Method of preparing a surface for diffusion bonding and method of diffusion bonding

A method of preparing a surface for diffusion bonding, the method comprising:

• contacting a binder material with a discontinuous surface comprising surface regions separated by gaps, the binder material being selectively deposited onto the surface regions and forming a self-supporting layer without flowing into the gaps, the self-supporting layer of binder material being uniformly deposited on the surface regions with a mass density in a range from about 0.001 g/in2 to about 0.050 g/in2, wherein the contacting comprises rolling a belt or roller coated with the binder material over the discontinuous surface, an axis of rotation of the belt or roller being parallel to the surface regions;
• distributing a braze powder over the binder material, a predetermined amount of the braze powder being attached to the binder material;
• and
• heating the discontinuous surface to remove the binder material and adhere the braze powder to the discontinuous surface, thereby forming a prewet surface with a braze deposit thereon.