RU2293717C1 - Ceramic composite material - Google Patents

Abstract

FIELD: radio physics; production of the wide range of the electronic devices and the components.

SUBSTANCE: the invention is pertaining to the field of radio physics, in particular, it may be used at manufacture of the wide range of the electronic devices and the components, mainly in production of the controlled by the electric field the dielectric resonators and the filters, the controlled capacitors, antennas, and also in boosters of the nuclear particles. The ceramic composite material includes BaTiO₃, SrTiO₃ and contains the solid solution of barium-lanthanidic tetratitanate of the thee general formula: (Ba_1-xSr_x) Ln₂Ti₄O₁₂, where 0.2≥x≥0, and Ln is the lanthanoid from of the series: Nd-Sm at the following components ratio (in mass %): BaTiO₃ - 40-60, SrTiO₃ - 20-30, (Ba_1-xSr_x) Ln₂Ti₄O₁₂ - the rest.. The ceramic composite material additionally can contain BaTiO₉ in amount of 1-5 % or Nd₂O₃*3ТiO₂ in amount of 5-25 %. As the result it allows to solve the problem of reduction of the level of the dielectric losses, of the increase of the coefficient of the controllability over the dielectric permittivity by the electric field including also at the values of the dielectric permittivity above 110, and also the increased value of the coefficient of the controllability of the dielectric permittivity by the electric field at the increased environmental temperature.

EFFECT: the invention ensures allows to solve the problem of reduction of the level of the dielectric losses, of the increase of the coefficient of the controllability over the dielectric permittivity by the electric field, to increased value of the coefficient of the controllability of the dielectric permittivity by the electric field at the increased environmental temperature.

3 cl, 1 tbl

Description

The invention relates to the field of radiophysics and can in particular be used in the manufacture of a wide class of electronic devices and components, in particular dielectric resonators and filters controlled by an electric field, controlled capacitors (variconds or varactors), antennas, and also in nuclear particle accelerators.

Known ceramic composite material for electronic devices, including BaTiO ₃ and SrTiO ₃ in the form of a solid solution, as well as ZrO ₂ , while (BaTiO ₃ + SrTiO ₃ ) is contained in the amount, wt.%: 99-40, a ZrO ₂ - 1 -60, US 5486491.

The disadvantages of this material are as follows: a high level of dielectric loss tgδ; low coefficient of controllability of dielectric constant ε by electric field.

Also known is a ceramic composite material for electronic devices, including BaTiO ₃ , SrTiO ₃ (solid solution), as well as additives containing magnesium oxide, US 6074971.

This substance is taken as a prototype of the present invention.

The disadvantages of the prototype are:

- a high level of dielectric loss tanδ: from 0.0003 to 0.0016 at an electric field frequency of 250 kHz and from 0.00694 to 0.01917 at a frequency of 10 GHz;

- low coefficient T of control of the dielectric constant of the electric field: from 4.44 to 6.57% with an electric field strength E of 2 V / μm.

These shortcomings occur even at low dielectric constant ε: from 79 to 110. In addition, the prototype has the disadvantage of decreasing the value of T with increasing ambient temperature (in the range of operating temperatures of electronic devices), which requires the creation of special additional systems to maintain this temperature at a level not higher than the maximum value of T.

The objective of the present invention is to reduce the dielectric loss, increase the coefficient of controllability of the dielectric constant of the electric field, including at higher values of the dielectric constant (above 110), as well as provide an increase in the coefficient of controllability of the dielectric constant of the electric field with increasing ambient temperature (within operating temperature range of electronic devices).

According to the invention, this problem is solved due to the fact that the ceramic composite material for electronic devices, including BaTiO ₃ , SrTiO ₃ additionally contains a solid solution of barium-lanthanide tetratitanate of the general formula:

(Ba _IX Sr _x ) Ln ₂ Ti ₄ O ₁₂ , where

0.2≥x≥0, a Ln is a lanthanide from the series: Nd-Sm,

in the following ratio of components, wt.%:

BaTiO ₃ - 40-60

SrTiO ₃ - 20-30

(Ba _IX Sr _x ) Ln ₂ Ti ₄ O ₁₂ - the rest

The ceramic composite material may additionally contain BaTi ₄ O ₉ in an amount of 1-5%; ceramic composite material may additionally contain Nd ₂ O ₃ · 3TiO ₂ in an amount of 5-25%.

The applicant has not identified sources containing information about technical solutions identical to the present invention, which allows us to conclude that it meets the criterion of "novelty."

The implementation of the distinguishing features of the invention (in conjunction with the characteristics given in the restrictive part of the claims) provides important new properties of the ceramic composite material for electronic devices.

Dielectric losses are significantly reduced in comparison with the prototype even at ultrahigh frequencies: from 0.0042 to 0.0075 at 11 GHz, from 0.0001 to 0.0004 at a frequency of 1 MHz. This provides a sharp decrease in the intrinsic noise of electronic devices, respectively, an increase in their sensitivity, as well as the possibility of increasing the operating frequencies of devices. The coefficient of controllability of the dielectric constant of the electric field increases and is from 5 to 21% at E = 1.8 V / μm and ambient temperature t ° = 25 ° C and from 6 to 44% at E = 1.8 V / μm at t ° = 50 ° C.

Increasing the value of T provides the opportunity to improve the tuning frequency of the devices at low control voltages.

It should also be noted that the present invention provided a completely unexpected, paradoxical effect: while all known ceramic composite materials for electronic devices are characterized by a sharp decrease in the value of T and an increase in tanδ with increasing ambient temperature, the claimed composition provides an increase in T while maintaining low values with increasing temperature. This eliminates the need for thermal stabilization, provides improved parameters of electronic devices.

The applicant has not found any sources of information containing information about the impact of the claimed distinctive features on the technical result achieved as a result of their implementation. This, according to the applicant, indicates that this technical solution meets the criterion of "inventive step".

The ceramic composite material according to the present invention is prepared as follows. The starting components: BaTiO ₃ and SrTiO ₃ are mixed with the remaining components in predetermined proportions in vibratory mills for 3 hours to obtain a powder with a specific surface area of 1-2 m ² / g. Then, disk samples are produced by hydraulic pressing at a specific pressure of 0.8-1 T / cm ² . The obtained samples are sintered in an electric furnace at temperatures in the range from 1260 to 1420 ° C for 3-5 hours until zero water absorption is achieved.

To measure the electrical parameters of samples at high frequencies, they are coated with a silver-containing paste, which is burned at t ° = 840 ± 20 ° C, resulting in the formation of electrodes. At ultrahigh frequencies, the measurements do not require the formation of electrodes and are carried out by the method of a waveguide-dielectric resonator according to the standard procedure registered in the State Register of the Russian Federation (MI 00173-2000).

To measure the controllability coefficient of dielectric constant by an electric field, electrodes are formed by vacuum deposition of copper.

The test results of the samples of the claimed material are shown in the table.

No. p / p Composition, wt.% ε tgδ at frequency T,% E = 1.8 V / μm at temperature BaTiO ₃ SrTiO ₃ (Ba _IX Sr _X ) Ln ₂ Ti ₄ O ₁₂ BaTi ₄ O ₉ Nd ₂ O ₃ · ₃ TiO ₂ 1 MHz 11 GHz 25 ° C 50 ° C one 40 twenty 40 - - 485 0.00015 0.0056 7 8 2 45 22 33 - - 528 0.00013 0.0061 9 10 3 fifty 25 25 - - 560 0.00012 0.0042 13 fifteen four 55 27 eighteen - - 600 0.00018 0.0052 fifteen 16 5 60 thirty 10 - - 650 0,00045 0.0075 fifteen eighteen 6 fifty 25 24 one - 640 0,00032 0.0068 eighteen 27 7 45 22 29th four - 760 0.00011 0.0056 21 44 8 fifty 23 22 5 - 730 0,00025 0.0062 eleven fifteen 9 fifty 23 22 - 5 670 0.00016 0.0071 8 12 10 fifty twenty fifteen - fifteen 655 0,00045 0.0068 6 7 eleven fifty 25 25 - 25 550 0,00044 0.0062 5 6

With an increase in the content of BaTiO ₃ over 60 wt.%, A significant increase in the level of dielectric losses occurs, with a decrease in the content of this component below 40 wt.%, The coefficient of controllability T decreases.

With an increase in the content of SrTiO ₃ above 30 wt.%, The coefficient T also decreases, and with a decrease in the content of SrTiO ₃ below 20 wt.%, The level of dielectric loss of the material increases.

The additional introduction of BaTi ₄ O ₉ or Nd ₂ O ₃ · 3TiO ₂ provides some further increase in the coefficient T while maintaining a low level of dielectric loss.

To implement the invention, common materials and conventional factory equipment are used, which determines, according to the applicant, the invention meets the criterion of "industrial applicability".

Claims (3)

1. Ceramic composite material for electronic devices, including BaTiO ₃ , SrTiO ₃ , characterized in that it further comprises a solid solution of barium-lanthanide tetratitanate of the General formula: (Ba _Ix Sr _x ) Ln ₂ Ti ₄ O ₁₂ , where 0.2≥x≥0, a Ln is a lanthanide from the series: Nd-Sm, in the following ratio of components, wt.%: BaTiO ₃ 40-60 SrTiO ₃ 20-30 (Ba _Ix Si _x ) Ln ₂ Ti ₄ O ₁₂ Rest 2. The ceramic composite material according to claim 1, characterized in that it further comprises BaTi ₄ O ₉ in an amount of 1-5%. 3. The ceramic composite material according to claim 1, characterized in that it further comprises Nd ₂ O ₃ · 3TiO ₂ in an amount of 5-25%.