Magnetic properties of nanocrystalline spherical Fe 3 O 4 particles deposited on a chitin surface were investigated, and the mechanisms of precipitation and magnetization were explained. The main investigations were performed by means of Mö ssbauer spectroscopy and by measurements of the saturation magnetization. The size of chitin particles used as magnetic carriers was 0.05-0.25 mm, and the Fe 3 O 4 particles were precipitated from a ferrofluid. The experimental results agreed well with the theoretical model of the superferromagnetic state. The remaining magnetic properties in nanometric Fe 3 O 4 particles were explained by collective magnetic interactions. It has been found that the saturation magnetization of magnetic carriers --nanocrystalline Fe 3 O 4 particles deposited on a chitin surface --is two or three times lower than that of bulk Fe 3 O 4 crystals of the same amount.

Oxidation of erosion products was studied by means of the Mössbauer spectroscopy and X-ray diffraction methods when the strip of stainless steel was cut with the laser. Different content of wustite and chromium doped magnetite Fe 3−x Cr x O 4 was found in the samples of erosion products depending on the place where the erosion products were collected in relation to the cutting slot. Conversion electron Mössbauer spectroscopy data showed that more magnetite was found at the surface while wustite distributes in the whole volume of particles of erosion products.

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Steel 20KhN2M is used for the production of gears and other components, for whose service enhanced wear resistance is required in retaining resistance to bnpact loadings. The deforvnation (warping) and increased brittleness of these components are observed after their bulk hardening. The deformation of the components cannot be completely eliminated, even on hardening with the use of superhigh-frequency radiation. Local laser heating lowers defopvnation to a significant degree, hz this connection, it was interesting to study the effect of laser radiation on the mechanical properties of the indicated components.

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