多孔質, 耐食性PM磁性材料の磁気シールド効果について On Magnetic Shielding Effectiveness of Porous, Corrosion-Resistant PM Magnetic Alloys
The objective of this study is mainly to evaluate PM ferritic stainless steel as magnetic shielding plate, comparing with PM PB-permalloy. In this case, PM plate thickness and sintering temperature (1173-1623K) were employed as parameters to optimize DC/AC (≤10kHz) magnetic shielding effect of materials, including magnetic measuring apparatus arrangement.<BR>The results obtained in these conditions were summarized as follows:<BR>(1) DC magnetic field is allowed to attenuate to a saturate level by using PM plate with 4mm thick which is sintered at 1273K at the lowest, while the saturate value decreases with the distance (r) from a magnetic source.<BR>(2) AC magnetic field also is allowed to attenuate to a saturate level by using PM plate with 4mm thick which is sintered at 1373K at the lowest, although the saturate value differentiates between the frequencies of 1 and 10 kHz.<BR>(3) Magnetic attenuation (dB) is fairly enhanced when a covering of the high-μ permalloy sheet is put on the periphery of PM plate in DC and 1 kHz range, although it is not effective in higher frequency range.<BR>(4) Bend strength of PM plate shows a higher value by being sintered at higher temperature (ex.-200MPa at 1373K), untouched by the direct influence of material itself.<BR>(5) PM ferritic stainless steel proved to have almost the same magnetic shielding effect as PM PB-permalloy, when sintered at 1373K or higher, and consequently, to be used as porous, corrosion-resistant magnetic shielding alloy.
粉体および粉末冶金 46(2), 156-162, 1999-02-15
Japan Society of Powder and Powder Metallurgy