JPH02239151A - Dielectric porcelain composition for temperature compensation - Google Patents

Abstract

PURPOSE:To obtain a compsn. reducing the temp. coefft. of the permittivity and having satisfactory sinterability at a low temp. by adding small amts. of MnO, Pb5Ge3O11 and SiO2 as secondary components to a compsn. consisting of BaO, TiO2 and NdO3/2 in a specified blending ratio. CONSTITUTION:1.0-15.0mol% BaO, 50.0-67.5mol% TiO2 and 20.0-47.5mol% NdO3/2 are prepd. as principal components by 100mol% in total and 0-0.3wt.% MnO, 2-20wt.% Pb5Ge3O11 and 0.3-10wt.% SiO2 as secondary components are added to the principal components to obtain a dielectric porcelain compsn. for temp. compensation. This dielectric material has high Q, a high permittivity, high insulation resistance and satisfactory sinterability at a sintering temp. below the conventional temp. by about 140-400 deg.C.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a dielectric ceramic composition for temperature compensation, which has a particularly high Q value, a high dielectric constant, and a dielectric constant temperature [which the invention can solve]. However, since these electrode materials are expensive, they end up significantly increasing the cost of multilayer chip capacitors.

By using a low-cost silver-palladium (Ag-Pd) alloy as the electrode material for the internal electrodes, it is possible to manufacture multilayer chip capacitors at low cost. In this case,
The firing temperature of the dielectric material must be lowered to 1200° C. or lower to prevent evaporation of Ag.

However, conventional dielectric materials have a problem in that when the firing temperature is lowered, the contact rate and insulation resistance (IR) decrease, making it impossible to obtain satisfactory characteristics such as device reliability.

Therefore, the object of the present invention is to have a high Q value, a high dielectric constant,
The main firing temperature of a dielectric ceramic composition with high insulation resistance and a small temperature coefficient of permittivity has been increased to approximately 140°C compared to conventional ones.
It is an object of the present invention to provide a dielectric ceramic composition with good sintering properties and a temperature lowered by 300°C to 300°C.

[Means to solve the problem]

In order to achieve the above object, the dielectric ceramic composition of the present invention contains BaO: 1, Qmol% ~ 1 5. Q mo
l%Ti02: 5 0. Omol%~6
7. 5 mol%Nd203 = 2 0.0m
Ol%~4 7. For the main component with a total of 5 mol % of 100 parts, the subcomponent -(, MnO is 0
~0. 3 wt%, 2 to 20 PbsGe30u
wt%, SiO2O2 is added at α'3 to 10 wt%. Although the temperature coefficient is small and the firing temperature is lower than conventional ones, it is possible to provide a dielectric ceramic composition with good sinterability.

〔Example〕

Examples of the present invention will be described in detail.

In order to obtain the dielectric ceramic composition of the present invention, starting materials such as Te, BaCOs, Ti02, Nd. 03,
MnCO3, PbO, CEO. , SiO20
．． Each powder is used. In addition, these raw material powders have a purity of 9
Except for 5% Nd203, all the materials used have a purity of 98% or higher.

Next, the main component of the dielectric ceramic composition of the present invention7) B
Powders of aCO3, TiOz, Nd2O3, and MnCO as an additive are weighed so as to have the composition range shown in Table 1 below, and wet-mixed in a ball mill.

Furthermore, this mixture was dehydrated and dried, pressure-molded into a cylindrical shape with a diameter of 609!11 and a height of 50+w, and
Preliminary firing is performed in air for 2 hours at a temperature of 0°C. Thereafter, this calcined product is further crushed.

PBS Ge3 011 and SiO202 as subcomponents were weighed to this pulverized powder so as to have the composition range shown in Table 1.
This is wet-mixed again in a ball mill.

Polyvinyl alcohol (PV) is added as a binder after dehydration and drying.
Add an appropriate amount of A) and apply a pressure of about 3 tons/d to a diameter of 1
Press and form into a disk with a thickness of 6.5cm and a thickness of 0.6mm. Thereafter, main firing is performed for 2 hours at a temperature of 900°C to 1300°C.

Silver electrodes are baked onto both end faces of each dielectric ceramic composition thus obtained to produce a ceramic capacitor. Dielectric constant ('-), Q value, temperature coefficient of dielectric constant (T tube C) PPM, /'c, insulation resistance (I-R) of these ceramic capacitor samples
etc., and the results obtained are shown in Table 1.

In Table 1, T-C is +2 with reference to +20℃.
Measurements were made at a frequency of I KHz in a temperature range of 0°C to 85°C. The firing temperature and sinterability during main firing are also listed.

Further, in Table 1, the sample numbers marked with a circle are within the scope of the embodiments of the present invention, and those marked with an X are outside the scope of the present invention.

From Table 1 in the margin below, it is clear that the dielectric ceramic composition of the present invention has a dielectric constant (ε
．． ), Q value, insulation resistance (work/R) are high, the temperature coefficient of dielectric constant is small, and the firing temperature is 900℃~116℃.
It is clear that the temperature can be lowered by 140 to 400 degrees Celsius compared to the conventional one, and a product with good sinterability can be obtained. The reason for the limitation will be explained using Table 1 and FIG. 1. FIG.
O20. This is a diagram showing the relationship between the addition amount of
．． The Q value becomes small and the temperature coefficient of dielectric constant (T-C) increases toward the 0 side, making it impractical (see floors 22 to 24 in Table 1).

On the other hand, BaO is 15. When it becomes 0 mol% or more, Q becomes small (see order 1 to 3 in Table 1).

Next is Tie, 50. Below O mol%, sinterability is poor and the dielectric constant ε. is also low (Table 1 Na9, 15.21
reference).

Also Tie. 6 7. The dielectric constant (C.) is small even at 5 mol% or more. Q value is small (Table 1 Nα4,10
Reference)○Nd20. is 20. Below OmOA%, the Q value becomes small (see floors 1 and 4 in Table 1).

On the other hand, Nd. 03 is 4 7. 5 mol% or more. Poor sinterability and dielectric constant ε. Although there is no practical problem even if MnO is not added at all, the insulation resistance (I-R) is improved by adding up to 0.3 wt%. The temperature coefficient of the power visit rate will also be advantageous. However, if more than 3 wt% of Q is added, the sinterability is poor and a dense porcelain composition cannot be obtained (Table 1 Na5-3.
(See 19-3).

Pb, , (} The amount of addition of e30u and SiO202 affects the firing temperature, but as is clear from Fig. 1, Pb
When 6Qe3 0 I1 is less than 2 wt%, the firing temperature is 1
The temperature is not lower than 200°C, which does not meet the purpose of the present invention (Table 1 INI 5-4.5-5.19-4.19-
5 and Figure 1).

In addition, the addition of pbs Ge3 011 was 20 Wt.
% or more, the firing temperature decreases, but not only does the sinterability worsen, but the electrical properties also become extremely poor, making it impossible to obtain a dense dielectric ceramic composition (Table 1 "qα5-
10.19-10). Furthermore, since the GeO2 raw material is expensive, this leads to high costs for split products.

Furthermore, when sio2 is used in combination with Pb and Ge3011, it contributes to lowering the sintering temperature. 8 If i0, is less than 0.3 wt%, the effect of lowering the sintering temperature cannot be obtained,
If it exceeds 1Qwt%, a dense dielectric ceramic composition cannot be obtained.
The dielectric constant becomes smaller (Table 1 NIl5-15.19-I
(See O, 19-16).

Note that FIG. 2 is a composition diagram showing the composition range of the main components of the dielectric ceramic composition of the present invention. Within the range of this main component, MnO is added as a subcomponent at 0 to Q, 3 wt%, Pbs Ge
s O u at 2 to 20 Wt%, 8i0. α'r=
The present invention is one in which 10 wt 4o is added.

Therefore, for example, 8Q wt%Ag - 20 wt%
It has become possible to manufacture temperature-compensating multilayer chip capacitors using Pd alloys as internal electrodes at low cost.

[Brief explanation of drawings]

Figure 1 shows the pb 5 Ge3 dielectric ceramic composition of the present invention.
FIG. 2 is a ternary component diagram showing the composition range of the main components of the dielectric ceramic composition of the present invention. Patent Applicant TDC Co., Ltd. Representative Patent Attorney Akira Yamatani (and 1 other person) [Effects of the Invention] By using a dielectric ceramic composition having a composition as in the present invention, a dielectric ceramic composition for temperature compensation can be obtained. The firing temperature of the porcelain composition, which has excellent properties as a product, is υ140 mm compared to the conventional one.
It can be obtained at temperatures as low as 400°C to 400°C. Figure 2 Procedural amendment (voluntary) Contents of amendment 1. Display of the incident 1999 Patent Application No. 5 50 Address 1-13-1 Nihonbashi, Chuo-ku, Tokyo Name (3
06) TDC Co., Ltd. Representative Hiroshi Sato 4. Agent address: 1-19-8-6, Kanda-Awajicho, Chiyoda-ku, Tokyo.
Target of correction 7. Contents of the amendment As per the claims of the specification, each column of the detailed description of the invention, and the attached drawings, 1. The full text of the claims set forth in lines 4 to 13 of page 1 of the specification is amended as follows. “As a dielectric ceramic composition for temperature compensation, B a O
1. O molχ~15.0IIlo]χT i
O2 50.0 molχ~67.5 molχN
d Osyt 20.0 notχ~47.5 m
For principal components whose total is 100 parts over olχ,
As a subcomponent, MnO O ~0.3w
tX and P b5G8so++ 2 ~ 2 0wt
A dielectric ceramic composition for temperature compensation, characterized in that it additionally contains χ and Sio20.3 to 10wtχ. ” 2. The rNdzozJ described in the 2nd line of page 4 of the same page is changed to “Nd(
)1/zJ. 3. rNdzozJ described on page 5, line 3 of the same page is “Ndo
Correct it as s/tJ. 4. The “diameter 609niJ” written on the 6th line of the same page is “60N”
Mφ”. ? ．． The rNdzOJ described on page 10, line 2 of the same
zz■" and correct it. 6. rNdzo*J described in the 4th line of the same page as rNdo37
■” and correct it. 7. Correct Figure 2 as shown in the attached sheet. More than 10,000 Q2

Claims (1)

[Claims] As a dielectric ceramic composition for temperature compensation, BaO 1.0 mol% to 15.0 mol% TiO_2
50.0mol~67.5mol%Nd_2O_5
For the main component consisting of 100 parts in total of 20.0 mol% to 47.5 mol%, MnO 0 to 0.3 wt% and Pb_5Ge_3 as subcomponents.
O_1_1 2~20wt% and SiO_2 0.3~1
A dielectric ceramic composition for temperature compensation, characterized in that it contains 0 wt%.