Wyniki wyszukiwania - BazTech

Ograniczanie wyników

1 2017

Znaleziono wyników: 1

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: rezonans magnetyczny EPR

Sortuj według:

Ogranicz wyniki do:

The magnetic properties of steel after the gas nitriding process

Michalski J., Fuks H., Kaczmarek S. M., Leniec G., Kucharska B., Wach P.

Inżynieria Materiałowa

2017

Vol. 38, nr 4

170--176

The paper presents the relationship between the chemical composition of the steel balls, their size and parameters of the nitriding process and magnetic properties defined in the study by EPR and SQUID. The balls made form non-alloyed AISI 1085 and alloyed AISI 420-C steels were investigated. At resonance spectra for both steels before the nitriding process, the resonance signal only existed for two magnetic induction values, 400 mT and 650 mT. This values are untypical because for magnetic centres in the form of iron ions, the expected EPR signal occurs usually in magnetic fields of approx. 340 mT, when the spectrometers operates in the so called microwave X band. This abnormality presumed that the resonance signals did not originate from isolated ions, but instead from magnetically more complex systems, e.g. Fe–Fe pairs or iron clusters, while the observed EPR line position is normally even lower and occurs for a magnetic induction below 200 mT. The fact, that the magnetic centres not had the nature of isolated Fe ions, additionally confirmed the abnormal increase in resonance signal intensity as a function of temperature, which is a behaviour inconsistent with the Curie-Weiss law. After nitriding the AISI 420-C steel in the Nx1021(580/600°C) process, the resonance line became distinctly wider and shifts towards greater magnetic induction values. After nitriding at a lower temperature (the Nx1025(490/520°C process), the resonance lines shifted towards greater magnetic induction values, but, at the same time, the line became more symmetric, closer to the shape of the Lorentz function derivative. The results obtained from measurements by the SQUID method, recording variations in magnetization as a function of temperature, confirm the untypical reinforcement of the magnetic conditions of the samples with the increase in temperature. For the samples tested, the magnetization was relatively weaker, when the tests were conducted in a stronger magnetic field.

Podczas tworzenia się warstwy azotowanej na stali zmianom ulegają jej właściwości elektryczne (przewodność) oraz magnetyczne, wśród których najbardziej czułe na zmiany fazowe i strukturalne azotowanej stali są względna przenikalność magnetyczna i natężenie pola koercji magnetycznej. W pracy podjęto się zbadania relacji pomiędzy składem chemicznym, rozmiarem i parametrami procesu azotowania stalowych kulek a ich właściwościami magnetycznymi.