Joined solid production method

A method for producing a joined solid, the method comprising:

• placing a metal for bonding between a first solid and a second solid;
• covering at least a portion of the periphery of the metal for bonding with a high-melting-point material having a melting point higher than the melting point of the metal for bonding;
• and
• irradiating the metal for bonding, at least a portion of the periphery of which is covered with the high-melting-point material, with microwaves to heat the metal for bonding, thereby sintering or melt-solidifying the metal for bonding to bond the first solid and the second solid;
• and
• removing at least a portion of the high-melting point material from the metal for bonding,
• wherein in the portion of the metal for bonding covered with the high-melting-point material, the metal for bonding and the high-melting-point material are in close contact with each other, and
• the high-melting-point material includes a mixture of:
• an insulation material that has a lower degree of absorption of the microwaves than the metal for bonding, and
• an absorbent material that absorbs the microwaves in a temperature zone at least a portion of which is lower than a temperature zone in which the metal for bonding absorbs the microwaves.