Magnetic force microscopy of a carburized ethylene pyrolysis tube

Magnetic force microscopy has been used to characterize the paramagnetic to ferromagnetic transition caused by carbide precipitation in a HPM alloy used in ethylene production. The MFM images are compared to conventional atomic force microscope micrographs. The element segregation in the alloy is quantified using scanning electron microscope energy dispersive x-ray analysis linescans, and compared to Curie temperature data for iron, nickel and chromium alloys.