JPS5978501A - Ceramic resistance material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a ceramic resistance material that is stable up to high temperatures and exhibits small changes in resistance.

[Technical background of the invention and its problems]

Conventional resistance materials include Cu-Ni alloy, carbon resistance material,
Ceramic resistance materials such as TiN and 8iC are used.

Among these, the temperature coefficient of resistance of Cu-Ni alloy is 50 ppm.
/℃, which is very small and stable, but the specific resistivity is 4 to 5 x 16'' Ωl, so when making a resistor with a high resistance value, it is necessary to reduce the cross-sectional area or increase the length. There was a drawback that it had to be done.

Further, carbon resistors are inexpensive and have a resistivity of about 10'fiΩ (minimum), but have a large temperature coefficient of -t500 ppm/'G, and have been used as low-cost resistive materials that do not require high precision.

Resistors using ceramic powders such as TiN, SiC, etc. and glass particles have the disadvantage that the manufacturing process is complicated and costs are high, and the resistor characteristics are not always satisfactory.

[Purpose of the invention]

The present invention was made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a ceramic resistance material that has a stable resistance value up to high temperatures, has a high specific resistance, and is inexpensive.

Summary of the invention] The present invention has a chemical formula of Ba(Pb, -XCrx)Os(Q,
It is a ceramic resistance material shown as 25<

That is, in the present invention, as a result of partially substituting BaPbO with various elements using BaPbO as a basic material, it was discovered that the addition of Cr is effective for stabilizing the resistance.

Note that the numerical limitations in the present invention are based on the following reasons.

When X is less than 025 in Ba(Pb, ->(Crx)O), the effect of reducing the temperature coefficient of resistance is small and the increase in specific resistance is also small.On the other hand, when X exceeds 035,
The temperature coefficient of resistance becomes a large negative value, and the specific resistance increases, reaching a specific resistivity that is three orders of magnitude higher than B a P bo when X=0.35. Therefore, the Cr content is set to 0.25≦X≦035, but from the viewpoint of specific resistivity, it is desirable to set the content to 0.3<X<Q, 35 for practical purposes.

Examples of the invention] The present invention will be illustrated using examples.

Ba(Pb, -XCrx)0. In X=0, 0.
Raw materials BaC0, Pb5O4, Cr, and 03 powders were mixed in seconds to give a powder of 0.1, 0.25, 0.3, and 0.35, and wet-mixed using a ball mill. After drying this mixed powder, the powder was calcined at 880°C for 3 hours in an oxygen flow using an alumina crucible.The powder was mixed again using a ball mill, dried, and then calcined at 880°C for 3 hours in an oxygen flow, pulverized, mixed,
It was dried. Although the two calcination steps were carried out in order to uniformly react the mixed powder, it is not necessarily necessary, and a sufficient effect can be obtained even with one calcination. The powder that has been calcined is generally used5! After mixing with indah, it was molded into a size of 20φ×5 using a double press.

The molded body was placed on a platinum plate and heated to too~1 in an oxygen flow.
Baked for 150''Q for 3 hours.

Next, a rectangle of approximately 15×3×1 (m3) was cut out from the pellet sample and used as a sample for resistivity measurement. Resistivity was measured from room temperature to 900° C. using the usual DC four-terminal method. As this electrode, a baked A31-Pd or PT base was used.

FIG. 1 shows the dependence of room temperature resistivity on the amount of Cr substitution.

Room temperature resistivity increases as the amount of substitution increases. Further, as shown in FIG. 2, the temperature coefficient of resistivity gradually decreases by substitution with cr, and takes a negative value when X≧0.35.

Here, the temperature dependence of resistivity ρ was determined as expressed by the following equation as room temperature resistivity ρ0° and temperature coefficient α.

ρ=ρo(t+α(T-TR)) However, Tn is room temperature.

As a result, as is clear from Figure 2, the value of X is 0.25<
When X < 0.35, a temperature coefficient of ±3o0ppm/'C or less is obtained, and when x=Q, 3, the lowest value (80ppm/'C) is obtained.
Excellent resistance characteristics with m/'G) were obtained.

In particular, in the range of 0.3≦X≦035, the specific resistance value is 1
Since it has a high value of o' (Ω-) or more, it is possible to downsize the high resistance element.

[Effects of the Invention] As described above, the ceramic resistor according to the present invention has a stable resistance value up to high temperatures and can obtain a large specific resistance.

Furthermore, in the present invention, °C is BaC0, Pb3 as a raw material.
Since 20 g of O41Cr can be used, in addition to its resistance properties, a ceramic resistance material that is cheaper than the conventional technology can be obtained.

[Brief explanation of drawings]

FIG. 1 shows the CR in the ceramic resistance material according to the present invention.
Curve diagram showing the effect of substitution amount on room temperature resistance, 2nd
The figure is a curve diagram showing the temperature dependence of the resistivity of Barb, CrxPbO, and the like according to the present invention. (7317) Agent: Patent Attorney Noriyuki Chika (
and 1 other person) Figure 1 C □ Rin Mosquito 1 Figure 2

Claims (1)

[Claims] A ceramic resistance material represented by the chemical formula Ba(Pb,-)(Crx)Os and having a composition of 0.25<x035.