Cold Welding Process
– Cold welding is a solid-state welding process.
– It joins two parts without fusion or heating.
– No liquid or molten phase is present in the joint.
– It was first recognized as a materials phenomenon in the 1940s.
– Clean, flat surfaces of similar metal strongly adhere when brought into contact in a vacuum.
Applications of Cold Welding
– Wire stock and electrical connections can be made using cold welding.
– Examples include insulation-displacement connectors and wire wrap connections.
– Cold welding has potential in nanofabrication processes.
– It is used in nanoscale cold welding for gold and silver nanowires.
– Potential applications extend to other bulk metals or metallic thin films.
Cold Welding in Space
– Mechanical problems in early satellites were attributed to cold welding.
– The European Space Agency published a paper on the significance of cold welding in spacecraft design.
– The Galileo spacecraft experienced cold welding issues with its high-gain antenna in 1991.
– Cold welding does not exclude relative motion between the surfaces being joined.
– Cold welding and other related phenomena like galling and fretting can overlap in some instances.
Nanoscale Cold Welding
– Single-crystalline ultra-thin gold nanowires can be cold-welded together at the nanoscale.
– Mechanical contact alone, under low applied pressures, can achieve cold welding of nanowires.
– Nanoscale welds exhibit the same crystal orientation, strength, and electrical conductivity as the rest of the nanowire.
– The high quality of nanoscale welds is attributed to nanoscale sample dimensions and oriented-attachment mechanisms.
– Cold welding has been demonstrated between gold and silver nanowires, as well as silver and silver.
Related Topics
– Abutment in dentistry is a connecting element related to cold welding.
– Gauge block wringing is a system for producing precision lengths using stacking components.
– Intermolecular force refers to the force of attraction or repulsion between molecules and neighboring particles.
– Nanoimprint lithography is a method of fabricating nanometer scale patterns using a special stamp.
– Spot welding is a process where contacting metal surfaces are joined by heat from resistance to electric current. Source: https://en.wikipedia.org/wiki/Cold_welding
This article needs additional citations for verification. (October 2010) |
Cold welding or contact welding is a solid-state welding process in which joining takes place without fusion or heating at the interface of the two parts to be welded. Unlike in fusion welding, no liquid or molten phase is present in the joint.
Cold welding was first recognized as a general materials phenomenon in the 1940s. It was then discovered that two clean, flat surfaces of similar metal would strongly adhere if brought into contact while in a vacuum (see Van der Waals force). Newly discovered micro- and nano-scale cold welding has shown potential in nanofabrication processes.
The reason for this unexpected behavior is that when the atoms in contact are all of the same kind, there is no way for the atoms to "know" that they are in different pieces of copper. When there are other atoms, in the oxides and greases and more complicated thin surface layers of contaminants in between, the atoms "know" when they are not on the same part.
— Richard Feynman, The Feynman Lectures on Physics, 12–5 Friction
Applications include wire stock and electrical connections (such as insulation-displacement connectors and wire wrap connections).