Glass article with metal member joined thereto, and junction structure using the same
View Patent ↗The present invention is intended to provide a glass article with a metal member joined thereto in which an electroconductive coating film is formed on at least a part of the surface of the glass article by baking a silver paste that includes Ag particles and a glass frit, a joining plane of the metal member is fixed onto the electroconductive coating film with a lead-free solder alloy containing Sn as a main component, and the lead-free solder alloy contains at least 1.5 mass % of Ag, which prevents the appearance of the electroconductive coating film and the bonding strength from degrading. Furthermore, in the present invention, when using a metal member having at least two joining planes, the total area of the joining planes is set within a range of 37 mm 2 to 50 mm 2 , which allows high bonding strength between the glass article and metal member to be maintained while using the lead-free solder alloy. Moreover, in the present invention, the volume of the lead-free solder alloy to be provided on each joining plane is set to be 1.0 to 2.0 times the product of the area of the joining plane concerned and the thickness of the lead-free solder alloy, which prevents cracks from occurring in the glass article.
1. A glass article with a metal member joined thereto, comprising:
an electroconductive coating film formed on at least a part of a surface of the glass article by baking a silver paste that includes Ag particles and a glass frit,
wherein the metal member comprises two joining planes, a leg part that bridges the two joining planes, and a connection part that projects unward from the leg part, and
wherein the two joining planes of the metal member are fixed onto the electroconductive coating film with a lead-free solder alloy containing Sn as a main component, and
wherein when the glass article undergoes a tension test in which the metal member is pulled upward, the glass article and the metal member are ruptured because of a breakage of an inner portion of the glass article in a vicinity of a junction portion soldered using the lead-free solder and not because of a breakage of the junction portion, and
wherein the lead-free solder alloy is a Sn—Ag based alloy that contains 2 to 4 mass % of Ag, and a content of other minor components except for Sn and Ag in the Sn—Ag based alloy is 0.5 mass % or less, and
wherein the Sn—Ag based alloy has a liguidus temperature of 230° C. or lower, and the difference of the liquidus temperature and a solidus temperature of the Sn—Ag based alloy is 10° C. or less, and
wherein a total area of the two joining planes is in a range of 40 mm 2 to 45 mm 2 .
2. The glass article according to claim 1 , wherein the electroconductive coating film is at least one selected from an antenna and a defogger.
3. The glass article according to claim 1 , wherein with respect to each of the two joining planes, a volume of the lead-free solder alloy is 1.0 to 2.0 times the product of an area of the joining plane concerned and a thickness of the lead-free solder alloy, and
wherein the alass article forms no cracks after 500 times of a thermal cycle, and each thennal cycle consists of a first period of retention for 30 minutes at −30° C. a second period of raisina tenperature to 80° C. in three minutes, a third period of retention for 30 minutes at 80° C. and a fourth period of decreasing temperature to −30° C. in three minutes.
4. A junction structure, comprising a glass article according to claim 1 ,
wherein a cable is connected to a connection part of the metal member, and the cable and the electroconductive coating film are connected electrically to each other.