SK289084B6 - Method of soldering ceramic or difficult-to-wet metal material with higher shear strength and soldered joints ceramic / ceramic, ceramic / metal and metal / metal with titanium-free solder - Google Patents

Abstract

The method of brazing a ceramic or difficult-to-wettable metal material is carried out by first forming a surface texture with square-shaped elemental elements of 1.5 mm to 3.0 mm x 1.5 mm to mm to 3.0 mm on the brazed smooth surface of the ceramic or difficult-to-wet metal material by laser microstructuring. with a conversion profile with a texture density of 12.5% to 51% and a texture depth of 0.05 to 0.2 mm. Subsequently, a Zn-free titanium-free solder is applied to the metal or ceramic part of the joint without microstructuring at a temperature of 250 ° C to 450 ° C, and an active ultrasound with a frequency of 40 kHz is applied.

Description

The field of technology

The invention relates to a method of soldering a ceramic or hard-to-wet metal material with a higher shear strength of ceramic/ceramic, ceramic/metal and metal/metal soldered joints and ceramic/ceramic, ceramic/metal and metal/metal soldered joints with titanium-free solder. The invention falls into the field of joining materials - soldering.

Current state of the art

Currently, ceramic materials (e.g. Al2O3, SiC, SÍ3N4, AlN, etc.) or combinations of ceramics and metal are soldered using two basic soldering methods. The first method uses the coating of a difficult-to-solder material, on which a metal with good wettability is applied. The second method is the use of active solder, which contains an active element for the purpose of ensuring the wettability of hard-to-solder material, such as ceramic materials.

The classic method is as follows: A solderable metal coating is applied to the surface of the ceramic material, and only then is the soldering itself carried out. Plating ceramics eliminates problems associated with the wettability of ceramic and some non-metallic materials. The created metal solder coating ensures excellent wettability of the surface of the material with solder, which is otherwise non-wettable.

The second method, which is currently being intensively researched, is direct soldering using a special so-called active solder, which contains a small amount of active metal Ti, La, In, Zr, etc. The time required to make joints is reduced, the hygiene of the working environment is improved and the economy of the production of soldered joints is improved. The active element is an important part of the solder because it ensures wetting and the formation of a bond between the metal solder and the ceramic material.

However, there is a group of lead-free soldering alloys for higher application temperatures, e.g. zinc-based, which do not contain an active metal with a significant affinity, such as titanium. Examples are solders of the type Zn-Al-Cu, Zn-Al-Ag, etc. In these soldering alloys, the active metal replaces Al and partly Zn. With these solders, relatively low shear strengths are also achieved when soldering ceramic materials.

It is known from the state of the art that laser microstructuring technology, which was originally intended for removing microvolumes of difficult-to-machine materials (materials in the hardened state, ceramics, Ti-alloys, Co-alloys, composite materials and others), with high requirements for the parameters of the integrity of the machined area, finds today an ever wider application, both in terms of the representation of the range of machined materials, as well as in terms of the breadth of the portfolio of implemented technological procedures. A typical product segment is mainly components intended for microelectronics, products for biomedical use, for the aviation, automotive industry and the field of tool production.

In terms of the described situation, there was an opportunity to solve the problem of soldering in combination with laser microstructuring, and the result of the efforts of the creators is a method of soldering ceramic or hard-to-wet metal material with a higher shear strength of the joint and the soldered joints ceramic/ceramic, ceramic/metal and metal/metal with solder without titanium content in the present invention.

The essence of the invention

The mentioned shortcomings are eliminated by the method of soldering a combination of ceramic or hard-to-wet metal material with higher shear strength of ceramic/ceramic, ceramic/metal and metal/metal soldered joints according to the present invention. In an effort to make a soldered ceramic material/metal joint, while Zn-based solder without titanium alloying would be used for soldering, a new soldering method was proposed, which will significantly increase the shear strength of the joint.

The essence of the method of soldering a ceramic or hard-to-wet metal material for the purpose of achieving higher shear strength of ceramic/ceramic, ceramic/metal and metal/metal soldered joints according to the invention is that a surface is created on the soldered smooth surface of a ceramic or hard-to-wet metal material by laser microstructuring texture with 1.5mm to 3.0mm x 1.5mm to 3.0mm square-shaped elementary elements with a conversion profile with a texture density of 12.5% to 51% and a texture depth of 0.05mm to 0.2 mm.

In the next step, a titanium-free Zn-based solder is applied to the metal or ceramic part of the joint without microstructuring as an active element in the cast state. They are solders, such as ZnAl5Mg3, ZnAl6Ag6, ZnAl5Cu3, etc. The soldering itself is carried out at a temperature from 250 °C to 450 °C using the technology of soldering with the support of active ultrasound with a frequency of 40 kHz, so that there is a high-quality wetting and flow of the solder into the created motifs on the surface of the ceramic material.

The essence of the invention is also the soldered joint with titanium-free solder created in the described manner, which is made of a ceramic or hard-to-wet metal material, on the soldered smooth surface of which a laser microstructuring has created a surface texture with elementary elements of a square shape of size 1.5 mm to 3, 0mm x 1.5mm to 3.0mm with a conversion (recessed) profile with a texture density of 12.5% to 51% and a texture depth of 0.05mm to 0.2mm. The second component of the solder joint is titanium-free solder based on Zn as an active element in the cast state. They are solders, such as ZnAl5Mg3, ZnAleAge, ZnAl5Cu3, etc. The third component of the solder joint is a metal or ceramic material without microstructuring.

It is important to find a suitable texture and optimize the depth of the elemental element of the texture. It was found that the depth has a significant effect on the shear strength of the joint. Motif depths of 50, 100 and 200 pm were investigated.

The highest shear strength of up to 57 MPa was achieved at a microstructuring depth of 200 pm.

The advantages of the technical solution of the method of soldering ceramic or hard-to-wet metal material with higher shear strength and soldered joints ceramic/ceramic, ceramic/metal and metal/metal with titanium-free solder are obvious from its effects, which are manifested externally. The effects of this invention consist mainly in the fact that the proposed solution achieves a higher shear strength of soldered joints of ceramic or hard-to-wet metal material.

Overview of images on drawings

The method of soldering ceramic or hard-to-wet metallic material with higher shear strength and soldered joints ceramic/ceramic, ceramic/metal and metal/metal with titanium-free solder according to the invention will be explained in more detail on specific implementations shown in the drawings, where Fig. 1 shows laser microstructuring on the surface of AuO3 ceramics. fig. 2 shows the influence of the depth of microstructuring on the shear strength of soldered joints.

Examples of implementation of the invention

Individual embodiments of the method of soldering ceramic or hard-to-wet metal material with higher shear strength and soldered joints ceramic/ceramic, ceramic/metal and metal/metal with titanium-free solder according to the invention are presented for illustration and not as limitations of the solutions. Those skilled in the art will find or be able to discover, using no more than routine experimentation, many equivalents to specific embodiments of the invention. Even such equivalents will then fall within the scope of the following patent claims.

A suitable choice of materials and dimensioning should not be a problem for experts familiar with the state of the art, therefore these features were not dealt with in detail.

Example 1

In this example of a specific embodiment of the subject of the invention, a method of soldering a ceramic or hard-to-wet metal material with a higher shear strength of the soldered joint is described. On a soldered smooth surface of a ceramic or hard-to-wet metal material, laser microstructuring produces a surface texture with square-shaped elementary elements of size 1.5 mm to 3.0 mm x 1.5 mm to 3.0 mm with a conversion profile with a texture density of 12.5 % to 51% and a texture depth of 0.05 mm to 0.2 mm. In the next step, ZnAl5Mg3 solder is applied in the cast state to the metal or ceramic part of the joint without microstructuring. The soldering itself is carried out at a temperature of 370 °C using soldering technology with the support of active ultrasound with a frequency of 40 kHz.

Example 2

In this example of a specific embodiment of the subject of the invention, a soldered joint of Al2O3 ceramics with Cu with titanium-free solder is described. A surface texture with ten 2.5 mm x 2.5 mm square-shaped elementary elements with a conversion profile with a texture density of 35.5% and a texture depth of 0.2 mm is laser micropatterned on a 15 mm diameter brazed smooth AuO3 surface, as it is shown in fig. 1. From fig. 2, it is apparent that the highest shear strength of 57 MPa was achieved at a microstructuring depth of 200 μm. The second component of the solder joint is ZnAIsMga solder in the cast state. The third component of the solder joint is Cu without microstructuring.

Alternatively, it is possible to use solders such as ZnAlsCua, ZnAleAge.

Industrial applicability

The method of soldering ceramic or hard-to-wet metallic material with higher shear strength of the soldered joint and ceramic/ceramic, ceramic/metal and metal/metal soldered joints with titanium-free solder 10 according to the invention finds application wherever ceramic, non-metallic and other difficult solderable materials to be soldered to each other or in combination with metals. It can be used in the electronic, electrotechnical, automotive industry, but also in vacuum technology, specifically when soldering bushings made of ceramic materials, when soldering a heat exchanger to a ceramic substrate, when soldering ceramic and non-metallic targets for PVD sputtering, soldering metal 15 contacts to glass and Come.

Claims (1)

1. A method of soldering a ceramic or hard-to-wet metal material with a higher shear strength of the soldered joint, characterized by the fact that first a surface texture with elementary elements of square shape 1.5 mm in size is created on the soldered smooth surface of the ceramic or hard-to-wet metal material by laser microstructuring up to 3.0 mm x 1.5 mm to 3.0 mm with a conversion profile with a texture density of 12.5% to 51% and a texture depth of 0.05 to 0.2 mm; subsequently, Zn-based solder is applied to the smooth metal or ceramic part of the joint at a temperature from 250 °C to 450 °C and active ultrasound is applied. 10 2. A ceramic/ceramic, ceramic/metal and metal/metal soldered joint with titanium-free solder created by the method according to claim 1, characterized in that it is made of a ceramic or hard-to-wet metal material, on the soldered smooth surface of which laser microstructuring has been created surface texture with 1.5 mm to 3.0 mm x 1.5 mm to 3.0 mm square shaped elemental elements with a conversion profile with a texture density of 12.5% to 51% and a texture depth of 0.05 mm to 0. 2 15 mm; it is also made of Zn-based solder and, finally, it is also made of metal or ceramic material with a smooth surface.