Diffusion BondingDiffusion bonding, also known as diffusion welding, is a solid state process used for welding certain specific materials for specialised applications. The process uses heat and pressure to put the components in very close surface contact and this is applied for a pre-set time at temperature to allow bonding to take place. The process may be carried out with or without filler. If filler is used it would be in the form of an insert or surface plating put in place prior to joint fit-up. Equipment requirements depend on the exact methods used but would include a means of bringing the components together under pressure, such as a press, and a method of heating, such as a furnace. The process may be operated automatically or semi-automatically and equipment and running costs can be high. Joint preparation, tolerances, and fit-up must be extremely accurate. The process is suited to the welding of expensive materials where fusion welding is undesirable because of metallurgical reactions that would take place, for fabrication of laminates, and where any distortion must be avoided. It finds applications mainly in nuclear, aerospace and similar industries.
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