JP3163664B2 - Piezoelectric material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric ceramic material,
In particular, for example, used for piezoelectric filters for communication equipment,
Related to piezoelectric ceramic materials.

[0002]

2. Description of the Related Art Conventionally, piezoelectric filters for communication devices have been used.
A {PbSr} (TiZr) (MnNb)｝ O ₃ -based piezoelectric ceramic material is used.

[0003]

However, in such a conventional piezoelectric ceramic material, about 0.8% by weight of lead oxide evaporates during firing, and a high-concentration lead atmosphere is formed in the firing furnace. I was As a result, factors that hinder sinterability, such as a concentration gradient in a lead atmosphere, are generated, and defective deformation of the sintered body is caused. In order to suppress the amount of lead oxide evaporated, there is no suitable means, but external means such as firing temperature, firing exhaust air volume, box density and the like are used. In the case of a conventional material, the firing temperature is 1250 ° C.
The above is high, and the electrical characteristics of the obtained sintered body vary.

[0004] Therefore, a main object of the present invention is to suppress the amount of lead oxide evaporated during firing, control the lead atmosphere during firing, sinter at a low temperature, and vary the electrical characteristics of the sintered body. It is an object of the present invention to provide a piezoelectric ceramic material capable of improving

[0005]

Means for Solving the Problems The present invention provides a ｛PbS
r｝ ｛(TiZr) (MnNb)｝ O ₃ -based piezoelectric ceramic material containing 0.005 to 0.040% by weight of SiO ₂
And Al ₂ O ₃ and having containing 0.005 to 0.040% by weight, a piezoelectric ceramic material.

[0006]

By adding SiO ₂ and Al ₂ O ₃ , a compound of these additives and lead is formed during firing. Thereby, the amount of evaporation of the lead oxide during firing is suppressed. The amount of these additives controls the state of the lead atmosphere in the firing furnace during firing.

Further, since the formed Si compound or Al compound is a low melting point substance, the diffusivity of the material during firing is improved.

[0008]

According to the present invention, since the evaporation amount of lead oxide is suppressed, factors that hinder sintering, such as the concentration gradient of the lead atmosphere during firing, are reduced, which is effective in improving deformation defects. It is a target. Furthermore, since the lead atmosphere during firing is controlled by the addition amounts of SiO ₂ and Al ₂ O ₃ , external means such as the conventional firing temperature, firing air volume, and box density can be reduced.

Further, since the diffusing power of the material is improved by the formation of the Si compound and the Al compound, low-temperature sintering and expansion of the sintering stable temperature range can be achieved, and the variation of the sintered body, that is, the electric mechanical property The variance of the coupling coefficient can be reduced.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0011]

[Example] {PbSr} (TiZr) (MnNb)}
In the manufacturing process of O ₃ -based piezoelectric ceramic materials, PbO, T
In the step of preparing raw materials such as iO ₂ and ZrO ₂ , or in the step of adding a binder or the like to these calcined materials, Si
A fixed amount of both O ₂ and Al ₂ O ₃ is added.

When this is used as a raw material and molded and fired,
A compound of lead and SiO ₂ and Al ₂ O ₃ is formed. Then, unreacted lead oxide is reduced, and the amount of evaporated lead oxide during firing is suppressed. Further, the amount of lead oxide evaporated varies depending on the amount of SiO ₂ and Al ₂ O ₃ added. for that reason,
The amount of lead oxide evaporated during firing and the concentration of lead atmosphere during firing can be adjusted by the addition amounts of SiO ₂ and Al ₂ O ₃ .

Further, since a low-melting substance such as a Si compound or an Al compound is formed, the diffusing power of the material at the time of sintering is improved, sintering can be performed at a low temperature, and variation in electrical characteristics of the sintered body is improved. can do.

(Example 1) First, PbO, TiO ₂ , ZrO ₂ , S
Using rCO ₃ , MnCO ₃ and Nb ₂ O ₅ , these powders were converted to {Pb _1.00 Sr _0.01 } (Ti _0.55 Z
r _0.45 ) (Mn _0.9 Nb _0.1 ) _0.01 ｝ O ₃ was weighed to obtain a chemical formula to obtain a weighed material. Cr ₂ O
₃ , a certain amount of WO ₃ was added, water was mixed with the medium and pulverized to obtain a slurry. The slurry thus obtained was dehydrated and dried, and then calcined at 900 ° C. to obtain a calcined product. further,
The calcined product is dry-pulverized with a hammer mill, and a polyvinyl alcohol-based binder is again used as a medium in an amount of 1.5% by weight.
Upon addition, a slurry was obtained. At this time, SiO ₂ was added to 0.1.
02-0.04% by weight and Al ₂ O ₃
0.04% by weight was added simultaneously, and sufficient mixing was performed.

This slurry was granulated by a spray dryer and dried to obtain a powder. This powder by a press machine, and molded at a molding pressure of 1t / cm ² to 25 × 35 mm of square plate-shaped,
A molded article was obtained. The molded body thus obtained was calcined at 700 ° C. for the purpose of once removing the binder, the weight of the calcined body was measured, and the calcined body was again calcined at 1260 ° C., and the weight of the sintered body was measured.

FIG. 1 is a graph showing the weight loss (%) at the time of main firing of one embodiment and a conventional example. . The weight loss (%) at the time of the main firing is calculated by the following equation.

[0017]

As shown in FIG. 1, the weight loss (%) at the time of the main firing is reduced by adding SiO ₂ and Al ₂ O ₃ . That is, the substance that evaporates during the main firing after the preliminary firing (700 ° C.) is limited to lead oxide.
By the combination of iO ₂ and Al ₂ O ₃ with lead oxide, the amount of lead oxide evaporated during the main firing can be suppressed.

Furthermore, the amount of lead oxide evaporated is SiO ₂ and
And the amount of addition of Al ₂ O _3, the amount of lead oxide evaporated during main firing and the concentration of lead atmosphere during main firing can be controlled by the amounts of SiO ₂ and Al ₂ O ₃ added.

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[Brief description of the drawings]

FIG. 1 is a graph showing the weight loss (%) at the time of main firing of one embodiment of the present invention and a conventional example.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-136399 (JP, A) JP-A-50-64799 (JP, A) JP-A-55-63890 (JP, A) 39640 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/42-35/49 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. {PbSr} (TiZr) (MnN
b) In an O ₃ -based piezoelectric ceramic material, 0.005 to 0.040% by weight of SiO ₂ and Al ₂
O _3, and having containing 0.005 to 0.040 wt%, the piezoelectric ceramic material.