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CN-122007711-A - Zn-CeO-containing material2Sn-Bi low-melting-point solder, and preparation method and application thereof

CN122007711ACN 122007711 ACN122007711 ACN 122007711ACN-122007711-A

Abstract

The invention relates to the technical field of electronic packaging materials, and provides a Sn-Bi low-melting-point solder containing Zn-CeO 2 , as well as a preparation method and application thereof, wherein the low-melting-point solder comprises Sn-Bi alloy powder, zn powder and CeO 2 powder, wherein the Sn accounts for 58wt% and the Bi accounts for 42wt% in the Sn-Bi alloy powder, the grain size is 5-15 mu m, the Zn powder purity is more than or equal to 99.99%, the grain size is 5-10 mu m, the CeO 2 powder is nano-sized, and the grain size is 30-50nm. The highest temperature of the solder in the preparation process is only 180 ℃, the energy consumption is low, the melting point can be reduced to 135-142 ℃, the shearing strength is increased to 45MPa, the oxidation resistance is strong, and the reliable welding can be realized at 150 ℃.

Inventors

  • ZHANG JUNJIE
  • ZHANG YANHUA
  • JIAO YU
  • He Kehan
  • GENG HAO

Assignees

  • 西昌学院

Dates

Publication Date
20260512
Application Date
20260312

Claims (10)

  1. 1. The Sn-Bi low-melting-point solder containing Zn-CeO 2 is characterized by comprising the following components in percentage by mass: 98-99.4% of Sn-Bi alloy powder, 0.5-1.5% of Zn powder and 0.1-0.5% of CeO 2 powder; The Sn-Bi alloy powder comprises 40-60wt% of Sn, 40-60wt% of Bi and 5-15 mu m of particle size; the purity of the Zn powder is more than or equal to 99.99 percent, and the grain diameter is 5-10 mu m; The CeO 2 powder is nano-scale and has the particle size of 30-50nm.
  2. 2. The solder according to claim 1, comprising the following components in percentage by mass: 98.5-99.0% of Sn-Bi alloy powder, 0.8-1.2% of Zn powder and 0.2-0.4% of CeO 2 powder.
  3. 3. Solder according to claim 1, wherein the low melting point solder has a melting point of 135-142 ℃.
  4. 4. The solder according to claim 1, wherein the low melting point solder has a shear strength of 45MPa or less.
  5. 5. The solder according to claim 1, wherein the low melting point solder has an oxidation mass increase rate of 0.05% or less after 100h high temperature aging.
  6. 6. A method for producing the low melting point solder according to any one of claims 1 to 5, comprising the steps of: S1, weighing Sn-Bi alloy powder, zn powder and CeO 2 powder, mixing, loading into a ball milling tank, and ball milling under a protective atmosphere to obtain composite powder; S2, carrying out hot press forming on the composite powder in vacuum or protective atmosphere to obtain a compact welding material block; s3, processing and forming the compact solder block to obtain the low-melting-point solder.
  7. 7. The method according to claim 6, wherein the ball milling conditions in the step S1 are ball material ratio (8-12) to 1, rotation speed 180-220rpm, time 1.5-2.5h, and protective atmosphere of nitrogen or argon.
  8. 8. The method according to claim 6, wherein the hot pressing condition in the step S2 is that the temperature is 170-180 ℃, the pressure is 25-35MPa, the holding time is 8-12min, and the vacuum degree is less than or equal to 10 -3 Pa.
  9. 9. The method of claim 6, wherein the forming in step S3 includes cutting the low-melting solder into a cylindrical shape, a sheet shape, or a wire shape.
  10. 10. Use of the low melting solder of any of claims 1-5 in flexible printed circuit boards or low temperature electronics packages resistant to temperatures of 150 ℃ or less.

Description

Sn-Bi low-melting-point solder containing Zn-CeO 2 and preparation method and application thereof Technical Field The invention relates to the technical field of electronic packaging materials, in particular to Sn-Bi low-melting-point solder containing Zn-CeO 2, and a preparation method and application thereof. Background Sn-Bi eutectic alloys are considered as ideal candidates for replacing conventional Sn-Pb solders due to their low melting point (139 ℃) and low cost. However, sn-Bi solders have the fatal defects of melting point still higher than the tolerance temperature (less than or equal to 150 ℃) of part of thermosensitive elements, low shearing strength, insufficient creep resistance at high temperature, bi easy segregation, causing embrittlement of welding spots, serious oxidation when aged at 200 ℃, and large drift of welding spot resistance. In the prior art, elements such as Ag, cu, ni, sb are added to improve the performance, but the melting point is raised, while the independent addition of trace Zn or rare earth oxide can refine the structure, but the problems of uneven dispersion, secondary smelting burning loss, aggravation of oxidization and the like exist, and the three indexes of low temperature, high strength and high reliability are difficult to consider. Therefore, a need exists for a new solder and mating process that maintains high shear strength. Disclosure of Invention In order to solve the problems, the invention provides the Sn-Bi low-melting-point solder containing Zn-CeO 2, and the preparation method and the application thereof, wherein the highest temperature of the solder in the preparation process is only 180 ℃, the energy consumption is low, the melting point can be reduced to 135-142 ℃, the shearing strength is increased to 45MPa, the oxidation resistance is strong, and the reliable welding can be realized at 150 ℃. In a first aspect, the invention provides a Sn-Bi low-melting-point solder containing Zn-CeO 2, wherein the low-melting-point solder comprises the following components in percentage by mass: 98-99.4% of Sn-Bi alloy powder, 0.5-1.5% of Zn powder and 0.1-0.5% of CeO 2 powder; The Sn-Bi alloy powder comprises 40-60wt% of Sn, 40-60wt% of Bi and 5-15 mu m of particle size; the purity of the Zn powder is more than or equal to 99.99 percent, and the grain diameter is 5-10 mu m; The CeO 2 powder is nano-scale and has the particle size of 30-50nm. Further, the low-melting-point solder comprises the following components in percentage by mass: 98.5-99.0% of Sn-Bi alloy powder, 0.8-1.2% of Zn powder and 0.2-0.4% of CeO 2 powder. Further, the melting point of the low-melting-point solder is 135-142 ℃. Further, the shearing strength of the low-melting-point solder is less than or equal to 45MPa. Further, the oxidation mass increase rate of the low-melting-point solder after 100h high-temperature aging is less than or equal to 0.05 percent. In a second aspect, based on the same inventive concept, the present invention provides a method for preparing the Sn-Bi low melting point solder containing Zn-CeO 2 according to any one of the first aspect, including the steps of: S1, weighing Sn-Bi alloy powder, zn powder and CeO 2 powder, mixing, loading into a ball milling tank, and ball milling under a protective atmosphere to obtain composite powder; S2, carrying out hot press forming on the composite powder in vacuum or protective atmosphere to obtain a compact welding material block; s3, processing and forming the compact solder block to obtain the low-melting-point solder. Further, the ball milling condition in the step S1 is that the ball-material ratio is (8-12) to 1, the rotating speed is 180-220rpm, the time is 1.5-2.5 hours, and the protective atmosphere is nitrogen or argon. Further, the hot pressing condition in the step S2 is that the temperature is 170-180 ℃, the pressure is 25-35MPa, the holding time is 8-12min, and the vacuum degree is less than or equal to 10 -3 Pa. Further, the processing and forming in the step S3 includes cutting the low-melting-point solder into a cylindrical shape, a sheet shape or a wire shape. Further, the cut is cylindrical with a dimension of Φ5mm and a thickness of 1mm. In a third aspect, based on the same inventive concept, the present invention provides an application of the Sn-Bi low melting point solder containing Zn-CeO 2 described in any one of the first aspects or the Sn-Bi low melting point solder containing Zn-CeO 2 prepared by the preparation method described in any one of the second aspects in flexible printed circuit board or low-temperature electronic device package with a tolerance temperature of less than or equal to 150 ℃. Compared with the prior art, the embodiment of the invention has at least the following advantages or beneficial effects: 1. the low-temperature performance is excellent, the melting point of the solder is reduced to 135-142 ℃, the welding requirement of a thermosensitive element (less than or equal to 150