithium titanate zinc powder body be Li in the present invention ₂znTi ₃o ₈powder, then by Li ₂znTi ₃o ₈powder and sintering agent mix and adopt solid reaction process to prepare lithium titanate zinc microwave-medium ceramics, and its pre-burning time is that 1～4 hour, sintering time are also only 1～4 hour, has saved widely the energy, has shortened the explained hereafter cycle, has improved production efficiency;

The lithium titanate zinc microwave-medium ceramics of half chemical preparation that three, the present invention adopts, greatly reduces the usage quantity of sintering agent in preparation process, reduced the impact of sintering agent volatilization on environment, more environmental protection.

Embodiment

Below in conjunction with embodiment, the invention will be further described.

The preparation method of lithium titanate zinc microwave dielectric ceramic materials prepared by described half chemical method, first with sol-gel method, preparing lithium titanate zinc powder body is Li ₂znTi ₃o ₈powder, then by Li ₂znTi ₃o ₈powder and sintering agent mix employing solid reaction process and prepare lithium titanate zinc microwave-medium ceramics.

Embodiment 1:

Step 1, at 60～80 ℃, by C ₁₆h ₃₆o ₄ti and methyl ethyl diketone by volume 5:1 mix, and add appropriate ethylene glycol monomethyl ether, after stirring, obtain C ₁₆h ₃₆o ₄ti(butyl (tetra) titanate) solution;

Step 2, by LiNO ₃, Zn (NO ₃) ₂press Li:Zn mol ratio 2:1 and mix, the mixture of acquisition adds appropriate ethylene glycol to stir, and makes LiNO ₃, Zn (NO ₃) ₂dissolve completely, obtain the mixing solutions of lithium zinc;

Step 3, by the lithium zinc mixing solutions of step 2 gained, be poured into the C of step (1) ₁₆h ₃₆o ₄in Ti solution, add appropriate Glacial acetic acid, control the pH value of solution in 2～3 scopes, constant temperature stirs 3～5h, obtains colored transparent clear liquid; After still aging stable 12h, in 100 ℃ of dry 24h, obtain dry gel powder, pre-burning 4h in 800 ℃ of air atmospheres, obtains Li ₂znTi ₃o ₈powder is crossed 100 mesh sieves, stand-by;

Step 4, get a certain amount of Li preparing ₂znTi ₃o ₈powder, according to B ₂o ₃account for Li ₂znTi ₃o ₈the 0.5wt% of quality, prepares burden, and formula number is BO ₁.By Li ₂znTi ₃o ₈powder and B ₂o ₃mixture pack in ball grinder, add zirconia ball and dehydrated alcohol, Li ₂znTi ₃o ₈powder and B ₂o ₃the mass ratio of mixture, anhydrous ethanol solvent and zirconia ball be 1:1.5:3, mixing and ball milling 24h, dries, and crosses 100 mesh sieves and obtains ceramic powder; Then in ceramic powder, add 5% polyvinyl alcohol water solution, mix, dry, cross 100 mesh sieve granulations; Pressed by powder after granulation is become to cylindrical sample, and in 850 ℃ of air atmospheres, sintering 4h makes.

Embodiment 2:

Step 1: at 60～80 ℃, by C ₁₆h ₃₆o ₄ti and methyl ethyl diketone by volume 5:1 mix, and add appropriate ethylene glycol monomethyl ether, after stirring, obtain C ₁₆h ₃₆o ₄ti solution;

Step 2: by LiNO ₃, Zn (NO ₃) ₂press Li:Zn mol ratio 2:1 and mix, the mixture of acquisition adds appropriate ethylene glycol to stir, and makes LiNO ₃, Zn (NO ₃) ₂dissolve completely, obtain the mixing solutions of lithium zinc;

Step 3: the C that is poured into step 1 by the lithium zinc mixing solutions of step 2 gained ₁₆h ₃₆o ₄in Ti solution, add appropriate Glacial acetic acid, control the pH value of solution in 2～3 scopes, constant temperature stirs 3～5h, obtains colored transparent clear liquid; After still aging stable 12h, in 100 ℃ of dry 24h, obtain dry gel powder, pre-burning 4h in 800 ℃ of air atmospheres, obtains Li ₂znTi ₃o ₈powder is crossed 100 mesh sieves, stand-by;

Step 4: get a certain amount of Li preparing ₂znTi ₃o ₈powder, according to B ₂o ₃account for Li ₂znTi ₃o ₈the 0.25wt% of quality, prepares burden, and formula number is BO ₂.By Li ₂znTi ₃o ₈powder and B ₂o ₃mixture pack in ball grinder, add zirconia ball and dehydrated alcohol, Li ₂znTi ₃o ₈powder and B ₂o ₃mixture, anhydrous ethanol solvent, the mass ratio of zirconia ball be 1:1.5:3, mixing and ball milling 24h, dries, and crosses 100 mesh sieves and obtains ceramic powder; Then in ceramic powder, add 5% polyvinyl alcohol water solution, mix, dry, cross 100 mesh sieve granulations; Pressed by powder after granulation is become to cylindrical sample, and in 900 ℃ of air atmospheres, sintering 4h makes.

Embodiment 3:

Step 1: at 60～80 ℃, by C ₁₆h ₃₆o ₄ti and methyl ethyl diketone by volume 5:1 mix, and add appropriate ethylene glycol monomethyl ether, after stirring, obtain C ₁₆h ₃₆o ₄ti solution;

Step 2: by LiNO ₃, Zn (NO ₃) ₂press Li:Zn mol ratio 2:1 and mix, the mixture of acquisition adds appropriate ethylene glycol to stir, and makes LiNO ₃, Zn (NO ₃) ₂dissolve completely, obtain the mixing solutions of lithium zinc;

Step 3: the C that is poured into step 1 by the lithium zinc mixing solutions of step 2 gained ₁₆h ₃₆o ₄in Ti solution, add appropriate Glacial acetic acid, control the pH value of solution in 2～3 scopes, constant temperature stirs 3～5h, obtains colored transparent clear liquid; After still aging stable 12h, in 100 ℃ of dry 24h, obtain dry gel powder, pre-burning 4h in 800 ℃ of air atmospheres, obtains Li ₂znTi ₃o ₈powder is crossed 100 mesh sieves, stand-by;

Step 4: get a certain amount of Li preparing ₂znTi ₃o ₈powder, according to Bi ₂o ₃account for Li ₂znTi ₃o ₈the 0.5wt% of quality, prepares burden, and formula number is B ₁.By Li ₂znTi ₃o ₈powder and Bi ₂o ₃mixture pack in ball grinder, add dehydrated alcohol and dehydrated alcohol, Li ₂znTi ₃o ₈powder and Bi ₂o ₃mixture, anhydrous ethanol solvent, the mass ratio of dehydrated alcohol be 1:1.5:3, mixing and ball milling 24h, dries, and crosses 100 mesh sieves and obtains ceramic powder; Then in ceramic powder, add 5% polyvinyl alcohol water solution, mix, dry, cross 100 mesh sieve granulations; Pressed by powder after granulation is become to cylindrical sample, and in 875 ℃ of air atmospheres, sintering 4h makes.

Embodiment 4:

Step 1: at 60～80 ℃, by C ₁₆h ₃₆o ₄ti and methyl ethyl diketone by volume 5:1 mix, and add appropriate ethylene glycol monomethyl ether, after stirring, obtain C ₁₆h ₃₆o ₄ti solution;

Step 2: by LiNO ₃, Zn (NO ₃) ₂press Li:Zn mol ratio 2:1 and mix, the mixture of acquisition adds appropriate ethylene glycol to stir, and makes LiNO ₃, Zn (NO ₃) ₂dissolve completely, obtain the mixing solutions of lithium zinc;

Step 3: the C that is poured into step 1 by the lithium zinc mixing solutions of step 2 gained ₁₆h ₃₆o ₄in Ti solution, add appropriate Glacial acetic acid, control the pH value of solution in 2～3 scopes, constant temperature stirs 3～5h, obtains colored transparent clear liquid; After still aging stable 12h, in 100 ℃ of dry 24h, obtain dry gel powder, pre-burning 4h in 800 ℃ of air atmospheres, obtains Li ₂znTi ₃o ₈powder is crossed 100 mesh sieves, stand-by;

Step 4: get a certain amount of Li preparing ₂znTi ₃o ₈powder, according to Bi ₂o ₃account for Li ₂znTi ₃o ₈the 0.75wt% of quality, prepares burden, and formula number is B ₂.By Li ₂znTi ₃o ₈powder and Bi ₂o ₃mixture pack in ball grinder, add zirconia ball and dehydrated alcohol, Li ₂znTi ₃o ₈powder and Bi ₂o ₃the mass ratio of mixture, anhydrous ethanol solvent and zirconia ball be 1:1.5:3, mixing and ball milling 24h, dries, and crosses 100 mesh sieves and obtains ceramic powder; Then in ceramic powder, add 5% polyvinyl alcohol water solution, mix, dry, cross 100 mesh sieve granulations; Pressed by powder after granulation is become to cylindrical sample, and in 825 ℃ of air atmospheres, sintering 4h makes.

Embodiment 5:

Step 1, at 60～80 ℃, by C ₁₆h ₃₆o ₄ti and methyl ethyl diketone by volume 5:1 mix, and add appropriate ethylene glycol monomethyl ether, after stirring, obtain C ₁₆h ₃₆o ₄ti solution;

Step 2, by LiNO ₃, Zn (NO ₃) ₂press Li:Zn mol ratio 2:1 and mix, the mixture of acquisition adds appropriate ethylene glycol to stir, and makes LiNO ₃, Zn (NO ₃) ₂dissolve completely, obtain the mixing solutions of lithium zinc;

Step 3, by the lithium zinc mixing solutions of step 2 gained, be poured into the C of step 1 ₁₆h ₃₆o ₄in Ti solution, add appropriate Glacial acetic acid, control the pH value of solution in 2～3 scopes, constant temperature stirs 3～5h, obtains colored transparent clear liquid; After still aging stable 12h, in 100 ℃ of dry 24h, obtain dry gel powder, pre-burning 4h in 800 ℃ of air atmospheres, obtains Li ₂znTi ₃o ₈powder is crossed 100 mesh sieves, stand-by;

Step 4, get a certain amount of Li preparing ₂znTi ₃o ₈powder, according to V ₂o ₅account for Li ₂znTi ₃o ₈the 0.5wt% of quality, prepares burden, and formula number is V ₁.By Li ₂znTi ₃o ₈powder and V ₂o ₅mixture pack in ball grinder, add zirconia ball and dehydrated alcohol, Li ₂znTi ₃o ₈powder and V ₂o ₅the mass ratio of mixture, anhydrous ethanol solvent and zirconia ball be 1:1.5:3, mixing and ball milling 24h, dries, and crosses 100 mesh sieves and obtains ceramic powder; Then in ceramic powder, add 5% polyvinyl alcohol water solution, mix, dry, cross 100 mesh sieve granulations; Pressed by powder after granulation is become to cylindrical sample, and in 850 ℃ of air atmospheres, sintering 4h makes.

Embodiment 6:

Step 1, at 60～80 ℃, by C ₁₆h ₃₆o ₄ti and methyl ethyl diketone by volume 5:1 mix, and add appropriate ethylene glycol monomethyl ether, after stirring, obtain C ₁₆h ₃₆o ₄ti solution;

Step 2, by LiNO ₃, Zn (NO ₃) ₂press Li:Zn mol ratio 2:1 and mix, the mixture of acquisition adds appropriate ethylene glycol to stir, and makes LiNO ₃, Zn (NO ₃) ₂dissolve completely, obtain the mixing solutions of lithium zinc;

Step 3, by the lithium zinc mixing solutions of step 2 gained, be poured into the C of step 1 ₁₆h ₃₆o ₄in Ti solution, add appropriate Glacial acetic acid, control the pH value of solution in 2～3 scopes, constant temperature stirs 3～5h, obtains colored transparent clear liquid; After still aging stable 12h, in 100 ℃ of dry 24h, obtain dry gel powder, pre-burning 4h in 800 ℃ of air atmospheres, obtains Li ₂znTi ₃o ₈powder is crossed 100 mesh sieves, stand-by;

Step 4, get a certain amount of Li preparing ₂znTi ₃o ₈powder, according to V ₂o ₅account for Li ₂znTi ₃o ₈the 1.0wt% of quality, prepares burden, and formula number is V ₂.By Li ₂znTi ₃o ₈powder and V ₂o ₅mixture pack in ball grinder, add zirconia ball and dehydrated alcohol, Li ₂znTi ₃o ₈powder and V ₂o ₅the mass ratio of mixture, anhydrous ethanol solvent and zirconia ball be 1:1.5:3, mixing and ball milling 24h, dries, and crosses 100 mesh sieves and obtains ceramic powder; Then in ceramic powder, add 5% polyvinyl alcohol water solution, mix, dry, cross 100 mesh sieve granulations; Pressed by powder after granulation is become to cylindrical sample, and in 800 ℃ of air atmospheres, sintering 4h makes.

Table 1 is formula and the dielectric properties of embodiment 1 to 6 correspondence.Wherein, dielectric properties are measured and are adopted Agilent E5071C network analyzer, according to Hakki-Coleman Resonant-cavity Method, measure DIELECTRIC CONSTANT ε _rand quality factor q * f, frequency-temperature coefficient τ _fin 25～80 ℃ of temperature ranges, measure, and by formula: τ _f=(f _t2-f _t1)/(f _t1* (t ₂-t ₁)) calculating, wherein f _t2and f _t1be respectively t ₁=80 ℃ and t ₂resonance center frequeH at=25 ℃.

Table 1 ceramic composition and dielectric properties

Formula number	Oxide compound	Oxide content (wt%)	Sintering temperature (℃)	ε r	Q×f(GHz)	τ f（×10 –6/℃）
							BO 1	B 2O 3	0.5	850	24.72	60580	-15.68
BO2	B 2O 3	0.25	900	26.83	58860	-16.75
							B1	Bi 2O 3	0.5	875	23.87	60390	-16.43
B2	Bi 2O 3	0.75	825	24.21	54320	-19.69
							V1	V 2O 5	0.5	850	23.91	56590	-17.32
V2	V 2O 5	1.0	800	22.69	49760	-21.48

Claims (3)

1. the lithium titanate zinc microwave dielectric ceramic materials that prepared by half chemical method, is characterized in that, by Li ₂znTi ₃o ₈powder+xwt% sintering agent forms, described Li ₂znTi ₃o ₈powder adopts sol-gel technique preparation, and sintering agent is low melting point oxide B ₂o ₃, Bi ₂o ₃, V ₂o ₅in a kind of, 0.25≤x≤1.0wt%, the mass percent that x is sintering agent.

2. described in, the preparation method of lithium titanate zinc microwave dielectric ceramic materials, is characterized in that, first with sol-gel method, preparing lithium titanate zinc powder body is Li ₂znTi ₃o ₈powder, then by Li ₂znTi ₃o ₈powder and sintering agent mix employing solid reaction process and prepare lithium titanate zinc microwave-medium ceramics.

3. the preparation method of lithium titanate zinc microwave dielectric ceramic materials according to claim 2, is characterized in that, described sol-gel method is prepared the processing step of lithium titanate zinc powder body, and it comprises the steps:

Step 1: at 60～80 ℃, by C ₁₆h ₃₆o ₄ti and methyl ethyl diketone by volume 5:1 mix, and add appropriate ethylene glycol monomethyl ether, after stirring, obtain C ₁₆h ₃₆o ₄ti solution;

Step 2: by LiNO ₃, Zn (NO ₃) ₂press Li:Zn mol ratio 2:1 and mix, the mixture of acquisition adds appropriate ethylene glycol to stir, and makes LiNO ₃, Zn (NO ₃) ₂dissolve completely, obtain the mixing solutions of lithium zinc;

Step 3: the lithium zinc mixing solutions by step 2 gained is poured into the C in step 1 ₁₆h ₃₆o ₄in Ti solution, add appropriate Glacial acetic acid, control the pH value of solution in 2～3 scopes, constant temperature stirs 3～5h, obtains colored transparent clear liquid; After still aging stable 12h, in 100 ℃ of dry 24h, obtain dry gel powder, pre-burning 4h in 800 ℃ of air atmospheres, obtains Li ₂znTi ₃o ₈powder is crossed 100 mesh sieves, stand-by;

Described solid reaction process is prepared lithium titanate zinc microwave-medium ceramics, comprises the steps:

Step 1: by the Li preparing ₂znTi ₃o ₈powder and B ₂o ₃, Bi ₂o ₃or V ₂o ₅in one or more sintering agents by proportioning, mix;

Step 2: by mixed Li ₂znTi ₃o ₈powder and sintering agent pack in ball grinder, add dehydrated alcohol and zirconia ball, mixed Li ₂znTi ₃o ₈the mass ratio of powder and sintering agent, anhydrous this alcoholic solvent of second, zirconia ball is 1:1.5:3, and mixing and ball milling 24h is dried, and crosses 100 mesh sieves and obtains ceramic powder;

Step 3: then add 5% polyvinyl alcohol water solution in ceramic powder, mix, dry, cross 100 mesh sieve granulations;

Step 4: the pressed by powder after granulation is become to cylindrical sample, and sintering 4h at 800～900 ℃ of temperature, obtains microwave dielectric ceramic materials.