Composite etching solution for coarsening stainless steel and coarsening method

Abstract

The invention relates to a composite etching solution for stainless steel coarsening and a coarsening method, and relates to the technical field of injection molding.The composite etching solution comprises a first etching solution, a second etching solution and a third etching solution, the first etching solution comprises 300-500 g / L of first inorganic acid, 20-120 g / L of first organic acid, 20-40 g / L of ferric salt and 10-30 g / L of corrosion inhibitor; and the second etching solution comprises 300-500 g / L of second inorganic acid, 10-30 g / L of second organic acid, 10-20 g / L of sulfate and 1-10 g / L of boron additive. According to the composite etching solution provided by the invention, a dual-scale porous structure of micron pores (1-10 microns) and nano pores (50-200 nm) can be synchronously formed on the surface of stainless steel when the stainless steel is coarsened by utilizing a matching effect among the etching solutions, and the fine parts of the micropores are filled with resin during injection molding, so that firm joint of the resin and the stainless steel is formed; therefore, the connecting capacity of stainless steel and resin is improved.

Description

Technical Field

[0001] This invention relates to the field of injection molding technology, and more specifically to a composite etching solution and roughening method for roughening stainless steel. Background Technology

[0002] Currently, composites of metals and polymers are widely used in home appliances, digital products, automobile manufacturing, and industrial manufacturing. They are usually made by insert injection molding, which encapsulates the metal part with polymer material through injection molding in one step, greatly improving production efficiency. However, this molding method results in poor bonding strength between the resin and stainless steel, which is not conducive to long-term use.

[0003] Currently, roughening is often used to improve the bonding performance between stainless steel and resin. Among them, the roughening of stainless steel surface mainly relies on a single chemical immersion method (which only forms micron pores) or an electrochemical method (which only generates nanostructures), which makes it difficult to achieve the controllable construction of micro-nano hierarchical porous structures. Composite structures can significantly increase the density of surface active sites, enhance coating adhesion and catalytic performance.

[0004] Chemical immersion can uniformly treat workpieces with complex geometries (such as internal cavities and blind hole structures) without having to consider the problem of uneven surface treatment caused by electrode distribution; chemical immersion does not consume electricity, and its long-term operating cost is significantly lower than that of electrolysis.

[0005] However, the current roughening process cannot ensure effective bonding between the resin and stainless steel due to the poor etching effect of the etching solution used. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a composite etching solution and roughening method for roughening stainless steel, so as to solve the defect of poor connection effect when stainless steel is injection molded.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a composite etching solution for roughening stainless steel, the composite etching solution comprising:

[0009] The first etching solution comprises: 300-500 g / L of a first inorganic acid, 20-120 g / L of a first organic acid, 20-40 g / L of an iron salt, and 10-30 g / L of a corrosion inhibitor;

[0010] The second etching solution comprises: 300-500 g / L of a second inorganic acid, 10-30 g / L of a second organic acid, 10-20 g / L of a sulfate, and 1-10 g / L of a boron additive.

[0011] The composite etching solution provided by this invention utilizes the synergistic effect between etching solutions to simultaneously form a dual-scale porous structure of micron-sized pores (1-10μm) and nano-sized pores (50-200nm) on the surface of stainless steel during roughening. During injection molding, the resin fills into the details of the micropores, forming a strong bond between the resin and the stainless steel, thereby improving the bonding ability between the stainless steel and the resin.

[0012] As a preferred embodiment of the present invention, the first inorganic acid includes sulfuric acid and / or phosphoric acid.

[0013] Preferably, the first organic acid includes one or a combination of at least two of citric acid, tartaric acid, or aminosulfonic acid.

[0014] Preferably, the iron salt comprises one or a combination of at least two of ferric chloride, ferric sulfate, or ferric nitrate.

[0015] Preferably, the corrosion inhibitor comprises one or a combination of at least two of polyethylene glycol 2000, polyethylene glycol 6000, or polyethylene glycol 20000.

[0016] As a preferred embodiment of the present invention, the second inorganic acid includes sulfuric acid and / or phosphoric acid.

[0017] Preferably, the second organic acid includes one or a combination of at least two of citric acid, tartaric acid, or aminosulfonic acid.

[0018] Preferably, the sulfate includes one or a combination of at least two of sodium persulfate, sodium sulfite, sodium thiosulfate, or sodium sulfate.

[0019] Preferably, the boron auxiliaries include one or a combination of at least two of sodium borate, boric acid, or sodium borohydride.

[0020] Secondly, the present invention provides a method for roughening stainless steel, the method comprising:

[0021] Stainless steel is subjected to pretreatment, first etching, and second etching in sequence to obtain roughened stainless steel.

[0022] The first etching is performed using the first etching solution as described in the first aspect;

[0023] The second etching is performed using the second etching solution as described in the first aspect.

[0024] As a preferred embodiment of the present invention, the pretreatment includes: degreasing and washing in sequence.

[0025] As a preferred technical solution of the present invention, the degreasing includes: treating with an alkaline degreasing agent at 45-55℃ for 170-200s.

[0026] Preferably, the concentration of the alkaline degreasing agent is 55-65 g / L.

[0027] Preferably, the washing time is 30-60 seconds.

[0028] As a preferred embodiment of the present invention, the air stirring pressure during the first etching is 0.2-0.3 m. 3 / (m 2 ·min).

[0029] Preferably, the temperature of the first etching is 95-100°C.

[0030] Preferably, the first etching time is 1-3 minutes.

[0031] As a preferred embodiment of the present invention, the first etching is performed at least once.

[0032] As a preferred embodiment of the present invention, the air stirring pressure during the second etching is 0.2-0.3 m. 3 / (m 2 ·min).

[0033] Preferably, the temperature of the second etching is 95-100°C.

[0034] Preferably, the second etching time is 3-5 minutes.

[0035] As a preferred embodiment of the present invention, the second etching is performed at least once.

[0036] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0037] (1) The composite etching solution provided by the present invention, in the first etching solution, ferric ions oxidize and dissolve metal ions such as iron, chromium and nickel on the product surface to form initial etching pits, the corrosion inhibitor selectively adsorbs on the grain boundary or specific crystal surface, resulting in anisotropic etching, promoting the directional expansion of micron-sized pores, and the organic acid enhances the activity of the solution to ensure the uniformity of etching.

[0038] (2) The composite etching solution provided by the present invention, in the second etching solution, thiosulfate salt generates elemental sulfur under acidic conditions, which reacts with iron on the stainless steel surface to form iron sulfide product, and then is uniformly deposited on the product surface through the adsorption of corrosion inhibitor and complexing agent to form nanopores.

[0039] (3) In this invention, when multiple etchings are performed, the layer-by-layer expansion and uniform distribution of holes are achieved through reaction kinetic control. Attached Figure Description

[0040] Figure 1 This is a SEM image of the roughened surface of Embodiment 1 of the present invention;

[0041] Figure 2 This is a SEM image of the roughened surface (×500) of Embodiment 1 of the present invention;

[0042] Figure 3 This is a SEM image of the roughened surface (×30k) of Embodiment 1 of the present invention.

[0043] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0044] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0045] Currently, composites of metals and polymers are widely used in home appliances, digital products, automobile manufacturing, and industrial manufacturing. They are typically produced using injection molding, a method that encapsulates a metal part with polymer material in a single injection molding process, significantly improving production efficiency. However, this molding method results in poor bonding strength between the resin and stainless steel, which is detrimental to long-term use. Although existing technologies use roughening to improve the bonding effect, the bonding effect between stainless steel and resin remains poor even after roughening. Therefore, this invention designs an etching solution to roughen stainless steel, thereby improving the roughening effect and ultimately enhancing the bonding effect between stainless steel and resin, as detailed below:

[0046] I. This embodiment provides a composite etching solution for roughening stainless steel, the composite etching solution comprising:

[0047] The first etching solution comprises: 300-500 g / L of a first inorganic acid, 20-120 g / L of a first organic acid, 20-40 g / L of an iron salt, and 10-30 g / L of a corrosion inhibitor;

[0048] The second etching solution comprises: 300-500 g / L of a second inorganic acid, 10-30 g / L of a second organic acid, 10-20 g / L of a sulfate, and 1-10 g / L of a boron additive.

[0049] In this invention, the stainless steel used is the commonly used stainless steel in the injection molding field, such as 304 stainless steel and 316L stainless steel.

[0050] In this invention, the concentration of the first inorganic acid in the first etching solution is 300-500 g / L, for example, it can be 300 g / L, 320 g / L, 340 g / L, 360 g / L, 380 g / L, 400 g / L, 420 g / L, 440 g / L, 460 g / L, 480 g / L or 500 g / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also acceptable.

[0051] In this invention, the concentration of the first organic acid in the first etching solution is 20-120 g / L, for example, it can be 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L or 120 g / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also acceptable.

[0052] In this invention, the concentration of iron salt in the first etching solution is 20-40 g / L, for example, it can be 20 g / L, 22 g / L, 24 g / L, 26 g / L, 28 g / L, 30 g / L, 32 g / L, 34 g / L, 36 g / L, 38 g / L or 40 g / L, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0053] In this invention, the concentration of the corrosion inhibitor in the first etching solution is 10-30 g / L, for example, it can be 10 g / L, 12 g / L, 14 g / L, 16 g / L, 18 g / L, 20 g / L, 22 g / L, 24 g / L, 26 g / L, 28 g / L or 30 g / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also acceptable.

[0054] The first inorganic acid includes sulfuric acid and / or phosphoric acid.

[0055] The first organic acid includes one or a combination of at least two of citric acid, tartaric acid, or aminosulfonic acid, preferably aminosulfonic acid.

[0056] In this invention, the combination of the first organic acids can be selected as: a combination of citric acid and tartaric acid, a combination of tartaric acid and aminosulfonic acid, or a combination of citric acid and aminosulfonic acid.

[0057] The iron salt includes one or a combination of at least two of ferric chloride, ferric sulfate, or ferric nitrate.

[0058] In this invention, the combination of iron salts can be selected as a combination of ferric chloride and ferric sulfate, a combination of ferric sulfate and ferric nitrate, or a combination of ferric nitrate and ferric chloride.

[0059] The corrosion inhibitor includes one or a combination of at least two of polyethylene glycol 2000, polyethylene glycol 6000, or polyethylene glycol 20000.

[0060] In this invention, the combination of corrosion inhibitors can be selected as: a combination of polyethylene glycol 2000 and polyethylene glycol 6000, a combination of polyethylene glycol 6000 and polyethylene glycol 20000, or a combination of polyethylene glycol 2000 and polyethylene glycol 20000.

[0061] In this invention, the concentration of the second inorganic acid in the second etching solution is 300-500 g / L, for example, it can be 300 g / L, 320 g / L, 340 g / L, 360 g / L, 380 g / L, 400 g / L, 420 g / L, 440 g / L, 460 g / L, 480 g / L or 500 g / L, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also acceptable.

[0062] In this invention, the concentration of the second organic acid in the second etching solution is 10-30 g / L, for example, it can be 10 g / L, 12 g / L, 14 g / L, 16 g / L, 18 g / L, 20 g / L, 22 g / L, 24 g / L, 26 g / L, 28 g / L or 30 g / L, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0063] In this invention, the concentration of sulfate in the second etching solution is 10-20 g / L, for example, it can be 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L or 20 g / L, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0064] In this invention, the concentration of boron additive in the second etching solution is 1-10 g / L, for example, it can be 1 g / L, 1.9 g / L, 2.8 g / L, 3.7 g / L, 4.6 g / L, 5.5 g / L, 6.4 g / L, 7.3 g / L, 8.2 g / L, 9.1 g / L or 10 g / L, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0065] The second inorganic acid includes sulfuric acid and / or phosphoric acid.

[0066] The second organic acid includes one or a combination of at least two of citric acid, tartaric acid, or aminosulfonic acid, preferably aminosulfonic acid.

[0067] In this invention, the combination of the second organic acid can be selected as: a combination of citric acid and tartaric acid, a combination of tartaric acid and aminosulfonic acid, or a combination of citric acid and aminosulfonic acid.

[0068] The sulfate includes one or a combination of at least two of sodium persulfate, sodium sulfite, sodium thiosulfate, or sodium sulfate.

[0069] In this invention, the combination of sulfates can be selected as: a combination of sodium persulfate and sodium sulfite, a combination of sodium sulfite and sodium thiosulfate, a combination of sodium thiosulfate and sodium sulfate, etc.

[0070] The boron auxiliaries include one or a combination of at least two of sodium borate, boric acid, or sodium borohydride.

[0071] In this invention, the combination of boron additives can be selected as a combination of sodium dihydrogen borate and boric acid, a combination of boric acid and sodium borohydride, or a combination of sodium dihydrogen borate and sodium borohydride.

[0072] II. This embodiment provides a roughening method for stainless steel, the roughening method comprising:

[0073] Stainless steel is subjected to pretreatment, first etching, and second etching in sequence to obtain roughened stainless steel.

[0074] The first etching is performed using a first etching solution;

[0075] The second etching is performed using a second etching solution.

[0076] The pretreatment includes degreasing and washing in sequence.

[0077] The degreasing includes: treating with an alkaline degreasing agent at 45-55℃ for 170-200s. The temperature can be, for example, 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃, 54℃, or 55℃, and the degreasing time is 170-200s, for example, 170s, 173s, 176s, 179s, 182s, 185s, 188s, 191s, 194s, 197s, or 200s, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0078] In this invention, alkaline degreasing agent refers to commonly used degreasing agents in the art, such as alkaline solutions, such as sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, etc.

[0079] The concentration of the alkaline degreasing agent is 55-65 g / L, for example, it can be 55 g / L, 56 g / L, 57 g / L, 58 g / L, 59 g / L, 60 g / L, 61 g / L, 62 g / L, 63 g / L, 64 g / L or 65 g / L, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0080] The washing time is 30-60 seconds, for example, it can be 30 seconds, 33 seconds, 36 seconds, 39 seconds, 42 seconds, 45 seconds, 48 ​​seconds, 51 seconds, 54 seconds, 57 seconds or 60 seconds, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0081] In the first etching process, the air stirring pressure is 0.2-0.3 m. 3 / (m 2 (·min), for example, could be 0.2m 3 / (m 2 ·min), 0.21m 3 / (m 2 ·min), 0.22m 3 / (m 2 ·min), 0.23m 3 / (m 2 ·min), 0.24m 3 / (m 2 ·min), 0.25m 3 / (m 2 ·min), 0.26m 3 / (m 2 ·min), 0.27m 3 / (m 2 ·min), 0.28m 3 / (m 2 ·min), 0.29m 3 / (m 2 ·min) or 0.3m 3 / (m 2 (e.g., min), but not limited to the listed values; other unlisted values ​​within this range also meet the requirements.

[0082] The temperature of the first etching is 95-100℃, for example, it can be 95℃, 95.5℃, 96℃, 96.5℃, 97℃, 97.5℃, 98℃, 98.5℃, 99℃, 99.5℃ or 100℃, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0083] The first etching time is 1-3 min, for example, it can be 1 min, 1.2 min, 1.4 min, 1.6 min, 1.8 min, 2 min, 2.2 min, 2.4 min, 2.6 min, 2.8 min or 3 min, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0084] The first etching is performed at least once, for example, once, twice, three times, four times, five times, six times, seven times, eight times, nine times, ten times or eleven times, but not limited to the listed values. Other unlisted values ​​within this range are also acceptable, and preferably more than three times.

[0085] In the second etching process, the air stirring pressure is 0.2-0.3 m. 3 / (m 2 (·min), for example, could be 0.2m 3 / (m 2 ·min), 0.21m 3 / (m 2 ·min), 0.22m 3 / (m 2 ·min), 0.23m 3 / (m 2 ·min), 0.24m 3 / (m 2 ·min), 0.25m 3 / (m 2 ·min), 0.26m 3 / (m 2 ·min), 0.27m 3 / (m 2 ·min), 0.28m 3 / (m 2 ·min), 0.29m 3 / (m 2 ·min) or 0.3m 3 / (m 2 (e.g., min), but not limited to the listed values; other unlisted values ​​within this range also meet the requirements.

[0086] The second etching temperature is 95-100℃, for example, it can be 95℃, 95.5℃, 96℃, 96.5℃, 97℃, 97.5℃, 98℃, 98.5℃, 99℃, 99.5℃ or 100℃, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0087] The second etching time is 3-5 minutes, for example, it can be 3 minutes, 3.2 minutes, 3.4 minutes, 3.6 minutes, 3.8 minutes, 4 minutes, 4.2 minutes, 4.4 minutes, 4.6 minutes, 4.8 minutes or 5 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0088] The second etching is performed at least once, for example, once, twice, three times, four times, five times, six times, seven times, eight times, nine times, ten times or eleven times, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable, and preferably more than three times.

[0089] III. To illustrate the roughening effect achievable by the composite etching solution for roughening stainless steel provided by this invention, the following practical example is used for explanation:

[0090] Example 1

[0091] This embodiment provides a method for roughening stainless steel, as detailed below:

[0092] Stainless steel is subjected to pretreatment, first etching, and second etching in sequence to obtain roughened stainless steel.

[0093] The pretreatment includes: sequential degreasing and washing; the degreasing includes: treatment with an alkaline degreasing agent at 50°C for 180 seconds; the concentration of the alkaline degreasing agent is 58 g / L; the washing time is 40 seconds;

[0094] The first etching is performed using a first etching solution; the first etching solution comprises: a first inorganic acid (sulfuric acid) 400 g / L, a first organic acid (citric acid) 40 g / L, an iron salt (ferric chloride) 30 g / L, and a corrosion inhibitor (polyethylene glycol 6000) 20 g / L; the air stirring pressure during the first etching is 0.25 m. 3 / (m 2 The etching process was performed at a temperature of 98°C for 2 minutes; the first etching was repeated 3 times.

[0095] The second etching is performed using a second etching solution; the second etching solution comprises: a second inorganic acid (sulfuric acid) of 400 g / L, a second organic acid (tartaric acid) of 20 g / L, a sulfate (sodium thiosulfate) of 18 g / L, and a boron additive (sodium dihydrogen borate) of 4 g / L; the air stirring pressure during the second etching is 0.25 m. 3 / (m 2 The etching process was carried out at a temperature of 98°C for 4 minutes; the second etching was performed three times.

[0096] Example 2

[0097] This embodiment provides a method for roughening stainless steel, as detailed below:

[0098] Stainless steel is subjected to pretreatment, first etching, and second etching in sequence to obtain roughened stainless steel.

[0099] The pretreatment includes: sequential degreasing and washing; the degreasing includes: treatment with an alkaline degreasing agent at 50°C for 190 seconds; the concentration of the alkaline degreasing agent is 55 g / L; the washing time is 50 seconds.

[0100] The first etching is performed using a first etching solution; the first etching solution comprises: a first inorganic acid (sulfuric acid) of 400 g / L, a first organic acid (citric acid) of 30 g / L, an iron salt (ferric sulfate) of 35 g / L, and a corrosion inhibitor (polyethylene glycol 6000) of 25 g / L; the air stirring pressure during the first etching is 0.28 m. 3 / (m 2 The etching process was performed at a temperature of 97°C for 2 minutes; the first etching was repeated 3 times.

[0101] The second etching is performed using a second etching solution; the second etching solution comprises: a second inorganic acid (phosphoric acid) 400 g / L, a second organic acid (tartaric acid) 25 g / L, a sulfate (sodium thiosulfate) 15 g / L, and a boron additive (boric acid) 7 g / L; the air stirring pressure during the second etching is 0.22 m. 3 / (m 2 The etching process was carried out at a temperature of 97°C for 4 minutes; the second etching was performed three times.

[0102] Example 3

[0103] This embodiment provides a method for roughening stainless steel, as detailed below:

[0104] Stainless steel is subjected to pretreatment, first etching, and second etching in sequence to obtain roughened stainless steel.

[0105] The pretreatment includes: sequential degreasing and washing; the degreasing includes: treatment with an alkaline degreasing agent at 55°C for 170 seconds; the concentration of the alkaline degreasing agent is 50 g / L; the washing time is 30 seconds.

[0106] The first etching is performed using a first etching solution; the first etching solution comprises: a first inorganic acid (sulfuric acid) of 500 g / L, a first organic acid (citric acid) of 20 g / L, an iron salt (ferric nitrate) of 20 g / L, and a corrosion inhibitor (polyethylene glycol 20000) of 30 g / L; the air stirring pressure during the first etching is 0.2 m. 3 / (m 2 The etching process was performed at a temperature of 100°C for 1 minute; the first etching was repeated twice.

[0107] The second etching is performed using a second etching solution; the second etching solution comprises: a second inorganic acid (sulfuric acid) 300 g / L, a second organic acid (sulfamic acid) 30 g / L, a sulfate (sodium sulfate) 20 g / L, and a boron additive (sodium borohydride) 1 g / L; the air stirring pressure during the second etching is 0.2 m. 3 / (m 2 The etching process is carried out at a temperature of 100°C for 3 minutes; the second etching is performed twice.

[0108] Example 4

[0109] This embodiment provides a method for roughening stainless steel, as detailed below:

[0110] Stainless steel is subjected to pretreatment, first etching, and second etching in sequence to obtain roughened stainless steel.

[0111] The pretreatment includes: sequential degreasing and washing; the degreasing includes: treatment with an alkaline degreasing agent at 45°C for 200 seconds; the concentration of the alkaline degreasing agent is 60 g / L; the washing time is 60 seconds.

[0112] The first etching is performed using a first etching solution; the first etching solution comprises: a first inorganic acid (sulfuric acid) of 300 g / L, a first organic acid (sulfamic acid) of 120 g / L, an iron salt (ferric chloride) of 40 g / L, and a corrosion inhibitor (polyethylene glycol 2000) of 10 g / L; the air stirring pressure during the first etching is 0.3 m. 3 / (m 2 The etching process is carried out at a temperature of 95°C for 3 minutes; the first etching is performed once.

[0113] The second etching is performed using a second etching solution; the second etching solution comprises: a second inorganic acid (sulfuric acid) 500 g / L, a second organic acid (sulfamic acid) 10 g / L, a sulfate (sodium sulfite) 10 g / L, and a boron additive (sodium borohydride) 10 g / L; the air stirring pressure during the second etching is 0.3 m. 3 / (m 2 The etching process is carried out at a temperature of 95°C for 5 minutes; the second etching is performed once.

[0114] Example 5

[0115] The only difference from Example 1 is that the first organic acid, citric acid, is replaced with an equal concentration of aminosulfonic acid.

[0116] Example 6

[0117] The only difference from Example 1 is that the second organic acid, tartaric acid, is replaced with aminosulfonic acid of the same concentration.

[0118] Example 7

[0119] The only difference from Example 1 is that the first organic acid, i.e., citric acid, and the second organic acid, i.e., tartaric acid, are replaced with aminosulfonic acid of equal concentration.

[0120] Example 8

[0121] The only difference from Example 1 is that the first organic acid, citric acid, is replaced with acetic acid of the same concentration.

[0122] Example 9

[0123] The only difference from Example 1 is that the second organic acid, tartaric acid, is replaced with acetic acid of the same concentration.

[0124] Example 10

[0125] The only difference from Example 1 is that the first inorganic acid, sulfuric acid, is replaced with hydrochloric acid of the same concentration.

[0126] Example 11

[0127] The only difference from Example 1 is that the second inorganic acid, sulfuric acid, is replaced with hydrochloric acid of the same concentration.

[0128] Example 12

[0129] The only difference from Example 1 is that polyethylene glycol 6000 is replaced with an equal concentration of 2-mercaptobenzimidazole.

[0130] Example 13

[0131] The only difference from Example 1 is that polyethylene glycol 6000 is replaced with thiourea of ​​equal concentration.

[0132] Example 14

[0133] The only difference from Example 1 is that the concentration of iron salt is 5 g / L.

[0134] Example 15

[0135] The only difference from Example 1 is that the concentration of iron salt is 50 g / L.

[0136] Example 16

[0137] The only difference from Example 1 is that the concentration of the corrosion inhibitor is 5 g / L.

[0138] Example 17

[0139] The only difference from Example 1 is that the concentration of the corrosion inhibitor is 50 g / L.

[0140] Example 18

[0141] The only difference from Example 1 is that the concentration of the second inorganic acid is 100 g / L.

[0142] Example 19

[0143] The only difference from Example 1 is that the concentration of sulfate is 5 g / L.

[0144] Example 20

[0145] The only difference from Example 1 is that the concentration of sulfate is 25 g / L.

[0146] Example 21

[0147] The only difference from Example 1 is that the concentration of boron additive is 0.5 g / L.

[0148] Example 22

[0149] The only difference from Example 1 is that the concentration of boron additive is 20 g / L.

[0150] Comparative Example 1

[0151] The only difference from Example 1 is that the iron salt, i.e., ferric chloride, is replaced with an equal amount of copper chloride.

[0152] Comparative Example 2

[0153] The only difference from Example 1 is that the iron salt, i.e., ferric chloride, is replaced with an equal amount of ferrous chloride.

[0154] Comparative Example 3

[0155] The only difference from Example 1 is that the sulfate, i.e., sodium thiosulfate, is replaced with an equal amount of sodium chloride.

[0156] Comparative Example 4

[0157] The only difference from Example 1 is that the boron additive, sodium dihydrogen borate, is replaced with an equal amount of EDTA.

[0158] Comparative Example 5

[0159] The only difference from Example 1 is that the boron additive, i.e., sodium dihydrogen borate, is replaced with an equal amount of copper chloride.

[0160] Comparative Example 6

[0161] The only difference from Example 1 is that the boron auxiliary, i.e., sodium dihydrogen borate, is replaced with an equal amount of acetic acid.

[0162] Comparative Example 7

[0163] The only difference from Example 1 is that the boron auxiliary, i.e., sodium dihydrogen borate, is replaced with an equal amount of citric acid.

[0164] The roughening methods described in the above embodiments and comparative examples were used to roughen 316L stainless steel. After roughening, corrosion, thrust, and residual adhesive content were analyzed on the surface. The results are shown in Table 1 below. The SEM image of the roughened surface obtained in Example 1 is detailed in [Table 1]. Figure 1 The image shows the junction of stainless steel and plastic (top), the Keyence VHX-7000 measuring residual adhesive (bottom), and a magnified view of the product surface. Figure 2 and Figure 3 As shown.

[0165] Corrosion detection: The instrument is a micrometer. First measurement (before roughening): The thickness of the untreated product is clamped with a micrometer and the data is recorded. Second measurement (after roughening): After the product is roughened, the thickness at the same position is clamped with a micrometer again and the data is recorded. Corrosion calculation: The thickness of the first measurement is subtracted from the thickness of the second measurement, and the difference is the corrosion amount.

[0166] Acceptable standard: The corrosion amount should be between 0.015 and 0.035 mm. Within this range, it indicates that the material surface has good uniformity.

[0167] Thrust test: Use a thrust gauge, model: YH-9000-2T, test force: 200kg, accuracy class: 0.5, test speed: 10mm / min, thrust standard > 2000N to be qualified;

[0168] Residual adhesive analysis: The bonding area of ​​the thrust product was inspected using the Keyence VHX-7000 digital microscope system. The selected area was 8×2.5mm (length×width), which is the interface between the injection molding material and the stainless steel.

[0169] Optical Recognition and Data Acquisition: The system automatically identifies the state of the bonding surface using photosensitive technology: when injection molding material remains on the stainless steel surface, it is displayed as a black area; areas without residue are displayed as red. The software automatically calculates the area ratio of the black area (residual adhesive) to the red area (no adhesive). When the residual adhesive area ratio is >50%, it is determined that micron-pores and nano-pores coexist; the higher the residual adhesive area ratio, the denser the micron-nano-pore structure. Principle: During the high-temperature and high-pressure injection molding process, molten plastic particles achieve a firm bond through two types of pore structures.

[0170] Micron-sized holes: provide macroscopic anchoring points, allowing the plastic to initially embed into the substrate surface;

[0171] Nanopores: exhibit a honeycomb-like microstructure, which enhances the bonding strength through mechanical interlocking effects;

[0172] When external forces are applied, the nanoporous structure forms a "mechanical tenon and mortise" effect, which significantly improves the interfacial adhesion. The larger the residual adhesive area, the denser the nanoporous distribution and the higher the bonding reliability.

[0173] Table 1

[0174]

[0175] Based on Table 1 and a comprehensive analysis of Examples 1-2, it can be seen that with the increase of the corrosion inhibitor in the first etching solution and the increase of the sulfate in the second etching solution, the thickness loss of the product decreases and the thrust increases.

[0176] Analysis of Example 1 and Comparative Example shows that in Comparative Example 1, replacing iron salt with ferric sulfate reduces the thickness of the product and decreases the surface thrust. In Comparative Example 3, replacing the sulfate in the second etching solution with sodium chloride results in no nanopores forming on the product surface. Furthermore, when other components are replaced, the roughening effect of the present invention is obviously not achieved.

[0177] Examples 3 and 4 show that as the number of roughening cycles decreases, the amount of corrosion and thrust on the material surface also gradually decreases.

[0178] Examples 5-7 show that when the first etching solution, the second etching solution, and the first and second etching solutions are replaced with organic acids and aminosulfonic acid, compared with Example 1, the amount of corrosion is reduced and the thrust is increased.

[0179] Examples 8-9 show that replacing the organic acid in the first and second etching solutions with acetic acid results in uneven corrosion of the material surface; compared with Example 1, both the amount of corrosion and the thrust are reduced.

[0180] Examples 10-11 show that replacing the inorganic acid in the first and second etching solutions with hydrochloric acid increases the corrosion rate. Under high temperature conditions, hydrochloric acid is easily volatilized, generating a large amount of acidic gas. Compared with Example 1, the corrosion amount increases and the thrust decreases.

[0181] Examples 12-13 show that when the corrosion inhibitors in the first and second etching solutions are replaced with 2-mercaptobenzimidazole and thiourea, the thiol group (-SH) in the 2-mercaptobenzimidazole molecule and the nitrogen atom in the benzimidazole ring can form a stable chemical adsorption layer with the metal surface, thereby significantly inhibiting corrosion; compared with Example 1, the corrosion amount is lower; the sulfur atoms and nitrogen atoms in the thiourea molecule can be adsorbed on the metal surface through coordination to form a protective film and inhibit the corrosion rate; compared with Example 1, the corrosion amount is reduced and the thrust is smaller.

[0182] Examples 14-15 show that the iron salt concentrations of the first etching solution are 5 g / L and 50 g / L. At 5 g / L, the etching rate decreases significantly because there are insufficient active iron ions (Fe³⁺), which slows down the metal dissolution reaction. Compared with Example 1, both the corrosion amount and the thrust decrease. Conversely, increasing the concentration to 50 g / L accelerates the etching rate. Compared with Example 1, the corrosion amount increases and the thrust decreases.

[0183] Examples 16-17 show that at corrosion inhibitor concentrations of 5 g / L and 50 g / L, the etching rate is significantly increased at 5 g / L, leading to a faster metal dissolution reaction; compared to Example 1, the corrosion amount increases and the thrust decreases; conversely, increasing the concentration to 50 g / L inhibits the etching rate; compared to Example 1, the corrosion amount decreases and the thrust decreases.

[0184] As shown in Example 18, when the inorganic acid concentration is 100 g / L, the sulfuric acid concentration is reduced from 400 g / L to 100 g / L, which significantly reduces the acidity of the etching solution, resulting in a significant decrease in the etching rate; compared with Example 1, both the corrosion amount and thrust are reduced.

[0185] Examples 19-20 show that when the sulfate concentration is 5 g / L and 25 g / L, the oxidizing power of the etching solution is weakened at 5 g / L, resulting in a decrease in etching rate; compared with Example 1, both corrosion amount and thrust are reduced. At 25 g / L, the oxidizing power of the etching solution is enhanced, the etching rate is accelerated, but the surface uniformity is worse; compared with Example 1, the corrosion amount is increased and the thrust is reduced.

[0186] Examples 21-22 show that at 0.5 g / L, the buffering capacity of the etching solution is weakened, the acidity is enhanced, the metal dissolution reaction is too fast, and the pH fluctuates, resulting in uneven corrosion on the material surface; compared with Example 1, the corrosion amount is greater and the thrust is smaller. At 20 g / L, the buffering capacity of the etching solution is enhanced, the metal dissolution is too slow, and the passivation film on the metal surface increases; compared with Example 1, both the corrosion amount and the thrust are smaller.

[0187] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0188] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0189] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A composite etching solution for roughening stainless steel, characterized in that, The composite etching solution comprises: The first etching solution comprises: 300-500 g / L of a first inorganic acid, 20-120 g / L of a first organic acid, 20-40 g / L of an iron salt, and 10-30 g / L of a corrosion inhibitor; The second etching solution comprises: 300-500 g / L of a second inorganic acid, 10-30 g / L of a second organic acid, 10-20 g / L of a sulfate, and 1-10 g / L of a boron additive.

2. The composite etching solution as described in claim 1, characterized in that, The first inorganic acid includes: sulfuric acid and / or phosphoric acid; Preferably, the first organic acid includes one or a combination of at least two of citric acid, tartaric acid, or aminosulfonic acid; Preferably, the iron salt comprises one or a combination of at least two of ferric chloride, ferric sulfate, or ferric nitrate; Preferably, the corrosion inhibitor comprises one or a combination of at least two of polyethylene glycol 2000, polyethylene glycol 6000, or polyethylene glycol 20000.

3. The composite etching solution as described in claim 1, characterized in that, The second inorganic acid includes: sulfuric acid and / or phosphoric acid; Preferably, the second organic acid includes one or a combination of at least two of citric acid, tartaric acid, or aminosulfonic acid; Preferably, the sulfate comprises one or a combination of at least two of sodium persulfate, sodium sulfite, sodium thiosulfate, or sodium sulfate; Preferably, the boron auxiliaries include one or a combination of at least two of sodium borate, boric acid, or sodium borohydride.

4. A method for roughening stainless steel, characterized in that, The coarsening method includes: Stainless steel is subjected to pretreatment, first etching, and second etching in sequence to obtain roughened stainless steel. The first etching is performed using the first etching solution as described in any one of claims 1-3; The second etching is performed using the second etching solution as described in any one of claims 1-3.

5. The coarsening method as described in claim 4, characterized in that, The pretreatment includes sequential degreasing and washing.

6. The coarsening method as described in claim 4, characterized in that, The degreasing process includes: treating with an alkaline degreasing agent at 45-55℃ for 170-200 seconds; Preferably, the concentration of the alkaline degreasing agent is 55-65 g / L; Preferably, the washing time is 30-60 seconds.

7. The coarsening method as described in claim 4, characterized in that, The air stirring pressure during the first etching process is 0.2-0.3 m. 3 / (m 2 ·min); Preferably, the temperature of the first etching is 95-100°C; Preferably, the first etching time is 1-3 minutes.

8. The coarsening method as described in claim 4, characterized in that, The first etching is performed at least once.

9. The coarsening method as described in claim 4, characterized in that, The air stirring pressure during the second etching process is 0.2-0.3 m. 3 / (m 2 ·min); Preferably, the temperature of the second etching is 95-100°C; Preferably, the second etching time is 3-5 minutes.

10. The coarsening method as described in claim 4, characterized in that, The second etching is performed at least once.

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