The structure and magnetic properties of bronze, stainless still and alloy layers formed by direct laser welding on nonmagnetic substrates

摘要

Investigations of crystal structure, microstructure and composition of laser welded coatings of bronze, IN625, PGSR-4 and stainless steel alloys on non-magnetic substrates have shown that from the raw alloy powders (wire) the additional crystalline phases are extracted with new compositions and sizes of units of microns, which randomly distributed in the coating volume. Due to formation of additional phases with increased electron concentration magnetic hysteresis loops have appeared at 4 K and 300 K for all welded coatings. Bronze and stainless steel coatings have demonstrated soft ferromagnetic properties with two type of magnetic domains with small magnetization that resulted in small value of saturation magnetization (60-146 emu/cm~3 at 300 K and 107-241 emu/cm~3 at 4 K) and low values of coercive force (40 - 90 Oe) at 300 K and (50-170 Oe) at 4 K. The formation of one type of ferromagnetic domains with middle Curie temperatures (230-270 K) in laser welded IN625 and PGSR-4 coatings has determined soft ferromagnetic nature of magnetism at low temperature and transition in paramagnetic conditions at 300 K due to main contribution only paramagnetic grains with different composition.