JPH07196366A - Production of porcelain composition for microwave dielectric substance - Google Patents

Abstract

PURPOSE:To obtain a microwave dielectric porcelain composition having a high dielectric constant, small absolute value of the temperature factor of resonant frequency and improved unload Q performance by firing a specific porcelain composition at a prescribed temperature for many hours. CONSTITUTION:Powders of zirconium oxide, tin oxide, titanium oxide, and zinc oxide are mixed so that the main composition becomes (Zr1Snx)TiO4 (0<x<1.0) and 0.1 to 7.0 pts.wt. of ZnO is added to 100 pts.wt. of the main composition, of ZnO as a result, then the mixture is preliminarily fired at about 900 deg.C in an air atmosphere for about 2 hours. The product is crushed, granulated. The granules are press-molded and the molded products are fired at a prescribed temperature of some 1425 deg.C over 20 hours to give the microwave dielectric porcelain composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a microwave dielectric ceramic composition (hereinafter referred to as a dielectric ceramic composition or simply composition). More specifically, the firing time is set to a specific long time. As a result, the composition having a high relative permittivity (hereinafter, simply referred to as ε _r ), a small absolute value of the temperature coefficient of resonance frequency (hereinafter, simply referred to as τ _f ), and a composition obtained by firing for a short time No load Q higher than that of objects
(Hereinafter, simply referred to as Qu.) The present invention relates to a method for producing a dielectric ceramic composition exhibiting performance. INDUSTRIAL APPLICABILITY The present invention is utilized for impedance matching of dielectric resonators, microwave integrated circuit substrates, various microwave circuits, etc. in the microwave region.

[0002]

2. Description of the Related Art Generally, a dielectric resonator or a dielectric substrate used in a high frequency region such as a microwave or a millimeter wave has a high Qu and a high ε _r, and has a temperature coefficient τ _f of a resonance frequency. A small absolute value is desired. That is, the dielectric porcelain composition tends to have a larger dielectric loss as the operating frequency becomes higher. Therefore, a dielectric porcelain composition having a large Qu and ε _{r in} the microwave region is desired.

Conventionally, as such a dielectric ceramic composition, a dielectric ceramic composition containing a predetermined amount of ZrO ₂ , SnO ₂ and TiO ₂ as main components and ZnO added thereto (Japanese Patent Publication No. 54-35678). ), ZnO and C as the main components
A composition containing oO ₃ (JP-A-51-67998), a composition containing ZnO and La ₂ O ₃ added to the main components (JP-A 51-67997), and ZnO containing the main component Composition containing NiO (Japanese Patent Application Laid-Open No. 3-2816
No. 2) and the like, and their compositions are 130
It is manufactured by firing for 4 hours at a temperature slightly exceeding 0 ° C. However, in the above-mentioned conventional technique, when the additive component such as ZnO is small, a sufficiently sintered porcelain cannot be obtained, and when the additive amount is increased, Qu and ε _r tend to decrease, and the sintering cannot be performed. Fully done and Qu, ε _r and τ
There is no known method for obtaining an excellent dielectric ceramic composition with well-balanced characteristics such as _f by a simple method.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems by adding an appropriate amount of ZnO to a (Zr _1-X Sn _X ) TiO ₄ type composition and then at a predetermined temperature for 20 hours. By firing for a long time as described above, ε _r is high, the absolute value of τ _f is small, and Qu is considerably improved as compared with the composition obtained by firing for a short time, which is excellent in balance of each property. It is an object to provide a method for producing a dielectric ceramic composition.

[0005]

The present inventors have found that (Zr
_1-X Sn _X ) TiO ₄ -based composition, a small amount of ZnO
As a result of various studies on a composition showing a high ε _r and an excellent τ _f and having a high Qu by adding the above, it was found that after reaching a predetermined firing temperature, the temperature was maintained for 20 hours or more and the firing was performed for a long time. As a result, they have found that Qu can be further improved, and completed the present invention.

That is, the method for producing a dielectric ceramic composition of the present invention is (Zr _1-X Sn _X ) TiO ₄ (where 0 <x1.
0) as the main component, to which (Zr
_1-X Sn _X ) TiO ₄ 0.1 to 100 parts by weight
Zirconium oxide powder (II) and tin oxide powder (I) were added so that the composition contained 7.0 parts by weight of ZnO.
I), titanium oxide powder (II) and zinc oxide powder (I)
And then calcining to produce a calcined powder, the calcined powder is crushed, and then calcined at a predetermined temperature for 20 hours or more. Further, the second invention is characterized in that 0.15 ≦ x ≦ 0.25 in the above main component, and that the amount of ZnO added is 0.1 part by weight to less than 1.0 part by weight.

The above x is 0 <x1.0, and the main components used in the manufacturing method of the present invention are ZrO ₂ , SnO ₂ and T.
iO ₂ is required. If x is in the above range, the effect of improving Qu by long-time firing of the present invention can be obtained,
When 0.15 ≦ x ≦ 0.25, the effect of improving Qu is particularly large, and a dielectric ceramic composition having a good balance of Qu, ε _r and τ _f characteristics is obtained, which is preferable. In addition, Zn
O is added in the range of 0.1 to 7.0 parts by weight with respect to the main component. If the amount of ZnO added is less than 0.1 parts by weight, a sufficiently sintered porcelain cannot be obtained even by firing for a long time.
If the amount exceeds 0 parts by weight, ε _r and Qu decrease. This addition amount is 0.1 to less than 1.0 part by weight, particularly 0.2.
To 0.5 part by weight is preferable, and when the amount of ZnO added is in the range of 0.2 to 0.5 part by weight, Q due to long-term firing is
The effect of improving u is particularly large, and a composition in which other characteristics are well balanced is obtained.

[0008]

The manufacturing method of the present invention is most characterized in that the firing time is as long as 20 hours or more. Conventionally, this kind of dielectric ceramic composition is generally fired at a temperature slightly higher than 1300 ° C. for about 4 hours. In that case, SnO _{2 in} the main component is limited to a specific amount with respect to ZrO ₂ . However, if SnO ₂ is less than the lower limit, Qu decreases, and if it exceeds the upper limit, τ _f becomes too small on the minus side. In contrast, the present invention provides compositions with excellent properties regardless of their relative amounts.
Furthermore, in the conventional example, the amount of the oxide added to the main component is at least 1.0 part by weight or more, and if the amount added is less than that, a sufficiently sintered dielectric ceramic composition cannot be obtained. On the other hand, in the present invention, from 7.0 parts by weight or less where ε _r and Qu start to decrease to less than 1.0 parts by weight, particularly 0.1
Even if the addition amount is reduced to the weight part, it is possible to obtain a dielectric porcelain composition which can be practically used sufficiently.

[0009]

EXAMPLES The present invention will be specifically described below with reference to examples. ZrO ₂ powder (purity; 99.35%), SnO ₂ powder (purity; 99.70%), TiO ₂ powder (purity; 9)
9.50%) and ZnO powder (purity; 99.50%) as starting materials, as shown in Tables 1 and 2, x and Zn
Predetermined amounts (each about 500 g in total) were weighed and mixed so that the composition was such that the amount of O added varied.

Then, after wet mixing (20 to 30 minutes) by an Erich mixer, 90 in an air atmosphere.
It was calcined at 0 ° C. for 2 hours. Next, an appropriate amount of organic binder (29 g) and water (500 g) were added to this calcined powder, and 2
It was crushed with a 0 mmφ alumina ball at 90 rpm for 23 hours. Then, it is granulated by vacuum freeze-drying (0.4 Torr, freezing temperature -20 ° C, drying temperature 50 ° C, about 23 hours), and the granulated raw material is used to press at a pressure of 1 ton / cm ^{2 with} a pressure of 19 mmφ × It was formed into a cylindrical shape having a height of 10 mmt.

Next, the molded body was placed in the atmosphere at 650 ° C. for 3 days.
After degreasing for a period of time, then 142 at a rate of 100 ° C / h
The temperature was raised to 5 ° C, and at that temperature, 0, 1, 5, 10, 3
The sample was held for 0, 40, and 50 hours for firing, and finally, both end faces were polished into a cylindrical shape of about 16 mmφ × 8 mmt (height) to obtain dielectric samples (Nos. 1 to 6 in Table 1 and Table 2). N
o. 7-12). A sample fired at 1400 ° C. and 1450 ° C. was prepared only when the holding time was 50 h. Then, for each of the above-mentioned samples, Qu, ε was measured by a parallel conductor plate type dielectric cylindrical resonator method (TE ₀₁₁ MODE) or the like.
_{The r} and τ _f were measured. The resonance frequency at the time of measurement is 4.
5 GHz, τ _f was measured in the temperature range of 20 ° C. to 80 ° C., and τ _f = (f ₈₀ −f ₂₀ ) / (f ₂₀ × ΔT), ΔT =
It was calculated at 80 ° C-20 ° C = 60 ° C. The results are shown in Tables 1 and 2 and FIGS. In addition, in FIGS.
X is 0.15, Δ is x 0.20 and □ is x 0.2
The results are for case 5.

[0012]

[Table 1]

[0013]

[Table 2]

According to FIGS. 1 to 3, the added amount of ZnO is 0.2.
Under the conditions of parts by weight, firing temperature of 1425 ° C. and holding time of 50 hours, as x increased in the range of 0.15 to 0.25, Qu increased (FIG. 1), ε _r decreased, and τ
_{Although f} varies within a range of about +10 to -10, all of them are within a practically satisfactory range, and a dielectric ceramic composition having excellent characteristics can be obtained by firing for a long time regardless of the variation of x. You can see that it has been obtained.

Further, x is 0.15, 0.2 under the condition that the addition amount of ZnO is 0.2 part by weight and the firing temperature is 1425 ° C.
Retention time and Qu in the case of 0 and 0.25 (No.
2, 5 and 8 and FIG. 4), ε _r (No. 2, 5 and 8 of Table 1 and FIG. 5) and τ _f (No. 2, 5 and 8 of Table 1 and FIG. 6) And Qu are not so different depending on the difference of x, and the fluctuations are small at the holding times of 1, 5 and 10 hours, but are greatly improved between the holding times of 10 hours and 30 hours, and thereafter, the holding times of 40 and 50. In time, the change is again small. From this, it is understood that the Qu is greatly improved by firing for 20 hours or more. Further, x is set to 0.25 and the addition amount of ZnO is set to 0.
The same can be said when the amount is 5 parts by weight (No. 11 in Table 2).

On the other hand, ε _r has a clear difference depending on the difference in x, but there is no remarkable change with the firing time, and it tends to be slightly improved when the holding time is lengthened.
Similarly to ε _r, the difference in τ _f due to the difference in x is clear, but the tendency due to the firing time is hardly seen. Above, Table 1
The dielectric ceramic compositions shown in FIGS. 4 to 6 all have practically sufficient performance, but the firing time is 20
When the time is longer than the time, a large improvement in Qu is observed, and a more preferable dielectric ceramic composition is obtained. Further, the firing temperature was 1400 ° C. (No. 1, No. 4 in Table 1, N in Table 2)
o. 7 and No. 10) and 1450 ° C. (N in Table 1
o. 3, No. 6, No. 6 in Table 2. 9 and No. 12) and the example in which the firing time is 50 hours,
The results are almost the same as those of the other examples, and it can be seen that the method of the present invention produces the same effect even if the firing temperature is slightly changed. The invention is not limited to the specific examples described above, and various modifications may be made within the scope of the invention according to the purpose and application. That is, various calcination conditions such as the calcination temperature and calcination conditions such as the calcination temperature can be selected.

[0017]

According to the method for producing a dielectric ceramic composition of the present invention, a predetermined amount of ZnO is added to the main component of ZrO ₂ —SnO ₂ —TiO ₄ system, and 20 hours or more after reaching the firing temperature,
By maintaining the temperature and firing, the composition can be sufficiently sintered over a wide range of the composition ratio of the main components and even in a wide range of the added amount of ZnO, particularly when the added amount of ZnO is very small. Of the dielectric porcelain composition described above, wherein Qu is improved as compared with the composition obtained by firing for a short time, and ε _r and τ
It is possible to produce a dielectric porcelain composition having excellent properties with well-balanced _f .

[Brief description of drawings]

FIG. 1 [(Zr _1-X Sn _X ) TiO ₄ +0.2 wt% Zn at a calcination temperature of 1425 ° C. and a calcination time of 50 hours
[O] is a graph showing the relationship between x and Qu of the dielectric ceramic composition.

FIG. 2 shows x and ε in the dielectric ceramic composition shown in FIG.
It is a graph which shows the relationship with _r .

FIG. 3 shows x and τ in the dielectric ceramic composition shown in FIG.
It is a graph which shows the relationship with _f .

FIG. 4 [(Zr _1-X Sn
₃ is a graph showing the relationship between the holding time and Qu of the dielectric ceramic composition of ( _{X 2} ) TiO ₄ +0.2 wt% ZnO].

5 is a graph showing the relationship between holding time and ε _r in the dielectric ceramic composition shown in FIG.

FIG. 6 is a graph showing the relationship between retention time and τ _f in the dielectric ceramic composition shown in FIG.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C04B 35/48

Claims (2)

[Claims] 1. (Zr _1-X Sn _X ) TiO ₄ (provided that 0
<X <1.0) is contained as a main component, and 0.1 to 7.0 parts by weight of ZnO is added to 100 parts by weight of (Zr _{1 -X} Sn _x ) TiO ₄ described above. Zirconium oxide powder (II), tin oxide powder (II), titanium oxide powder (II) and zinc oxide powder (I) are mixed so as to have the above composition, and then calcined to produce a calcined powder. A method for producing a microwave dielectric ceramic composition, which comprises pulverizing a calcined powder and then firing the powder at a predetermined temperature for 20 hours or more. 2. In the above main component, 0.15 ≦ x ≦ 0.
25, and the amount of ZnO added is 0.1 parts by weight to
The method for producing a microwave dielectric ceramic composition according to claim 1, wherein the amount is less than 1.0 part by weight.