In order to reduce the accumulation of moisture on a welding wire (2, 2, 2) arranged in a welding wire cartridge (1, 1a, 1b) or to remove existing moisture in a simple and reliable manner, it is provided that a flow (D.sub.1) of purging air supplied to the welding wire cartridge (1, 1a, 1b) is adjusted by a flow control unit (14), the purging air is supplied to the flow control unit (14) at a first pressure (p) and is discharged at a purging air discharge (24) of the welding wire cartridge (1, 1a, 1b) at a third pressure (p.sub.at), and at a purging air feed (15) of the welding wire cartridge (1, 1a, 1b) a second pressure (p.sub.1) at the purging air feed (15) that is lower than the first pressure (p) results from the adjusted flow (D.sub.1), the third flow (p.sub.at) and a flow resistance between the purging air feed (15) and the purging air discharge (24), the relative humidity (rF.sub.1) of the purging air being reduced by the relief of pressure from the first pressure (p) to the second pressure (p.sub.1).

In order to reduce the accumulation of moisture on a welding wire (2, 2, 2) arranged in a welding wire cartridge (1, 1a, 1b) or to remove existing moisture in a simple and reliable manner, it is provided that a flow (D.sub.1) of purging air supplied to the welding wire cartridge (1, 1a, 1b) is adjusted by a flow control unit (14), the purging air is supplied to the flow control unit (14) at a first pressure (p) and is discharged at a purging air discharge (24) of the welding wire cartridge (1, 1a, 1b) at a third pressure (p.sub.at), and at a purging air feed (15) of the welding wire cartridge (1, 1a, 1b) a second pressure (p.sub.1) at the purging air feed (15) that is lower than the first pressure (p) results from the adjusted flow (D.sub.1), the third flow (p.sub.at) and a flow resistance between the purging air feed (15) and the purging air discharge (24), the relative humidity (rF.sub.1) of the purging air being reduced by the relief of pressure from the first pressure (p) to the second pressure (p.sub.1).

A solder scattering is prevented at the time of reflow and the oxide films formed on the surfaces of solder or electrodes are thoroughly removed. The soldering method according to the present invention contains the steps of: applying solder paste to the electrode on a printed circuit board and mounting an electronic part on the solder paste, volatilizing the residue-free flux contained in the solder paste by heating the printed circuit board in a chamber set to be a vacuum state and approximately 180 degree C. at the time of pre-heating (interval A), removing oxide films formed on the electrode and the like by heating the printed circuit board in the chamber set to be a formic acid atmospheric state and the temperature of approximately 200 degree C. at the time of reducing (interval B), and melting solder powder contained in the solder paste by heating the printed circuit board in the chamber set to be a vacuum state and the temperature of 250 degree C. at the time of main heating (interval C).

A solder scattering is prevented at the time of reflow and the oxide films formed on the surfaces of solder or electrodes are thoroughly removed. The soldering method according to the present invention contains the steps of: applying solder paste to the electrode on a printed circuit board and mounting an electronic part on the solder paste, volatilizing the residue-free flux contained in the solder paste by heating the printed circuit board in a chamber set to be a vacuum state and approximately 180 degree C. at the time of pre-heating (interval A), removing oxide films formed on the electrode and the like by heating the printed circuit board in the chamber set to be a formic acid atmospheric state and the temperature of approximately 200 degree C. at the time of reducing (interval B), and melting solder powder contained in the solder paste by heating the printed circuit board in the chamber set to be a vacuum state and the temperature of 250 degree C. at the time of main heating (interval C).

Disclosed is a method for activating a surface of metals, such as self-passivated metals, and of metal-oxide dissolution, effected using a fluoroanion-containing composition. Also disclosed is an electrochemical cell utilizing an aluminum-containing anode material and a fluoroanion-containing electrolyte, characterized by high efficiency, low corrosion, and optionally mechanical or electrochemical rechargeability. Also disclosed is a process for fusing (welding, soldering etc.) a self-passivated metal at relatively low temperature and ambient atmosphere, and a method for electrodepositing a metal on a self-passivated metal using metal-oxide source.

A solder alloy includes Sn, optional Ag, Cu, and Al wherein the solder alloy composition together with the solder alloy superheat temperature and rapid cooling rate from the superheat temperature are controlled to provide a dispersion of fine hard CuAl intermetallic particles in an as-solidified solder alloy microstructure wherein the particles are retained even after multiple solder reflow cycles often used in modern electronic assembly procedures to provide a particle strengthening to the solder joint microstructure as well as exert a grain refining effect on the solder joint microstructure, providing a strong, impact- and thermal aging-resistant solder joint that has beneficial microstructural features and is substantially devoid of Ag.sub.3Sn blades.

A solder alloy includes Sn, optional Ag, Cu, and Al wherein the solder alloy composition together with the solder alloy superheat temperature and rapid cooling rate from the superheat temperature are controlled to provide a dispersion of fine hard CuAl intermetallic particles in an as-solidified solder alloy microstructure wherein the particles are retained even after multiple solder reflow cycles often used in modern electronic assembly procedures to provide a particle strengthening to the solder joint microstructure as well as exert a grain refining effect on the solder joint microstructure, providing a strong, impact- and thermal aging-resistant solder joint that has beneficial microstructural features and is substantially devoid of Ag.sub.3Sn blades.

The present invention provides a solder paste free of reducing agents and activators, and a method for producing a soldered product in which the solder paste is used to achieve solder bonding. The solder paste for reducing gas of the present invention is a solder paste for reducing gas used together a reducing gas. The solder paste contains a solder powder; a thixotropic agent that is solid at normal temperature; and a solvent, and is free of reducing agents for removal of oxide films and free of activators for improvement of reducibility.

The present invention provides a solder paste free of reducing agents and activators, and a method for producing a soldered product in which the solder paste is used to achieve solder bonding. The solder paste for reducing gas of the present invention is a solder paste for reducing gas used together a reducing gas. The solder paste contains a solder powder; a thixotropic agent that is solid at normal temperature; and a solvent, and is free of reducing agents for removal of oxide films and free of activators for improvement of reducibility.

Properties and performance of weld material between metals in a weldment is controlled by modifying one or more of the nitrogen content and the carbon content to produce carbide (e.g. MC-type), nitride and/or complex carbide/nitride (e.g. MX-type) type precipitates. Fusion welding includes (i) adjusting shield gas composition to increase nitrogen/carbon gas and nitride/carbide species, (ii) adjusting composition of nitrogen/carbon in materials that participate in molten welding processes, (iii) direct addition of nitrides/carbides (e.g. powder form), controlled addition of nitride/carbide forming elements (e.g. Ti, Al), or addition of elements that increase/impede solubility of nitrogen/carbon or nitride/carbide promoting elements (e.g. Mn), and (iv) other processes, such as use of fluxes and additive materials. Weld materials have improved resistance to different cracking mechanisms (e.g., hot cracking mechanisms and solid state cracking mechanisms) and improved tensile related mechanical properties.