| 摘要 |
A sintered stainless steel coating is formed on steel strip by applying a powder containing a maximum of 0.25% carbon and at least 20% chromium, the strip containing a maximum of 0.01% free carbon, and sintering in a protective atmosphere to form a coating containing a minimum of 12% chromium and a maximum of 0.1% carbon. The powder coating may be applied by a fluidized bed technique, electrophoresis or by electrostatic spraying. Prior to coating, the strip may be decarburized in moist hydrogen at 1150 DEG -1450 DEG F. to reduce the free carbon to 0.01%. The strip is first coated with a liquid binder such as tridecyl alcohol, kerosene, transformer or straw oil or naphthene base oils. The coating powder of minus 150 mesh may be chromium; iron and chromium as a mixture or an alloy with or without nickel; or chromium and nickel as a mixture or an alloy. The powder coating is preferably applied by a fluidized bed and the powder coated strip is rolled to an elongation of 1-10%. Sintering is carried out on the open wound coil in vacuum, hydrogen or a noble gas at 1550 DEG -1900 DEG F. for a minimum of 12 hours. Optionally the atmosphere may contain 0.25 to 1% by volume of a halogen e.g. HCl, HF, Cl, or NH4Cl, CrF6. After sintering rolling may be carried out to an elongation of 1 to 2% and the surface may be brightened by buffing or brushing. |
