US-12623433-B2 - Metal member, metal-resin joined body, and method for manufacturing same

US12623433B2US 12623433 B2US12623433 B2US 12623433B2US-12623433-B2

Abstract

Provided is a metal-resin joined body having a high joint strength and sufficient airtightness and a metal member for obtaining the same. The metal member includes a metal base material made of a metal and a marking pattern having an uneven part formed on a surface of the metal base material, in which the marking pattern is one continuous straight line or curved line, a plurality of the marking patterns is formed to be adjacent to each other and run parallel, and, in a direction orthogonal to a running direction of the plurality of marking patterns, a maximum height roughness Rz of unevenness of the uneven parts and an average interval Rsm of the unevenness by the uneven parts have a relationship of 45≤(180/π)×arctan(Rz/(Rsm/2))≤75, and a metal-resin joined body includes a resin molded body formed on a surface of this metal member.

Inventors

Yusuke Nishikori
Masanori Endo
Hiroki Ikeda
Yuta ENDO

Assignees

NIPPON LIGHT METAL COMPANY, LTD.

Dates

Publication Date: 20260512
Application Date: 20221007
Priority Date: 20211015

Claims (14)

1 . A metal member comprising: a metal base material made of a metal; and a marking pattern having an uneven part formed on a surface of the metal base material, wherein the marking pattern is one continuous straight line or curved line, a plurality of the marking patterns is formed to be adjacent to each other and run parallel, and, in a direction orthogonal to a running direction of the plurality of marking patterns, a maximum height roughness Rz of unevenness of the uneven parts and an average interval Rsm of the unevenness by the uneven parts have a relationship of 45≤(180/π)×arctan (Rz/(Rsm/2))≤75.
2 . The metal member according to claim 1 , wherein, in the direction orthogonal to the running direction of the plurality of marking patterns, an arithmetic average roughness Ra of the uneven parts and the average interval Rsm of the unevenness by the uneven parts have a relationship of 2.5≤Rsm/Ra≤9.5.
3 . The metal member according to claim 1 , wherein, on the surface of the metal base material, the uneven part is formed that is made up of a recess part that is formed in a recess shape in a depth direction from the surface in a central part of the marking pattern and a projection part that is formed in a projection shape in a height direction from the surface at a peripheral part of the marking pattern, and on the surface of the metal base material, in a region that is sandwiched by the marking patterns adjacent to each other, the projection parts that are included in the marking patterns adjacent to each other, respectively, are formed to be in contact with each other and integrated together, and an untreated part where the metal base material is exposed is not formed.
4 . The metal member according to claim 1 , wherein the metal is aluminum, copper, iron or an alloy containing each of these metals.
5 . A metal-resin joined body comprising: the metal member according to claim 1 ; and a resin molded body formed on the surface of the metal member, wherein the metal member and the resin molded body are joined together in a state where a resin has entered the uneven parts of the marking patterns.
6 . The metal-resin joined body according to claim 5 , wherein the resin molded body contains a thermoplastic resin or a thermosetting resin.
7 . A method for manufacturing a metal member, comprising: an irradiation step of irradiating a surface of a metal base material made of a metal with laser light to form a marking pattern having an uneven part that continues along an irradiation trajectory of the laser light on the surface of the metal base material, to manufacture a metal member having a plurality of the marking patterns formed on the surface of the metal base material, wherein the marking pattern is one continuous straight line or curved line, in the irradiation step, the plurality of marking patterns that is adjacent to each other and runs parallel is formed by irradiation of adjacent portions with the laser light, and, in a direction orthogonal to the irradiation trajectories of the plurality of marking patterns, a maximum height roughness Rz of unevenness of the uneven parts and an average interval Rsm of the unevenness by the uneven parts have a relationship of 45≤(180/π)×arctan (Rz/(Rsm/2))≤75.
8 . The method for manufacturing a metal member according to claim 7 , wherein, in a direction orthogonal to a running direction of the plurality of marking patterns, an arithmetic average roughness Ra of the uneven parts and the average interval Rsm of the unevenness by the uneven parts have a relationship of 2.5≤Rsm/Ra≤9.5.
9 . The method for manufacturing a metal member according to claim 7 , wherein, on the surface of the metal base material, the uneven part is formed that is made up of a recess part that is formed by dispersion of the metal in a place irradiated with the laser light outward from an irradiation central part of the laser light and a projection part that is formed by accumulation of the metal that has dispersed from the recess part in a periphery of the recess part, and on the surface of the metal base material, in a region that is sandwiched by the marking patterns adjacent to each other, the projection parts that are included in the marking patterns adjacent to each other, respectively, are formed to be in contact with each other and integrated together, and an untreated part where the metal base material that is to be irradiated with the laser light is exposed is not formed.
10 . The method for manufacturing a metal member according to claim 7 , wherein the metal is aluminum, copper, iron or an alloy containing each of these metals.
11 . A method for manufacturing a metal-resin joined body, comprising: a resin molding step of forming a resin molded body on the surface of the metal member obtained by the manufacturing method according to claim 7 , to manufacture a metal-resin joined body having the metal base material and the resin molded body joined together, wherein, in the resin molding step, the metal member and the resin molded body are joined together in a state where a resin has entered the uneven parts of the marking patterns.
12 . The method for manufacturing a metal-resin joined body according to claim 11 , wherein, in the resin molding step, molding on the metal member is performed by using a resin composition containing a thermoplastic resin or a thermosetting resin.
13 . The metal member according to claim 1 , wherein the maximum height roughness Rz of the unevenness of the uneven parts is 50 μm or more and 250 μm or less, and the average interval Rsm of the unevenness by the uneven parts is 60 μm or more and 400 μm or less.
14 . The method for manufacturing a metal member according to claim 7 , wherein the maximum height roughness Rz of the unevenness of the uneven parts is 50 μm or more and 250 μm or less, and the average interval Rsm of the unevenness by the uneven parts is 60 μm or more and 400 μm or less.

Description

TECHNICAL FIELD This invention relates to a metal member including a specific joint surface, a joined body of the metal member and a resin molded body, and a method for manufacturing the same. BACKGROUND ART Recently, in the field of a variety of sensor parts of automobiles, home appliance parts, industrial equipment parts and the like, metal-resin joined bodies obtained by integrally joining a metal material such as a copper base material composed of copper or a copper alloy having extremely high heat dissipation properties or conductivity or an aluminum base material composed of aluminum or an aluminum alloy having high heat dissipation properties and being lightweight compared with other metals and a resin molded body having high insulation performance and being lightweight and inexpensive have been in wide use, and the use thereof is expanding. In addition, conventionally, as an industrially suitable method for manufacturing such a metal-resin joined body obtained by integrally joining a metal material and a resin molded body, which are dissimilar materials, together, a method in which a metal material is inserted into a mold for injection molding, a molten thermoplastic resin is injected toward the surface of this inserted metal material and the metal material and a resin molded body are joined together at the same time as the molding of the resin molded body by the injection molding of the thermoplastic resin has been developed, and several methods for further improving joint strength at a lower cost have been proposed. For example, according to the present inventors, techniques in which an oxygen-containing film containing oxygen is formed on the surface of a metal base material by performing a specific treatment on the surface of the metal base material and a resin molded body is joined through this formed oxygen-containing film have been proposed (for example, Patent Literatures 1 to 3). These techniques are methods in which there is little risk of the corrosion of a metal part or a device or the contamination of the ambient environment, which is a problem of previously proposed surface treatment techniques, and a certain joint strength or airtightness can be obtained. However, in a case where a wet-type treatment for forming a hydrated oxide film or a zinc-containing film is performed to form an oxygen-containing film, since no macro uneven parts are formed, the joint strength of the resin joined body is not sufficient, and there is thus a room for additional improvement in the treatment method. In contrast, in a case where laser light is used in the methods of Patent Literatures 1 to 3, there is an advantage in that a macro uneven part can be formed, but the treatment is performed under a condition where the irradiation interval (pit width) is equal to or smaller than the intrinsic spot diameter (beam diameter) of a laser oscillator. In this case, a predetermined macro uneven part is not formed, consequently, a decrease in the joint strength is caused, there are cases where it becomes difficult to guarantee airtightness, and there is thus a room for additional improvement thereof. As a method for forming a metal-resin joined body, several techniques have been proposed as described above in which the surface of a metal material is treated with laser light. For example, Patent Literature 4 describes that a metal/resin composite structure is made to include one or more straight parts having surface roughness for which the load length ratio (Rmr) of a roughness profile with a cut level of 20% and an evaluation length of 4 mm is 30% or less when surface roughness is measured according to JIS B 0601 at a total of six straight parts that are three arbitrary straight parts in a parallel relationship on the surface of a metal member and three arbitrary straight parts orthogonal to the above-described three straight parts. That is, it is described that an uneven shape having sharp edges is formed on the surface of the metal member, whereby not only does the joint strength become high, but airtightness or watertightness also becomes excellent. Patent Literature 5 describes that a joint part having a plurality of groove parts is formed on the metal surface during laser scanning processing in the interface where a dissimilar material and a metal material have been joined together and, in a cross-sectional view of this joint part cut in a direction perpendicular to the groove parts, when the groove width in the groove part is indicated by W, the groove depth is indicated by H, the area of the groove parts that are formed during the laser scanning processing is indicated by A, and the areas of projection parts made of burrs that are formed on both side surfaces of the groove parts during the laser scanning processing are indicated by B and C, the ratio of these areas is made to be within a predetermined range. That is, regarding pores that are formed in a metal molded body, it is described that, in a case where