JPS62226879A - Aluminum nitride sintered body with sealed portion - 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] [Object of the Invention] (Industrial Application Field) The present invention relates to an aluminum nitride sintered body having a sealed portion, and more particularly, to a conductive metallized layer formed in the sealed portion. The present invention relates to an aluminum nitride sintered body which has good adhesion to a sintered body base material and is particularly useful as an envelope for a power tube, an oscillation part for a magnetron, an insulating tube for a laser tube, etc.

(Prior art) Aluminum nitride (AuN) sintered bodies have excellent thermal conductivity, insulation, thermal shock resistance, and high frequency properties, as well as high high-temperature strength, so they have recently been used as a material for various electronic and electrical parts. Attention has been paid.

By the way, among such AfLN sintered parts, there are cylindrical A! An LN sintered body,
In addition, there are some in which one end or both ends are sealed with, for example, a metal member. Incidentally, conventionally, these parts have generally been formed from sintered oxide ceramics such as alumina (Afl 203 ) and beryllia (B e O). However, since all of these parts are required to have excellent heat dissipation and, in some cases, high frequency characteristics, AM does not have sufficient thermal conductivity and high frequency characteristics. AiN has been proposed as an alternative to 03 and eO, which have satisfactory properties but are toxic and expensive.

A cylindrical part having a sealing part made of a sintered body has a conductive metallized layer formed on its sealing surface for joining an M attachment member made of metal, for example, by rolling or soldering. It is necessary that the however,
When forming a conductive metallized layer on the surface of the AIN sintered body, the above-mentioned A intersection 203. The molybdenum-manganese (Mo-Mn) method applied to Beo cannot be applied as is. On the other hand, on the surface of the AQN sintered body, the direct pound copper method (D
A metallized layer can be formed by a thick film method (BC method) or a thick film method, but this metallized layer has A! ; Since the adhesion with the LN sintered body is low, there is a disadvantage that the reliability in brazing and soldering, that is, the reliability of the joint over a long period of time is not sufficient.

(Problems to be Solved by the Invention) As described above, the AJIN sintered body is extremely useful as a material for the above-mentioned power tube envelopes, magnetron oscillation parts, laser tube insulating tubes, etc. due to its characteristics. However, the current situation is that the quality of the conductive metallized layer formed in the sealing part is still not satisfactory, which prevents its application to the above-mentioned parts.

The present invention solves this conventional problem and provides a cylindrical AiN sintered body with a sealing part, in which the conductive metallized layer formed in the sealing part and the AiN sintered body CI material are in close contact with each other. For example, the bonding reliability is high when a sealing metal is brazed or soldered to the metallized layer, and the airtightness of the sealed portion can be maintained well after sealing. The object of the present invention is to provide an A-type N sintered body useful as each of the above-mentioned parts.

[Structure of the Invention] (Means for Solving the Problems) The present inventors mainly focused on the combination of constituent elements of the metallized layer formed on the surface of the sealed part of the A/N sintered body base material. As a result of intensive research, we have found a specific combination that can achieve target 1 above.

Namely, in the cylindrical aluminum nitride sintered body having a sealed portion of the present invention, the conductive metallized layer formed in the sealed portion is (a) (1) a group consisting of molybdenum, tungsten, and tantalum (the first At least one element selected from the group (group 2) consisting of group Ⅰ elements, group IVa elements, rare earth elements, and actinide elements of the iD fA periodic table); (b) a layer made of an alloy containing at least one element of group IVa of the periodic table, or (c) (1) from the group consisting of molybdenum, tungsten, and tantalum. At least one selected element and (ii) at least one element constituting the sintering aid used in producing the aluminum nitride sintered body are added to the imaginary component of the anchored phase. If the layer is included as a car, it will be charged 4 yen.

First, the AuN sintered body of the present invention has a cylindrical shape with a sealed part,
That is, it is a hollow sintered body, and a conductive metallized layer is formed on the sealed portion of one end or both ends depending on the purpose of use.

In this cylindrical A-shaped N sintered body, the surface on which the conductive metallized layer is to be formed is not particularly limited as long as it is the end thereof; It is preferable that the attachment is set appropriately depending on the position. moreover.

There are no particular limitations on the properties of the AuN sintered body itself, but! When applied to various applications, such as power tube envelopes, magnetron oscillation parts, and laser tube insulation tubes.

Since high heat dissipation is required, the heat transfer rate is 50w/
It is preferable that m- be less than or equal to "2".

Now, in the present invention, the conductive metallized layer is 111
It is formed as a layer shown in (a), (b), or (c) mentioned above.

First, in the metallized layer shown in (A), the first
Elements belonging to the group, namely molybdenum (Mo), tungsten (W) and tantalum (Ta), have excellent heat resistance and have a coefficient of thermal expansion almost similar to that of the AIN sintered body base material. It is a component that contributes to improving the heat resistance and heat cycle resistance of the metallized layer.

These component elements are contained in the constituent phase singly or in combination of two or more. In that case, these elements may be used, for example, as each element alone, as a compound or solid solution containing each element, or as a compound or solid solution containing each element, or as a compound or solid solution containing each element. It exists as a mixture of two or more selected from nn-formed compounds and solid solutions. Among these, compounds include oxides of these elements,
Nitride, ) father compound, oxynitride, first daughter nitride, carbonate,
These compounds include carbonitrides, borides, silicides, etc., and such compounds contain, in addition to the L elements, at least one element belonging to the second group described below and/or an element other than the second group. It may be a composite compound containing at least one kind of, or it may be a solid solution.

・On the other hand, the element J that succumbs to the second group, that is, the m-th group element J (B, Ai, Sc, Ga, In, TM) of the periodic table, the r-th group
Va group elements (Ti, Zr, Hf), rare 1: group elements (Y,
La, Ce, Pr, Nd, Pm.

Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b, Lu) and actinide elements (Ac, Th, Pa
, U, Np, Pu, Am, Cm, Bk, Cf, Es, F
m, Md, No.

"Lr) is a component that has excellent wettability with AuN in the metallized layer forming step, that is, the heating step, which will be described later, and contributes to the adhesion between the conductive metallized layer and the AuN sintered body. Among the elements belonging to this second group, particularly preferred are All, Ti, Zr,
Hf, Y, Ce, Dy.

Th, Sm, etc.

These component elements, like the component elements belonging to the first group, are contained in the constituent phase singly or in combination of two or more. The memorandum may exist alone, as a compound or solid solution as listed above containing each memorandum, or as a mixture of two components selected from these entities, compounds and solid solutions.

In addition, in the present invention, an element belonging to the first group;
The composition ratio with the elements belonging to the first group is not particularly limited and may be set appropriately depending on the type of element used or the M1 combination. It is preferable that the ratio to the total of elements belonging to the group is set to about 90:LO to 10:90 in terms of atomic ratio.

No. 9 having the conductive metallized layer of (A) in its sealing part. For example, the N sintered body is manufactured as follows.

That is, first, AIN powder and yttrium oxide (Y2
O2), oxidizing power), Lt sium (Cab), aluminum oxide (AJ1203), lanthanum oxide (La20), cerium oxide (CeO), etc. are mixed and shaped. A cylindrical molded body is produced, and then the molded body is sintered by a conventional method to obtain a cylindrical A-cross-N sintered body.

Thereafter, a paste or liquid containing an element selected from the first group and the second group is applied to the sealing surface of this cylindrical AuN sintered body. Specifically, this paste or liquid material is obtained by dispersing a single substance or a powder of a compound in a viscous agent such as ethyl cellulose or nitrocellulose. At this time, the raw material powders include simple powders of each of the elements listed above, and conductive inorganic compounds containing each element, such as oxides, nitrides, carbides, silicides, borides, oxynitrides, and carbonitrides. , boronitride, silicon nitride, hydride, chloride, fluoride, bromide, iodide, nitrate, nitrite, sulfate, sulfite,
borates, phosphates, phosphites, carbonates, oxalates, chlorates, silicates, hydroxides, ammonium salts, or inorganic or organic compounds that become conductive when fired, e.g. , alkoxide, sol-gel), etc. can be used. Further, it is desirable that such a paste or liquid contains an element selected from the first and second groups or a compound containing the element in an amount of 5% by weight or more of the total amount. .

Next, as described above, a paste or a liquid material is applied to the surface of the A pattern N sintered body base material, dried, and then heat treated to form a metallized layer.

The heating temperature at this time varies depending on the type and combination of component elements, but is usually about 1100 to 1800°C.

Further, as the atmospheric gas, nitrogen gas, dry homing gas, wet homing gas, etc. can be used, and the processing time is preferably set to about 0.5 to 2 hours.

Note that instead of the above method of first manufacturing the A pattern N sintered body and then forming the conductive metallized layer, A! ;LN
After applying the paste to become the metallized layer to the molded body, it is fired at a temperature that satisfies both the sintering temperature of A-N and the formation temperature of the metallized layer, thereby sintering the AIN and forming the conductive metallized layer. It is also possible to apply a so-called simultaneous sintering method in which formation and formation are performed at the same time.

Next, the conductive metallized layer shown in (b) is
It is an alloy layer containing at least one of Va group elements, that is, titanium (Ti), zirconium (Zr), and hafnium (Hf). In such an alloy layer, the alloy components other than the Group Ⅰa elements are not particularly limited, but are preferably those that form an alloy with good wettability with the AuN sintered body. .

Silver (Ag), ¥14 (Cu), =-/Kel (Ni)
, molybdenum (Mo), etc., and these can be used alone or in an appropriate combination.

Group IVa elements such as Ti may form alloys with alloying elements other than the rVa group elements mentioned above.
It may exist, for example, in a dispersed state in an alloy consisting of the at least two types of alloy components without forming an alloy, of which at least a part of the alloy layer is a eutectic alloy. It is further advantageous because it can be wetted well. Specific examples of such eutectic alloys include Ag and Cu or Mo
Examples include combinations of Ni, Ag, and Cu each having a eutectic composition.

The proportion of at least one of Ti, Zr, and Hf in such an alloy is not particularly limited, but is usually preferably about 1 to 10% by weight.

The conductive metallized layer in I-(b) can be formed, for example, as follows.

That is, the same as above <on the desired surface of the AuN sintered body,
A paste or liquid material containing a group IVa element and other alloy component elements may be applied to the two legs and then fired.

The adhesive used at this time may be the same as described above. As the raw material powder, it is possible to use powders of each of the elements mentioned above or compound powders as described above. Further, the firing is preferably carried out in a vacuum or in an inert gas such as Ar, and the firing temperature is set to form one alloy layer. The temperature is usually about 800 to 100°C, although it is also low.

Furthermore, in addition to the method of using such a paste or liquid, a method of placing foil or powder of each alloy component element or both on the A pattern N substrate and firing in the same manner as above is adopted. You can also do that.

Furthermore, it is also possible to apply the simultaneous sintering method as described for the metallized layer shown in (a) above.

Finally, the conductive metallized layer indicated by (c) is made of Mo,
At least one element selected from W and Ta;
It contains at least one metal element constituting the sintering aid used in producing the AnN sintered body as a constituent element of the constituent phase. Mo, W, and Ta have the same form as the layer shown in (a) above, and are contained in the metallized layer singly or in combination of two or more. On the other hand, the sintering aids include those listed above, and the constituent metals of these sintering aids, ie, Y, Ca, A! At least one selected from L, La, Ce, etc. is contained. These metal principals exist as simple metals as described above, or as various compounds or solid solutions.

When forming the conductive metallized layer shown in (c), the raw material paste consisting of the single element or compound powder of each element is applied to the AfLN sintered body in the same way as shown in (a) and (b) above. After applying to the desired surface, 11
The firing may be performed at a temperature of about 00 to 1800'C. Now, if the sintering aid used when producing the AfLN sintered body is Y2O3, the raw material paste contains Yi.
It may contain i-form, YF, Y2O3, or the like.

Contained in the conductive metallized layer shown in (c),
The content of the same metal element as the sintering aid is 3 to 50%,
In particular, it is preferable to set it to 10 to 20%.

When joining a sealing member made of gold-14 to the sealing part of the cylindrical A vertical N sintered body having a conductive metallized layer on the sealing part thus obtained, first, the conductive metallized The layer may be plated with Ni, followed by annealing the plated layer in a homing gas at 600 to 850 DEG C. for 7 cycles, and then brazing or soldering.

(Example) Example 1 An insulating tube for a laser tube as shown in FIG. 1 was manufactured. That is, first, A4N powder containing 1% by weight of Y2O3 as a sintering aid was molded by a conventional method, and then heated at approximately 1800°C.
Cylindrical shape A with shell hole 1a in the axis center is sintered for about 1 hour at
A sintered body l was obtained. Next, conductive metallized layers 2 and 3 were formed on the outer peripheral surface of the A-shaped N sintered body 1 in regions corresponding to the sealing parts 1b and 1b at both ends. In this metallization process, first, a raw material paste is prepared by mixing Li2MoO4 powder, TiO2 powder, and nitrocellulose in a weight ratio of 3:2:10, and this paste is applied to a predetermined surface of the sintered body 1 and dried. Heat treated in air, then H2/
This was done by heating at about 1100°C for 1 hour in N2 gas.

This conductive metallized layer is then plated with Ni and annealed at approximately 800°C, followed by Kovar (
Sealing members 4 and 5 made of a Fe--Ni--Co alloy were brazed to the conductive metallized layers 2 and 3, respectively. After that, a helium leak test was performed on this sealing part tb and the IC, and the leak rate was I x 10-
It was confirmed that there was no change for a long time at acc atm/see or less, and the sealing performance was good.

In this way, the insulating tube for a laser tube made of the /IN sintered body has high thermal conductivity and insulation properties comparable to those of BeO, which is a conventional material.

It doesn't have the iIi characteristics like BeO, and the price is 1/3 of BeO.
It has the advantage of being extremely inexpensive with ~I15.

Moreover, the bonding reliability at the sealed portion is high, and the sealing performance is also excellent.

Example 2 A power tube envelope as shown in FIG. 2 was manufactured. That is, first, Amon powder containing 1% by weight of Y2O3 as a sintering aid was molded by a conventional method, and then heated at about 1800°C.
The material was sintered for about 1 hour to obtain a cylindrical A-cross-N sintered body 11 having a through hole 11a in its axis. Next, this A/N sintered body 1
Conductive metallized layers 12 and 13 were formed on the outer circumferential surface of regions corresponding to sealing parts 11b and llb at both ends of 1. This metallization process first consists of Ag, Cu and Ti.
The respective powders were mixed in a weight ratio of 71:27:2 (Ag and Cu have a eutectic composition), and 30 parts of methylcellulose was added to 100 parts by weight of this mixed powder. A raw material paste was prepared by blending part IiQ, and this paste was applied to a predetermined surface of the sintered body 110, and after drying, it was heated to about 830°C in Ar gas and held for about 5 minutes. .

Thereafter, this conductive metallized layer was plated with Ni and annealed at about 600° C. for 7 times, and then Kovar sealing members 14 and 15 were brazed to the conductive metallized layers 12 and 13, respectively. After that, a helium leak test was performed on the sealing parts 11b and 11c, and the leak rate was found to be LXI 0-8cc at
It was confirmed that there was no change for a long time at m/sec or less, and the sealing performance was good.

Furthermore, this power tube envelope is made of conventional material A! ;L
It was confirmed that the efficiency, especially in the high frequency range, was increased by about 10% compared to that made of 203. This is Ai
This is due to the fact that the heat dissipation of N is much higher than that of Al2O3.

Example 3 An oscillation component for a magnetron as shown in FIG. 3 was manufactured. That is, first, 1% Y as a sintering aid is used as a sintering aid.
AfLN powder containing 2O3 is molded by a conventional method and then sintered at about 1800°C for about 1 hour to form a through hole 21a in the axial center.
A cylindrical AiN sintered body 21 was obtained. Next, a region corresponding to the sealing part 21b at one end of this A-view N sintered body 21, that is.

A conductive metallized layer 22 was formed on one end surface of the A-shaped N sintered body 21.

In this metallization process, first, a raw material paste is prepared by mixing MO powder, Y2O3 powder containing the same metal element as the above-mentioned sintering aid, and nitrocellulose in a weight ratio of 2:1:1. Apply the paste to a predetermined surface of the sintered body 21.
After drying, the test was carried out by heating at about 1700° C. for 1 hour in N2 gas.

Thereafter, this conductive metallized layer was plated with Ni and annealed at about 800° C. for 7 times, and then Kovar sealing members 23 were brazed to the conductive metallized layer 22, respectively. Afterwards, when a helium leak test was conducted on this 11th contact portion 21b, the leak rate I
It was confirmed that there was no change for a long time at 10' cc atIl/sec or less, and the sealing performance was good. Also, 11
The bonding strength of the attachment member 23 was 5 to 10 kg/am2 when evaluated as tensile strength.

In this way, the magnetron oscillation member made of AIN sintered body has improved efficiency especially in the high frequency range compared to the conventional material made of Al2O3, and has extremely high heat dissipation, so it can be used as a cooling fan or fan. Miniaturization is achieved.

In addition, in this embodiment, the three types of parts listed in I have been described as examples, but the scope of application of the cylindrical A-N sintered body having an uninvented sealing part is not limited to these. However, it is useful for application to various parts that require the various excellent properties of AfLN sintered bodies and also require high sealing properties, such as nuclear fusion talistron entrance windows.

[Effects of the Invention] 1. As is clear from this explanation, the J+j7?
The aluminum nitride sintered body with the right part has a conductive metallized layer with good sealability having a specific constituent phase formed in the li part. /I
The properties of the N sintered body, that is, high heat dissipation, insulation, and high frequency properties are required, and its industrial value is high as it is applied to various electronic and electrical parts where it is necessary to form a sealing part.

[Brief explanation of drawings]

1 to 3 are longitudinal cross-sectional views showing an embodiment of an aluminum nitride sintered body having a sealing portion according to the present invention. 1.11.21...Cylindrical A-shaped N sintered body, la, 11
a, 21a...through hole, lb, lc, llb, lie, 21b...sealing part, 2
．． 3.12.13.22... Conductive metallized layer, 4
．． 5.14.15.23...Sealing member.

Claims (2)

[Claims] (1) An aluminum nitride sintered body having a sealed portion at least at one end and a conductive metallized layer formed on the sealed portion, the conductive metallized layer comprising (a) (i) ) at least one member selected from the group consisting of molybdenum, tungsten, and tantalum (first group), and (ii) the group consisting of Group III elements, Group IVa elements, rare earth elements, and actinide elements of the periodic table. (2) a layer containing at least one element selected from (2nd group) as a component element of a constituent phase; (b) a layer made of an alloy containing at least one element of group IVa of the periodic table; or (c) (i) at least one element selected from the group consisting of molybdenum, tungsten, and tantalum, and (ii) at least one element constituting the sintering aid used in producing the aluminum nitride sintered body. 1. An aluminum nitride sintered body having a sealing part characterized by being a layer containing the component element of a constituent phase. (2) The aluminum nitride sintered body according to claim 1, wherein at least a part of the alloy is a eutectic alloy.