CN210167512U

CN210167512U - Magnesium alloy structural member and terminal

Info

Publication number: CN210167512U
Application number: CN201921189932.XU
Authority: CN
Inventors: 薛永强; 许坚强
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-07-25
Filing date: 2019-07-25
Publication date: 2020-03-20
Anticipated expiration: 2029-07-25

Abstract

An embodiment of the utility model provides a magnesium alloy structure is equipped with at least one electricity connection point region on it, be in including magnesium alloy body, setting the protective layer on magnesium alloy body surface and setting are in conducting strip on the regional protective layer of electricity connection point, the conducting strip with the magnesium alloy body passes through the solder joint and connects, the conducting strip is used for forming the electricity after contacting with the external world as the electricity connection point and is connected. This magnesium alloy structure adopts welding process to be connected conducting strip and magnesium alloy body through adopting in the electricity connection point region, can avoid getting rid of the regional protective layer of whole electricity connection point, and isolated magnesium alloy body slows down corruption and galvanic corrosion with the contact of outside air, realizes the stable electricity of parts such as magnesium alloy structure and mainboard and is connected. The embodiment of the utility model provides a cell-phone, panel computer, notebook and the portable machine that contains this magnesium alloy structure are still provided.

Description

Magnesium alloy structural member and terminal

Technical Field

The embodiment of the utility model provides a relate to magnesium alloy structure technical field, especially relate to a magnesium alloy structure and terminal.

Background

At present, in most electronic products, the metal piece is used as an appearance structural part and the body is also used as an antenna, so that the metal piece and other parts such as a mainboard, a touch display screen and the antenna have stable electric connection requirements, and especially under high-power emission (power is more than or equal to 33dbm) scenes such as GSM (global system for mobile communications), the requirements on low impedance and reliability of the electric connection between the metal piece and the other parts are higher. Fig. 1 is a schematic structural diagram of a metal part and a main board of a mobile phone in the prior art; FIG. 2 is a schematic partial cross-sectional view taken along A-A of FIG. 1 (circled in dashed lines in FIG. 1); referring to fig. 1,

electrical connection points

111 and 112 are disposed on the inner side of the mobile phone metal part 11 for electrically connecting with the mobile phone motherboard 12; referring to fig. 2, a metal dome 121 is disposed on the main board 12, and the electrical connection point 111 contacts the metal dome 121, so that the main board 12 is electrically connected to the metal member 11, and the metal member 11 serves as an antenna or a part of the antenna.

The magnesium alloy material is light, and the application of the magnesium alloy as a metal piece has great benefits on weight reduction and light weight of products. However, magnesium alloy materials are extremely susceptible to oxidation corrosion in air, and in a humid or solution environment, when other conductors/metals are in contact with the magnesium alloy materials, severe galvanic corrosion is easily formed, so that the magnesium alloy cannot form reliable electrical connection at a connection point, and cannot meet the requirements of high-power emission scenes, thereby greatly limiting the application of the magnesium alloy in electronic products.

SUMMERY OF THE UTILITY MODEL

In view of this, the embodiment of the utility model provides a magnesium alloy structure, adopt welding process with conducting strip and this body coupling of magnesium alloy through the electric connection point region on magnesium alloy structure, can avoid getting rid of the regional magnesium protective layer of electric connection point, effectively isolated magnesium alloy body and outside air's contact, slow down air corrosion and galvanic corrosion, realize magnesium alloy structure and mainboard, the stable electricity of parts such as liquid crystal display is connected, it is not high to solve the electric connection reliability between parts such as current magnesium alloy structure and mainboard to a certain extent, can't satisfy the problem of high power transmission scene demand.

Specifically, the embodiment of the utility model provides a first aspect provides a magnesium alloy structure is equipped with at least one electrical connection point region on it, and this magnesium alloy structure includes the magnesium alloy body, sets up the protective layer on magnesium alloy body surface and setting are in conducting strip on the regional protective layer of electrical connection point, the conducting strip with the magnesium alloy body passes through the solder joint and connects, the conducting strip is used for forming the electricity after contacting with the external world as the electrical connection point and is connected.

In an embodiment of the present invention, the solder joints include at least two solder joints.

The utility model discloses in the embodiment, the conducting strip includes workspace and non-workspace, the workspace is used for forming the electricity with external contact and is connected, two at least solder joints set up in the non-workspace of conducting strip.

In the embodiment of the utility model, the size of the welding spot is 0.5mm-0.8 mm.

In an embodiment of the present invention, the solder joint penetrates the conductive sheet and the protective layer, and is partially embedded in the magnesium alloy body.

In an embodiment of the present invention, the solder joint is embedded in the depth of the magnesium alloy body is greater than 0.1mm and less than 0.5 mm.

The utility model discloses in the embodiment, the solder joint expose outside a lateral surface with the surface of conducting strip flushes or exceeds the first height in surface of conducting strip, first height is less than 0.5 mm.

The utility model discloses in the embodiment, the conducting strip includes the substrate, the substrate is that wearability and corrosion resistance are higher than the magnesium alloy, and keep away from the surface resistance of one side of magnesium alloy body is less than 0.5 ohm conductor. Wherein, the base material can be at least one of copper alloy, aluminum alloy and multi-element alloy.

In an embodiment of the present invention, the thickness of the substrate is 0.08mm to 0.6 mm.

In the embodiment of the utility model, the conducting strip is still including setting up the anticorrosive coating on substrate surface. The thickness of the anticorrosive coating is 0.0005mm-0.05 mm. The anti-corrosion layer comprises nickel layers arranged on the surfaces of two opposite sides of the base material and gold layers arranged on the nickel layers on one side, far away from the magnesium alloy body, of the base material.

In the embodiment of the present invention, the protective layer is any one of a chemical film, a micro-arc oxidation film, an electrophoresis film, a paint coating or an anodic oxidation film.

In an embodiment of the present invention, the thickness of the chemical conversion coating is 0.0005mm to 0.003 mm.

In the embodiment of the utility model, the thickness of the micro-arc oxidation film layer is 0.002mm-0.012 mm.

In the embodiment of the present invention, the thickness of the electrophoresis film layer is 0.005mm-0.01 mm.

In the embodiment of the utility model, the thickness of the coating is 0.005mm-0.01 mm.

In the embodiment of the present invention, the thickness of the anodic oxide film layer is 0.005mm-0.01 mm.

The embodiment of the utility model provides a magnesium alloy structure that first aspect provided, through adopt welding process with conducting strip and this body coupling of magnesium alloy in the electricity connection point region, can avoid getting rid of the regional protective layer of whole electricity connection point, effectively isolated magnesium alloy body and outside air's contact slows down air corrosion and galvanic corrosion, realizes that the magnesium alloy structure is connected with the stable electricity of parts such as mainboard to satisfy high power transmission such as radio frequency antenna GSM/accept the low impedance of scene, the electric connection demand of high reliability.

In a second aspect, an embodiment of the present invention further provides a terminal, including the first aspect of the present invention, the magnesium alloy structure passes through the conductive sheet with the main board component electricity at terminal is connected. Specifically, the magnesium alloy structural member may be a middle frame, a rear cover, a display screen support plate, or the like.

The utility model provides a terminal, including assembling at the shell in the terminal outside, and be located the inside mainboard of shell, the shell is including assembling at the display screen of terminal front side and the back lid at the terminal rear side at the back, back lid inboard is equipped with at least one electricity connection point region, the back lid includes magnesium alloy body, sets up protective layer on magnesium alloy body surface and setting are in conducting strip on the regional protective layer of electricity connection point, the conducting strip with the magnesium alloy body is connected through two at least solder joints, the conducting strip includes workspace and non-workspace, two at least solder joints set up in the non-workspace of conducting strip, the workspace of conducting strip with the mainboard with electricity connection point contact on the display screen forms the electricity and connects. The terminal can be a mobile phone, a tablet computer, a notebook computer, a portable computer and other products.

Drawings

FIG. 1 is a schematic structural diagram of a conventional metal part and a motherboard of a mobile phone;

FIG. 2 is a schematic partial cross-sectional view taken along A-A of FIG. 1;

FIG. 3 is a schematic structural diagram of an electrical connection scheme of a magnesium alloy part provided by the prior art;

FIG. 4 is a schematic cross-sectional view taken along A-A of FIG. 3;

fig. 5 is a schematic structural diagram of a magnesium alloy structural member according to an embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view taken along A-A of FIG. 5;

fig. 7 is a corrosion result graph of a magnesium alloy structural member subjected to a 24-hour neutral salt spray test according to an embodiment of the present invention;

FIG. 8 is a diagram showing corrosion results of a magnesium alloy part in the prior art after 24-hour neutral salt spray test;

FIG. 9 is a schematic view of a solder joint according to another embodiment of the present invention;

fig. 10 is a schematic structural view of a conductive sheet according to an embodiment of the present invention;

fig. 11 is a schematic structural diagram of a terminal according to an embodiment of the present invention;

fig. 12 is a schematic diagram of electrical connection between the rear cover and other components according to an embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be described below with reference to the accompanying drawings.

At present, in the prior art, for products without a high-power emission scene (such as most of notebook computers only have wifi requirements, and do not have GSM communication requirements), the electric connection scheme of the magnesium alloy part is as follows: as shown in fig. 3 and 4, a magnesium passivation layer 120 is formed on the surface of the magnesium alloy substrate 110, but because the magnesium passivation layer 120 has the defect of non-conductivity or unstable contact resistance, in order to achieve low resistance conduction, the magnesium passivation layer 120 in the whole electrical connection point region needs to be radium-etched away to expose the magnesium alloy substrate 110, and then a conductive cloth/cotton 130 (containing a conductive back adhesive 140) is adhered to the exposed magnesium alloy substrate 110, and the conductive cloth/cotton 130 is used as an external connection point. However, for a high-power emission scene, the electric connection scheme cannot meet the strict requirements of low impedance and reliability, firstly, because the magnesium protective layer of the whole electric connection area is removed, the conductive cloth and the conductive cotton cannot completely isolate air, the magnesium alloy is still exposed in the air atmosphere to a certain extent, air corrosion and galvanic corrosion can occur, and the surface resistance of the magnesium alloy substrate gradually rises to cause the connection performance to be reduced; secondly, after the conductive back adhesive carried by the conductive cloth is used for a certain time in a high-temperature and low-temperature environment of an electronic product, the back adhesive can age, and the contact resistance changes; the conductive fabric has elasticity and is electrically connected to a component such as an antenna or a liquid crystal display under a certain pressure (for sufficient contact), but the elasticity of the conductive fabric is attenuated after a certain period of use, and the on-resistance is also changed by vibration. And the conductive cotton has the phenomenon of hair chip falling in the using process, so that the risk of short circuit of the device is caused.

Referring to fig. 5 and 6, for solving the above problem, an embodiment of the present invention provides a magnesium alloy structure 100, the magnesium alloy structure 100 is provided with at least one electrical connection point region, which is used for forming an electrical connection with other components, the magnesium alloy structure 100 includes a magnesium alloy body 10, a protection layer 20 disposed on the surface of the magnesium alloy body 10, and a conductive sheet 30 disposed on the protection layer 20 of the electrical connection point region, the conductive sheet 30 is connected with the magnesium alloy body 10 through a solder joint 40, the solder joint 40 sequentially runs through the conductive sheet 30, the protection layer 20, and is partially embedded in the magnesium alloy body 10, the region outside the solder joint 40 of the conductive sheet 30 is in direct contact with the protection layer 20, the conductive sheet 30 is used for forming an electrical connection with the outside after contacting as an.

The utility model discloses in the embodiment, solder joint 40 is condensed and forms after fusion welding by conducting strip 30, protective layer 20 and magnesium alloy body 10, therefore has formed seamless zonulae occludens in solder joint 40 department for the magnesium alloy body 10 that is located solder joint 40 department is isolated with external. Specifically, the conductive sheet 30 and the magnesium alloy protective layer 20 may be broken down at the position of the welding point 40 in a small range by using laser welding, ultrasonic welding, friction welding, or the like, so that the conductive sheet 30 and the magnesium alloy body 10 are fused at the welding point, thereby forming a stable closed joint structure. Compare in prior art and need the scheme of getting rid of the whole radium carving of the regional protective layer of whole electric connection point, the utility model discloses the scheme is owing to only the minizone puncture protective layer 20, and the region beyond solder joint 40 on the conducting strip 30 is with protective layer 20 direct contact, and the magnesium alloy body 10 of easy oxidation can not expose in the air like this, therefore can effectively avoid or slow down magnesium alloy body 10 and take place air corrosion and galvanic corrosion problem to and avoid magnesium alloy body 10, conducting strip 30 and both hookup location to take place ageing and vibrations inefficacy problem, finally form stable electric connection structure. And (4) adopting a drawing force tester to carry out drawing force test on the welding spots, wherein the drawing force of a single welding spot is more than 3N. And (3) carrying out the drawing force test again after carrying out the neutral salt spray test for 24 hours, wherein the drawing force of a single welding spot is still larger than 3N, which indicates that the conducting strip and the magnesium alloy body form reliable physical connection. Will the embodiment of the utility model provides a magnesium alloy structure spare observes the corruption condition after carrying out 24 hours neutral salt fog tests, and the result is as shown in figure 7, and after the salt fog test, the magnesium alloy body does not have the corruption basically, and the solder joint is clear visible, does not have the corruption. Fig. 8 is a graph showing corrosion results of a magnesium alloy part (shown in fig. 3 and 4) using conductive cotton as an electrical connection point in the prior art after 24-hour neutral salt spray test, and fig. 8 shows that erosive corrosion occurs in the magnesium alloy substrate where the conductive cotton is disposed.

In the embodiment of the present invention, in order to form the stable physical connection between the conductive sheet 30 and the magnesium alloy body 10, the solder joints 40 penetrate the conductive sheet 30 and the protective layer 20, and are partially embedded in the magnesium alloy body 10. The depth of the welding spot 40 embedded in the magnesium alloy body 10, i.e. the fusion depth of the welding spot 40 in the magnesium alloy body 10, may be more than 0.1mm and less than 0.5mm, and may be determined according to the thickness of the magnesium alloy body 10, and further, the fusion depth may be more than 0.1mm and less than 0.2 mm. The proper depth setting can ensure the base material strength of the magnesium alloy body 10 at the bottom of the welding spot 40 and can also take into account the connection reliability of the welding spot 40.

The utility model discloses in the embodiment, solder joint 40 exposes outside a lateral surface and flushes or exceeds the first height in surface of conducting strip 30 with the surface of conducting strip 30, and first height is less than 0.5 mm. Of course, in other embodiments, the exposed end surface of the solder joint 40 may be slightly lower than the surface of the conductive sheet 30.

The utility model discloses in the embodiment, in order to make conducting strip 30 and magnesium alloy body 10 form stable physical connection, solder joint 40 need set up at least two, can be even number, also can be odd number, and specific quantity can be according to conducting strip 30's shape, size of a dimension, solder joint 40's concrete distribution mode and decide, ensure firmly connect can. The conductive sheet 30 includes a working area and a non-working area, the working area is used for contacting with the outside to form an electrical connection, and the solder joint 40 is disposed in the non-working area of the conductive sheet, and the specific position is not limited. The shape of the conductive sheet is not limited, and the specific shapes of the working area and the non-working area are not limited. Specifically, the solder joint 40 may be disposed near the edge of the conductive sheet 30, or may be disposed in the middle of the conductive sheet 30 so as not to interfere with the external connection. The at least two pads 40 may be symmetrically disposed at opposite ends of the conductive sheet, or may be uniformly distributed at positions close to the edge of the conductive sheet, and the specific arrangement is determined according to the shape and size of the conductive sheet 30. The utility model discloses in, the concrete shape of conducting strip 30 is not limited, can set for according to actual product needs, can be rectangular shape as shown in fig. 5, also can be other shapes such as circular. The utility model discloses an in the embodiment, solder joint 40 is two, and two solder joints 40 set up respectively in the relative both ends of conducting strip 30, and for improving the connection effect, two solder joints 40 can be the symmetry and set up the relative both ends at conducting strip 30. In another embodiment of the present invention, as shown in fig. 5, six solder joints 40 are provided, and the six solder joints 40 are symmetrically disposed at two opposite ends of the conductive sheet 30, in this embodiment, the conductive sheet 30 is in a strip shape, wherein three solder joints 40 are disposed at one end of the conductive sheet 30, and another three solder joints 40 are disposed at the other end of the conductive sheet 30. In another embodiment of the present invention, as shown in fig. 9, the conductive sheet 30 is circular, the number of the solder joints 40 is four, and the four solder joints 40 are uniformly distributed on the conductive sheet 30 near the edge. A certain distance may be maintained between two adjacent welding spots 40. The edge of the solder joint 40 is at a distance from the edge of the conductive sheet 30.

The embodiment of the present invention provides that the shape of the solder joint 40 is not limited, and can be any shape that can be realized in the process, specifically, it can be circular, triangular, square, etc., wherein the shape of the solder joint 40 refers to the shape that appears on the surface of the conductive sheet 30. The size of the solder bumps 40 may be 0.5mm to 0.8 mm. The size of the solder joint 40 refers to the largest dimension in a direction parallel to the surface of the conductive sheet 30. When the spot weld 40 is circular, the dimension refers to the diameter dimension of the spot weld. The proper size can ensure the firm physical connection between the conducting strip 30 and the magnesium alloy body 10, and can control the welding process parameters in a proper range, thereby avoiding the deformation of the connection part and the reduction of the reliability caused by the rise of the temperature requirement of the welding process due to the overlarge size design.

In the embodiment of the present invention, as shown in fig. 10, the conductive sheet 30 includes a substrate 31, the substrate 31 is a magnesium alloy body with higher wear resistance and corrosion resistance, and the surface resistance of the side far away from the magnesium alloy body 10 is lower than 0.5 ohm metal or other conductors. Specifically, the substrate 31 may be at least one of a copper alloy, an aluminum alloy, or a multi-element alloy. The thickness of the base material 31 may be 0.08mm to 0.6mm, and further, the thickness of the base material 31 may be 0.1mm to 0.5 mm.

In the embodiment of the present invention, as shown in fig. 10, the conductive sheet 30 further includes an anticorrosive layer disposed on the surface of the substrate 31. The thickness of the corrosion protection layer may be 0.0005mm to 0.05 mm. Taking the substrate 31 as a copper alloy as an example, the anti-corrosion layer may include a nickel layer 32 disposed on two opposite side surfaces of the substrate 31, and a gold layer 33 disposed on the nickel layer 32 on a side of the substrate 31 away from the magnesium alloy body, that is, the substrate 31 is plated with nickel on both sides and gold on one side, and the gold layer 33 is in contact with other components to form electrical connection.

The utility model discloses in the embodiment, be connected with a plurality of external parts electricity in order to realize magnesium alloy body 10, can set up a plurality of electrical connection point regions according to actual need, set up the conducting strip on a plurality of electrical connection point regional protective layers, utilize the conducting strip to form a plurality of electrical connection points. After 24-hour neutral salt spray test is carried out on the magnesium alloy structural member, the electrical property between any two conducting strips on the magnesium alloy structural member is tested, the resistance is stably less than 0.5 ohm in the static and long-term fretting friction test process, no resonance or harmonic occurs in harmonic analysis, and the performance requirement of a terminal radio frequency antenna can be met.

The utility model discloses in the embodiment, magnesium alloy body 10 specifically can be die-casting magnesium alloy substrate, and magnesium alloy body 10's thickness can be greater than 0.5 mm. Specifically, it may be 0.6mm to 1.2 mm.

The utility model discloses in the embodiment, the whole surface of magnesium alloy body 10 all is provided with protective layer 20, and protective layer 20 can be the rete that current conventional magnesium alloy surface protection technology preparation obtained performance such as have anticorrosion, and protective layer 20 specifically can be become involucra, micro arc oxidation film layer, electrophoresis rete, coating or anodic oxidation rete. Wherein the chemical film is a layer of oxidation-resistant coat formed on the surface of the magnesium alloy part by chemical soaking treatment. The chemical immersion treatment may be a phosphoric acid treatment, or a treatment such as a manganate or vanadate treatment. The thickness of the chemical conversion coating may be 0.0005mm to 0.003 mm. The micro-arc oxidation film layer is a ceramic film which is formed on the surface of the magnesium alloy by adopting a micro-arc oxidation process and takes MgO as a main component. The thickness of the micro-arc oxidation film layer can be 0.002mm-0.012 mm. The anodic oxidation film layer is a coating which takes MgO as a main component and is obtained by carrying out anodic oxidation treatment on the magnesium alloy under the action of certain voltage and current by adopting a common anodic oxidation process. The thickness of the anodic oxide film layer may be 0.005mm-0.01 mm. The paint coating may be a polyurethane coating, a photo-curable paint coating, or the like. The thickness of the paint coating may be 0.005mm to 0.01 mm. The thickness of the electrophoresis film layer is 0.005mm-0.01 mm.

Above-mentioned different kinds of protective layers through corresponding suitable thickness setting, can effectively equalize the connection reliability of anticorrosive effect and solder joint. The film layer has low thickness and poor anti-corrosion effect, and a large amount of corrosion products are easily generated under a long-term test environment, so that the electric connection strength of the magnesium alloy is reduced; the thickness of the film layer is too high, the welding process is unstable, the adjustment difficulty is high, the welding spot cannot stably connect the magnesium alloy structural part with the conducting strip, and the connection reliability of the welding spot cannot be guaranteed.

The embodiment of the utility model provides a magnesium alloy structure through adopting spot welding technology with conducting strip and this body coupling of magnesium alloy in the electricity connection point region, can avoid getting rid of the regional protective layer of whole electricity connection point, effectively completely cuts off the contact of magnesium alloy body and outside air, humid environment, slows down corruption and galvanic corrosion, realizes that the stable electricity of parts such as magnesium alloy structure and mainboard is connected.

As shown in fig. 11, the embodiment of the present invention further provides a terminal 200, where the terminal 200 may be a mobile phone, or an electronic product such as a tablet computer, a notebook, a portable device, an intelligent wearable product, and the terminal 200 includes a housing 201 assembled outside the terminal, and a main board and a battery located inside the housing 201, and the housing 201 may include a display screen assembled in front of the terminal and a rear cover assembled in the rear, and the rear cover is the above-mentioned magnesium alloy structure provided in the embodiment of the present invention. Specifically, the inner side of the rear cover is provided with at least one electric connection point area, the rear cover comprises a magnesium alloy body, a protective layer arranged on the surface of the magnesium alloy body and a conductive sheet arranged on the protective layer of the electric connection point area, the conductive sheet is connected with the magnesium alloy body through a welding point, and the welding point sequentially penetrates through the conductive sheet and the protective layer and is partially embedded into the magnesium alloy body. As shown in fig. 12, a plurality of electrical connection points 113 may be disposed on the rear cover 101, each electrical connection point 113 is formed by a conductive sheet fixed on the surface protection layer of the magnesium alloy body, and the rear cover 101 is electrically connected to the main board 12, the touch display 13, the antenna 14, and other components through each electrical connection point 113.

In another embodiment of the present invention, the housing 201 may also include a middle frame, and the middle frame may also be the magnesium alloy structural member provided in the embodiment of the present invention. In the utility model discloses in other embodiments, terminal 200 also can be flexible terminal, and flexible terminal includes flexible display screen and display screen backup pad, and the display screen backup pad does the utility model provides an above-mentioned magnesium alloy structure that provides.

Claims

1. The magnesium alloy structural member is provided with at least one electric connection point area and is characterized by comprising a magnesium alloy body, a protective layer arranged on the surface of the magnesium alloy body and a conducting strip arranged on the protective layer of the electric connection point area, wherein the conducting strip is connected with the magnesium alloy body through a welding spot and is used as an electric connection point to be in contact with the outside to form electric connection.

2. The magnesium alloy structural member of claim 1, wherein the weld comprises at least two.

3. The magnesium alloy structural member of claim 2, wherein the conductive sheet comprises an active area and a non-active area, the active area is used for contacting with the outside to form an electrical connection, and the at least two solder joints are arranged on the non-active area of the conductive sheet.

4. The magnesium alloy structural member of claim 1, wherein the size of the weld is 0.5mm to 0.8 mm.

5. The magnesium alloy structural member of claim 1, wherein the solder joint penetrates the conductive sheet and the protective layer and is partially embedded in the magnesium alloy body.

6. The magnesium alloy structural member of claim 5, wherein the depth of the solder joint embedded into the magnesium alloy body is greater than 0.1mm and less than 0.5 mm.

7. The magnesium alloy structural member as claimed in claim 1, wherein an end surface of the solder joint exposed outside is flush with the surface of the conductive sheet or is higher than the surface of the conductive sheet by a first height, and the first height is less than 0.5 mm.

8. The magnesium alloy structure of claim 1, wherein the electrically conductive sheet comprises a substrate that is a conductor having a higher wear and corrosion resistance than the magnesium alloy body and a surface resistance of less than 0.5 ohms on a side away from the magnesium alloy body.

9. The magnesium alloy structural member of claim 8, wherein the substrate is a copper alloy, an aluminum alloy, or a multi-element alloy.

10. The magnesium alloy structural member of claim 8, wherein the substrate has a thickness of 0.08mm to 0.6 mm.

11. The magnesium alloy structural member of claim 8, wherein the conductive sheet further comprises an anti-corrosion layer disposed on the surface of the substrate, the anti-corrosion layer having a thickness of 0.0005mm to 0.05 mm.

12. The magnesium alloy structural member of claim 1, wherein the protective layer is a chemical film, a micro-arc oxide film, an electrophoretic film, a paint coating, or an anodic oxide film.

13. The magnesium alloy structural member of claim 12, wherein the chemical conversion coating has a thickness of 0.0005mm to 0.003 mm.

14. The magnesium alloy structural member of claim 12, wherein the micro-arc oxide film layer has a thickness of 0.002mm to 0.012 mm.

15. The magnesium alloy structural member of claim 12, wherein the thickness of the electrophoretic film layer, the paint coating layer, and the anodic oxide film layer is 0.005mm to 0.01 mm.

16. A terminal comprising the magnesium alloy structural member as set forth in any one of claims 1 to 15, wherein the magnesium alloy structural member is electrically connected to a main board of the terminal through the conductive sheet.

17. The terminal of claim 16, wherein the magnesium alloy structural member is a center frame, a back cover, or a display support panel.

18. A terminal is characterized by comprising a shell assembled on the outer side of the terminal and a mainboard positioned in the shell, wherein the shell comprises a display screen assembled on the front side of the terminal and a rear cover assembled on the rear side of the terminal, at least one electric connection point area is arranged on the inner side of the rear cover, the rear cover comprises a magnesium alloy body, a protective layer arranged on the surface of the magnesium alloy body and a conducting strip arranged on the protective layer of the electric connection point area, the conducting strip is connected with the magnesium alloy body through at least two welding points, the conducting strip comprises a working area and a non-working area, the at least two welding points are arranged in the non-working area of the conducting strip, and the working area of the conducting strip is in contact with the mainboard and the electric connection points on the display screen to form electric connection.