3. Key Steps in the Low-Temperature Brazing Process
1) Substrate and Diamond Pre-treatment: Clean the steel substrate and apply a coating (e.g., nickel plating). Treat the diamond surface with a metallised coating (e.g., titanium plating) to enhance the wettability and bonding strength of the brazing filler metal.
2) Ordered Arrangement: Precisely position diamond particles on the substrate working surface according to predetermined patterns, spacings, and orientations. This forms the foundation for achieving 'ordered cutting'.
3) Filler Application: Place active filler material (commonly silver-, copper-, or nickel-based alloys containing active elements like Ti or Cr) in sheet, powder, or paste form around the diamond particles.
4) Vacuum brazing: The workpiece is placed in a vacuum brazing furnace. Under vacuum or a protective atmosphere, it is heated above the brazing filler's melting point. The filler melts, wetting both the diamond and substrate. Reactive elements chemically react with the diamond surface, forming a carbide layer. Mutual diffusion occurs between the filler and substrate, creating a metallurgical bond.
5) Cooling and forming: Following gradual cooling, the filler metal solidifies, forming a high-strength, high-integrity bonding layer. The diamond is thus firmly "welded" to the substrate.
