JPH02192460A - Dielectric porcelain composition for microwave - Google Patents

Abstract

PURPOSE:To obtain a dielectric porcelain for microwave having improved Q- value by firing at relatively low temperature and for short time, by adding CoO and Nb2O5 to TiO2-ZrO2-SnO2 based substance of a specific composition. CONSTITUTION:A substance having a composition expressed by the formula (0.30<=x<=0.60; 0.25<=y<=0.60; 0.025<=z<=0.20) for mole fraction of x, y and z (x+y+z=1) is used as principal component and <=5wt.% CoO or alphaCoO+betaCo3O4 (0<=alpha<=1; 0<=beta<=1; alpha+beta=1) and <=10wt.% Nb2O5 or Ta2O5 are contained as additives. Further, <=2wt.% Ni2O3 or Sb2O3 may be contained as an additive other than above-mentioned additives to especially improve sintering ability and perform sintering of porcelain at relatively low temperature for short time.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a dielectric ceramic composition used as a resonator material in the microwave region.

(b) Conventional technology In recent years, dielectric ceramics have been used as resonators and M
It is widely used as a material for IC (microwave integrated circuit) substrates, etc.

Conventionally, as this type of dielectric porcelain material, for example, JP-A-61
-T i Os -Z r Ot -S nO proposed in Publication No. 259405 [HOIB 3/12]
, -ZnO-N 1o-NbxOs.

However, as described in the above-mentioned publication, this conventional porcelain material has a Q value of 7GH2-, which is at most 9.
000, and as the frequency becomes higher, the Q value decreases, so there was a drawback that a sufficient Q value could not be obtained in a frequency band of 8 GHz or higher.

(c) Problems to be solved by the invention When using at a higher frequency of 8 GHz or higher in the microwave band, it is better to have a higher Q value, even if only a little, and by increasing the Q value, the heat generation in the dielectric can be reduced. In addition, the resonance peak becomes sharper.

Therefore, the first problem to be solved by the present invention is to further improve the Q value of microwave dielectric porcelain, and the second problem to be solved by the present invention is to make such IT body porcelain as low temperature as possible. This is achieved by short-time sintering.

(d) Means for Solving the Problems The dielectric ceramic composition of the present invention has molar fractions of X, Y, and z.
When (x+y+z=1), the composition formula is X・Tio*
-y-Z rot-z-5nOt (0.30≦X
≦0.60.0.25≦y≦0.60.0.025≦2
≦0.20) as the main component, and 5% by weight of Coo or αCoo+βCo504 (0≦α≦1.0≦β≦1, a+β=1) as an additive.
Below, Nb, O, or Ta carbon dioxide O3 is contained in an amount of 10% by weight or less.

In addition, in order to particularly improve the sinterability and sinter the porcelain at a relatively low temperature and in a short time, in addition to the above additives, Ni1Oi or Sb*Os is additionally added in an amount of 2% by weight or less. I tried to let him do it.

(E) Effect The dielectric ceramic having the above composition may be Nb*Os or Ta, 0.
The Q value increases with the addition of CoO or αCoO
+βCo*04 and further Ni, 0. The sinterability is improved by the addition of or sbO0.

(F) Embodiment First, a first embodiment of the present invention will be described. In this example, we first used high-purity Ti as a dielectric ceramic material.
O*, Z r O and S n O! were weighed so that the molar fraction was 0.51: 0.42: 0.07 in this order, and each weight percent of CoO and N shown in Table 1 was added to this.
Add b, o, and keep wet for 5-10 hours. Next, this is dehydrated and dried, and the obtained powder is heated to 1000-1200℃.
Preliminary sintering is performed for 1 to 2 hours. Then, this pre-sintered product is subjected to wet pulverization for 20 to 60 hours. Next, it is dehydrated and dried, and the resulting powder is 2000~3000k
The molded material is molded into a disc with a diameter of 10 mm and a thickness of 6 mm by applying a pressure of "g/cm".Then, this molded material is sintered in air at a higher temperature than the previous preliminary sintering for several hours.Then, Finally, both sides are polished so that the thickness of the sintered product obtained by this main sintering is 1/2 of the diameter to obtain a dielectric ceramic sample.

For each porcelain sample thus obtained, 20°C, 7
The dielectric constant (ε) and Q at ~8.5 GHz were measured by the Hucki-Coleman method. The results are shown in Table 1.

Table 1 below is a margin. However, TiO*: 0.51 mol, Zn0t; 0.
42 mol, 5nOx: 0.07 mol Also, for each sample in this Table 1, +20°C to +70°C
When the temperature coefficient (Tf) of the resonant frequency was measured in the range of °C, it was within +5±8.

As can be seen from Table 1, CoO and Nb, 0.
When these are individually added, neither the dielectric constant (ε) nor the Q characteristic is significantly improved. That is, C.

When O is added alone, the sinterability gradually increases compared to when no O is added, but the Q value does not become so high, and on the contrary, when it exceeds 5.0% by weight, it decreases. Further, when NbIOs is added alone, the sinterability deteriorates significantly, but when Coo is added at the same time, the sinterability improves and the Q value becomes extremely high. But that's also Nb.

0 exceeds 10% by weight, conversely, sinterability deteriorates.

Next, TiOt-Zr which is the main component of the porcelain composition of the present invention
The characteristics of ε and Q also change depending on the composition ratio of Ot-SnOw. For this reason, Coo was added to 1°0% by weight, Nb*
Os is added at 2.5% by weight, and TiQ
Table 2 shows the results of experiments with various composition ratios (molar ratios) of Z r O* and SnO.

Table 2 However, CoO: 1.0% by weight, Nb1Os: 2.5% by weight As is clear from this Table 2, Tie, Zro,...
ε, Q, and Tf change depending on the composition ratio of SnO.

Therefore, in the present invention, this composition ratio is limited to the range described in the claims above, and this is for the following reason. That is, when T i O* is 0.6 mol or more, Tf becomes too large on the plus side, and when it is 0.3 or less, ε becomes small. Further, if ZrO is less than 25 moles, Tf becomes too large on the positive side, and conversely, if it is more than 0.6 moles, the Q value becomes low. Further, if S n O* is 0.025 mol or less, Tf becomes large on the plus side, and conversely, if S n O* is 0.2 mol or more, Tf becomes too large on the minus side.

Therefore, the main components T i ol, Z r O
x and SnO from the above Table 2, and the additives Coo, Nb, and O from the above Table 1, by limiting each to the range described in the above patent claim 1,
Dielectric ceramics with ε of about 36 to 43 and Q of about 5000 to 9600 can be freely obtained, especially at 8 GHz when c=38 and Q≧
9000 can be easily realized.

Next, a second example will be described.

In the first example above, CoO was used as one of the additives.
However, this type of cobalt oxide contains Coo, C
There are various types such as otOs and CO30+, and usually a
coo+βCo5t- (however, 0≦a<1, Okuβ≦
1, α+β=1), and cobalt oxide in this form is inexpensive and easily available. On the other hand, Co
o It is expensive when used alone.

Therefore, in the second embodiment, the main component Tie.

Z r Os and Snow were respectively 0.52 mol, 0.42 mol, and 0.06 mol in this order, and Coo, acoO + βCOsO4 of each weight% shown in Table 3 were added as additives.
, N b to s , and Ta t Os were sintered to produce dielectric ceramics.

At this time, each operation from weighing the above-mentioned materials to the double-sided polishing step in the finishing stage is performed in the same manner as in the first embodiment.

For each porcelain sample thus obtained, 20°C, 7
-Hack the permittivity (ε) and Q at 8.5GHz.
Measured by Coleman method. The results are shown in Table 3.

Margin below Table 3 However, for sample fish 7 to IO, α = 0.85, β = 0.15
, for sample Na1l-16, α = 0.5, β = 0.5, for samples NQI7-20, α = 0.15, β = 0.85, for sample fish 21-24, α = 0, β = 1.0. , sample bottle 25-2
8 is αC0,5, β=0.5 T i O2: 0.52 mol, Zr01: 0.42 mol, SnQ: o, os mol Also, for each sample in this Table 3, +20°C to +70
When the temperature coefficient (Tr) of the resonant frequency was measured in the range of °C, it was within +8±10.

As is clear from Table 3, when αCoo+βCO30 is added (7 to 2 g of sample fish), Co.

Even when compared with the case where only one substance was added (samples N111 to 6), there were no disadvantages in terms of characteristics, and good results were obtained.

Furthermore, when the amount of crcoo+βCoco4 added exceeds 5.0% by weight, sintering failure occurs and the characteristics are also deteriorated.

Next, TiO2-Zr which is the main component of the porcelain composition of the present invention
Depending on the composition ratio of Ot-5nOt, C1Q and Tf
The characteristics of change. For this reason, Co.

When 1.0% by weight of NbtOs and 2.5% by weight of NbtOs were added, acoo+βC0,0,((2=β=0.5)
Ti0t, Zr01 and 5nO-, respectively, when 1.0% by weight of 5 and 2.5% by weight of Nb and Os were added.
The results of experiments with various composition ratios (molar ratios) of
Shown in the table.

In the margin table below, however, A in the "Cobalt oxide" column means aCoO.
+βCo504 addition, B indicates Co.

Indicates addition.

As shown in Table 4, the characteristics change depending on the amounts of Tie, ZrO*, and SnO3, but the addition of acoo+βC05Oa shows similar changes compared to the addition of Coo alone.

? Then, replace Coo with acoo+βCo5t.

By using , there is no inferiority in terms of characteristics and it can be produced at low cost.

By the way, in the first and second embodiments, the above-mentioned main sintering takes about 2 hours when the sintering temperature is high (approximately 1500°C), but when the sintering temperature is relatively low (approximately 1350°C)
) required about 5 hours. However, considering the durability of the sintering furnace, it is better to perform the sintering at a low temperature and for a short time, preferably at 1350° C. for about 3 hours.

Therefore, a third embodiment will now be described in which the sinterability is further improved than in the previous embodiments and the above-mentioned octopus can be sintered at a relatively low temperature and in a short period of time.

In the third example, T i O*, ZrO*, SnO2
is the main component and CoO and Nb t Os are additives, and Ni! is added as a third additive to the ceramic composition of the first embodiment. A dielectric ceramic was created by additionally containing Os or 5bsOs and sintering it. At this time, each operation from weighing the above-mentioned materials to the double-sided polishing step in the finishing stage is performed in the same manner as in the first embodiment.

For each porcelain sample obtained in this way, 20°C, 7-8.
The ε and Q values at 5 GHz are shown in Tables 5 and 6 along with the sintering conditions for each sample. However, Table 5 shows Nime
Table 6 shows the case when sblog was added, but each sample shown in this chart contains the main components Tie,
, Zr0t, and SnO are respectively 0.53 mol, 0.40 mol, and 0.07 mol in this order, and other additives are Co.
1.0% by weight of Nb.

2.5% by weight of O.

Table 1 As can be seen from the characteristic diagrams in the attached drawings drawn based on Tables 5 and 6 or both, Ni, 0. or 5
If btO* is not added, a product with Q exceeding 9000 cannot be obtained unless the sintering temperature is set to 1400°C or higher, but Ni20s or sb, 0. When this is added, a product with a Q of 9000 or more can be obtained even at a sintering temperature of 1350°C. That is, N i! 03 or 5bsOs
Although the addition of sinterability improves the sinterability and increases the Q value,
The effect is 0.5 for Ni, 01, and S b t Os.
The Q value is large when added in an amount of ~1.0% by weight, and conversely decreases when added in an amount exceeding 2.0% by weight.

(G) Effects of the Invention As described above, according to the present invention, a dielectric material having a large dielectric constant (ε) of about 38 in the microwave band of about 8 GHz and a sufficiently high Q value of 9000 or more compared to the conventional example. By sintering at a relatively low temperature and in a short time, it is possible to realize a dielectric ceramic having the above-mentioned ε value and Q value due to the improved sinterability.

[Brief explanation of the drawing]

The drawing is a characteristic diagram showing the relationship between sintering temperature and Q value of dielectric ceramic according to the present invention.

Claims (3)

[Claims] (1) When the mole fractions are x, y, z (x+y+z=1), the composition formula is x・TiO_2-y・ZrO_2-z・Sn
O_2 (However, 0.30≦x≦0.60, 0.25≦y
≦0.60, 0.025≦z≦0.20) as a main component, and contains as additives CoO of 5% by weight or less and Nb_2O_5 of 10% by weight or less. Body porcelain composition. (2) When the mole fractions are x, y, z (x+y+z=1), the composition formula is x・TiO_2-y・ZrO_2-z・Sn
O_2 (However, 0.30≦x≦0.60, 0.25≦y
≦0.60, 0.025≦z≦0.20) as the main component, and αCoO + βC as additives.
o_3O_4 (however, 0≦α≦1, 0≦β≦1, α+β
= 1) with 5% by weight or less of Nb_2O_5 or Ta_2
A microwave dielectric ceramic composition containing 10% by weight or less of O_5. (3) Ni_2 is added as an additive to the main component.
The microwave dielectric ceramic composition according to claim 1 or 2, further comprising 2% by weight or less of O_3 or Sb_2O_3.