JPH04206185A - Ain ceramics heater and its manufacture - Google Patents

Abstract

PURPOSE:To enable formation of a heating body by means of a direct printing method by printing and forming a sintered film of a specific metal mixture on a specific ceramic substrate. CONSTITUTION:On a AIN ceramic substrate on which formation of a heating body by printing method is difficult, is directly printed with a sintered film of Pd, Pt mixture which contains 10 to 85 weight part of crystallized glass against the total 100 weight part consisting of 15 to 90 weight part of Pt and 10 to 85 weight part of Pd. By this direct printing a heating body can be formed on the AIN substrate and an AIN ceramic heater can be manufactured.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is applicable to AlN, which is extremely difficult to form a heating element by printing.
This invention relates to a method of forming a heating element on ceramics by a printing method.

[Prior Art] AlN has excellent thermal conductivity and high electrical insulation, so it is optimal as a substrate for a heater, and by using AlN, it is possible to create a heater that can be used up to very high temperatures. but,
When nichrome windings were used, high power density could not be obtained and the performance could not be fully demonstrated.

On the other hand, AlN has poor wettability with metals, and the printing method for forming a resistor cannot be applied to AlN because it reduces strength and generates surface defects, and it has been difficult to form a heating element by the printing method. Therefore, conventionally, there has been no technology for directly printing a heating element on AlN.

JP-A-63-146483 discloses a technique for forming a thick film conductor layer containing PT powder as a fissure on an AρN substrate. This technology is used for Au, Ag, Ag-Pd, C
A thick film multilayer conductor layer is formed by adding up to 10% of PT as fission to a conductor paste composed of u, etc.
It cannot be applied to the formation of thin film heating elements by printing methods.

Furthermore, in Japanese Patent Application Laid-Open No. 62-36090, Cr, Ti, A
, j2, MOlW, at least one first metal selected from the group of Mn, Pd, Pt, Zr; and Si,
A substance consisting of at least one second metal selected from the group of Ge and Mn is deposited on AlN, and the second metal is A!
! , a technique is disclosed in which N is diffused into N to form an intermetallic compound with AlN.

This technique is a direct bonding method that replaces conventional brazing to bond AlN to metal. This technology is considered useful when electronic circuits are mounted on this bonded part, but it requires many steps such as deposition, diffusion, and top surface circuit bonding to form the heating element of the heater. It becomes expensive.

Problems to be Solved by the Invention] Unlike the above-mentioned conventional techniques, the present invention aims to provide a method for forming a heating element on an AlN substrate by a direct printing method.

[Means for Solving the Problems] The present invention is an AlN ceramic heater characterized in that a film of a fired body of a mixture of Pd and Pt is provided on an AlN substrate.

Such a ceramic heater is made by mixing 100 parts by weight of crystallized glass with a total of 100 parts by weight of Pt: 10 to 85 parts by weight, Pd: 15 to 90 parts by weight, and printing the paste material on an AβN substrate. It can be manufactured by firing to form a heating element.

In addition, in addition to the above Pt and Pd, 10 parts by weight or less of Au,
There is no problem in adding oxidation-resistant metals such as Ag, Rh, and Ir to adjust the sintering temperature and electric resistance value.

[Operation 1] The ceramic heater of the present invention has a fired film of a mixture of Pd and Pt adhered to an AlN substrate. This ceramic heater is made by printing and firing a paste in which crystallized glass is mixed into a raw material containing Pd and Pt at a certain ratio.

This paste can be printed on AlN substrates, and heating elements made using this paste can be used at high power densities, making it possible to form high-current, high-temperature heaters suitable for Af2N. Ta.

Crystallized glass crystallizes at 700-1000°C. Heat resistance is improved by using crystallized glass frit. This is because the frit melts and crystallizes depending on the temperature during firing (800-1100°C), so the heat resistance can be increased to the melting temperature of the formed crystals (generally higher than the softening temperature of the original glass). Because it will be. Also,
Since the frit crystallizes immediately after melting, defects such as blisters and peeling, which are caused by the reaction between AgN and the frit melt, which are problems when using amorphous glass as a frit, are less likely to occur, and high strength metallization is possible. It becomes possible.

AβN can withstand an oxidizing atmosphere up to about 1000°C. Metals that can be used in an oxidizing atmosphere at temperatures above 400°C and below 1000°C include Pd, Pt, Au, and alloys and/or mixtures thereof. Paste formation is performed by mixing metal powder glass frit, organic binder, and solvent. For metallization, this paste is patterned using a screen printing method, then dried and fired.

The amount of Pd and pt is Pd/Pt=15/85 to 9 in weight ratio.
It is set as 0/10. In this range, the temperature coefficient of resistance is small, so a large current will not flow even when the heater is started.

The electrical resistance value of the heating element formed can be freely adjusted between 0.05 and 5 Ω/mouth by increasing or decreasing the amount of glass frit. If the amount of glass frit is less than 1 part by weight per 100 parts by weight of the Pt--Pd mixed powder, the electrical resistance of the heating element will be too low and sufficient adhesion strength will not be obtained. 20
If the weight exceeds the weight, the resistance will become excessive.

The material of the present invention can be printed on AβN surfaces, has good adhesion, and then is fired to form a good, close-fitting heating element. AflN ceramics have high thermal conductivity and electrical insulation resistance, and have excellent properties as a base material for heaters. The heater of the present invention has a long life and can be used in a wide variety of fields.

[Example] Pt: 18 parts by weight Pd: 82 parts by weight, particle size 0. A composition prepared by mixing LLLm powder with 8 parts by weight of glass frit with a softening point of 700°C and a crystallization temperature of 800°C and making a paste was printed on an AlN substrate to a thickness of 10 μm and baked at 900°C for 1 hour. A heater was formed.

This heater has a power density of 10'W/cm and a maximum of 8'W/cm.
Even after 2000 hours of use at 00°C, no deterioration or disconnection of the heater was observed, and the heater was highly durable and had a long life.

[Effects of the Invention] The heater of the present invention can adjust the resistance value arbitrarily,
It can be easily printed on an AlN substrate and fired to form a heating element, and has excellent stability over time and a long life.

Claims (1)

[Scope of Claims] 1. An AlN ceramic heater comprising a film of a fired mixture of Pd and Pt on an AlN substrate. 2 Pt: 15 to 90 parts by weight Pd: 10 to 85 parts by weight A total of 100 parts by weight is mixed with 1 to 20 parts by weight of crystallized glass, and the paste material is printed on an AlN substrate and fired to form a heating element. 1. A method for manufacturing an AlN ceramic heater, comprising: forming an AlN ceramic heater.