JPH0834123B2 - A.l.N ceramic heater and method for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to AlN in which it is extremely difficult to form a heating element by printing.
The present invention relates to a method for forming a heating element on ceramics by a printing method.

[Prior Art] AlN is most suitable as a substrate for a heater because it has excellent thermal conductivity and high electric insulation, and using AlN makes it possible to produce a heater that can be used at extremely high temperatures. However, using Nichrome winding, high power density cannot be obtained,
The performance could not be fully exhibited.

On the other hand, AlN has poor wettability to metals, and the resistor forming method by the printing method cannot be applied to AlN due to the decrease in strength and the generation of surface defects, and it is difficult to form the heating element by the printing method. Therefore, heretofore, there has been no technique for directly printing a heating element on AlN.

Japanese Unexamined Patent Publication No. 63-144643 discloses a technique for forming a thick film conductor layer containing Pt powder as a filler on an AlN substrate. This technique is to form a thick-film multi-layer conductor layer by adding up to 10% Pt as a filler to a conductor paste composed of Au, Ag, Ag-Pd, Cu, etc. It cannot be applied.

Further, in JP-A-62-36090, Cr, Ti, Al, Mo,
A material consisting of at least one first metal selected from the group of W, Mn, Pd, Pt, and Zr and at least one second metal selected from the group of Si, Ge, and Mn is coated on AlN. A technique for depositing and diffusing a second metal into AlN to form an intermetallic compound with AlN is disclosed. This technique is a direct joining method that replaces the conventional joining of AlN and metal by brazing.
This technique is considered useful when mounting an electronic circuit on this joint, but many steps such as deposition, diffusion, and upper surface circuit joining are required to form the heating element of the heater. It becomes expensive.

[Problems to be Solved by the Invention]

An object of the present invention is to provide a method for forming a heating element on an AlN substrate by a direct printing method, which is different from the above-mentioned conventional technique.

[Means for solving the problem]

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 ceramics heater has Pt: 10 to 85 parts by weight, Pd: 15 to 90 parts by weight, 100 parts by weight in total, and 1 to 20 parts by weight of crystallized glass, and the paste material is printed on an AlN substrate. It can be manufactured by firing to form a heating element.

In addition, Pt and Pd above 10 parts by weight of Au, Ag, R
There is no problem in adding an oxidation resistant metal such as h or Ir for adjusting the sintering temperature and the electric resistance value.

[Action]

The ceramic heater of the present invention comprises a fired body 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 in a raw material having a fixed ratio of Pd and Pt.

This paste can be printed on an AlN substrate, and the heating element created using this paste can be used at high power density, making it possible to form a high-current high-temperature heater suitable for AlN. It was

Crystallized glass crystallizes at 700 to 1000 ° C. The heat resistance is improved by using the crystallized glass frit. This is because the frit melts and crystallizes depending on the temperature (800-1100 ° C) during firing, so heat resistance can be raised to the melting temperature of the generated crystals (generally higher than the softening temperature of the original glass). Because it will be. Further, since the frit is crystallized immediately after melting, defects such as blister and peeling generated by the reaction between AlN and the frit melt, which are problems when using amorphous glass as the frit, are less likely to occur, and high strength is obtained. Metallization is possible.

AlN can withstand an oxidizing atmosphere up to around 1000 ° C. The metals that can be used in an oxidizing atmosphere at 400 ° C. or higher and 1000 ° C. or lower include Pd, Pt, Au and alloys and / or mixtures thereof. Pasting is performed by mixing a metal powder glass frit, an organic binder, and a solvent. For metallization, this paste is patterned by a screen printing method or the like, and then dried and baked.

The amount of Pd and Pt is Pd / Pt = 15/85 to 90/10 by weight.
In this range, since the temperature coefficient of resistance is small, a large current does not flow even when the heater is started.

The electric resistance value of the formed heating element can be freely adjusted within the range of 0.05 to 5 Ω / □ by increasing / decreasing the compounding amount of the glass frit. When the glass frit is 1 part by weight with respect to 100 parts by weight of the Pt-Pd mixed powder, the electric resistance of the heating element is too small, and sufficient adhesion strength cannot be obtained. If it exceeds 20 parts by weight, the resistance becomes excessive.

The material of the present invention can be printed on the surface of AlN, has good adhesion, and is then fired to form a closely adhered and excellent heating element. AlN ceramics have high thermal conductivity and high 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 widely used in various fields.

〔Example〕

Pt: 18 parts by weight Pd: 82 parts by weight A powder having a particle diameter of 0.1 μm and 8 parts by weight of a glass frit having a softening point of 700 ° C. and a crystallization temperature of 800 ° C. was mixed to form a paste composition on an AlN substrate. A heater was formed by printing on the top to a thickness of 10 μm and firing at 900 ° C. for 1 hour.

This heater has a power density of 10 ⁴ W / cm ³ and a maximum temperature of 800 ° C.
Even after 2,000 hours of use, the heater was not deteriorated or broken, and it was durable and had a long life.

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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Kumagai, 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Technical Research Division (72) Toshihiko Funabashi, 1 Kawasaki-machi, Chiba, Chiba Kawasaki Steel Co., Ltd. (72) Inventor Masao Komatsu 3-34-2-101 Akatsukashinmachi, Itabashi-ku, Tokyo (56) References JP-A-3-236186 (JP, A) JP-A-3-226986 (JP, A) JP-A-3-53488 (JP, A) JP-A-63-96884 (JP, A)

Claims (2)

[Claims] 1. An AlN ceramic heater comprising a film of a fired body of a 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 baked. A method for manufacturing an AlN ceramics heater, comprising forming a heating element.