| 摘要 |
PURPOSE:Base material is immersed into alloy forming metal bath and then pulled out. While the outermost flux layer is still flowing, metal powder of base material composition is coated on the surface and thermally diffused at high temperature. This process forms an alloy layer which provides the base material with resistance to high temperature oxidation, heat resistance and high temperature hardness. CONSTITUTION:Base material such as steel iron is immersed into a molten metal such as Al for one to ten minumtes and pulled out to form on the surface of base iron 6, an alloy layer of iron and Al 7a, an Al layer 8 and a flux layer 9, while the flux layer 9 is still flowing at high temperature, iron powder 10 is spray-coated onto the flux layer 10. The coated steel is placed into a thermal diffusion furnace having innert or flux gas atomosphere in which the Al layer 8 is alloyed quickly at high temperature. The Al layer 8 is thermally diffused to both outside and inside direction, causing high Al concentration at center zone low Al concentrations at both outside and inside zones. |
