A unique sequence of steps is provided to reduce contaminants along one or more surfaces and faces of gold evaporative sources without deleteriously impacting the structure of the gold evaporative sources. Edges are deburred; contaminants are successfully removed therealong; and surface smoothness is substantially retained. The resultant gold evaporative source is suitable for use in evaporative processes as a precursor to gold film deposition without the occurrence or a substantial reduction in the likelihood of spitting by virtue of significantly reduced levels of contaminants, in comparison to gold evaporative sources subject to a standard cleaning protocol.

The disclosure provides gold alloys. The alloys can have improved strength and hardness. The gold alloys can have various gold colors, including yellow gold and rose gold. The gold alloys can be used as enclosures for electronic devices.

The disclosure provides gold alloys. The alloys can have improved strength and hardness. The gold alloys can have various gold colors, including yellow gold and rose gold. The gold alloys can be used as enclosures for electronic devices.

Disclosed herein is a high-temperature lead-free Au—Sn—Ag-based solder alloy that is excellent in sealability, joint reliability, and wet-spreadability, that can be kept at a high quality level for a long period of time, and that is provided at a relatively low cost. The lead-free Au—Sn—Ag-based solder alloy contains 27.5 mass % or more but less than 33.0 mass % of Sn, 8.0 mass % or more but 14.5 mass % or less of Ag, and a balance being Au except for elements inevitably contained therein during production. When having a plate- or sheet-like shape, the Au—Sn—Ag-based solder alloy has a surface whose L*, a*, and b* in an L*a*b* color system in accordance with JIS Z8781-4 are 41.1 or more but 57.1 or less, −1.48 or more but 0.52 or less, and −4.8 or more but 9.2 or less, respectively. When having a ball-like shape, the Au—Sn—Ag-based solder alloy has a surface whose L*, a*, and b* are 63.9 or more but 75.9 or less, 0.05 or more but 0.65 or less, and 1.3 or more but 11.3 or less, respectively.

Disclosed herein is a high-temperature lead-free Au—Sn—Ag-based solder alloy that is excellent in sealability, joint reliability, and wet-spreadability, that can be kept at a high quality level for a long period of time, and that is provided at a relatively low cost. The lead-free Au—Sn—Ag-based solder alloy contains 27.5 mass % or more but less than 33.0 mass % of Sn, 8.0 mass % or more but 14.5 mass % or less of Ag, and a balance being Au except for elements inevitably contained therein during production. When having a plate- or sheet-like shape, the Au—Sn—Ag-based solder alloy has a surface whose L*, a*, and b* in an L*a*b* color system in accordance with JIS Z8781-4 are 41.1 or more but 57.1 or less, −1.48 or more but 0.52 or less, and −4.8 or more but 9.2 or less, respectively. When having a ball-like shape, the Au—Sn—Ag-based solder alloy has a surface whose L*, a*, and b* are 63.9 or more but 75.9 or less, 0.05 or more but 0.65 or less, and 1.3 or more but 11.3 or less, respectively.

A method for producing a metal particle which includes the steps of: mixing a metal salt and a polycarboxylic acid in a liquid phase; adding a reducing agent to the resultant mixture to deposit metal particles; and drying the deposited metal particles.

A method for producing a metal particle which includes the steps of: mixing a metal salt and a polycarboxylic acid in a liquid phase; adding a reducing agent to the resultant mixture to deposit metal particles; and drying the deposited metal particles.

Provided in one embodiment is a method of identifying a stable phase of an ordering binary alloy system comprising a solute element and a solvent element, the method comprising: determining at least three thermodynamic parameters associated with grain boundary segregation, phase separation, and intermetallic compound formation of the ordering binary alloy system; and identifying the stable phase of the ordering binary alloy system based on the first thermodynamic parameter, the second thermodynamic parameter and the third thermodynamic parameter by comparing the first thermodynamic parameter, the second thermodynamic parameter and the third thermodynamic parameter with a predetermined set of respective thermodynamic parameters to identify the stable phase; wherein the stable phase is one of a stable nanocrystalline phase, a metastable nanocrystalline phase, and a non-nanocrystalline phase.

Provided in one embodiment is a method of identifying a stable phase of an ordering binary alloy system comprising a solute element and a solvent element, the method comprising: determining at least three thermodynamic parameters associated with grain boundary segregation, phase separation, and intermetallic compound formation of the ordering binary alloy system; and identifying the stable phase of the ordering binary alloy system based on the first thermodynamic parameter, the second thermodynamic parameter and the third thermodynamic parameter by comparing the first thermodynamic parameter, the second thermodynamic parameter and the third thermodynamic parameter with a predetermined set of respective thermodynamic parameters to identify the stable phase; wherein the stable phase is one of a stable nanocrystalline phase, a metastable nanocrystalline phase, and a non-nanocrystalline phase.

The present invention provides a non-cyanide based Au—Sn alloy plating solution capable of performing a Au—Sn alloy plating treatment by a plating solution composition that is neutral and does not contain cyanide. In the present invention, a non-cyanide soluble gold salt, a Sn compound composed of tetravalent Sn, and a thiocarboxylic acid-based compound are contained. The non-cyanide based Au—Sn alloy plating solution of the present invention can further contain sugar alcohols, and, in addition, can further contain a dithioalkyl compound.