Heat Treatment Chemicals Used as Catalysts or Addi...

Heat Treatment Chemicals Used as Catalysts or Additives 1. Ammonium Chloride (Naushadar) Role: Flux in galvanizing and annealing Function: Removes oxide scale from metal surfaces during heat treatment Common Use: Pickling steel before hot-dip galvanizing 2. Sodium Nitrate (NaNO₃) & Potassium Nitrate (KNO₃) Role: Oxidizing salts in salt baths for nitriding and carburizing Function: Provide nitrogen/oxygen to harden steel surface layers Common Use: Salt bath nitriding to increase surface hardness 3. Sodium Carbonate (Na₂CO₃) (Soda Ash) Role: Flux and cleaning agent in heat treatment Function: Helps remove impurities and scales; used in carburizing powders 4. Boric Acid (H₃BO₃) Role: Protective coating in brazing and annealing Function: Prevents oxidation during heating by forming a glassy protective layer 5. Sodium Silicate Role: Binder in heat treatment powders/coatings Function: Holds carburizing compounds on the metal surface during heat treatment 6. Potassium Fluoride (KF) Role: Catalyst in surface treatment and brazing fluxes Function: Helps remove oxides from surfaces, improves wetting 7. Zinc Chloride (ZnCl₂) Role: Flux in annealing and galvanizing Function: Removes oxide layers and promotes clean metal surfaces 8. Sodium Thiosulfate (Na₂S₂O₃) Role: Used in quenching baths and pickling Function: Acts as an oxygen scavenger, preventing scale formation 9. Ammonium Sulfate ((NH₄)₂SO₄) Role: Used in some carburizing and nitriding powders Function: Supplies sulfur and nitrogen to modify surface properties Summary Table Chemical Role in Heat Treatment Application Ammonium Chloride Flux / oxide remover Annealing, galvanizing Sodium/Potassium Nitrate Oxidizer / nitrogen source Salt bath nitriding, carburizing Sodium Carbonate Flux / impurity remover Carburizing powders, cleaning Boric Acid Protective coating Brazing, annealing Sodium Silicate Binder Carburizing coatings Potassium Fluoride Catalyst in fluxes Surface cleaning, brazing Zinc Chloride Flux Annealing, galvanizing Sodium Thiosulfate Oxygen scavenger Pickling, quenching baths Ammonium Sulfate Surface modifier Carburizing, nitriding powders