Nanometer reinforced bismuth base lead-free high-temperature solder and preparation method thereof

A nano-enhanced, high-temperature welding technology, applied in welding equipment, welding/cutting media/materials, welding media, etc., can solve the problem of difficulty in controlling the uniformity of nano-enhanced particles, limited use of size restrictions, poor brightness of solder joints, etc. problems, to achieve the effect of improving electrical conductivity, good sealing, and bright solder joints

Active Publication Date: 2010-06-23
BEIJING COMPO ADVANCED TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The medium-temperature solder published by Beijing Institute of Technology (Chinese patents 01144487.8 and 200310116809.2) also uses particle reinforcement, but the size limitation of the reinforcement particles limits the use in the field of smaller and smaller micro-solder joints
In comparison, Chinese patents 02125594.6, 200810112441.5 and 200510013430.8 all use nano-reinforced particles to improve the mechanical properties and wettability of the solder. Among them, Chinese patent 02125594.6 mixes nanoparticles by mechanical stirring during the preparation of solder paste, while Chinese patent 200510013430.8 By adding ZrO to molten liquid Sn-Ag eutectic solder 2 Nanoparticles, Chinese patent 200810112441.5 innovatively introduces organic nanostructure materials, but because its preparation methods are all mechanical mixing, it is difficult to control the uniformity of its nano-reinforced particles, and it belongs to the field of medium-temperature solder
[0009] In order to overcome the current technical defects of high-temperature lead-free solder, solve problems such as low strength, short service life, poor sealing, and poor solder joint halo brightness, it is urgent for those skilled in the art to provide a high-temperature lead-free solder with improved performance. question

Method used

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  • Nanometer reinforced bismuth base lead-free high-temperature solder and preparation method thereof
  • Nanometer reinforced bismuth base lead-free high-temperature solder and preparation method thereof
  • Nanometer reinforced bismuth base lead-free high-temperature solder and preparation method thereof

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Embodiment 1

[0038] figure 1 It is a schematic diagram of the preparation device of the nano-reinforced bismuth-based lead-free high-temperature solder of the present invention. Among them, 1 is a stirrer; 2 is a feeding port for bismuth-based powder, ammonia water (or other weak base), reducing agent, etc.; 3 is a turbid liquid container.

[0039] like figure 2 Shown is a flow chart of the preparation process for preparing the nano-reinforced bismuth-based lead-free high-temperature solder of the present invention. The first step: take bismuth powder (or prepare bismuth / antimony powder in proportion), and its preparation method can be any known powder-making technology such as mechanical crushing or medium atomization; Second step: quantitative bismuth powder (or bismuth powder / antimony powder) evenly import a quantitative silver nitrate solution with a certain concentration of stirring device, and constantly stir to make the solution become a uniform turbid liquid; the third step: ta...

Embodiment 2

[0047] Embodiment 2 (Bi-10Sb)+2.5%Ag nano-reinforced bismuth-based lead-free high-temperature solder and its preparation:

[0048] Prepare 20kg of Bi-10Sb alloy solder, atomize the molten Bi-10Sb alloy solder by ultrasonic atomization powder making technology, and sieve and classify, take 975g of 3# powder (25-45um);

[0049] Weigh 25g of silver scraps, pour into nitric acid and stir thoroughly to dissolve Ag completely;

[0050] Pour the weighed Bi-10Sb alloy powder into the prepared AgNO 3 Solution, stir to make the solution a uniform turbid liquid, in order to prevent the precipitation of Bi-10Sb alloy powder;

[0051] Gradually add sufficient amount of ammonia water (1mol solute) to the turbid liquid under stirring, so that the silver nitrate can completely form a complex (complex (Ag(NH3) n + ) solution);

[0052] Slowly drop excess formaldehyde into the turbid liquid and continue stirring to reduce the complex to form a uniform composite powder of nano-Ag powder and ...

Embodiment 3

[0055] Embodiment 3 (Bi-10Sb-0.5Sn)+5%Ag nano-reinforced bismuth-based lead-free high-temperature solder and its preparation:

[0056] Prepare 50kg of Bi-10Sb-0.5Sn alloy solder, atomize the molten Bi-10Sb-0.5Sn alloy solder by centrifugal atomization powder making technology, and sieve and classify, take 950g of 3# powder (25-45um);

[0057] Pour the weighed Bi-10Sb-0.5Sn powder into 0.463mol (78.7g solute) of AgNO 3 Solution, stirring, so that the solution becomes a uniform turbid liquid, in order to prevent the precipitation of Bi-10Sb-0.5Sn alloy powder;

[0058] Gradually add a mixed solution of dilute NaOH and ammonia water to the turbid liquid under stirring, so that silver nitrate can completely form a complex (complex (Ag(NH3) n + ) solution);

[0059] Slowly add excess glucose solution to the turbid solution under stirring conditions, and reduce the complex to form a uniform composite powder of nano-Ag powder and Bi-10Sb-0.5Sn alloy powder;

[0060] Pour the solu...

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Abstract

The invention relates to a nanometer reinforced bismuth base lead-free high-temperature solder and a preparation method thereof, belonging to the technical field of lead-free solder manufacture. The nanometer reinforced bismuth base lead-free high-temperature solder comprises silver nanopowder and bismuth powder or powder blending bismuth and antimony or alloy powder, wherein the silver nanopowder accounts for 2-12wt%. The preparation method comprises: firstly, preparing bismuth powder (or bismuth / antimony powder); evenly introducing bismuth powder (or bismuth / antimony powder) with ration proportioning into silver nitrate solution provided with a stirring device; adding ammonia water to form silver-amino complex; reducing complex compound into the even compound of nano Ag powder and Bi powder (or bismuth / antimony powder). The lead-free high-temperature solder can improve the problems of poor electric conduction and thermal conductivity of Bi-Ag (or Bi-Sb-AG) alloy solder and has the advantages of high strength, long service life, favourable tightness, light round halo of welding points and the like in the welding and using process. According to different compositions between powders, the nanometer reinforced bismuth base lead-free high-temperature solder can be prepared into high-temperature solder with any melting point at the temperature of 260-380 DEG C so as to replace high-Pb solder for electronic packaging.

Description

technical field [0001] The invention relates to a nano-reinforced bismuth-based lead-free high-temperature solder and a preparation method thereof. The solder is chemically compounded by metal bismuth powder (or bismuth and antimony mixed powder / alloy powder) and nano-Ag powder, and belongs to the lead-free solder manufacturing technology field. Background technique [0002] Emphasizing environmental protection and advocating green products are the general trend of economic development in the world today, and lead-free electronic products are one of the major measures. In terms of lead-free substitution of medium and low temperature lead-containing solder, after nearly 10 years of research, the reliability has been gradually verified and has been widely used. However, high-lead solder [w (Pb) > 85%] has not yet been Suitable substitutes are therefore temporarily exempted in the RoHS directive. However, according to the directive plan: the EU RoHS directive will graduall...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/28B23K35/40
Inventor 徐骏胡强贺会军张富文
Owner BEIJING COMPO ADVANCED TECH
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