The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform

C. Miclea - One of the best experts on this subject based on the ideXlab platform.

  • Magnetic Temperature Transducers Made from Copper Based Soft Ferrite
    Advances in Science and Technology, 2008
    Co-Authors: C. Miclea, Cosmina Tanasoiu, Ion Spanulescu, M. Cioangher
    Abstract:

    Soft ferrites in the CuZnTi system, having the chemical composition Cu1-x-yZnxTiyFe2O4 with 0.5£x£0.7 and 0.00£y£0.05 were investigated as a function of composition, sintering Temperature and cooling speed, in order to obtain materials with different Curie Temperatures, between 30 and 180 oC and very high change rate of permeability with Temperature around their Curie points. Such materials are well suited to use as high sensitive Magnetic Temperature sensors and transducers for Temperature control. Zn and Ti additions to copper ferrite change the Curie Temperature in a controllable manner, thus being possible to produce ferrite material with a fine control of the Curie point at any desired Temperature. Most important was the behavior of Magnetic permeability with Temperature around the Curie point, where it may change with about 60 %/oC by a proper choice of the cooling speed of samples from the sintering Temperature to room Temperature. This makes such materials extremely attractive as Magnetic Temperature sensors of high sensitivity. Two applications of such materials as Temperature sensors, namely an ultrathermostat and an on-off switch type relay were designed. Their functionality and performances are presented and discussed.

  • Soft ferrite materials for Magnetic Temperature transducers and applications
    Journal of Magnetism and Magnetic Materials, 2005
    Co-Authors: C. Miclea, Cosmina Tanasoiu, Alexandru Gheorghiu, V. Tanasoiu
    Abstract:

    Abstract Soft ferrites in the CuZnTi system, having the formula Cu 1− x Zn x Ti y Fe 2− y O 4 , with 0.50⩽ x ⩽0.60 and 0.00⩽ y ⩽0.05 were investigated as a function of composition, sintering Temperature and cooling speed, in order to obtain materials with controlled T C and very high change rate of permeability with Temperature around their T C . The effect of Zn and Ti additions was a drastic change of the Curie Temperature with about 10–12 °C for each atomic percent of Zn and Ti introduced into the spinel lattice while the cooling speed changed the behaviour of Magnetic permeability with Temperature around the Curie point. An application using such Magnetic Temperature sensors for a thermostat is presented.

  • Time Temperature Stability of Magnetic Properties of Ceramic Magnetic Temperature Transducers
    Journal of The European Ceramic Society, 1999
    Co-Authors: C. Tanasoiu, C. Miclea, Ion Spanulescu, C.n. Plăviţu, E. Barna
    Abstract:

    Abstract Three ceramic Magnetic compositions within the CuZnTi ferrite system, having the Curie Temperatures centered around 60, 80 and 100°C, respectively, were investigated in order to determine the time-Temperature stability of their main Magnetic properties. Permeability and the slope of permeability around their Curie points were determined on ring shaped samples, before and after being subjected to long term (over 6000 h) ageing at their Curie Temperature and for a shorter time of about 50 h at higher Temperatures up to 700°C. Rates of changes of 33, 66 and 100 ppm h −1 of the maximum slopes of permeability were found for the samples aged at 60, 80 and 100°C, respectively. The samples aged at Temperatures higher than 200°C show a rather sudden decrease of maximum slope of permeability, but no shift of the Curie Temperature and the working point, corresponding to the Temperature where the slope has the maximum value. This is the most interesting result as concerns the use of such Magnetic Temperature sensors for the construction of highly sensitive Temperature controllers, for example ultrathermostats. The results are discussed in terms of the migration processes of the cations, especially Cu 2+ , from metastable positions on which they were frozen during the rapid cooling of the sample from the sintering Temperature, to the more stable ones, namely the octahedral sites into the spinel lattice. ©

  • Properties and stability of ferrite materials for Magnetic Temperature transducers
    Materials Science and Engineering B-advanced Functional Solid-state Materials, 1996
    Co-Authors: C. Tanasoiu, C. Miclea, E. Dimitriu
    Abstract:

    Abstract Magnetic materials in the CuZnTi ferrite system with the chemical composition Cu1 − xZnxTiyFe2 − yO4, with 0.5 ⩽ x ⩽ 0.62 and 0 ⩽ y ⩽ 0.05 were investigated as a function of sintering Temperature and time and cooling speed in order to see the influence of these factors upon the Curie Temperature and the permeability behaviour around the Curie point. The quality of the Magnetic Temperature transducers made from such materials is directly connected with the value of the slope of the μ(T) curve. The higher the slope the more sensitive will be the transducer. Slopes as high as 50% °C−1 were obtained by a proper cooling of the samples, this value being the highest reported so far for such materials. The results are discussed in terms of the ionic distribution of the Cu, Zn and Ti ions over the tetrahedral and octahedral sites of the spinel lattice. The materials proved to be stable in time if the Temperature does not exceed 200°C, but higher Temperatures may induce irreversible change in the material structure due to cation migration and electron transfer from copper ions to iron ions.

M. A. K. Azad - One of the best experts on this subject based on the ideXlab platform.

Li Bo - One of the best experts on this subject based on the ideXlab platform.

  • New Magnetic Temperature Compensation Alloy 1J30M
    Journal of Iron and Steel Research, 2020
    Co-Authors: Li Bo
    Abstract:

    After cryogenic Temperature treatment,the Magnetic Temperature compensation ability of 1J30 decreased.It was found that part of austenite in 1J30 was transformed to martensite.Adjusting the content of Ni and adding Cr,the new Magnetic Temperature compensation alloy 1J30M was found.1J30M had both high Magnetic Temperature compensation property of 1J30 and cryogenic Temperature property of 1J32.

  • Research and Development of Magnetic Temperature Compensation Alloys
    Metallic Functional Materials, 2020
    Co-Authors: Li Bo
    Abstract:

    In instrument such as anemometer and electric meter,the compensation ability of Magnetic Temperature compensation materials to the permanent magnets determines the apparatus's accuracy.This article summarizes the characteristics of Magnetic Temperature compensation materials,introduces the improvement methods of compensation ability and compensation Temperature scope of Magnetic Temperature compensation materials.

C. Tanasoiu - One of the best experts on this subject based on the ideXlab platform.

  • A new type of thermostat of high stability using a Magnetic Temperature transducer
    Journal of Physics E: Scientific Instruments, 2000
    Co-Authors: C. Tanasoiu, I Nicolae, P. Nicolau, H. Niculescu, C Mihalache
    Abstract:

    Mechanical and electrical details together with performance tests are presented for a new type of thermostat for use at a given Temperature (about 353K), which uses a Magnetic Temperature transducer in the shape of a small toroidal core of CuZnTi ferrite for the Temperature control system. The thermostat gave a stability of +or-0.5 mK over a long period of time and a short term stability better than +or-0.1 mK when the ambient Temperature was constant to within +or-0.5K. The thermostat was designed for thermostatting quartz oscillators. The associated electronics is simple and allows the use of readily available components at a low total cost.

  • Time Temperature Stability of Magnetic Properties of Ceramic Magnetic Temperature Transducers
    Journal of The European Ceramic Society, 1999
    Co-Authors: C. Tanasoiu, C. Miclea, Ion Spanulescu, C.n. Plăviţu, E. Barna
    Abstract:

    Abstract Three ceramic Magnetic compositions within the CuZnTi ferrite system, having the Curie Temperatures centered around 60, 80 and 100°C, respectively, were investigated in order to determine the time-Temperature stability of their main Magnetic properties. Permeability and the slope of permeability around their Curie points were determined on ring shaped samples, before and after being subjected to long term (over 6000 h) ageing at their Curie Temperature and for a shorter time of about 50 h at higher Temperatures up to 700°C. Rates of changes of 33, 66 and 100 ppm h −1 of the maximum slopes of permeability were found for the samples aged at 60, 80 and 100°C, respectively. The samples aged at Temperatures higher than 200°C show a rather sudden decrease of maximum slope of permeability, but no shift of the Curie Temperature and the working point, corresponding to the Temperature where the slope has the maximum value. This is the most interesting result as concerns the use of such Magnetic Temperature sensors for the construction of highly sensitive Temperature controllers, for example ultrathermostats. The results are discussed in terms of the migration processes of the cations, especially Cu 2+ , from metastable positions on which they were frozen during the rapid cooling of the sample from the sintering Temperature, to the more stable ones, namely the octahedral sites into the spinel lattice. ©

  • Properties and stability of ferrite materials for Magnetic Temperature transducers
    Materials Science and Engineering B-advanced Functional Solid-state Materials, 1996
    Co-Authors: C. Tanasoiu, C. Miclea, E. Dimitriu
    Abstract:

    Abstract Magnetic materials in the CuZnTi ferrite system with the chemical composition Cu1 − xZnxTiyFe2 − yO4, with 0.5 ⩽ x ⩽ 0.62 and 0 ⩽ y ⩽ 0.05 were investigated as a function of sintering Temperature and time and cooling speed in order to see the influence of these factors upon the Curie Temperature and the permeability behaviour around the Curie point. The quality of the Magnetic Temperature transducers made from such materials is directly connected with the value of the slope of the μ(T) curve. The higher the slope the more sensitive will be the transducer. Slopes as high as 50% °C−1 were obtained by a proper cooling of the samples, this value being the highest reported so far for such materials. The results are discussed in terms of the ionic distribution of the Cu, Zn and Ti ions over the tetrahedral and octahedral sites of the spinel lattice. The materials proved to be stable in time if the Temperature does not exceed 200°C, but higher Temperatures may induce irreversible change in the material structure due to cation migration and electron transfer from copper ions to iron ions.

H. Yoshida - One of the best experts on this subject based on the ideXlab platform.

  • Magnetic Temperature Standards for TG
    Journal of Thermal Analysis and Calorimetry, 2003
    Co-Authors: P. K. Gallagher, R. Blaine, E. L. Charsley, N. Koga, R. Ozao, H. Sato, S. Sauerbrunn, D. Schultze, H. Yoshida
    Abstract:

    Magnetic transition Temperatures, T c , are measured by simultaneous TM/DTA for Alumel, cobalt, nickel, and three alloys of Ni and Co. The observed values of T c are corrected using the values for the melting Temperatures of pure metals used to define the International Temperature Scale. These corrections are based on the simultaneous melting of these pure metals alongside, but separate from, the Magnetic sample. Nine investigators, using a wide variety of instrumentation, have made these measurements utilizing a standard protocol. The results are compared for several heating rates. It is planned to make these same Magnetic materials ultimately available to the public for calibration of Temperature of their TG instruments.