Concentrated water-based cutting fluid with low spontaneous combustion risk for multi-wire cutting of aluminum alloy and method

Abstract

The invention provides a low-spontaneous-combustion-risk water-based cutting fluid concentrated solution for aluminum alloy multi-wire cutting and a method, and belongs to the technical field of metal working fluids. The scheme aims to solve the problems of spontaneous combustion risk of high-activity aluminum powder in aluminum alloy multi-wire cutting and high cost and unstable operation in the prior art. The concentrated solution comprises an aqueous base solution and a synergistic composite passivation system, wherein the system is composed of an inorganic synergistic passivator group A and an organic synergistic passivator group B; the component A is selected from phosphate, silicate or borate; and the component B is selected from C6-C12 saturated dicarboxylic acid or salt thereof and hydroxy carboxylic acid or salt thereof. The method comprises the step of supplying the water-based cutting fluid formed by diluting the concentrated solution to a cutting area. Through the synergistic effect of the inorganic passivator and the organic passivator, a compact composite protective film is formed on the surface of the aluminum powder, spontaneous combustion can be efficiently inhibited, the cost is reduced, and the operation stability is guaranteed.

Description

Technical Field

[0001] This application relates to the field of metalworking fluid technology, and in particular to a water-based cutting fluid for suppressing the spontaneous combustion of aluminum powder during multi-wire cutting of aluminum alloys. Background Technology

[0002] Multi-wire cutting technology is widely used in the machining of metal materials such as aluminum alloys due to its high efficiency and precision. Water-based cutting fluids are commonly used in multi-wire cutting processes because of their excellent cooling and lubrication properties. However, aluminum is a chemically reactive metal, and the multi-wire cutting process generates a large amount of micron-sized aluminum powder with a huge specific surface area and high activity. This fresh aluminum powder is highly susceptible to a violent exothermic reaction in the presence of water and oxygen. When heat accumulates in the filtration system or waste collection, it can cause a rapid temperature rise, potentially leading to spontaneous combustion or even explosion of the aluminum powder, posing a serious safety hazard.

[0003] To address this issue, existing technologies typically attempt to add passivating agents to the cutting fluid. For example, some solutions use inorganic phosphates, silicates, or borates as passivating agents. However, these solutions all have drawbacks: while using inorganic phosphates alone or at high concentrations can be effective, they easily react with calcium and magnesium ions in hard water to form precipitates, affecting the stability of the cutting fluid, and high phosphorus emissions can cause environmental pollution; using silicates alone or at high concentrations can easily lead to gelling or scaling in the cutting fluid, clogging pipelines and filtration systems, severely affecting continuous production; and the use of some borates is restricted by regulations in some countries and regions. Other solutions use expensive proprietary aluminum alloy corrosion inhibitors, which, although stable in performance, have a high cost that severely hinders the commercialization of multi-wire EDM in the aluminum alloy machining field.

[0004] In addition, some technical solutions, such as rust-preventive cutting fluids for conventional metalworking, may combine certain inorganic salts (such as silicates) with organic acids (such as long-chain dicarboxylic acids). However, the purpose of these solutions is to provide conventional corrosion protection for the surface of shaped metal workpieces. They do not reveal or solve the entirely different technical problem of how to rapidly and effectively passivate the large amount of highly active, fine metal powder generated instantaneously under extreme conditions such as multi-wire cutting to suppress its spontaneous combustion risk. Therefore, existing technologies lack a comprehensive solution that can simultaneously satisfy the requirements of efficiently suppressing aluminum powder spontaneous combustion, cost-effectiveness, stable operation, and environmental friendliness. Summary of the Invention

[0005] The purpose of this application is to provide a synergistic composite water-based cutting fluid for suppressing the spontaneous combustion of aluminum powder and a method for suppressing the risk of spontaneous combustion of aluminum powder, aiming to solve the problems of poor suppression effect, high cost, unstable operation or environmental unfriendliness of aluminum powder in the prior art.

[0006] To address the aforementioned technical problems, this application provides a low-self-ignition risk water-based cutting fluid concentrate for multi-wire cutting of aluminum alloys, comprising the following components by weight percentage: a synergistic composite passivation system: 10%-50%; an aqueous base fluid: 50%-90%; wherein the synergistic composite passivation system is composed of substances from group A and group B, and at least one substance from each group is selected; group A is an inorganic synergistic passivating agent, accounting for 1%-10% of the total concentrate, and selected from one or more of phosphates, silicates, and borates; group B is an organic synergistic passivating agent, accounting for 5%-35% of the total concentrate, and selected from one or more of C6-C12 saturated dicarboxylic acids or their salts, hydroxycarboxylic acids or their salts; and the total amount of groups A and B accounts for 10%-50% of the total concentrate.

[0007] This application also provides a method for suppressing the risk of spontaneous combustion of aluminum powder generated during aluminum alloy multi-wire cutting, comprising the following steps: during aluminum alloy multi-wire cutting, supplying a water-based cutting fluid to the cutting area, the water-based cutting fluid being diluted from the concentrate as described above.

[0008] Optionally, the weight percentage of group A is 2%-10%.

[0009] Optionally, the weight percentage of group B is 10%-30%.

[0010] In a preferred embodiment of this application, the weight percentage of group A is 2%-10%, and the weight percentage of group B is 10%-30%.

[0011] Optionally, the inorganic synergistic passivating agent in Group A is a phosphate, specifically selected from one or more of sodium orthophosphate, sodium pyrophosphate, and sodium tripolyphosphate.

[0012] Optionally, the inorganic synergistic passivating agent in Group A is a silicate, specifically selected from one or more of sodium metasilicate and potassium silicate.

[0013] Optionally, the inorganic synergistic passivating agent in Group A is a borate, specifically selected from one or more of borax, sodium metaborate, and borate-amine neutralizers.

[0014] Optionally, the inorganic synergistic passivating agent of Group A comprises at least two substances selected from phosphates, silicates, and borates.

[0015] Optionally, the organic synergistic passivating agent of group B is a C6-C12 saturated dicarboxylic acid or its salt.

[0016] Furthermore, the C6-C12 saturated dicarboxylic acid is selected from one or more of the following: iodic acid, octanoic acid, sebacic acid, and dodecanoic acid.

[0017] Optionally, the organic synergistic passivating agent of group B is a hydroxycarboxylic acid or a salt thereof.

[0018] Furthermore, the hydroxycarboxylic acid is selected from one or more of citric acid and gluconic acid.

[0019] In a preferred embodiment of this application, group A is phosphate, and group B is sebacic acid or its salt.

[0020] In a preferred embodiment of this application, group A is a silicate, and group B contains octanoic acid or its salt and citric acid or its salt.

[0021] In a preferred embodiment of this application, group A is a borate, and group B is a dodecanoic acid or its salt.

[0022] In a preferred embodiment of this application, group A comprises phosphates and silicates, and group B comprises sebacic acid or its salts.

[0023] Optionally, the aqueous base fluid comprises water, a water-soluble lubricant, a pH buffer, a surfactant, and a bactericide.

[0024] Furthermore, at least one of the following conditions must be met: the water-soluble lubricant is a polyether or a polyol; the pH buffer is triethanolamine.

[0025] Compared with the prior art, this application has the following beneficial effects:

[0026] 1. Highly effective in inhibiting spontaneous combustion and ensuring high safety. This application utilizes the synergistic effect of inorganic and organic passivating agents to form a dense and stable composite protective film on the surface of aluminum powder, which significantly increases the auto-ignition point of the aluminum powder and fundamentally solves the safety hazard of spontaneous combustion during the multi-wire cutting process of aluminum alloys.

[0027] 2. Significant cost advantages and good economic efficiency. The raw materials for the synergistic passivation system used in this application are all inexpensive and readily available basic chemical materials. Compared with the scheme using proprietary corrosion inhibitors, it can significantly reduce the cost of the passivation system and improve the economic feasibility of aluminum alloy multi-wire cutting process.

[0028] 3. Excellent operational stability. By controlling the inorganic salt concentration at a low level, this application completely avoids system failures caused by precipitation, gelation, and scaling of the cutting fluid during long-term circulation, ensuring the continuity and stability of production.

[0029] 4. Environmentally friendly and highly compliant with regulations. The formulation of this application is flexible, allowing for the selection of different combinations of components, completely avoiding the use of substances restricted by environmental protection or regulations, reducing the difficulty and cost of wastewater treatment, and exhibiting good regulatory compliance. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram illustrating an application scenario of a synergistic composite water-based cutting fluid for suppressing spontaneous combustion of aluminum powder, provided in an embodiment of this application.

[0032] Figure 2 This is a flowchart illustrating a method for suppressing the risk of spontaneous combustion of aluminum powder, as provided in an embodiment of this application.

[0033] Explanation of reference numerals in the attached drawings: 10-Multi-wire cutting machine; 20-Aluminum alloy workpiece; 30-Diamond wire; 40-Nozzle; 50-Cutting fluid; 60-Collection system; 70-Passivated aluminum powder; S101-Step of preparing a concentrated cutting fluid containing a synergistic composite passivation system; S102-Step of diluting the concentrated fluid to obtain a working fluid; S103-Step of supplying the working fluid to the cutting area during aluminum alloy multi-wire cutting; S104-Step of contacting the working fluid with the aluminum powder generated during cutting to form a composite passivation film on the surface of the aluminum powder; S105-Step of collecting waste liquid containing passivated aluminum powder. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments. It is understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0035] This application provides a synergistic composite water-based cutting fluid for suppressing the spontaneous combustion of aluminum powder and its application. The technical concept involves compounding specific types of inorganic synergistic passivating agents (Group A) and specific types of organic synergistic passivating agents (Group B) within a specific concentration range to construct a synergistic composite passivation system. This system can rapidly form a dense and stable composite protective film, consisting of an inner inorganic film and an outer organic film, on the surface of the instantaneously generated, highly active, micron-sized aluminum powder during multi-wire cutting of aluminum alloys. This composite film structure effectively isolates the aluminum powder from contact with water and oxygen, thereby significantly increasing the spontaneous combustion initiation temperature of the aluminum powder. This fundamentally solves the safety hazard of aluminum powder spontaneous combustion in a cost-effective, stable, and environmentally friendly manner.

[0036] Reference Figure 1This illustration demonstrates an application scenario of a synergistic composite water-based cutting fluid for suppressing spontaneous combustion of aluminum powder, as provided in this application embodiment. Inside a multi-wire cutting machine 10, a high-speed diamond wire 30 cuts an aluminum alloy workpiece 20. During this process, a nozzle 40 located in the cutting area continuously sprays the cutting fluid 50 provided in this application embodiment onto the contact area between the diamond wire 30 and the aluminum alloy workpiece 20. The cutting fluid 50 serves a cooling function to remove the large amount of heat generated during cutting, and also acts as a lubricant to reduce friction between the diamond wire 30 and the workpiece 20. More importantly, when the cutting fluid comes into contact with the highly reactive aluminum powder generated during cutting, its built-in synergistic composite passivation system can form a protective film on the surface of the aluminum powder, generating passivated aluminum powder 70. Finally, the waste cutting fluid containing the passivated aluminum powder 70 flows into the collection system 60 below for subsequent filtration, circulation, or waste liquid treatment.

[0037] Reference Figure 2 This is a flowchart illustrating a method for suppressing the risk of spontaneous combustion of aluminum powder, provided in an embodiment of this application. Figure 2 As shown, the method may include the following steps: Step S101: Prepare a cutting fluid concentrate containing a synergistic composite passivation system according to the formulation provided in this application. Step S102: Dilute the concentrate with deionized water or other industrial water to a predetermined concentration (e.g., 5%) before use, according to actual working conditions, to obtain a working fluid. Step S103: During the production process of aluminum alloy multi-wire cutting, the working fluid is continuously supplied to the cutting area through a pump and pipeline system. Step S104: The supplied working fluid comes into full contact with the fresh aluminum powder with extremely high chemical activity generated during cutting. The synergistic composite passivation system in the working fluid then undergoes chemical adsorption and reaction on the surface of the aluminum powder to form a composite passivation film, thereby inhibiting its activity. Step S105: Draw the waste liquid carrying the passivated aluminum powder out from the cutting area and collect it by the collection system 60 for subsequent solid-liquid separation and waste liquid treatment.

[0038] The formulation, preparation process, and effects of the water-based cutting fluid concentrate provided in this application will be described in detail below with reference to specific embodiments.

[0039] Example 1

[0040] This embodiment provides a water-based cutting fluid concentrate with phosphate and sebacic acid as the core synergistic components.

[0041] 1. Preparation of cutting fluid concentrate (corresponding to...) Figure 2 Step S101)

[0042] First, a cutting fluid concentrate is prepared, the components of which are as follows by weight: Aqueous base fluid: 80 parts; Synergistic composite passivation system: 20 parts. The synergistic composite passivation system consists of the following components: Group A (inorganic synergistic passivating agent): Sodium tripolyphosphate 3 parts; Group B (organic synergistic passivating agent): Sebacic acid 17 parts.

[0043] In this embodiment, the composition of the concentrate, converted to weight percentage, is as follows: 80% aqueous base solution and 20% synergistic composite passivation system. In the synergistic composite passivation system, sodium tripolyphosphate (Group A) accounts for 3% of the total weight of the concentrate, and sebacic acid (Group B) accounts for 17% of the total weight of the concentrate. It should be noted that the content of each component falls within the range defined in this application: aqueous base solution (50%-90%), synergistic composite passivation system (10%-50%), Group A (1%-10%), and Group B (5%-35%). Furthermore, the content of Group A and Group B also falls within the preferred range, i.e., Group A is 2%-10%, and Group B is 10%-30%.

[0044] As a specific implementation, the aqueous base fluid may be composed of the following conventional components (in percentage of the total weight of the base fluid): 25% polyethylene glycol (average molecular weight 400, as a water-soluble lubricant), 10% triethanolamine (as a pH buffer and neutralizer), 2.5% fatty alcohol polyoxyethylene ether (as a nonionic surfactant), 0.25% isothiazolinone bactericide, and the balance being deionized water.

[0045] The specific preparation steps are as follows: In a clean stainless steel reactor equipped with a stirrer and a heating jacket, first add approximately 60% of the total formula amount of deionized water. Start stirring and slowly add triethanolamine at room temperature (e.g., 25°C), stirring until completely dissolved. Next, add polyethylene glycol and continue stirring until a homogeneous and transparent solution is formed. Then, slowly add component A, sodium tripolyphosphate powder, stirring until completely dissolved; the solution remains clear at this point. Subsequently, add component B, sebacic acid powder. Considering the low solubility of sebacic acid in cold water, the heating jacket can be turned on to raise the reactor temperature to 50-60°C and maintain this temperature while stirring for approximately 30-60 minutes until all sebacic acid is completely dissolved and the solution becomes clear and transparent. After the solution becomes clear, stop heating and cool down to below 40°C while stirring. Then, add fatty alcohol polyoxyethylene ether and isothiazolinone bactericide sequentially, stirring until homogeneous. Finally, add the remaining deionized water to 100 parts of the total formula weight, and continue stirring for 30 minutes to ensure that all components are mixed evenly, finally obtaining a colorless to pale yellow transparent liquid, which is the cutting fluid concentrate of this embodiment.

[0046] 2. Technical Principles and Synergistic Effects

[0047] The core technology of this embodiment lies in the synergistic passivation effect between sodium tripolyphosphate (Group A) and sebacic acid (Group B). Aluminum is an amphoteric metal, and the micron-sized aluminum powder produced during multi-wire cutting possesses extremely high surface energy and chemical activity. When these fresh aluminum powders are exposed to a cutting fluid environment containing water and oxygen, a rapid reaction occurs: and Both of these reactions are strongly exothermic; when heat accumulates, it can lead to spontaneous combustion.

[0048] The synergistic passivation mechanism of this embodiment is as follows: First, upon contact between the cutting fluid and fresh aluminum powder, sodium tripolyphosphate, with a low concentration (3%) but high reactivity, immediately reacts with the active sites on the aluminum powder surface, or hydrolyzes on the aluminum surface to form phosphate ions, which then combine with aluminum ions, thereby rapidly generating a thin film of amorphous aluminum phosphate or its composite oxide. This inorganic film forms extremely quickly, covering most of the aluminum powder surface immediately, providing initial isolation and passivation, and effectively suppressing the occurrence of violent reactions. Maintaining the sodium tripolyphosphate concentration at a low level (3%) ensures rapid film formation while avoiding the problem of phosphate precipitation caused by its reaction with calcium and magnesium ions in hard water at high concentrations, thus guaranteeing the long-term stability of the cutting fluid.

[0049] Secondly, although the inorganic phosphate membrane formed in the first step can quickly cover the surface, its structure may contain microscopic pores or defects. At this point, sebacic acid (a C10 saturated dicarboxylic acid) with a relatively long molecular chain begins to play a role. Sebacic acid has a carboxyl group at each end of its molecular structure, giving it excellent surface adsorption and complexation capabilities. One of the carboxyl groups will chemically adsorb or complex with aluminum ions or hydroxyl groups on the inorganic membrane surface, firmly anchoring itself to the inorganic membrane, especially preferentially adsorbing at defects in the inorganic membrane, thus playing a "filling and repair" role. Simultaneously, the other end of the sebacic acid molecule, the saturated carbon chain of up to 10 carbon atoms, is hydrophobic due to its nonpolarity. A large number of sebacic acid molecules are arranged in an orderly manner on the surface of the inorganic membrane in this way, with their hydrophobic carbon chains facing the external cutting fluid, forming a dense, ordered organic hydrophobic layer.

[0050] Ultimately, an "inorganic-organic" bilayer composite passivation film is formed on the surface of the aluminum powder. The inner inorganic film provides basic chemical inertness, while the outer organic film provides physical hydrophobic isolation. This composite film structure is far denser, more stable, and more complete than any film formed by a single component, and can more effectively prevent water molecules and dissolved oxygen from penetrating to the surface of the aluminum powder, thus achieving a synergistic passivation effect.

[0051] 3. Application and Effect Verification (corresponding to) Figure 2 Steps S102 to S105)

[0052] In use, the concentrated solution prepared above is diluted 20 times with deionized water (1 part concentrated solution to 19 parts water) to obtain a working solution with a solid content of 5% (step S102). This working solution is pumped to the nozzle 40 of the multi-wire cutting machine 10 for continuous cutting of 6061 aluminum alloy profiles (step S103). During the cutting process, the working solution comes into full contact with the newly generated aluminum powder, instantly completing the aforementioned synergistic passivation process (step S104). The waste liquid containing the passivated aluminum powder 70 is recovered by the collection system 60 (step S105).

[0053] To verify its effectiveness, aluminum powder obtained after cutting and filtration was collected, washed with acetone, dried, and then subjected to autoignition point testing using differential scanning calorimetry. The test results showed that the aluminum powder treated with the cutting fluid of this embodiment had an autoignition onset temperature (the starting point of the exothermic peak) as high as 295°C. In contrast, the autoignition point of untreated aluminum powder under the same test conditions was only about 175°C. This indicates that the technical solution of this embodiment can greatly improve the chemical stability of aluminum powder and effectively suppress its autoignition risk.

[0054] Meanwhile, the stability of the working solution was evaluated. A 5% working solution was placed in a 50°C oven for 168 hours (one week). Upon removal and observation, the liquid remained clear and transparent, with no visible sediment at the bottom and no gelation. The pH and viscosity changes were within the acceptable range of ±5%. This demonstrates the excellent long-term operational stability of this formulation.

[0055] In terms of cost, both sodium tripolyphosphate and sebacic acid are readily available basic chemical raw materials with low prices. Calculations show that the raw material cost of the passivation system (3% sodium tripolyphosphate + 17% sebacic acid) in this embodiment is reduced by approximately 65% ​​compared to a solution using a commercially available proprietary aluminum alloy corrosion inhibitor that achieves the same effect.

[0056] Example 2

[0057] This embodiment provides a water-based cutting fluid concentrate that is free of phosphorus and boron and uses silicates, succinic acid and citric acid as the core synergistic components, to demonstrate the advantages of this application in terms of environmental adaptability and formulation flexibility.

[0058] 1. Preparation of cutting fluid concentrate (step S101)

[0059] A cutting fluid concentrate was prepared, the components of which are as follows by weight: Aqueous base fluid: 85 parts; Synergistic composite passivation system: 15 parts. The synergistic composite passivation system consists of the following components: Group A (inorganic synergistic passivating agent): Sodium metasilicate (pentahydrate) 2 parts; Group B (organic synergistic passivating agent): Octadiic acid 8 parts, Citric acid (monohydrate) 5 parts.

[0060] Converted to weight percentage, the concentrate consists of: 85% aqueous base solution and 15% synergistic composite passivation system. Specifically, sodium metasilicate (Group A) accounts for 2% of the total weight of the concentrate, and the organic synergistic passivating agents (octanoic acid and citric acid) (Group B) together account for 13% of the total weight of the concentrate. The contents of these components also fall within the scope of protection claimed in this application.

[0061] The formulation of the aqueous base solution is the same as in Example 1. The preparation process is also similar to that in Example 1, except that when adding component B, octanoic acid is added first, and after it dissolves under heating conditions, citric acid, which has better solubility, is added and stirred until completely dissolved.

[0062] 2. Technical Principles and Synergistic Effects

[0063] The synergistic passivation mechanism in this embodiment is similar to that in Example 1, but the component characteristics differ. Sodium metasilicate in Group A hydrolyzes in aqueous solution to generate silicic acid, which can rapidly form an amorphous aluminum silicate or silica-alumina composite protective film on the surface of fresh aluminum powder, thus also playing a role in rapid initial passivation. Strictly controlling the concentration of sodium metasilicate at a low level of 2% is one of the keys to the success of this embodiment. This is because high concentrations of silicates readily polymerize under acidic or neutral conditions, forming silica sols or even gels, leading to a sharp increase in cutting fluid viscosity and scaling and pipe blockage. By using a low concentration and synergizing with subsequent organic acids, the advantage of rapid film formation is utilized while mitigating the risk of instability.

[0064] Group B employed a combination of octanoic acid (a C8 saturated dicarboxylic acid) and citric acid (a hydroxycarboxylic acid). This combination offers significant advantages compared to single organic acids. Octanoic acid, a medium-chain dicarboxylic acid, functions similarly to sebacic acid in Example 1, adsorbing onto the inorganic silicate membrane via its carboxyl groups, forming a hydrophobic layer with its C8 carbon chain. The introduction of citric acid provides additional synergistic effects. The citric acid molecule contains one hydroxyl group and three carboxyl groups, giving it a strong multidentate complexing ability. It not only adsorbs onto the inorganic membrane surface like octanoic acid but also more effectively complexes aluminum ions at defects in the inorganic membrane, forming highly stable five- or six-membered cyclic complexes, thus more thoroughly "repairing" and "sealing" the micropores of the inorganic membrane. The hydrophobic carbon chain of octanoic acid and the strong complexing ability of citric acid combine to construct an exceptionally dense and robust organic composite protective layer on the silicate membrane.

[0065] 3. Application and Effect Verification

[0066] The concentrate from this embodiment was also diluted 20 times and used for multi-wire cutting of 6061 aluminum alloy. DSC testing showed that the collected aluminum powder had a self-ignition initiation temperature of up to 280°C, exhibiting excellent self-ignition suppression. A stability test was conducted at 50°C for 168 hours; the working fluid was clear, without sediment or gelation, demonstrating good stability.

[0067] A significant advantage of this embodiment is that its formulation is completely free of phosphorus and boron. This makes it more environmentally friendly in areas with strict restrictions on phosphorus emissions and simplifies wastewater treatment. Simultaneously, it avoids the use of any regulated borates, resulting in greater adaptability to the global market. This embodiment demonstrates that combinations of different chemical substances in groups A and B, as well as combinations of various organic acids within group B, can achieve the desired technical effects of this application.

[0068] Example 3

[0069] This embodiment provides a scheme to achieve excellent passivation effect, using borates and long-chain dodecanoic acid as core synergistic components.

[0070] 1. Preparation of cutting fluid concentrate (step S101)

[0071] A cutting fluid concentrate was prepared, the components of which are as follows by weight: Aqueous base fluid: 80 parts; Synergistic composite passivation system: 20 parts. The synergistic composite passivation system consists of the following components: Group A (inorganic synergistic passivating agent): Borax (sodium tetraborate decahydrate) 4 parts; Group B (organic synergistic passivating agent): Dodecanoic acid 16 parts.

[0072] Converted to weight percentage, the composition of this concentrate is: 80% aqueous base solution, 4% borax from group A, and 16% dodecanoic acid from group B. The content of each component is within the range required by this application.

[0073] The aqueous base solution formulation is the same as in Example 1, containing 10% triethanolamine. The preparation process is similar to that in Example 1. It should be noted that dodecanoic acid has a higher melting point and hydrophobicity, so the dissolution temperature may need to be increased to 65-75°C, and the stirring time may need to be appropriately extended to ensure complete dissolution.

[0074] 2. Technical Principles and Synergistic Effects

[0075] In this embodiment, the borax from group A reacts in an aqueous base solution containing triethanolamine to form a borate-amine neutralizer with superior corrosion inhibition properties. This borate-amine complex can be effectively adsorbed onto the surface of aluminum powder, forming a thin and dense borate passivation film.

[0076] Group B selected dodecanoic acid (C12), which has a longer chain. According to the theory of molecular self-assembly, the longer the carbon chain, the stronger the van der Waals forces between molecules, resulting in a denser, more ordered, and more hydrophobic organic film. Compared to the C10 chain in Example 1 and the C8 chain in Example 2, the long C12 chain of dodecanoic acid can form a more robust and hydrophobic "molecular fence" on the surface of the borate inorganic film. This highly hydrophobic organic film can maximally prevent water and oxygen from contacting the inner passivation film and aluminum substrate, thus providing top-notch protection.

[0077] 3. Application and Effect Verification

[0078] The concentrated solution from this embodiment was diluted and used for multi-wire cutting of aluminum alloys. DSC testing showed that the collected aluminum powder had an auto-ignition onset temperature as high as 310°C. This value is not only significantly higher than that of untreated aluminum powder but also surpasses many expensive proprietary corrosion inhibitor solutions (typically in the 280-290°C range), demonstrating extremely excellent auto-ignition suppression performance. Stability test results also showed that the working solution remained stable under long-term high-temperature operation without any adverse phenomena. This embodiment demonstrates that by optimizing the specific chemical structures of groups A and B, the performance of the technical solution in this application can be further improved.

[0079] Example 4

[0080] This embodiment provides a scheme in Group A that uses a mixture of multiple inorganic passivating agents to demonstrate the flexibility of the formulation design in this application.

[0081] 1. Preparation of cutting fluid concentrate (step S101)

[0082] A cutting fluid concentrate was prepared, the components of which are as follows by weight: Aqueous base fluid: 85 parts; Synergistic composite passivation system: 15 parts. The synergistic composite passivation system consists of the following components: Group A (inorganic synergistic passivating agent): sodium pyrophosphate 1.5 parts, potassium silicate 1.5 parts; Group B (organic synergistic passivating agent): sebacic acid 12 parts.

[0083] Converted to weight percentage, the composition of the concentrate is as follows: 85% aqueous base solution, 3% inorganic salt mixture from group A, and 12% sebacic acid from group B. The content of each component is within the range required by this application.

[0084] The formulation of the aqueous base solution is the same as in Example 1. The preparation process is similar to that in Example 1, except that when adding component A, sodium pyrophosphate and potassium silicate are added sequentially and stirred until completely dissolved.

[0085] 2. Technical Principles and Synergistic Effects

[0086] The innovation of this embodiment lies in the use of a mixture of phosphate (sodium pyrophosphate) and silicate (potassium silicate) in Group A. Studies have shown that when phosphate and silicate ions coexist on an aluminum surface, they can form a phosphorus-silicon co-deposited inorganic composite film. Compared to single phosphate or silicate films, this composite film has a more complex and stable structure, fewer microscopic defects, and a stronger bond with the aluminum substrate.

[0087] Building upon this foundation, sebacic acid (C10) from group B is further adsorbed and self-assembled on this superior inorganic composite membrane, forming a dense hydrophobic organic layer. The improved performance of the base membrane further enhances the overall protective properties of the final "phosphorus-silicon inorganic composite / organic membrane."

[0088] 3. Application and Effect Verification

[0089] The concentrated solution from this embodiment was diluted and used for multi-wire cutting of aluminum alloys. DSC testing showed that the collected aluminum powder reached a self-ignition onset temperature of 305°C, demonstrating excellent results, approaching the best performance of Example 3. Stability testing also passed. This embodiment demonstrates that the synergistic passivation mechanism of this application is applicable not only to combinations of single inorganic salts and organic acids, but also to combinations of multiple inorganic salts and organic acids. This provides ample room for flexible formulation design based on different water qualities, cost budgets, and environmental requirements.

[0090] Example 5

[0091] This embodiment provides a formulation with sodium orthophosphate, boric acid, and citric acid as synergistic components.

[0092] 1. Preparation of cutting fluid concentrate (step S101)

[0093] The components are as follows by weight: aqueous base solution: 82 parts; synergistic composite passivation system: 18 parts; wherein, the synergistic composite passivation system is composed of the following components: Group A (inorganic synergistic passivating agent): sodium orthophosphate 2 parts, boric acid 3 parts; Group B (organic synergistic passivating agent): citric acid 13 parts.

[0094] Preparation Instructions: The aqueous base solution formulation is the same as in Example 1 (containing triethanolamine). During preparation, boric acid, upon addition, will neutralize the triethanolamine in the base solution to generate amine borate corrosion inhibitor. Citric acid has good solubility and can be added at room temperature or under warm conditions with stirring until dissolved.

[0095] 2. Application and Effect Verification

[0096] After diluting the concentrate of this embodiment by 20 times and testing, the auto-ignition onset temperature of the aluminum powder was 290°C, the stability test was qualified, and the relative cost was low (about 30%).

[0097] Comparative Example 1

[0098] To compare the effects, a comparative example was prepared using a commercially available high-performance proprietary aluminum alloy corrosion inhibitor. Its concentrate formulation, by weight, consisted of: 80 parts aqueous base solution and 20 parts a proprietary aluminum alloy corrosion inhibitor (mainly composed of organophosphonates and heterocyclic compounds). The aqueous base solution formulation was the same as in Example 1.

[0099] The same methods as in the examples were used for application and testing. Test results showed that the aluminum powder treated with this comparative cutting fluid had an auto-ignition onset temperature of 285°C. Although the effect was good, the raw material cost of its passivation system was approximately three times that of Example 1 of this application (approximately 200% higher).

[0100] Comparative Example 2

[0101] To demonstrate the necessity of the synergistic system in this application, a comparative example using only a high concentration of a single inorganic salt was prepared. Its concentrate formulation, by weight, consisted of 90 parts aqueous base solution and 10 parts sodium tripolyphosphate.

[0102] The same methods as in the examples were used for application and testing. Test results showed that the aluminum powder treated with this comparative cutting fluid had an auto-ignition onset temperature of only 225°C, and its suppression effect was far inferior to that of the examples in this application. More importantly, in the stability test, when diluted with hard water containing 300 ppm calcium carbonate and left at 50°C for less than 24 hours, a noticeable white precipitate appeared, proving that it could not be used stably in an industrial environment for a long period.

[0103] Comparative Example 3

[0104] To further demonstrate the necessity of the synergistic system, a comparative example using only a high concentration of a single organic acid was prepared. Its concentrate formulation, by weight, consisted of 80 parts aqueous base solution and 20 parts sebacic acid.

[0105] The same methods as in the examples were used for application and testing. Test results showed that the aluminum powder treated with this comparative cutting fluid had an auto-ignition onset temperature of 240°C. While this effect was better than Comparative Example 2, it was still significantly lower than the effect of Example 1 (295°C). This indicates that without the rapid film-forming effect of inorganic salts, relying solely on the adsorption of organic acids, the passivation film's formation rate and density are insufficient to provide efficient protection.

[0106] Summarize

[0107] A detailed comparison of Examples 1-4 and Comparative Examples 1-3 shows that the synergistic composite water-based cutting fluid provided in this application, by compounding a low concentration of group A inorganic synergistic passivating agent with a specific structure of group B organic synergistic passivating agent, successfully achieves the following beneficial effects:

[0108] 1. High efficiency in inhibiting spontaneous combustion: The spontaneous combustion points of aluminum powder treated in Examples 1, 2, 3 and 4 reached 295℃, 280℃, 310℃ and 305℃ respectively, which are comparable to or even higher than expensive proprietary corrosion inhibitors (Comparative Example 1, 285℃), and far superior to single-component schemes (Comparative Examples 2 and 3).

[0109] 2. Significant cost advantage: The passivating agent raw materials used in the embodiments of this application are inexpensive, and the cost can be significantly reduced compared with Comparative Example 1.

[0110] 3. Excellent operational stability: By controlling the inorganic salt concentration at a low level (1-4%), all embodiments of this application exhibit excellent long-term thermal stability, solving problems such as precipitation and scaling caused by high-concentration inorganic salt solutions (such as Comparative Example 2).

[0111] 4. Flexible and environmentally friendly formulation: Example 2 demonstrates that an environmentally friendly formulation can be formulated that is completely free of phosphorus and boron; Example 4 demonstrates that a variety of inorganic salts can be mixed and used, providing great freedom in formulation design.

[0112] In summary, the technical solution of this application effectively balances performance, cost, stability and environmental protection requirements through a specific synergistic compounding system, solves the shortcomings of the existing technology, and has high industrial application value.

[0113] The above description is merely a preferred embodiment of this application and is not intended to limit this application. For those skilled in the art, various improvements and modifications can be made without departing from the spirit and principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A water-based cutting fluid concentrate for multi-wire cutting of aluminum alloys, characterized in that, Includes a synergistic composite passivation system; By weight percentage, the synergistic composite passivation system comprises: 1%-10% of group A inorganic synergistic passivating agent and 5%-35% of group B organic synergistic passivating agent; The synergistic composite passivation system is composed of inorganic synergistic passivating agents of group A and organic synergistic passivating agents of group B, and at least one agent from group A and group B shall be selected. The inorganic synergistic passivating agents in Group A are selected from one or more of phosphates, silicates, and borates; The group B organic synergistic passivating agents are selected from one or more of C6-C12 saturated dicarboxylic acids or their salts and C6-C12 hydroxycarboxylic acids or their salts.

2. The water-based cutting fluid concentrate according to claim 1, characterized in that, The water-based cutting fluid concentrate includes an aqueous base fluid, which contains triethanolamine as a pH buffer. By weight percentage, the content of the inorganic synergistic passivating agent of group A in the concentrate is 2%-10%, and the content of the organic synergistic passivating agent of group B in the concentrate is 10%-30%.

3. The water-based cutting fluid concentrate according to claim 1, characterized in that, The inorganic synergistic passivating agents in Group A are selected from one or more silicates and borates.

4. The water-based cutting fluid concentrate according to claim 1, characterized in that, The inorganic synergistic passivating agents in Group A are selected from one or more of phosphates and silicates.

5. The water-based cutting fluid concentrate according to claim 1, characterized in that, The inorganic synergistic passivating agent in group A is a phosphate, and the organic synergistic passivating agent in group B is sebacic acid or its salt.

6. The water-based cutting fluid concentrate according to claim 1, characterized in that, The inorganic synergistic passivating agent in group A is a borate, and the organic synergistic passivating agent in group B is a dodecanoic acid or its salt.

7. The water-based cutting fluid concentrate according to claim 1, characterized in that, The group A inorganic synergistic passivating agents include phosphates and silicates.

8. The water-based cutting fluid concentrate according to claim 1, characterized in that, The group B organic synergistic passivating agent comprises at least one C6-C12 saturated dicarboxylic acid or a salt thereof, and at least one C6-C12 hydroxycarboxylic acid or a salt thereof.

9. A method for suppressing the risk of spontaneous combustion of aluminum powder generated during multi-wire cutting of aluminum alloys, characterized in that, The method includes: During the aluminum alloy multi-wire cutting process, a working fluid prepared from the water-based cutting fluid concentrate according to claim 1 is supplied to the cutting area so that the working fluid comes into contact with the aluminum powder generated during cutting.

10. A water-based cutting fluid for multi-wire cutting of aluminum alloys, characterized in that, It is prepared by diluting the water-based cutting fluid concentrate according to any one of claims 1 to 8 with water.

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