Some implementations of the disclosure relate to a lead-free solder paste with mixed solder powders that is particularly suitable for high temperature soldering applications involving multiple board-level reflow operations. In one implementation, the solder paste consists of 10 wt % to 90 wt % of a first solder alloy powder, the first solder alloy powder consisting of an SnSbCuAg solder alloy that has a wt % ratio of Sn:Sb of 0.75 to 1.1; 10 wt % to 90 wt % of a second solder alloy powder, the second solder alloy powder consisting of an Sn solder alloy including at least 80 wt % of Sn; and a remainder of flux.

A flux paste composition including one or more fluoroaluminate based flux agents, one or more thickening agents, a carrier, a dispersant, a wetting agent, a defoamer, a moderator, and a biocide agent. The flux past composition can be blended with one or more rheological additives selected based upon printing the blended flux composition by a contactless inkjet printing system.

A lead-free, antimony-free tin solder which is reliable at high temperatures and comprises from 3.5 to 4.5 wt.% of silver, 2.5 to 4 wt.% of bismuth, 0.3 to 0.8 wt.% of copper, 0.03 to 1 wt.% nickel, 0.005 to 1 wt.% germanium, and a balance of tin, together with any unavoidable impurities.

A method includes inserting a high temperature superconductor (HTS) cable into a groove of a support structure; and flowing a molten metal into the HTS cable while the HTS cable is in the groove. A magnet structure includes a support structure having a groove; and a high temperature superconductor (HTS) cable comprising a metal at least partially filling the HTS cable, the HTS cable being disposed in the groove.

A flux dotting tool is provided that includes: a housing having an internal space and a plurality of through-holes extending from the internal space to an outside of the housing; a plurality of flux pins disposed in the internal space to correspond to the plurality of through-holes, respectively, wherein each of the plurality of flux pins includes a flux holding portion extending in a first direction and that is exposed to the outside of the housing, and a flux blocking structure protruding in a second direction, perpendicular to the first direction, from a side surface of the flux holding portion, and the flux blocking structure is configured to limit a flux wetting region; and an elastic structure disposed on the plurality of flux pins in the internal space and configured to impart elastic force in the first direction.

Implementations of the disclosure are directed to a lead-free mixed solder powder paste suitable for low temperature to middle temperature soldering applications. The lead-free solder paste may consist of: an amount of a first solder alloy powder between 44 wt % and 83 wt %, the first solder alloy powder comprising Sn; an amount of a second solder alloy powder between 5 wt % to 44 wt %, the second alloy powder comprising Sn, where the first solder alloy powder has a liquidus temperature lower than a solidus temperature of the second solder alloy powder; and a remainder of flux. The solder paste may be used for reflow at a peak temperature below the solidus temperature of the higher solidus temperature solder powder but above the melting temperature of the lower solidus temperature one.

The present application provides a reflow oven (100) and a gas recovery method. The reflow oven (100) comprises a reflow oven hearth (101), a separator (105), the separator inlet (110) being connected to the gas outlet (102) of the reflow oven hearth (101) so that the gases in the reflow oven hearth (101) can flow into the separator (105), a zeolite box (107), the zeolite box inlet (112) being connected to the separator outlet (111), and the zeolite box outlet (113) being connected to the gas inlet (103) of the reflow oven hearth (101) so that the gases flowing through the separator (105) can enter the zeolite box (107) and the gases flowing through the zeolite box (107) can flow out of the zeolite box outlet (113), a sensor (106), which is provided in the gas passage between said zeolite box outlet (113) and the gas inlet (103) of the reflow oven hearth (101). The reflow oven (100) in the present application enables the gases flowing through the separator (105) to enter the zeolite box (107). After most of the flux is removed from the gases in the separator (105), the flux is further removed in the zeolite box (107). In addition, polygonal zeolites have certain volumes and are supported in the zeolite box (107) to form clearances, and thus almost no resistance is brought about to the flow of the gases in the zeolite box (107).

A method of making a semiconductor including soldering a conductor to an aluminum metallization is disclosed. In one example, the method includes substituting an aluminum oxide layer on the aluminum metallization by a substitute metal oxide layer or a substitute metal alloy oxide layer. Then, substitute metal oxides in the substitute metal oxide layer or the substitute metal alloy oxide layer are at least partly reduced. The conductor is soldered to the aluminum metallization using a solder material.

A water heater includes an outer casing defining a longitudinal axis, an axial direction being defined as extending along the longitudinal axis. The water heater further includes a combustor for production of hot flue gases, a primary heat exchanger including a tube positioned within the outer casing, and a secondary heat exchanger including a plurality of plates coupled together by brazing to form a brazed plate heat exchanger. The secondary heat exchanger includes a first set of passages defined between the plates, and a second set of passages defined between the plates and alternating with the first set of passages in the axial direction. The primary and secondary heat exchangers are in fluid communication such that the flue gases flow through the second set of passages before being exhausted, and water to be heated flows through the first set of passages to a delivery point for use upon demand.

A closed socket brazed joint assembly is provided. The assembly comprises: a first member composed of a first base material; a second member composed of a second base material with a first end composed of a first profile with at least first and second faying surfaces; a socket formed in said first member configured to receive the first end of the second member with a faying surface with at least two portions separated by a first fillet; wherein the socket further is configured such that in a first state before the application of energy to the joint there is a gap with a width between the faying surfaces of the first member and the faying surfaces of the second member; and, in the first state a slug of brazing fill material is disposed between the first end of the second member and at least one faying surface of the socket; and, wherein a second state is created when upon application of energy the brazing fill material melts and flows from between first end of the second member and the at least one faying surface of the socket filling aforesaid gap between the faying surfaces of the first and second members.