Keum-boo (Korean: 금부; also Geumbu, Kum-Boo or Kum-bu—Korean "attached gold") is an ancient Korean gilding technique used to apply thin sheets of gold to silver, to make silver-gilt.

Then 24 carat gold foil is applied with heat and pressure—mechanical gilding—to produce a permanent diffusion bond.

Pure precious metals such as gold and silver have a very similar atomic structure and therefore have a good potential for bonding.

When pressure is added, this causes an electron exchange at the surface between the two metals, creating a permanent diffusion bond.

Examples of this technique have probably been observed, but not positively identified on pieces from the second half of the first millennium B.C.