A wave soldering alloy formula and preparation method thereof

Abstract

The invention relates to the technical field of wave soldering, and discloses an alloy formula for wave soldering and a preparation method thereof. The alloy is prepared from the following components by weight percentage: 5-8% Zn, 1-2% Cu, 0.3-0.8% Ni, 2-3% Cr, 0.5-0.9% Mn, and the rest is Sn. The alloy for wave soldering prepared by the invention can significantly improve its organizational structure by optimizing each component and optimizing the ratio, and can not only improve its wetting performance by introducing coated titanium diboride, but also promote the nucleation of the alloy in the solidification process, and has the effects of metamorphism and homogenization, so that the welding performance of the solder alloy can be improved, especially the hardness performance of the solder joint is significantly increased, and the application field of the alloy is expanded.

Description

Technical Field

[0001] The invention relates to the technical field of wave soldering, in particular to an alloy formula for wave soldering and a preparation method thereof. Background Art

[0002] Wave soldering is a process of bringing the soldering surface of the plug-in board into direct contact with high-temperature liquid tin to achieve the purpose of soldering. The high-temperature liquid tin maintains an inclined surface, and a special device is used to form a wave-like phenomenon in the liquid tin, so it is called "wave soldering". Its main material is solder bar.

[0003] Sn-Pb alloy, with its excellent performance and low price, is the most widely used brazing material in electronic assembly and welding. However, due to the significant harm of Pb to humans and the environment, legislation has been enacted both domestically and internationally to achieve lead-free use in the electronics sector. As a result, lead-free solder has emerged and is gradually being promoted worldwide.

[0004] With the advancement of lead-free, Sn-Zn alloys have been continuously promoted and applied, but Sn-Zn alloys have the disadvantages of poor wettability and oxidation resistance, which need to be improved.

[0005] For example, a Chinese invention patent with prior art publication number CN106041353B discloses a Sn-Zn-Bi lead-free solder alloy and its preparation method. The elemental composition of the lead-free solder alloy, calculated by mass percentage, is as follows: Zn: 6-8%, Bi: 1-3%, Ti: 0.2-1%, Al: 0.02-0.1%, B: 0.001-0.005%, with the balance being Sn. Compared to the prior art, the Sn-Zn-Bi lead-free solder alloy provided by the present invention exhibits superior solder joint strength, oxidation resistance, and wettability. However, its solderability is mediocre and its solderability is poor, limiting its application.

[0006] Based on this, we proposed an alloy formula for wave soldering, hoping to solve the shortcomings of the existing technology. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the present invention provides an alloy formula for wave soldering and a preparation method thereof.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0009] The invention discloses an alloy formula for wave soldering, which is prepared from the following components by weight percentage: Zn 5-8%, Cu 1-2%, Ni 0.3-0.8%, Cr 2-3%, Mn 0.5-0.9%, and the remainder is Sn.

[0010] As a further technical solution, titanium diboride is further added to the alloy formula for wave soldering, accounting for 1.2-1.6% of the total weight of the alloy formula.

[0011] As a further technical solution, the titanium diboride is coated with TC4 titanium alloy to obtain coated titanium diboride.

[0012] As a further technical solution, the method for preparing the coated titanium diboride comprises the following steps:

[0013] (1) depositing nano-cobalt particles on the surface of TC4 titanium alloy to obtain surface-deposited TC4 titanium alloy powder;

[0014] (2) adding the surface-deposited TC4 titanium alloy powder and titanium diboride powder into a stirring device and stirring them uniformly to obtain a mixed powder;

[0015] (3) The mixed powder obtained above is ball-milled in a ball mill at a ball-to-material ratio of 10:1-2 and a ball milling speed of 120-150 r / min under an inert atmosphere for 6-8 h to obtain a ball-milled material;

[0016] (4) The ball mill obtained above was added to a tube furnace for heating, kept warm for 40-50 minutes, and naturally cooled to room temperature to obtain coated titanium diboride.

[0017] As a further technical solution, the method for preparing the surface-deposited TC4 titanium alloy is as follows:

[0018] (1) mixing cobalt sulfamate, boric acid, and deionized water to obtain an electrodeposition solution, specifically: first adding cobalt sulfamate to deionized water, adjusting the temperature to 60-70° C., keeping the temperature and stirring for 30-40 minutes, then adding boric acid dropwise while stirring, and mixing evenly to obtain an electrodeposition solution;

[0019] (2) Using nickel plate as anode and TC4 titanium alloy plate as cathode, single pulse current mode is adopted with current density of 1-1.5A / dm 2 , perform electrodeposition treatment for 2-3 hours, and then take out the deposited TC4 titanium alloy;

[0020] (3) The deposited TC4 titanium alloy is crushed and ground to obtain surface-deposited TC4 titanium alloy powder.

[0021] As a further technical solution, the mass ratio of the cobalt sulfamate, boric acid and deionized water is 12-15:1-2:30-40.

[0022] As a further technical solution, the surface-deposited TC4 titanium alloy powder and titanium diboride powder are mixed in a mass ratio of 1:3-5.

[0023] As a further technical solution, the inert atmosphere is nitrogen.

[0024] As a further technical solution, the heating temperature in the tubular furnace is 500-600°C.

[0025] A method for preparing an alloy formula for wave soldering comprises the following steps:

[0026] (1) Weighing a tin ingot by weight, then adding the tin ingot into a smelting furnace, and melting it under nitrogen protection to obtain a tin liquid;

[0027] (2) Adjust the temperature of the smelting furnace to 470-480°C, keep it warm for 20-30 minutes, then add Zn, Cu, Ni, Cr, and Mn, stir evenly, and continue to keep it warm for 40-50 minutes to obtain an intermediate solution;

[0028] (3) Add the coated titanium diboride to the above intermediate solution, heat it to 600-620°C, stir it, and keep it warm for 10-15 minutes;

[0029] (4) After the above smelting is uniform, remove the slag and cast the molten alloy into solder bars, which are then cooled naturally to room temperature.

[0030] The introduction of boric acid can effectively reduce the surface activity of the cathode, inhibit crystal growth, promote grain refinement, reduce internal stress, and improve surface smoothness. At the same time, it can reduce the brittleness of the deposited layer. Boron elements can segregate at the grain boundaries, improve the thermal stability of the grains, increase the wettability of the cathode and the uniformity of the precipitated cobalt, so that cobalt can be evenly distributed on the surface of TC4 titanium alloy.

[0031] The present invention has been studied through a large number of experiments and the components are rationally proportioned. The alloy formula for wave soldering prepared by the present invention is not prone to tissue segregation during use, the wetting performance is significantly improved, the spreadability is further enhanced, and the oxidation tendency is significantly suppressed during use, thereby improving the welding quality.

[0032] The wave soldering alloy of the present invention solves the problem of copper dissolving into molten solder in the solder joints and printed circuit substrates of conventional wave soldering. If this problem occurs, short circuits in the solder joints are likely to occur. The present invention can better avoid this problem by optimizing the formula.

[0033] Compared with the prior art, the present invention provides an alloy formula for wave soldering, which has the following beneficial effects:

[0034] The wave soldering alloy prepared by the present invention can significantly improve its organizational structure through the optimization of various components and the optimization of the ratio. In addition, the introduction of coated titanium diboride not only improves its wettability, but also promotes the nucleation of the alloy during the solidification process, has a metamorphic and homogenizing effect, thereby improving the welding performance of the solder alloy, especially the hardness of the solder joint is significantly increased, and its application field is expanded. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] The following are specific embodiments:

[0037] Example 1

[0038] The invention discloses an alloy formula for wave soldering, which is prepared from the following components by weight percentage: 5% Zn, 1% Cu, 0.3% Ni, 2% Cr, 0.5% Mn, and the remainder Sn.

[0039] As a further technical solution, titanium diboride is further added to the above alloy formula for wave soldering, accounting for 1.2% of the total weight of the alloy formula.

[0040] As a further technical solution, the titanium diboride is coated with a TC4 titanium alloy to obtain coated titanium diboride.

[0041] As a further technical solution, the above-mentioned method for preparing coated titanium diboride includes the following steps:

[0042] (1) depositing nano-cobalt particles on the surface of TC4 titanium alloy to obtain surface-deposited TC4 titanium alloy powder;

[0043] (2) adding the surface-deposited TC4 titanium alloy powder and titanium diboride powder into a stirring device and stirring them uniformly to obtain a mixed powder;

[0044] (3) The mixed powder obtained above was ball-milled in a ball mill at a ball-to-material ratio of 10:1 and a ball-milling speed of 120 r / min under an inert atmosphere for 6 h to obtain a ball-milled material;

[0045] (4) The ball mill obtained above was added to a tube furnace for heating, kept warm for 40 minutes, and naturally cooled to room temperature to obtain coated titanium diboride.

[0046] As a further technical solution, the above-mentioned surface deposited TC4 titanium alloy production method is as follows:

[0047] Cobalt sulfamate, boric acid, and deionized water are mixed to obtain an electrodeposition solution, specifically: first, cobalt sulfamate is added to deionized water, the temperature is adjusted to 60° C., and the mixture is stirred for 30 minutes, and then boric acid is added dropwise while stirring, and the mixture is evenly mixed to obtain an electrodeposition solution;

[0048] The nickel plate was used as the anode and the TC4 titanium alloy plate was used as the cathode. The single pulse current method was used and the current density was 1A / dm 2 , perform electrodeposition treatment for 2 hours, and then take out the deposited TC4 titanium alloy;

[0049] The deposited TC4 titanium alloy is crushed and ground to obtain surface-deposited TC4 titanium alloy powder.

[0050] As a further technical solution, the mass ratio of the above-mentioned cobalt aminosulfonate, boric acid and deionized water is 12:1:30.

[0051] As a further technical solution, the mass ratio of the surface-deposited TC4 titanium alloy powder and titanium diboride powder is 1:3.

[0052] As a further technical solution, the above-mentioned inert atmosphere is nitrogen.

[0053] As a further technical solution, the heating temperature in the above-mentioned tubular furnace is 500°C.

[0054] A method for preparing an alloy formula for wave soldering comprises the following steps:

[0055] (1) Weighing a tin ingot by weight, then adding the tin ingot into a smelting furnace, and melting it under nitrogen protection to obtain a tin liquid;

[0056] (2) The smelting furnace temperature was adjusted to 470°C and kept warm for 20 minutes, and then Zn, Cu, Ni, Cr, and Mn were added, stirred evenly, and kept warm for another 40 minutes to obtain an intermediate solution;

[0057] (3) Add the coated titanium diboride to the above intermediate solution, heat it to 600°C, stir it, and keep it warm for 10 minutes;

[0058] (4) After the above smelting is uniform, remove the slag and cast the molten alloy into solder bars, which are then cooled naturally to room temperature.

[0059] Example 2

[0060] The invention discloses an alloy formula for wave soldering, which is prepared from the following components by weight percentage: 6% Zn, 1.2% Cu, 0.4% Ni, 2.3% Cr, 0.6% Mn, and the remainder Sn.

[0061] As a further technical solution, titanium diboride is further added to the above alloy formula for wave soldering, accounting for 1.3% of the total weight of the alloy formula.

[0062] As a further technical solution, the titanium diboride is coated with a TC4 titanium alloy to obtain coated titanium diboride.

[0063] As a further technical solution, the above-mentioned method for preparing coated titanium diboride includes the following steps:

[0064] (1) depositing nano-cobalt particles on the surface of TC4 titanium alloy to obtain surface-deposited TC4 titanium alloy powder;

[0065] (2) adding the surface-deposited TC4 titanium alloy powder and titanium diboride powder into a stirring device and stirring them uniformly to obtain a mixed powder;

[0066] (3) The mixed powder obtained above was ball-milled in a ball mill at a ball-to-material ratio of 10:1.2 and a ball milling speed of 125 r / min under an inert atmosphere for 7 h to obtain a ball-milled material;

[0067] (4) The ball mill obtained above was added to a tube furnace for heating, kept warm for 42 minutes, and naturally cooled to room temperature to obtain coated titanium diboride.

[0068] As a further technical solution, the above-mentioned surface deposited TC4 titanium alloy production method is as follows:

[0069] (1) mixing cobalt sulfamate, boric acid, and deionized water to obtain an electrodeposition solution, specifically: first adding cobalt sulfamate to deionized water, adjusting the temperature to 63° C., keeping the temperature stirred for 35 minutes, then dropping boric acid while stirring, and mixing evenly to obtain an electrodeposition solution;

[0070] (2) Using nickel plate as anode and TC4 titanium alloy plate as cathode, a single pulse current method was used with a current density of 1.1A / dm 2 , perform electrodeposition treatment for 2.3 hours, and then take out the deposited TC4 titanium alloy;

[0071] (3) The deposited TC4 titanium alloy is crushed and ground to obtain surface-deposited TC4 titanium alloy powder.

[0072] As a further technical solution, the mass ratio of the above-mentioned cobalt aminosulfonate, boric acid and deionized water is 13:1.2:35.

[0073] As a further technical solution, the mass ratio of the surface-deposited TC4 titanium alloy powder and titanium diboride powder is 1:4.

[0074] As a further technical solution, the above-mentioned inert atmosphere is nitrogen.

[0075] As a further technical solution, the heating temperature in the above-mentioned tubular furnace is 520°C.

[0076] A method for preparing an alloy formula for wave soldering comprises the following steps:

[0077] (1) Weighing a tin ingot by weight, then adding the tin ingot into a smelting furnace, and melting it under nitrogen protection to obtain a tin liquid;

[0078] (2) The smelting furnace temperature was adjusted to 472°C and kept warm for 25 minutes. Then, Zn, Cu, Ni, Cr, and Mn were added, stirred evenly, and kept warm for another 45 minutes to obtain an intermediate solution.

[0079] (3) Add the coated titanium diboride to the above intermediate solution, heat it to 610°C, stir it, and keep it warm for 12 minutes;

[0080] (4) After the above smelting is uniform, remove the slag and cast the molten alloy into solder bars, which are then cooled naturally to room temperature.

[0081] Example 3

[0082] The invention discloses an alloy formula for wave soldering, which is prepared from the following components by weight percentage: 7% Zn, 1.3% Cu, 0.5% Ni, 2.6% Cr, 0.7% Mn, and the remainder Sn.

[0083] As a further technical solution, titanium diboride accounting for 1.4% of the total weight of the alloy formula is further added to the above alloy formula for wave soldering.

[0084] As a further technical solution, the titanium diboride is coated with a TC4 titanium alloy to obtain coated titanium diboride.

[0085] As a further technical solution, the above-mentioned method for preparing coated titanium diboride includes the following steps:

[0086] (1) depositing nano-cobalt particles on the surface of TC4 titanium alloy to obtain surface-deposited TC4 titanium alloy powder;

[0087] (2) adding the surface-deposited TC4 titanium alloy powder and titanium diboride powder into a stirring device and stirring them uniformly to obtain a mixed powder;

[0088] (3) The mixed powder obtained above was ball-milled in a ball mill at a ball-to-material ratio of 10:2 and a ball-milling speed of 150 r / min under an inert atmosphere for 6 h to obtain a ball-milled material;

[0089] (4) The ball mill obtained above was added to a tube furnace for heating, kept warm for 50 minutes, and naturally cooled to room temperature to obtain coated titanium diboride.

[0090] As a further technical solution, the above-mentioned surface deposited TC4 titanium alloy production method is as follows:

[0091] (1) mixing cobalt sulfamate, boric acid, and deionized water to obtain an electrodeposition solution, specifically: first adding cobalt sulfamate to deionized water, adjusting the temperature to 60° C., keeping the temperature and stirring for 40 minutes, then adding boric acid dropwise while stirring, and mixing evenly to obtain an electrodeposition solution;

[0092] (2) Using nickel plate as anode and TC4 titanium alloy plate as cathode, a single pulse current method was used with a current density of 1A / dm 2 , perform electrodeposition treatment for 3 hours, and then take out the deposited TC4 titanium alloy;

[0093] (3) The deposited TC4 titanium alloy is crushed and ground to obtain surface-deposited TC4 titanium alloy powder.

[0094] As a further technical solution, the mass ratio of the above-mentioned cobalt aminosulfonate, boric acid and deionized water is 13:1:40.

[0095] As a further technical solution, the mass ratio of the surface-deposited TC4 titanium alloy powder and titanium diboride powder is 1:3.

[0096] As a further technical solution, the above-mentioned inert atmosphere is nitrogen.

[0097] As a further technical solution, the heating temperature in the above-mentioned tubular furnace is 520°C.

[0098] A method for preparing an alloy formula for wave soldering comprises the following steps:

[0099] (1) Weighing a tin ingot by weight, then adding the tin ingot into a smelting furnace, and melting it under nitrogen protection to obtain a tin liquid;

[0100] (2) The smelting furnace temperature was adjusted to 480°C and kept warm for 20 minutes, and then Zn, Cu, Ni, Cr, and Mn were added, stirred evenly, and kept warm for 50 minutes to obtain an intermediate solution;

[0101] (3) Add the coated titanium diboride to the above intermediate solution, heat it to 600°C, stir it, and keep it warm for 15 minutes;

[0102] (4) After the above smelting is uniform, remove the slag and cast the molten alloy into solder bars, which are then cooled naturally to room temperature.

[0103] Example 4

[0104] The invention discloses an alloy formula for wave soldering, which is prepared from the following components by weight percentage: 7% Zn, 1.8% Cu, 0.6% Ni, 2.8% Cr, 0.6% Mn, and the remainder Sn.

[0105] As a further technical solution, titanium diboride accounting for 1.5% of the total weight of the alloy formula is further added to the above alloy formula for wave soldering.

[0106] As a further technical solution, the titanium diboride is coated with a TC4 titanium alloy to obtain coated titanium diboride.

[0107] As a further technical solution, the above-mentioned method for preparing coated titanium diboride includes the following steps:

[0108] (1) depositing nano-cobalt particles on the surface of TC4 titanium alloy to obtain surface-deposited TC4 titanium alloy powder;

[0109] (2) adding the surface-deposited TC4 titanium alloy powder and titanium diboride powder into a stirring device and stirring them uniformly to obtain a mixed powder;

[0110] (3) The mixed powder obtained above was ball-milled in a ball mill at a ball-to-material ratio of 10:1 and a ball-milling speed of 120 r / min under an inert atmosphere for 6 h to obtain a ball-milled material;

[0111] (4) The ball mill obtained above was added to a tube furnace for heating, kept warm for 50 minutes, and naturally cooled to room temperature to obtain coated titanium diboride.

[0112] As a further technical solution, the above-mentioned surface deposited TC4 titanium alloy production method is as follows:

[0113] (1) mixing cobalt sulfamate, boric acid, and deionized water to obtain an electrodeposition solution, specifically: first adding cobalt sulfamate to deionized water, adjusting the temperature to 70° C., keeping the temperature and stirring for 40 minutes, then adding boric acid dropwise while stirring, and mixing evenly to obtain an electrodeposition solution;

[0114] (2) Using nickel plate as anode and TC4 titanium alloy plate as cathode, a single pulse current method was used with a current density of 1A / dm 2, perform electrodeposition treatment for 3 hours, and then take out the deposited TC4 titanium alloy;

[0115] (3) The deposited TC4 titanium alloy is crushed and ground to obtain surface-deposited TC4 titanium alloy powder.

[0116] As a further technical solution, the mass ratio of the above-mentioned cobalt aminosulfonate, boric acid and deionized water is 15:2:30.

[0117] As a further technical solution, the mass ratio of the surface-deposited TC4 titanium alloy powder and titanium diboride powder is 1:3.

[0118] As a further technical solution, the above-mentioned inert atmosphere is nitrogen.

[0119] As a further technical solution, the heating temperature in the above-mentioned tubular furnace is 600°C.

[0120] A method for preparing an alloy formula for wave soldering comprises the following steps:

[0121] (1) Weighing a tin ingot by weight, then adding the tin ingot into a smelting furnace, and melting it under nitrogen protection to obtain a tin liquid;

[0122] (2) The smelting furnace temperature was adjusted to 470°C and kept warm for 30 minutes, and then Zn, Cu, Ni, Cr, and Mn were added, stirred evenly, and kept warm for another 40 minutes to obtain an intermediate solution;

[0123] (3) Add the coated titanium diboride to the above intermediate solution, heat it to 620°C, stir it, and keep it warm for 15 minutes;

[0124] (4) After the above smelting is uniform, remove the slag and cast the molten alloy into solder bars, which are then cooled naturally to room temperature.

[0125] Example 5

[0126] The invention discloses an alloy formula for wave soldering, which is prepared from the following components by weight percentage: 8% Zn, 2% Cu, 0.8% Ni, 3% Cr, 0.9% Mn, and the remainder Sn.

[0127] As a further technical solution, titanium diboride accounting for 1.6% of the total weight of the alloy formula is further added to the above alloy formula for wave soldering.

[0128] As a further technical solution, the titanium diboride is coated with a TC4 titanium alloy to obtain coated titanium diboride.

[0129] As a further technical solution, the above-mentioned method for preparing coated titanium diboride includes the following steps:

[0130] (1) depositing nano-cobalt particles on the surface of TC4 titanium alloy to obtain surface-deposited TC4 titanium alloy powder;

[0131] (2) adding the surface-deposited TC4 titanium alloy powder and titanium diboride powder into a stirring device and stirring them uniformly to obtain a mixed powder;

[0132] (3) The mixed powder obtained above was ball-milled in a ball mill at a ball-to-material ratio of 10:2 and a ball-milling speed of 150 r / min under an inert atmosphere for 8 h to obtain a ball-milled material;

[0133] (4) The ball mill obtained above was added to a tube furnace for heating, kept warm for 50 minutes, and naturally cooled to room temperature to obtain coated titanium diboride.

[0134] As a further technical solution, the above-mentioned surface deposited TC4 titanium alloy production method is as follows:

[0135] (1) mixing cobalt sulfamate, boric acid, and deionized water to obtain an electrodeposition solution, specifically: first adding cobalt sulfamate to deionized water, adjusting the temperature to 70° C., keeping the temperature and stirring for 40 minutes, then adding boric acid dropwise while stirring, and mixing evenly to obtain an electrodeposition solution;

[0136] (2) Using nickel plate as anode and TC4 titanium alloy plate as cathode, a single pulse current method was used with a current density of 1.5A / dm 2 , perform electrodeposition treatment for 3 hours, and then take out the deposited TC4 titanium alloy;

[0137] (3) The deposited TC4 titanium alloy is crushed and ground to obtain surface-deposited TC4 titanium alloy powder.

[0138] As a further technical solution, the mass ratio of the above-mentioned cobalt aminosulfonate, boric acid and deionized water is 15:2:40.

[0139] As a further technical solution, the mass ratio of the surface-deposited TC4 titanium alloy powder and titanium diboride powder is 1:5.

[0140] As a further technical solution, the above-mentioned inert atmosphere is nitrogen.

[0141] As a further technical solution, the heating temperature in the above-mentioned tubular furnace is 600°C.

[0142] A method for preparing an alloy formula for wave soldering comprises the following steps:

[0143] (1) Weighing a tin ingot by weight, then adding the tin ingot into a smelting furnace, and melting it under nitrogen protection to obtain a tin liquid;

[0144] (2) The melting furnace temperature was adjusted to 480°C and kept warm for 30 minutes, and then Zn, Cu, Ni, Cr, and Mn were added, stirred evenly, and kept warm for 50 minutes to obtain an intermediate solution;

[0145] (3) Add the coated titanium diboride to the above intermediate solution, heat it to 620°C, stir it, and keep it warm for 15 minutes;

[0146] (4) After the above smelting is uniform, remove the slag and cast the molten alloy into solder bars, which are then cooled naturally to room temperature.

[0147] Comparative Example 1: The difference from Example 1 is that no coated titanium diboride is added.

[0148] Comparative Example 2: The difference from Example 1 is that no surface-deposited TC4 titanium alloy powder is added in the preparation of the coated titanium diboride.

[0149] test:

[0150] The wettability test of the examples and comparative examples was carried out in accordance with GB / T11364-2008.

[0151] Table 1

[0152]

[0153]

[0154] It can be seen from Table 1 that the alloy for wave soldering prepared by the present invention has excellent wetting properties, and the spreading rate and wetting angle are greatly improved, thereby significantly improving its soldering performance.

[0155] The weld hardness test of the examples and comparative examples was carried out according to GB 7997-1987.

[0156] Table 2

[0157] Hardness / HV Example 1 303.8 Example 2 311.2 Example 3 308.8 Example 4 310.6 Example 5 301.5 Comparative Example 1 235.3 Comparative Example 2 270.1

[0158] It can be seen from Table 2 that the hardness of the solder joints after welding with the alloy for wave soldering prepared by the method of the present invention is greatly increased.

[0159] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An alloy for wave soldering, characterized in that: It is made of the following ingredients by weight percentage: Zn5-8%, Cu1-2%, Ni0.3-0.8%, Cr2-3%, Mn0.5-0.9%, and the rest is Sn; The wave soldering alloy is added with titanium diboride accounting for 1.2-1.6% of the total weight of the alloy; The titanium diboride is subjected to TC4 titanium alloy coating treatment to obtain coated titanium diboride; The method for preparing the coated titanium diboride comprises the following steps: (1) depositing nano-cobalt particles on the surface of TC4 titanium alloy to obtain surface-deposited TC4 titanium alloy powder; (2) adding the surface-deposited TC4 titanium alloy powder and titanium diboride powder into a stirring device and stirring them uniformly to obtain a mixed powder; (3) The mixed powder obtained above is placed in a ball mill for ball milling, wherein the ball-to-material ratio of the ball milling is 10:1-2, the ball milling speed is 120-150 r / min, and the ball milling is carried out under the protection of an inert atmosphere for 6-8 hours to obtain a ball mill material; (4) The ball mill obtained above is added to a tubular furnace for heating, kept warm for 40-50 minutes, and naturally cooled to room temperature to obtain coated titanium diboride.

2. An alloy for wave soldering according to claim 1, characterized in that: The method for preparing the surface deposited TC4 titanium alloy is as follows: (1) mixing cobalt sulfamate, boric acid and deionized water to obtain an electrodeposition solution, specifically: first adding cobalt sulfamate to deionized water, adjusting the temperature to 60-70° C., stirring at the temperature for 30-40 minutes, and then dropping boric acid while stirring, and after mixing evenly, obtaining an electrodeposition solution; (2) Using the nickel plate as the anode and the TC4 titanium alloy plate as the cathode, a single pulse current method is used with a current density of 1-1.5A / dm² for electrodeposition for 2-3 hours, and then the deposited TC4 titanium alloy is taken out; (3) The deposited TC4 titanium alloy is crushed and ground to obtain surface-deposited TC4 titanium alloy powder.

3. An alloy for wave soldering according to claim 2, characterized in that: The mixing mass ratio of the cobalt sulfamate, boric acid and deionized water is 12-15:1-2:30-40.

4. The wave soldering alloy according to claim 1, characterized in that: The mixed mass ratio of the surface deposited TC4 titanium alloy powder and titanium diboride powder is 1:3-5.

5. The wave soldering alloy according to claim 1, characterized in that: The inert atmosphere is nitrogen.

6. The alloy for wave soldering according to claim 1, characterized in that: The heating temperature in the tubular furnace is 500-600°C.

7. A method for preparing a wave soldering alloy according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) weighing a tin ingot according to weight percentage, and then adding the tin ingot into a smelting furnace, and melting it under nitrogen protection to obtain tin liquid; (2) The temperature of the smelting furnace is adjusted to 470-480°C, and the temperature is kept for 20-30 minutes, and then Zn, Cu, Ni, Cr, and Mn are added, and after stirring evenly, the temperature is kept for another 40-50 minutes to obtain an intermediate liquid; (3) adding the coated titanium diboride to the above intermediate solution, heating to 600-620° C., stirring, and keeping warm for 10-15 minutes; (4) After the above smelting is uniform, remove the slag and cast the molten alloy into solder bars, which are then cooled naturally to room temperature.

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