Lead-free halogen-free solder and preparation method thereof

Abstract

The invention relates to the technical field of welding flux, in particular to lead-free halogen-free welding flux and a preparation method thereof.The preparation method comprises the following steps that a tin raw material, a silver raw material, a bismuth raw material and a zinc raw material are weighed according to the proportion, and an ingredient is obtained; the ingredients are put into a vacuum smelting furnace to be smelted and evenly stirred, and raw material liquid is obtained; pouring the raw material liquid into a mold for cooling and shaping to obtain a mixed raw material; rolling the mixed raw material to obtain a semi-finished product; and performing performance and quality detection on the semi-finished product to obtain the lead-free and halogen-free solder. According to the invention, tin, silver, bismuth and zinc raw materials with high purity (greater than 99%) are adopted, and the mass percentage of the raw materials is strictly controlled, so that the prepared solder is lead-free and halogen-free solder, and the use of harmful substances such as lead and halogen is fundamentally avoided, thereby reducing the release of toxic gases in the melting process of the solder, effectively guaranteeing the health of workers, and reducing the production cost. Therefore, the problem that the health of workers is threatened due to the fact that poisonous gas is possibly released after existing welding flux is melted is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of solder, and in particular to a lead-free and halogen-free solder and a preparation method thereof. Background Art

[0002] In conventional solder alloys, metallic lead is often an indispensable component. However, this fact has raised deep concerns about the release of toxic gases from molten solder during the brazing process, which poses a serious threat to workers' health. Under the high temperature environment of brazing, the lead in the solder may react with other elements to generate a series of toxic gases. Long-term exposure of workers to such an environment will undoubtedly increase the risk of occupational diseases.

[0003] What is more serious is that as the manufacturing process of microelectronic devices increasingly relies on soldering technology, the lead pollution problem on discarded IC chips or printed circuit boards has become increasingly prominent. During the treatment and disposal of these wastes, harmful substances such as lead are likely to seep into the groundwater system through flushing and other means, thereby causing a series of environmental problems. Lead is a typical heavy metal pollutant that can accumulate in organisms and be transmitted through the food chain, ultimately causing long-term and far-reaching harm to human health, including but not limited to serious diseases such as lead poisoning. Summary of the invention

[0004] The purpose of the present invention is to provide a lead-free and halogen-free solder and a preparation method thereof, aiming to solve the problem that the existing solder may release toxic gases after melting, posing a threat to the health of workers.

[0005] To achieve the above object, in a first aspect, the present invention provides a method for preparing a lead-free and halogen-free solder, comprising the following steps:

[0006] Weigh a tin raw material, a silver raw material, a bismuth raw material and a zinc raw material in proportion to obtain a batch;

[0007] The ingredients are placed in a vacuum furnace for smelting and stirred evenly to obtain a raw material liquid;

[0008] Pour the raw material liquid into a mold, cool and shape it, and obtain a mixed raw material;

[0009] Rolling the mixed raw material to obtain a semi-finished product;

[0010] The semi-finished product is subjected to performance and quality testing to obtain lead-free and halogen-free solder.

[0011] Among them, the step of “weighing the tin raw material, the silver raw material, the bismuth raw material and the zinc raw material in proportion to obtain the ingredients” includes the following steps:

[0012] Based on the proportion, the tin raw material, the silver raw material, the bismuth raw material and the zinc raw material are weighed respectively using a weighing device;

[0013] The symmetrically taken tin raw material, silver raw material, bismuth raw material and zinc raw material are pre-treated;

[0014] The pretreated tin raw material, silver raw material, bismuth raw material and zinc raw material are mixed to obtain a batch.

[0015] Among them, in “using weighing equipment to weigh the tin raw material, silver raw material, bismuth raw material and zinc raw material respectively based on the proportion”, the purity of the tin, the silver, the bismuth and the zinc is greater than 99%, and the mass percentages of the tin, the silver, the bismuth and the zinc are 90%-95%: 2%-5%: 0.5%-2%: 1%-3%.

[0016] Among them, in “pre-treating the symmetrically taken tin raw material, silver raw material, bismuth raw material and zinc raw material”, the pre-treatment is to remove surface impurities and oxide layers of the raw materials.

[0017] Among them, the step of “placing the ingredients into a vacuum furnace for smelting and stirring evenly to obtain a raw material liquid” includes the following steps:

[0018] Put the ingredients into a preheated vacuum furnace and melt them under the protection of inert gas;

[0019] The melted ingredients are fully stirred to obtain a raw material liquid.

[0020] Among them, the step of “pouring the raw material liquid into a mold, cooling and shaping, and obtaining a mixed raw material” includes the following steps:

[0021] Pour the evenly stirred raw material liquid into the preheated mold;

[0022] The mold is placed in a cooling device to rapidly cool the raw material liquid and shape it into a mixed raw material.

[0023] In a second aspect, a lead-free and halogen-free solder is prepared by the lead-free and halogen-free solder preparation method described in the first aspect.

[0024] The invention comprises tin, silver, bismuth and zinc, wherein the mass percentages of the tin, the silver, the bismuth and the zinc are 90%-95%: 2%-5%: 0.5%-2%: 1%-3%.

[0025] The invention discloses a method for preparing a lead-free and halogen-free solder, comprising the following steps: weighing a tin raw material, a silver raw material, a bismuth raw material and a zinc raw material in proportion to obtain a batch; placing the batch in a vacuum furnace for smelting and stirring to obtain a raw material liquid; pouring the raw material liquid into a mold for cooling and shaping to obtain a mixed raw material; rolling the mixed raw material to obtain a semi-finished product; and testing the performance and quality of the semi-finished product to obtain a lead-free and halogen-free solder. The invention adopts high-purity (>99%) tin, silver, bismuth and zinc raw materials and strictly controls the mass percentage of the prepared solder to obtain a lead-free and halogen-free solder, thereby fundamentally avoiding the use of harmful substances such as lead and halogen, thereby reducing the release of toxic gases during the solder melting process, effectively protecting the health of workers, and thus solving the problem that the existing solder may release toxic gases after melting to threaten the health of workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further illustrated by means of the non-limiting examples given in the accompanying drawings.

[0027] Figure 1 The present invention is a flow chart of a method for preparing lead-free and halogen-free solder.

[0028] Figure 2 The invention is a flow chart of weighing tin raw material, silver raw material, bismuth raw material and zinc raw material in proportion to obtain ingredients.

[0029] Figure 3 The invention is a flow chart of putting the ingredients into a vacuum furnace for melting and stirring evenly to obtain a raw material liquid.

[0030] Figure 4 The process is to pour the raw material liquid into a mold, cool it down and set it, and obtain a mixed raw material.

[0031] Figure 5 This is a flow chart of rolling the mixed raw material to obtain a semi-finished product.

[0032] Figure 6 The flowchart is to perform performance and quality inspection on the semi-finished product to obtain lead-free and halogen-free solder. DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0034] See also Figures 1 to 6 In a first aspect, the present invention provides a method for preparing a lead-free and halogen-free solder, comprising the following steps:

[0035] S1 weighs a tin raw material, a silver raw material, a bismuth raw material and a zinc raw material in proportion to obtain a batch;

[0036] S11 weighs the tin raw material, the silver raw material, the bismuth raw material and the zinc raw material respectively using a weighing device based on the proportion;

[0037] The purity of the tin, the silver, the bismuth and the zinc is greater than 99%, and the mass percentages of the tin, the silver, the bismuth and the zinc are 90%-95%: 2%-5%: 0.5%-2%: 1%-3%.

[0038] Specifically, high-precision weighing equipment is used to weigh the raw materials strictly according to the predetermined ratio (tin: 90%-95%, silver: 2%-5%, bismuth: 0.5%-2%, zinc: 1%-3%). The purity of all raw materials exceeds 99% to ensure the quality and performance of the final product.

[0039] S12 pre-treats the symmetrically taken tin raw material, silver raw material, bismuth raw material and zinc raw material;

[0040] The pretreatment is to remove surface impurities and oxide layers of the raw materials.

[0041] Specifically, impurities and oxide layers on the surface of the raw materials are removed to ensure the purity and smelting effect of the raw materials. The surface of the raw materials is cleaned by physical or chemical methods, such as pickling, sandblasting, etc.

[0042] S13: Mixing the pretreated tin raw material, silver raw material, bismuth raw material and zinc raw material to obtain a batch.

[0043] Specifically, the pre-treated raw materials will be sent to the mixing equipment for thorough mixing. The purpose of this step is to ensure that the various raw materials can be evenly distributed before smelting, thereby improving smelting efficiency and product quality.

[0044] S2: placing the ingredients into a vacuum furnace for smelting and stirring to obtain a raw material liquid;

[0045] S21 puts the ingredients into a preheated vacuum furnace and melts them under the protection of inert gas;

[0046] The melting temperature is 600°C-1000°C

[0047] Specifically, before smelting, the vacuum furnace will be preheated to ensure the smooth progress of the smelting process. The ingredients are fed into the preheated furnace and heated under the protection of inert gas. The use of inert gas can effectively prevent the raw materials from being oxidized during the smelting process, thereby improving the purity and quality of the product.

[0048] S22 fully stirs the melted ingredients to obtain a raw material liquid.

[0049] Specifically, when the ingredients are completely melted, professional stirring equipment will be used to fully stir the melt. The purpose of this step is to ensure that the various raw materials are evenly distributed in the melt, thereby forming a uniform raw material liquid.

[0050] S3: pouring the raw material liquid into a mold, cooling and shaping, to obtain a mixed raw material;

[0051] S31 pouring the evenly stirred raw material liquid into the preheated mold;

[0052] Specifically, after the raw material liquid is stirred evenly, it will be quickly poured into the preheated mold. The preheating of the mold can effectively prevent the raw material liquid from cracking or deforming due to a sudden drop in temperature during the pouring process.

[0053] S32 places the mold in a cooling device to rapidly cool the raw material liquid and shape it into a mixed raw material.

[0054] Specifically, the raw material liquid in the mold will be quickly sent to the cooling equipment for rapid cooling and shaping, so that the raw material liquid will solidify quickly, thereby forming a mixed raw material with a certain shape and size.

[0055] S4 rolling the mixed raw material to obtain a semi-finished product;

[0056] S41 performs preliminary cold rolling on the mixed raw material after cooling and shaping;

[0057] Specifically, after the mixed raw materials are cooled and shaped, they will undergo a preliminary cold rolling process. The purpose of this step is to make preliminary plasticity and shape adjustments to the raw materials in preparation for subsequent finishing rolling.

[0058] S42 performs finish rolling on the mixed steel after preliminary cold rolling to obtain a semi-finished product.

[0059] Specifically, the mixed raw materials after preliminary cold rolling will be sent to the finishing rolling equipment for further rolling. The purpose of finishing rolling is to make the raw materials reach the required thickness and precision, so as to obtain semi-finished products that meet the requirements.

[0060] S5 performs performance and quality inspection on the semi-finished product to obtain lead-free and halogen-free solder.

[0061] S51 randomly samples semi-finished products for component analysis, mechanical property test, and electrical conductivity test to obtain test results;

[0062] Specifically, after the semi-finished products are prepared, random samples will be taken for a series of performance and quality tests. These tests include component analysis, mechanical properties test, electrical conductivity test, etc., to ensure that the performance and quality indicators of the semi-finished products meet the standard requirements.

[0063] S52 evaluates the performance and quality of the semi-finished product based on the test results. If the performance and quality meet the requirements, lead-free and halogen-free solder is obtained. If the performance and quality do not meet the requirements, the semi-finished product is marked and recorded, and the process parameters of batching, smelting, cooling and shaping, cold rolling and rolling are adjusted and optimized.

[0064] Specifically, the performance and quality of the semi-finished products will be evaluated based on the test results. If the evaluation results meet the standard requirements, the semi-finished products will be considered qualified lead-free and halogen-free solder. If the evaluation results do not meet the standard requirements, the unqualified semi-finished products will be marked and recorded, and the process parameters such as ingredients, smelting, cooling and shaping, cold rolling and rolling will be adjusted and optimized to ensure the quality of subsequent products.

[0065] In a second aspect, a lead-free and halogen-free solder is prepared by the lead-free and halogen-free solder preparation method described in the first aspect.

[0066] The invention comprises tin, silver, bismuth and zinc, wherein the mass percentages of the tin, the silver, the bismuth and the zinc are 90%-95%: 2%-5%: 0.5%-2%: 1%-3%.

[0067] The present invention provides a lead-free and halogen-free solder and a preparation method thereof, which has the following beneficial effects:

[0068] 1. By using tin, silver, bismuth and zinc raw materials with a purity of more than 99% and weighing them strictly according to the predetermined ratio, the high quality and stable performance of the final solder are ensured. The precise ratio not only improves the welding performance of the solder, but also ensures the reliability and durability of the product.

[0069] Second, the raw materials are strictly pretreated before smelting to remove surface impurities and oxide layers, improving smelting efficiency and product quality. The optimization of the mixing process ensures the uniform distribution of various raw materials before smelting, further improving the uniformity and consistency of the final product.

[0070] 3. Melting in a vacuum furnace and heating under the protection of inert gas effectively prevents oxidation and contamination of the raw materials during the melting process, improving the purity and quality of the product. This step ensures that the solder has excellent welding performance and physical properties.

[0071] Fourth, the raw material liquid is quickly cooled and shaped in the preheated mold, ensuring the shape and size accuracy of the mixed raw material. The subsequent rolling process further adjusts the plasticity and shape of the raw material to obtain a semi-finished product that meets the requirements. This step improves the processing efficiency and yield rate of the product.

[0072] 5. Random sampling and a series of performance and quality tests are carried out on semi-finished products to ensure that all performance and quality indicators of the final product meet the standard requirements. The process parameters are adjusted and optimized based on the evaluation results, further improving the quality and reliability of the product.

[0073] 6. The entire production process uses lead-free and halogen-free environmentally friendly materials, avoiding harmful substances that may exist in traditional solders and reducing harm to the environment and workers. At the same time, by optimizing process parameters and improving production efficiency, energy consumption and waste emissions are reduced, meeting the requirements of sustainable development.

[0074] What is disclosed above is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A method for preparing lead-free and halogen-free solder, characterized in that: The following steps are involved: Weigh a tin raw material, a silver raw material, a bismuth raw material and a zinc raw material in proportion to obtain a batch; The ingredients are placed in a vacuum furnace for smelting and stirred evenly to obtain a raw material liquid; Pour the raw material liquid into a mold, cool and shape it, and obtain a mixed raw material; Rolling the mixed raw material to obtain a semi-finished product; The semi-finished product is subjected to performance and quality testing to obtain lead-free and halogen-free solder.

2. The method for preparing lead-free and halogen-free solder according to claim 1, characterized in that: In “weighing tin raw material, silver raw material, bismuth raw material and zinc raw material in proportion to obtain ingredients”, the following steps are included: Based on the proportion, the tin raw material, the silver raw material, the bismuth raw material and the zinc raw material are weighed respectively using a weighing device; The symmetrically taken tin raw material, silver raw material, bismuth raw material and zinc raw material are pre-treated; The pretreated tin raw material, silver raw material, bismuth raw material and zinc raw material are mixed to obtain a batch.

3. The method for preparing lead-free and halogen-free solder according to claim 2, characterized in that: In "using weighing equipment to weigh the tin raw material, the silver raw material, the bismuth raw material and the zinc raw material respectively based on the proportion", the purity of the tin, the silver, the bismuth and the zinc is greater than 99%, and the mass percentages of the tin, the silver, the bismuth and the zinc are 90%-95%: 2%-5%: 0.5%-2%: 1%-3%.

4. The method for preparing lead-free and halogen-free solder according to claim 2, characterized in that: In “pre-treating the symmetrically taken tin raw material, silver raw material, bismuth raw material and zinc raw material”, the pre-treatment is to remove surface impurities and oxide layers of the raw materials.

5. The method for preparing lead-free and halogen-free solder according to claim 1, characterized in that: The step of “placing the ingredients into a vacuum furnace for smelting and stirring evenly to obtain a raw material liquid” includes the following steps: Put the ingredients into a preheated vacuum furnace and melt them under the protection of inert gas; The melted ingredients are fully stirred to obtain a raw material liquid.

6. The method for preparing lead-free and halogen-free solder according to claim 1, characterized in that: In "pouring the raw material liquid into a mold, cooling and shaping, and obtaining a mixed raw material", the following steps are included: Pour the evenly stirred raw material liquid into the preheated mold; The mold is placed in a cooling device to rapidly cool the raw material liquid and shape it into a mixed raw material.

7. A lead-free and halogen-free solder prepared by the lead-free and halogen-free solder preparation method according to any one of claims 1 to 6, characterized in that: The invention comprises tin, silver, bismuth and zinc, wherein the mass percentages of the tin, the silver, the bismuth and the zinc are 90%-95%: 2%-5%: 0.5%-2%: 1%-3%.

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