CN1029761C

CN1029761C - Composite charicteristic thermistor and its making method

Info

Publication number: CN1029761C
Application number: CN 92112906
Authority: CN
Inventors: 周世平; 李龙土; 桂治轮; 张孝文
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 1992-11-12
Filing date: 1992-11-12
Publication date: 1995-09-13
Anticipated expiration: 2007-11-12
Also published as: CN1086922A

Abstract

The present invention discloses a composition of compound characteristic thermal sensitive resistor and a manufacturing method thereof. The present invention can greatly reduces firing temperature (1120 to 1200 DEG C and 0.5 to 6 hours), reduces cost and can simultaneously obtain multifunctional thermal sensitive resistor materials with NTC and L type NTC and V-PTC compound characteristics.

Description

Composite charicteristic thermistor and its making method

The present invention relates to combined characteristic thermosensitive resistor device and manufacture method thereof.

Up to now, thermistor material is as BaTiO ₃, (Ba, Sr) TiO ₃, (Ba, Pb) TiO ₃Be mainly used in constant temperature heater, current limliting and temperature detection, temperature-compensating etc., its firing temperature is generally all at 1280～1350 ℃, and energy consumption is big, the cost height, and though this material has less negative temperature characteristic (NTC), not possessing useful NTC-PTC(is V-shaped ptc) characteristic.

Negative temperature coefficient heat-sensitive resistance material (NTCR), mainly the oxide by transition metal constitutes, be used for thermometric, temperature-compensating, current limliting etc., this material, the gradient of adjusting resistance-temperature characteristics in wide temperature range is very difficult, in addition, resistivity-temperature characteristics is non-linear, and, under excessive voltage condition, owing to descend gradually, there is breakdown danger from thermal resistance.

For this reason, someone gets up the NTC element of limit inrush currents with the PTC elements combination that stops overcurrent under the abnormal conditions, realize compoundization of function with this, the way that realizes has two kinds, a kind of is to have NTC, weld together after the element of PTC performance burns till, but resistance easily produces non-linear and hop phenomenon, another kind of way is to adopt (Bal-x-y Yx Wy) TiO again ₃On pottery, but performance is undesirable, and firing temperature very high (about about 1350 ℃) has improved cost greatly.

The objective of the invention is to,, provide the combined characteristic thermosensitive resistor device and the manufacture method thereof of low temperature sintering at the above weak point, and make it have good multiple function, can reduce firing temperature again, simplify technical process control, reduce production costs.

To achieve these goals, in the present invention,

Ceramic systems is (Srl-x-y-z Pbx Ry Mz) TiuO ₃

Wherein, 0.05≤x≤0.95

0.006≤y≤0.05

0≤z≤0.02

0.95≤u≤1.4

R is called donor adulterant, is rare earth element, Bi, V, W, Ta, Nb, one or more among the Sb.

M is Ca, Ba modifier.

Combined characteristic thermosensitive resistor device manufacture method comprises selected composition batch mixing according to a certain ratio, grinds calcining, moulding, burns till, and it is characterized in that said certain proportioning is (Srl-x-y-z Pbx Ry Mz) TiuO ₃Accurate proportioning,

0.05≤x≤0.95 wherein

0.006≤y≤0.05

0≤z≤0.02

0.95≤u≤1.4

Wherein R is a rare earth element, Bi, V, W, Ta, Nb, one or more among the Sb

M is Ca, Ba modifier;

Said firing temperature is 1120～～1200 ℃, and the time is 0.5～6 hour, then through air cooling or stove is cold or temperature was reduced to before 1000～800 ℃, and control cooling or after 0.5～2 hour, reduce to room temperature 700～1000 ℃ of heat treatments.

In the present invention, in order to reduce sintering temperature, promote that semiconductor transformation also can add sintering aid such as SiO ₂, Li ₂CO ₃Deng, they regulate the effect of temperature coefficient simultaneously in addition.

In the present invention, raw material can be selected SrCO for use ₃, PbO, CaCO ₃, BaCO ₃, Y ₂O ₃And Li ₂CO ₃SiO ₂The employing agate ball is an abrasive body, absolute ethyl alcohol is an abrasive media, batch mixing is 18～50 hours in the agate jar, in baking oven in 75～85 ℃ of oven dry, cross 120 mesh sieves at least 2 times then, because the harmful effect that the component layering that causes greatly of raw material components difference of specific gravity brings, the raw material that mixes is put into corundum crucible to avoid as far as possible, seal, place Muffle furnace in 800～1050 ℃ of calcinings 1-4 hour, the powder after the calcining adds 2-10 ml distilled water, compression moulding under 200MP pressure behind the mixing by every 100g ceramic powders, burnt till 0.5 to 6 hour in 1120～1200 ℃ then, through air cooling, stove cold or 800～1000 ℃ before control cooling, or 700～1000 ℃ heat treatment 0.5-2 hour, the gained semiconductive ceramic, the surface is cleaned through grinding, and obtains finished product after the drying.

With table 1, table 2 is listed 15 embodiment below

Table one, embodiment forms

Sequence number (embodiment) is formed

1 to 3 (Sr0.594Pb0.376Y0.03) TiO ₃+ 10Wt%SiO ₂+ 0.01W+%Li

4 to 5 (Sr0.48Pb0.48Y0.03Ca0.01) TiO ₃+ 10Wt%SiO ₂+ 0.01W+%Li

6 （Sr0.48Pb0.48Y0.03Ca0.01）TiO ₃+7Wt%SiO ₂+0.01W+%Li

7 （Sr0.48Pb0.48Y0.03Ca0.01）TiO ₃+6Wt%SiO ₂+0.01W+%Li

8 （Sr0.48Pb0.48Y0.03Ca0.01）TiO ₃+5.5Wt%SiO ₂+0.01W+%Li

9 （Sr0.48Pb0.48Y0.03Ca0.01）Ti1.2O ₃+5.5Wt%SiO ₂+0.01W+%Li

10.15 （Sr0.48Pb0.48Y0.03Ca0.01）TiO ₃+4Wt%SiO ₂+0.02W+%Li

11 （Sr0.48Pb0.48Y0.03Ca0.01）TiO ₃+3Wt%SiO ₂+0.01W+%Li

12 to 14 (Sr0.485Pb0.485Y0.02Ca0.01) TiO ₃+ 5Wt%SiO ₂+ 0.01W+%Li

Table two. the specimen preparation condition

Embodiment sequence number firing temperature/time cooling condition heat-treat condition

1 1,170 4 stoves are cold

2 1180 2 960℃

3 1180 4.5 920℃

4 1130 6 920℃

5 1,130 2 stoves are cold

6 1130 6 920

7 1,130 6 stoves are cold

8 1130 4.5 880℃ 700℃/1h

9 1130 4.5 880℃ 700℃/1h

10 1,150 4.5 air coolings

11 1,130 6 air coolings

12 1,130 6 air coolings

13 1130 6 960℃

14 1130 6 1000℃/1h

15 1,180 0.5 air coolings

Table 1 is a proportion of raw materials among 15 embodiment, and Wt% is weight percentage in the table.

Table 2 is used process conditions among 15 embodiment

The Y that uses among all 15 embodiment ₂O ₃Purity is 99.99%, SrCO ₃, PbO, TiO ₂, SiO ₂, Li ₂CO ₃Deng purity be at least 99%, carry out in the agate jar by the listed composition batching of table 1 batch mixing, abrading-ball is an agate ball, add 140 milliliters of absolute ethyl alcohols in per 50 gram compounds, evenly mix to guarantee various components, through the slip of ball mill mixing after 24 hours, pour in the enamel tray, it is 80 ℃ baking oven that the porcelain dish of charge slurry is put into temperature, forced air drying, the time is 4 hours, dried compound is through the 120 mesh sieves high alumina crucible of packing at twice, add the corundum cover plate after the tamping, put into Muffle furnace in 860 ℃ of calcinings 2 hours, the ceramic powders after the calcining is crossed at least 2 gained fine powders of 120 mesh sieves add 4 ml distilled waters in 100 gram material ratio after ceramic mortar is smashed to pieces, adding distil water, after mixing, compression moulding under the pressure of 200MPa, the firing temperature of different embodiment, temperature retention time, cooling condition (listed temperature be meant from firing temperature by 16 ℃/minute the cooling final temperatures, this below temperature with the stove natural cooling) undertaken by table 2 is listed.

Table 3 has been listed according to the made thermistor of above-mentioned condition, and after tested, embodiment 2 gained thermistors have the linear PTC feature.

Embodiment 1,2, because Sr content is higher, thereby firing temperature is higher in 3, and Sr content is lower than 1 to 3 among the embodiment 4,5, thereby firing temperature and semiconductor transformation temperature are all very low.SiO ₂The metal increase helps sintering and semiconductor transformation, and this can be by finding out in embodiment 4 and 6.Work as SiO ₂Content＞7wt%, Tmin increase, and when its during greater than 10wt%, finished product is yielding, SiO among the embodiment 11 ₂Content is 3wt%, and it has the NTCR characteristic.

Among the present invention, by changing TiO ₂Amount can be adjusted ρ 25, ρ min TiO ₂Amount increases ρ 25, ρ min, and α all rises, and sees embodiment 8,9.

Donor concentration is remarkable to the sensitive characteristic influence, and when alms giver's amount was 0.02mol, ρ 25, and ρ min is very low, and the Tmin asymptotic Curie temperature to burning till, cools off, and the sensitiveness of heat-treat condition weakens.As embodiment 12,13, shown in 14, can obtain good V-shaped ptc characteristic in 1 hour 1000 ℃ of heat treatments in the temperature-fall period.

Li has the function of adjusting α, and as embodiment 10,15, Li content is 0.02wt%, and 1180 ℃ are burnt till, and are incubated 0.5 hour, and air cooling, finished product have L type NTC characteristic.

Table 3 has been listed embodiment performance table

Table three. embodiment performance table

25 ℃ of ρ min of embodiment ρ Tmin (% ℃)

Sequence number (Ω .cm) (Ω .cm) (℃)-α+α β

1 1.01×10 ⁵1.16×10 ⁴123 2.26 1.52 2614

2 9.34×10 ⁴7.29×10 ⁴40 1.65 1.31 1552

3 4.57×10 ⁴6.37×10 ³130 1.88 1.42 2253

4 1.85×10 ⁶3.13×10 ³170 4.40 2.38 5810

5 4.44×10 ⁵3.11×10 ³165 3.54 1.51 4625

6 7.90×10 ⁶1.04×10 ⁴155 5.10 1.69 6266

7 2.92×10 ⁷1.69×10 ⁵115 5.72 4.09 3468

8 1.67×10 ⁷4.50×10 ⁴115 180 5.14 1.18 5377

9 4.94×10 ⁷4.48×10 ⁵120 4.11 3.14 4407

10 2.27×10 ⁵2.78×10 ²225 3.09 0.07 4693

11 7.75×10 ⁶3.00×10 ³240 3.60 0.00 5415

12 1.35×10 ³2.62×10 ²110 1.81 0.70 2.49

13 7.17×10 ⁴4.35×10 ³115 2.97 2.74 3538

14 1.91×10 ⁵5.36×10 ³113 3.94 5.56 4460

15 4.69×10 ³2.85×10 ³170 5.07 0.00 6673

Probe temperature is 20～500 ℃

All the other are 20～240 ℃

Resistivity when featured resistance ρ 25 is meant 25 ℃ of room temperatures; ρ min refers to resistivity minimum in the resistivity-temperature characteristics, and min is corresponding with temperature T, and ρ 25, and its unit of ρ min is Ω .cm

The thermistor constant of NTCR is calculated as follows

R＝RoExp[B 1/T-1/To）]

B thermistor constant

T is absolute temperature (° K)

R is the thermosensitive resistance (Ω) of corresponding temperature T

Claims

1, a kind of combined characteristic thermosensitive resistor device is characterized in that, the sensitive body material of this thermistor be ceramic based material its consist of:

(Srl-x-y-z Pb _xR _yM _z)TiuO ₃

Wherein, 0.05≤X≤0.95

0.006≤y≤0.95

0≤2≤0.02

0.95≤u≤1.4

R is a rare earth element, Bi, V, W, T _a, Nb, at least a M among the Sb is C _a, B _aModifier

2,, add sintering aid SiO in it is characterized in that forming according to the combined characteristic thermosensitive resistor device of claim 1 record ₂, Li ₂CO ₃

3, a kind of combined characteristic thermosensitive resistor device manufacture method comprises selected composition, and step is burnt till in batch mixing, grinding, calcining, moulding according to a certain ratio, it is characterized in that, said composition and certain proportioning are (Srl-x-y-z P _BxR _yM _z) TiuO ₃

0.05≤x≤0.95 wherein

0.006≤y≤0.05

0≤2≤0.02

0.95≤u≤1.4

Wherein R is a rare earth element, Bi, V, W, T _m, N _b, S _bIn at least a

M is Ca, Ba modifier

Said burning till in the step, firing temperature are that 1120～1200 ℃ of times are 0.5～6 hour, and then through air cooling, the cold or temperature of stove was reduced to before 1000～800 ℃, the control cooling, and the heat treatment of control again/under this temperature 0.5～2 hour drops to room temperature then naturally.

4, the composite attribute thermal resistor manufacture method of putting down in writing according to claim 3, it is characterized in that, said grinding, the employing agate ball is an abrasive body, absolute ethyl alcohol is an abrasive media, and in the agate jar batch mixing 18～50 hours, in baking oven,, cross 120 mesh sieves at least twice then in 75～85 ℃ of oven dry.

5, according to claim 3, the 4 combined characteristic thermosensitive resistor device manufacture methods of being put down in writing is characterized in that, said calcining is 800～1050 ℃ of calcinings 1-4 hour.