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CN-116393868-B - Lead-free solder based on indium-tin-silver

CN116393868BCN 116393868 BCN116393868 BCN 116393868BCN-116393868-B

Abstract

Indium-tin-silver alloys suitable for use as lead-free solders are described herein. The alloy may contain primarily indium or primarily tin. The alloy may further comprise copper, nickel, and iron or copper, antimony, and zinc. The composition may be used to solder an electrical connector (18, 30) to an electrical contact surface (16) on a glass assembly (10). Methods of forming the alloy are also described herein.

Inventors

  • J. Perera
  • S - C - Antara

Assignees

  • 安波福技术有限公司

Dates

Publication Date
20260508
Application Date
20160512
Priority Date
20150515

Claims (7)

  1. 1. An alloy suitable for use as a solder, the alloy comprising: about 14 to about 15 weight percent tin; About 1% by weight antimony; About 1% by weight copper; About 5 to 6 weight percent silver; About 1 to 3 weight percent nickel; About 1% by weight of zinc, and About 75 wt% indium, where "about X%" means that the percentage of elements varies by + -0.5 wt% for elements containing less than 25 wt% of the alloy, or by + -2 wt% for elements containing more than 25 wt% of the alloy.
  2. 2. The alloy of claim 1, wherein the alloy comprises about 14 wt.% tin, about 5 wt.% silver, and about 3 wt.% nickel.
  3. 3. The alloy of claim 1, wherein the alloy comprises about 15 wt.% tin, about 6 wt.% silver, and about 1 wt.% nickel.
  4. 4. The alloy of claim 1, wherein the alloy has a solidus temperature in the range between 122 ℃ and 124 ℃ and a liquidus temperature in the range between 136 ℃ and 138 ℃.
  5. 5. An electrical connector on a glass assembly, comprising: A glass assembly; an electrical contact surface on the glass component comprising silver; Electric connector and An alloy layer suitable for use as a solder according to claim 1, said alloy layer being located between said electrical connector and said electrical contact surface, thereby attaching said electrical connector to said electrical contact surface.
  6. 6. The electrical connector of claim 5, wherein the alloy comprises about 14 wt% tin, about 5 wt% silver, and about 3 wt% nickel.
  7. 7. The electrical connector of claim 5, wherein the alloy comprises about 15 wt.% tin, about 6 wt.% silver, and about 1 wt.% nickel.

Description

Lead-free solder based on indium-tin-silver The present application is a divisional application proposed again for divisional application 202211008509.1. The divisional application 202211008509.1 is a divisional application proposed for the divisional application 202110190195.0, and the divisional application 202110190195.0 is a divisional application of the application patent application titled "indium-tin-silver-based lead-free solder" with PCT international application number PCT/US 2016/032976, international application date 2016-05-12, and application number 201680028036.8 entering the national stage of china. Technical Field The invention relates to a solder, in particular to a lead-free solder based on indium-tin-silver. Background Windshields and backlites of vehicles (e.g., automobiles) often include electrical devices located in or on the glass. Typically, the electrical device is an antenna or defroster. To provide electrical connection to the electrical device, a small area of metal coating is applied to the glass to produce a metallized surface that is electrically connected to the electrical device. Subsequently, electrical connectors for connecting the lead or the lead itself are soldered to the metallized surface. Electrical connectors are typically soldered to the metallized surface of the glass with a solder containing lead (Pb). Most industries now use or plan for use of lead-free solders in soldering applications due to environmental problems and/or regulatory requirements in various countries. Conventional lead-free solders employed in certain industries contain high tin (Sn) content, such as tin in excess of 80%. Lead-free solders for use on automotive glass as described herein are disclosed in U.S. patent No. 6,253,988 issued to John Pereira (hereinafter "Pereira") at month 7 and 3 of 2001. Among several lead-free solders, pereira discloses solders having, by weight, 64.35% to 65.65% indium (In), 29.7% to 30.3% tin (Sn), 4.05% to 4.95% silver (Ag), 0.25% to 0.75% copper (Cu) (hereinafter referred to as "65 indium solders"). When welding devices to automotive glass, difficulties are encountered that are not present in many other applications. Automotive glass tends to be brittle and conventional high tin lead-free solders suitable for use in other applications typically cause cracking of the automotive glass. While materials such as ceramic and silicon may appear similar in some respects to automotive glass, solders that are partially suitable for soldering ceramic or silicon devices are not suitable for soldering automotive glass. Two materials with significantly different Coefficients of Thermal Expansion (CTE) for soldering, such as glass and copper in the present application, impose stresses on the solder during cooling after solder joint formation, or during subsequent temperature excursions. Solder needs to have a melting point (liquidus) low enough so as not to cause cracking of the automotive glass during the soldering process, as higher melting points and corresponding higher processing temperatures increase CTE mismatch, imposing higher stresses during cooling. However, the melting point of the solder needs to be high enough so that the solder does not melt during normal use of the automobile, such as when the automobile is under the sun with a window sealed, or under other extreme harsh environmental conditions. However, solders containing indium typically have a melting point much lower than other solders. For example, the solidus temperature of 65 indium solder is 109 ℃ compared to the solidus temperature of 160 ℃ of lead solder, and the liquidus temperature of 65 indium solder is 127 ℃ compared to the liquidus temperature of 224 ℃ of lead solder. Some vehicle manufacturers expect that the glass product should be able to withstand elevated temperatures (e.g., 110 ℃ for one vehicle manufacturer and 120 ℃ for another vehicle manufacturer) without any performance degradation. There is therefore a need for a lead-free solder suitable for use on glass that is able to withstand higher elevated temperatures than the compositions currently available, while imparting all other properties required for this application field. The subject matter discussed in the background section is only referenced in the background section and should not be assumed to be prior art. Similarly, the problems mentioned in the background section or related to the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different methods, which may themselves be inventions. Disclosure of Invention According to one embodiment of the present invention, an indium-tin-silver based solder is provided. A first embodiment is an alloy suitable for use as a solder having a mixture comprising about 40 wt% tin, about 0.5 wt% copper, about 50 wt% indium, about 4.5 wt% silver, about 1.8 wt% to abou