A lead-free soldering foil, for connecting metal and/or metal-coated components. allows the setting of a defined connecting-zone geometry and, with pores and/or voids being formed only to a minimal extent, achieves a high-temperature-resistant soldered connection that ensures great reliability even in staged soldering processes and increases the thermal conductivity of the connecting zone. The lead-free soldering foil is constructed so that, in a soft-solder matrix, two or more composite wires are each individually sandwiched by roll cladding between two soft-solder strips, parallel to one another and parallel to the edges of the strips. These composite wires include a core, which contains a higher-melting, stronger metal/metal alloy in comparison with the soft-solder matrix and around which a shell of another metal/metal alloy is arranged, and, after the roll-cladding operation, there is still 5 pm to 15 pm of soft-solder material arranged above and below at least one of the cores.

A method for step-soldering includes applying a first solder alloy having a melting point in a temperature range from 160 to 210° C. to a jointed portion of a first electronic component and a substrate, and heating them in the temperature range from 160 to 210° C., and applying a second solder alloy having the melting point in a temperature range lower than 160° C. to a joint portion of a second electronic component and the substrate, and heating them in the temperature range lower than 160° C. The first solder alloy consists of 13-22 mass % of In, 0.5-2.8 mass % of Ag, 0.5-5.0 mass % of Bi, 0.002-0.05 mass % of Ni and a balance Sn.

A method for step-soldering includes applying a first solder alloy having a melting point in a temperature range from 160 to 210° C. to a jointed portion of a first electronic component and a substrate, and heating them in the temperature range from 160 to 210° C., and applying a second solder alloy having the melting point in a temperature range lower than 160° C. to a joint portion of a second electronic component and the substrate, and heating them in the temperature range lower than 160° C. The first solder alloy consists of 13-22 mass % of In, 0.5-2.8 mass % of Ag, 0.5-5.0 mass % of Bi, 0.002-0.05 mass % of Ni and a balance Sn.

The present invention provides a thermoelectric material excellent in heat resistance with less degradation of thermoelectric characteristics even in a high temperature environment. The thermoelectric material comprises a compound represented by a chemical formula Mg.sub.2Si.sub.1-xSn.sub.x (0<x<1) wherein at least one of the Si site and the Sn site of the compound is replaced with at least one of Sb and Bi, and an added Fe.

A system for smelting tin-containing materials is disclosed. The system includes a pretreatment mechanism, a screening mechanism, a feeding mechanism, a smelting mechanism, a slag treatment mechanism and a tail gas treatment mechanism. In addition, the disclosure discloses a method by using the above system. In the disclosure, dry tin-containing materials can be sieved, and fine tin-containing materials can be conveyed into top-blown furnace molten pool for smelting through the belt, while the coarse tin-containing materials can be sprayed into the molten pool through the spray gun, which can reduce the splashing or material leakage loss of the tin-containing materials with smaller particle size during the transportation process, and also avoid the mechanical inclusion or flying loss caused by the belt; furthermore, the fine dry materials are prevented from adding water before entering furnace, thereby reducing smelting energy consumption and smelting flue gas quantity, and realizing environment-friendly and energy-saving smelting.

An electronic component includes a component body, a base electrode that has a surface exposed from the component body and contains at least one of silver and copper, an alloy layer deposited on the surface of the base electrode, and a nickel layer deposited on a surface of the alloy layer. The material of the alloy layer is an alloy containing nickel and tin.

An electronic component includes a component body, a base electrode that has a surface exposed from the component body and contains at least one of silver and copper, an alloy layer deposited on the surface of the base electrode, and a nickel layer deposited on a surface of the alloy layer. The material of the alloy layer is an alloy containing nickel and tin.

A manufacturing method of a flexible electronic substrate and a substrate structure are disclosed. The manufacturing method includes: providing a first substrate comprising a first surface and a second surface which are opposite; forming a separation layer on the first surface of the first substrate, the separation layer being in a film form; providing a second substrate on the separation layer, the second substrate being configured as a flexible substrate; and processing the separation layer, such that at least a part of the separation layer is cracked from the film form, thereby separating the second substrate from the first substrate.

A solder paste includes a first solder alloy powder in an amount ranging from 30% to 95% by weight. The first solder alloy powder includes a first solder alloy with a solidus temperature of 200° C. to 260° C. The first solder alloy includes an Sn—Cu alloy or an Sn—Cu—Ag alloy. The solder paste further includes a second solder alloy powder in an amount ranging from 5% to 70% by weight, and a solder flux. The second solder alloy powder includes a second solder alloy with a solidus temperature below 250° C. The solder paste has a variable melting point. In multiple reflow soldering, a remelting of the solder paste is inhibited under different temperature conditions so that no functional failure occurs during assembly and/or packaging of PCBs or electronic devices due to melting of solder.

A solder paste includes a first solder alloy powder in an amount ranging from 30% to 95% by weight. The first solder alloy powder includes a first solder alloy with a solidus temperature of 200° C. to 260° C. The first solder alloy includes an Sn—Cu alloy or an Sn—Cu—Ag alloy. The solder paste further includes a second solder alloy powder in an amount ranging from 5% to 70% by weight, and a solder flux. The second solder alloy powder includes a second solder alloy with a solidus temperature below 250° C. The solder paste has a variable melting point. In multiple reflow soldering, a remelting of the solder paste is inhibited under different temperature conditions so that no functional failure occurs during assembly and/or packaging of PCBs or electronic devices due to melting of solder.