Technology： Other surface modification technologiesTD process
The TD process produces a high-functional coating formed from carbide including niobium and chromium. In the process, the workpiece is uniformly coated by dipping it into the high-temperature salt bath. The coating is applicable to workpieces of complicated shapes and achieves high hardness of HV2,500 to 2,700. The TD process is a vital technology that is highly regarded in the mold production industry.
TD-VC coating
TD-VC coating is an extremely hard vanadium carbide (VC) coating produced by the TD process, a high temperature salt bath treatment. The coating, which has cross-sectional hardness as high as HV2,500 to 2,700, protects the workpiece surface from wear and seizure. TD-VC coating greatly improves workpiece durability and is highly evaluated as a superior and indispensable surface modification in the metal mold industry.
The salt bath treatment produces a uniform coating on any shape of workpiece, including on internal blind areas.
Properties of TD-VC coating
Coating type
Thickness (μm)
Hardness (HV)
Adherence mechanism
TD-VC
3–15
2,500–2,700
Diffusion type
Cr-plating
20–50
900–1,000
Mechanical type
Cross sectional structure of TD-VC coating
Wear resistance by coining
Molten aluminum resistance
TBS-1500 coating
TBS-1500 coating is an iron-boride hard coating produced by a high temperature salt bath treatment as well as TD-VC coating. TBS-1500 exhibits unparalleled durability against erosion with high temperature particles. Materials to be processed are transition metals, such as iron, where the coating chemically reacts to the base metal to form a boride compound on the processed material surface. The TBS-1500 method can generally form a thicker coating than the TD-VC method.
Cross sectional structure of TBS-1500 coating
Hardness and thickness of TBS-1500 coating by processed substrate
