CN101894642A - Manufacturing method of positive temperature coefficient thermal resistor - Google Patents

Abstract

The invention relates to a manufacturing method of a positive temperature coefficient thermal resistor. The manufacturing method comprises the following steps of: performing ball milling on 0.75 to 0.83 mol of BaTiO3, 0.12 to 0.16 mol of CaTiO3, 0.04 to 0.08 mol of PbTiO3, 0.01 to 0.03 mol of SrTiO3, 0.01 to 0.02 mol of TiO2, 0.0020 to 0.0028 mol of Y2O3, 0.021 to 0.027 mol of SiO2 and 0.0006 to 0.0009 mol of MnO2 by using a ball mill; pre-burning the mixture after the ball milling at the temperature of 1,100 DEG C; performing secondary ball milling, and adding PVA solution into the mixture for granulation; forming ring-shaped blank sheets by using different ring-shaped molds respectively; sintering the ring-shaped blank sheets for one hour at the temperature of between 1,200 and 1,400 DEG C to form ceramic matrixes; coating ohmic electrodes on the circular ring surfaces of the ceramic matrixes; burning and permeating the ceramic matrixes, coating surface layer Ag electrodes, and performing calcination to obtain a product. In the manufacturing method, the conventional wafer-shaped chip is changed into ring-shaped chip, and the ring-shaped shape can improve the temperature distribution of the positive temperature coefficient thermal resistor during working, so the heat dissipation environment of the thermal resistor is improved, the thermal resistor can avoid lamination crack invalidation caused by over-high temperature differences between the center of the chip and a part close to the periphery under a large power rush, and the reliability of a product is enhanced.

Description

A kind of manufacture method of semistor

Technical field

The present invention relates to a kind of manufacture method of semistor.

Background technology

It is lower that semistor (PTC) has when temperature is low resistance value, and the temperature characteristic that resistance sharply rises when rising to a certain degree.Because its unique characteristic, thus at the air-conditioning refrigerator motor starting, the communication equipment overcurrent protection, fields such as television set degaussing are widely used.Because industrial expansion is more and more higher to the working voltage current range requirement of PTC.Add voltage for semistor (PTC) two ends, PTC can generate heat, and the centre of element, makes element internal follow the outside to have temperature difference and produces stress because heat dissipation environment is widely different with the element periphery.Bearing under high voltage and the big current conditions at PTC especially, the PTC electrothermal calefactive rate is very fast, and stress produced in the extremely short time, caused the product Cracking Failure easily.

Summary of the invention

The objective of the invention is at above-mentioned present situation, aim to provide a kind of slabbing that can under big power rush, not produce and lost efficacy the manufacture method of the reliable semistor of product.

The implementation of the object of the invention is, a kind of manufacture method of semistor, and concrete steps are as follows:

1) with 0.75-0.83molBaTiO ₃, 0.12-0.16molCaTiO ₃, 0.04-0.08mol PbTiO ₃, 0.01-0.03molSrTiO, 0.01-0.02molTiO ₂, 0.0020-0.0028molY ₂O ₃, 0.021-0.027mol SiO2,0.0006-0.0009mol MnO ₂Through ball milling, 1100 ℃ of pre-burnings, secondary ball milling, and add the PVA solution granulation of powder weight 12%,

2) use different ring mould moulding respectively, became circular ceramic matrix in 1 hour at 1200-1400 ℃ of sintering, the ceramic matrix external diameter is 10-30mm, internal diameter 3-10mm, thick 2.5mm,

3) at the annulus surface-coated Ohmic electrode of ceramic matrix, apply top layer Ag electrode after the burning infiltration again, burn till product, wherein Ohmic electrode is one or more the combination in nickel, aluminium, zinc, the silver metal.

The present invention is transformed into into traditional disk shape chip circular, annular-shape can be improved the Temperature Distribution of semistor when work, thereby improve the heat dissipation environment of thermistor, make it under big power rush, can avoid having strengthened reliability of products because slabbing that produce lost efficacy with close periphery temperature difference is too high in the middle of the chip.

Description of drawings

Fig. 1 is the semistor structural representation with the present invention's preparation,

Fig. 2 is the semistor structure cut-away view with the present invention's preparation.

Embodiment

The present invention is with BaTiO ₃, 0.15mol CaTiO ₃, 0.04mol PbTiO ₃, 0.02mol SrTiO ₃, 0.01mol TiO ₂, 0.0022mol Y ₂O ₃, 0.0250mol SiO ₂, 0.0007mol MnO ₂Through ball milling, 1100 ℃ of pre-burnings, secondary ball milling, and add the granulation of PVA solution, be molded into annular blank with different ring moulds respectively, became ceramic matrix in 1 hour at 1200-1400 ℃ of sintering,, apply the circular product 1 that top layer Ag electrode 3 (see figure 2)s are burnt till as shown in Figure 1 after the burning infiltration again at the annulus surface-coated Ohmic electrode 2 of ceramic matrix 4.

Principle of the present invention is: during the heating power of semistor (PTC) two ends, central temperature is higher than the appearance temperature, the present invention circularizes it, middle nothing heating part, thereby can improve heating temp distributes, reduce because the stress that temperature difference produces is avoided the product Cracking Failure, reach the purpose that improves product reliability.

Enumerate specific embodiments of the invention below.

Example 1, with 0.75molBaTiO3,0.16mol CaTiO3,0.08mol PbTiO3,0.01mol SrTiO3,0.01mol TiO2,0.002mol Y2O3,0.0210mol SiO2,0.0009mol MnO2 be through ball milling, 1100 ℃ of pre-burnings, secondary ball milling, and add the PVA solution granulation of powder weight 12%, and circularize the base sheet with mould molding, became ceramic matrix in 1 hour at 1320 ℃ of sintering, record the ceramic matrix external diameter and be that 16mm, thickness are 2.5mm, internal diameter is respectively 0mm, 4mm, 8mm, correspondingly be numbered 1,2,3.Apply Ohmic electrode 2 at every kind of sample surfaces then, apply top layer Ag electrode 3 after the burning infiltration again and burn till.No. 1,2,3, sample thief, under 25 ℃, 350V, 8A switched on 1 minute, cut off the power supply 1000 times 5 minutes.

The applicant has made cirque structure to above three products and has avoided the product Cracking Failure, improves the test of product reliability, test result such as following table 1:

Numbering	Sample number	Resistance	Switch on 200 times	Switch on 1000 times
					1	10	13.2Ω	2 layerings	10 layerings
2	10	13.9Ω	Bad 0	Bad 0
					3	10	17.3Ω	Bad 0	Bad 0

As seen from the table, internal diameter is the semistor of 0mm, and the energising of promptly acyclic semistor has two layerings 200 times, 1000 times 10 equal layerings of layering is arranged.As seen, utilize annular can improve the heat dissipation environment of semistor, reliability of products can significantly improve.

Example 2, with example 1, different is, with 0.83molBaTiO ₃, 0.12mol CaTiO ₃, 0.04molPbTiO ₃, 0.01mol SrTiO ₃, 0.02mol TiO ₂, 0.0028mol Y ₂O ₃, 0.027mol SiO2,0.0006mol MnO ₂Through ball milling, 1100 ℃ of pre-burnings, secondary ball milling, and add the PVA solution granulation of powder weight 12%, circularize the base sheet with mould molding, became ceramic matrix in 1 hour at 1400 ℃ of sintering, recording the ceramic matrix external diameter is that 25mm, thickness are 2.5mm, are the ceramic matrix that is respectively 0mm, 5mm, 10mm for 20mm, internal diameter at 1 hour external diameter of 1400 ℃ of sintering.

Example 3, with example 1, different is, with 0.79molBaTiO ₃, 0.14mol CaTiO ₃, 0.05molPbTiO ₃, 0.02mol SrTiO ₃, 0.02mol TiO ₂, 0.0026mol Y ₂O ₃, 0.025mol SiO2,0.0008mol MnO ₂Through ball milling, 1100 ℃ of pre-burnings, secondary ball milling, and add the PVA solution granulation of powder weight 12%, circularize the base sheet with mould molding, became ceramic matrix in 1 hour at 1400 ℃ of sintering, recording the ceramic matrix external diameter is that 25mm, thickness are 3.0mm, external diameter is that 25mm, internal diameter are the ceramic matrix of 0mm, 5mm, 10mm.

Claims (1)

1. the manufacture method of a semistor is characterized in that concrete steps are as follows:

1) with 0.75-0.83molBaTiO ₃, 0.12-0.16molCaTiO ₃, 0.04-0.08mol PbTiO ₃, 0.01-0.03molSrTiO ₃, 0.01-0.02molTiO ₂, 0.0020-0.0028molY ₂O ₃, 0.021-0.027molSiO2,0.0006-0.0009mol MnO ₂Through ball milling, 1100 ℃ of pre-burnings, secondary ball milling, and add the PVA solution granulation of powder weight 12%,

2) use different ring mould moulding respectively, became circular ceramic matrix in 1 hour at 1200-1400 ℃ of sintering, the ceramic matrix external diameter is 10-30mm, internal diameter 3-10mm, thick 2.5mm,

3) at the annulus surface-coated Ohmic electrode of ceramic matrix, apply top layer Ag electrode after the burning infiltration again, burn till product, wherein Ohmic electrode is one or more the combination in nickel, aluminium, zinc, the silver metal.

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