JP3100178B2 - Microwave dielectric porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave dielectric ceramic composition. By adjusting the amount, τf
Can be arbitrarily controlled on the plus side and the minus side around zero. INDUSTRIAL APPLICABILITY The present invention is used in a microwave region for impedance matching of a dielectric resonator, a microwave integrated circuit board, various microwave circuits, and the like.

[0002]

2. Description of the Related Art Conventional microwave dielectric ceramic compositions (hereinafter simply referred to as dielectric ceramic compositions) include Ba.
O-4TiO ₂ ceramic composition and the like are known.

[0003]

[SUMMARY OF THE INVENTION However, in the conventional the dielectric ceramic composition, a dielectric constant (hereinafter, simply referred to as epsilon _r.) Is high, the unloaded Q (hereinafter, simply referred to as Qu.) Is large, There is a problem that stability is lacking because τf is relatively large.

[0004] The present invention is intended to overcome the above drawbacks, by adjusting the addition amount of MgO, while maintaining a practical characteristic range epsilon _r and Qu, small values around the zero τf Further, it is an object of the present invention to provide a dielectric ceramic composition which can arbitrarily control τf to desired values on the plus side and the minus side with zero as a center.

[0005]

Means for Solving the Problems The present inventor has proposed BaO-4.
In a TiO ₂ -based dielectric porcelain composition, as a result of various investigations on a composition for bringing τ _f close to zero, it was found that adding MgO to this composition would eliminate this disadvantage, and completed the present invention. It is. That is, the first
The dielectric porcelain composition of the invention comprises BaO, TiO ₂ and M
a composition comprising only gO, wherein BaO-4TiO ₂
Against the (BaTi ₄ O _9), characterized by comprising the addition of MgO having 6 to 14 wt%.

The dielectric porcelain composition of the second invention is a first porcelain composition.
The bright composition is characterized in that the temperature coefficient (τ _f ) of the resonance frequency is −10 to +10 (ppm / ° C.).

[0007]

The present invention will be described below in detail with reference to examples. Example 1 (1) Preparation of each sample BaCO ₃ powder having a purity of 99.9% and T having a purity of 99.9%
The iO ₂ powder was added in a predetermined amount so as to have a composition of BaO-4TiO ₂ (BaTi ₄ O ₉ ).
O powder [0, 5, 10, 15% by weight (BaO-
For 4TiO _2)] was weighed mixed. Then, after performing dry mixing and primary pulverization with a mixer, the mixture was calcined at 1100 ° C. for 2 hours in an air atmosphere. Then
An appropriate amount of an organic binder and water are added to this calcined powder,
After being crushed with alumina balls having a diameter of mm, the mixture is granulated by atomization, and 1000 kg / c using the granulated raw material.
It was formed into a disk shape of 19 mmφ × 8 mmt (thickness) under a press pressure of m ² .

[0008]

[Table 1]

[0009]

[Table 2]

Next, this molded body was placed in the air in Tables 1 and 2
At the respective temperatures in the range of 1200 to 1325 ° C. for 4 hours, and finally polished both end surfaces into a disk shape of about 16 mmφ × 6 mmt (thickness). 1 to 22. For each sample, ε _r , Qu value, τ _f , and sintered density were measured by a parallel conductor plate type dielectric resonator method (TE ₀₁₁ MODE) or the like. Note that the resonance frequency is 4.5 GHz. These results are shown in Tables 1 and 2, and FIG.
3 to FIG.

According to these results, as shown in FIG. 1, when no MgO component is contained and when 5 wt% is contained, τ _f is large. Except for the case where the firing temperature is 1225 ° C., the addition of 5% by weight of the MgO component shows almost the peak τ _f . If the content exceeds 5% by weight, then τ _f decreases to the minus side. When the firing temperature is 1225 ° C., the temperature decreases from the beginning. Also, 15
When the weight% is reached, it becomes a large value on the minus side as about -16 to 20 ppm / ° C. Therefore, the MgO component is reduced to
In the case where the weight percentage is included, it can be almost equal to or higher than zero in the case where the MgO component is not included. In particular,
In the case of addition of 10 to 12% by weight, τ _f can be set to approximately zero. Further, it is possible to arbitrarily control the desired value in the plus side and the minus side by adjusting the addition amount of MgO.

Further, as shown in FIG. 2, ε _r almost peaks in the case where 5 wt% of MgO is added, and then decreases. The Qu value shows a bottom at 5% by weight, as shown in FIG. 3, and increases with subsequent additions. Further, as shown in Tables 1 and 2, the density gradually decreases with the addition of MgO. Therefore, when 6 to 14% by weight of MgO is added, these properties tend to slightly decrease as compared with the case where MgO is not added, but they are in a practical performance range.
Even when the firing temperature is changed, the same tendency is exhibited,
It shows stable performance even in a wide firing temperature range. Therefore, a porcelain composition having stable performance can be manufactured.

FIGS. 4 to 6 show that the firing temperature is 1225.
1 shows an X-ray diffraction pattern of a porcelain composition (sintered body) at ℃. FIG. 4 shows that No. 5 containing 5% by weight of MgO. 17 and FIG. 5 shows No. 17 in which 10% by weight of MgO was added. 6 and FIG. 6 shows No. 18 in which MgO was added at 15% by weight. The results of 19 samples are shown. According to this result, when 5 wt% of MgO was added, JCPDS (Joint Committee) was used.
PowerDiffraction Standa
rd) (not shown in the figure,? is assigned to this assigned peak), BaTiO ₃ (also shown as □ in the figure), Ba ₂ Ti ₅ O ₁₂ (shown as ○ in the figure) ) And Ba ₄ Ti ₁₃ O ₃₀ (denoted by △ in the figure) were confirmed, and the most frequent substances are those not listed above.

On the other hand, when 10% by weight of MgO is added, B
a ₆ Ti ₁₇ O ₄₀ approximation structural material (in the figure, ×; described as B ₆ T ₁₇ ), the above-mentioned unlisted substance and MgTiO ₃ (in the figure,
MT is shown. ) Was confirmed, and the most common was B ₆ T
It is ₁₇ . This B ₆ T ₁₇ notation material is Ba ₆ Ti ₁₇ O ₄₀
X-ray diffraction pattern very similar to
It is considered that a part of Ba of a ₆ Ti ₁₇ O ₄₀ was substituted with Mg.

Further, the addition of MgO at 15% by weight shows almost the same tendency as the addition at 10% by weight, and the substance represented by B ₆ T ₁₇ is the most common.
iO ₃ is generated more than in the case of 5% by weight. From the above results, it is considered that the adjustment of τ _f is influenced by the presence of the B ₆ T ₁₇ -listed substance and MgTiO ₃ , the composition ratio of MgTiO ₃ , and the like.

The present invention is not limited to the specific embodiments described above, but can be variously modified within the scope of the present 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. The raw material to be BaO is also BaC
In addition to O ₃ , peroxides, hydroxides, nitrates and the like can also be used.

[0017]

As it is evident from the foregoing description, the dielectric ceramic composition of the present invention, the addition of MgO, while maintaining a practical characteristic range epsilon _r, Qu, the direction of the minus τf from a large positive value It was made smaller. In the dielectric ceramic composition of the present invention, τf is arbitrarily controlled to a desired value on the plus side and the minus side with respect to zero by adjusting the addition amount of MgO. Therefore, the addition ratio of MgO can be changed according to the purpose. Departure
According to the bright composition, as in the second invention, τ _f is +10
It can be as small as -10 ppm / ° C.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a firing temperature and a temperature coefficient τ _{f in} a change in the amount of added MgO.

FIG. 2 is a graph showing a relationship between a sintering temperature and a relative dielectric constant ε _{r in} a change in the amount of added MgO.

FIG. 3 is a graph showing a relationship between a firing temperature and a Qu value in a change in the amount of added MgO.

FIG. It is explanatory drawing which shows the X-ray-diffraction pattern of the dielectric ceramic composition of 17 (MgO addition is 5 weight%).

FIG. It is explanatory drawing which shows the X-ray-diffraction pattern of the dielectric ceramic composition of 18 (MgO addition is 10 weight%).

FIG. It is explanatory drawing which shows the X-ray diffraction pattern of the dielectric ceramic composition of 19 (MgO addition is 15 weight%).

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/42-35/49 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. Only from BaO, TiO ₂ and MgO
A composition _{comprising, BaO-4TiO 2 (BaTi 4} O 9) in contrast, the microwave dielectric ceramic composition characterized by comprising the addition of MgO having 6 to 14 wt%. 2. The temperature coefficient (τ _f ) of the resonance frequency is -10.
Claims, characterized in that a ~ + 10 (ppm / ℃)
2. The microwave dielectric porcelain composition according to 1.