Bismuth-based firearm projectiles, optionally firearm cartridges containing the same, and methods for forming bismuth-tin-copper alloys or bismuth-nickel alloys and bismuth-based firearm projectiles are disclosed herein. The bismuth-based firearm projectiles include a projectile body comprising a bismuth-tin-copper alloy or bismuth-nickel alloy that forms at least 90 wt % of the projectile body.

Bismuth-based firearm projectiles, optionally firearm cartridges containing the same, and methods for forming bismuth-tin-copper alloys or bismuth-nickel alloys and bismuth-based firearm projectiles are disclosed herein. The bismuth-based firearm projectiles include a projectile body comprising a bismuth-tin-copper alloy or bismuth-nickel alloy that forms at least 90 wt % of the projectile body.

A flux containing 1 to 10 wt % of an organic sulfonic acid activator, 10 to 40 wt % of a high-molecular-weight nonionic surfactant that is a nonionic surfactant having a mass-average molecular weight Mw of more than 1200 and 5 to 75 wt % of a low-molecular-weight nonionic surfactant that is a nonionic surfactant having a mass-average molecular weight Mw of 1200 or less, in which the content of the low-molecular-weight nonionic surfactant is equal to or larger than the content of the organic sulfonic acid activator. This flux contains no cationic surfactant or contains more than 0 wt % and 5 wt % or less of the cationic surfactant. A solder paste containing this flux and a Sn-based solder metal.

A droplet comprises a core including an alloy comprising a majority of a first metallic element and a minority of a second element, wherein the core is in a liquid state below a solidus temperature of the alloy. A shell is arranged to enclose the core and includes an exterior surface comprising a majority of the second element and a minority of the first metallic element, wherein the shell is in a solid state below the solidus temperature of the alloy. The alloy can comprise a solder material that can be used to form solder connections below a solidus temperature of the alloy.

A chemical reaction heat source for use in heaters used in down-hole applications is provided. The heat source has a fuel composition that comprises thermite and a damping agent. The use of the thermite mix enables the heaters of the present invention to generate hotter temperatures down wells. This in turn allows the use of Bismuth/Germanium alloys, which have higher melting points, to enable the production of plugs for the abandonment of deeper wells where subterranean temperatures are higher.

A chemical reaction heat source for use in heaters used in down-hole applications is provided. The heat source has a fuel composition that comprises thermite and a damping agent. The use of the thermite mix enables the heaters of the present invention to generate hotter temperatures down wells. This in turn allows the use of Bismuth/Germanium alloys, which have higher melting points, to enable the production of plugs for the abandonment of deeper wells where subterranean temperatures are higher.

A thermoelectric conversion material having a high dimensionless figure of merit ZT includes: a large number of polycrystalline grains which include a skutterudite-type crystal structure containing Yb, Co, and Sb; and an intergranular layer which is between the neighboring polycrystalline grains and includes crystals in which an atomic ratio of O to Yb is more than 0.4 and less than 1.5. A method for manufacturing a thermoelectric conversion material includes: a weighing step; a mixing step; a ribbon preparation step by rapidly cooling and solidifying a melt of the raw materials by using a rapid liquid cooling solidifying method; a first heat treatment step including heat treating in an inert atmosphere with an adjusted oxygen concentration; a second heat treatment step including heat treating in a reducing atmosphere; and manufacturing the thermoelectric conversion material by a pressure sintering step in an inert atmosphere.

A thermoelectric conversion material having a high dimensionless figure of merit ZT includes: a large number of polycrystalline grains which include a skutterudite-type crystal structure containing Yb, Co, and Sb; and an intergranular layer which is between the neighboring polycrystalline grains and includes crystals in which an atomic ratio of O to Yb is more than 0.4 and less than 1.5. A method for manufacturing a thermoelectric conversion material includes: a weighing step; a mixing step; a ribbon preparation step by rapidly cooling and solidifying a melt of the raw materials by using a rapid liquid cooling solidifying method; a first heat treatment step including heat treating in an inert atmosphere with an adjusted oxygen concentration; a second heat treatment step including heat treating in a reducing atmosphere; and manufacturing the thermoelectric conversion material by a pressure sintering step in an inert atmosphere.

Provided are a thermoelectric material having excellent thermoelectric characteristics at room temperature; a method for producing same; and a thermoelectric power generation element. In an embodiment of the present invention, the thermoelectric material contains an inorganic compound containing magnesium (Mg), silver (Ag), antimony (Sb) and copper (Cu), and is represented by the formula Mg.sub.1−aCu.sub.aAg.sub.bSb.sub.c, and the parameters a, b and c satisfy: 0<a≤0.1, 0.95≤b≤1.05 and 0.95≤c≤1.05. The inorganic compound may be an a phase of a half-Heusler structure and have the symmetry of the space group I-4c2.

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.