20.500.12556/DKUM-67758 The magnetic and colloidal properties of $CoFe_2O_4$ nanoparticles synthesized by co-precipitation Magnetic $CoFe_2O_4$ nanoparticles were synthesized by co-precipitation at 80 °C. This co-precipitation was achieved by the rapid addition of a strong base to an aqueous solution of cations. The investigation of the samples that were quenched at different times after the addition of the base, using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDXS) and X-ray powder diffractometry, revealed the formation of a Co-deficient amorphous phase and $Co(OH)_2$, which rapidly reacted to form small $CoFe_2O_4$ nanoparticles. The nanoparticles grew with the time of aging at elevated temperature. The colloidal suspensions of the nanoparticles were prepared in both an aqueous medium and in a non-polar organic medium, with the adsorption of citric acid and ricinoleic acid on the nanoparticles, respectively. The measurements of the room-temperature magnetization revealed the ferrimagnetic state of the $CoFe_2O_4$ nanoparticles, while their suspensions displayed superparamagnetic behaviour. Magnetne nanodelce $CoFe_2O_4$ smo sintetizirali s soobarjanjem na temperaturi 80 °C. Soobarjanje smo dosegli s hitrim dodatkom močne baze k vodni raztopini kationov. Mehanizem nastanka nanodelcev $CoFe_2O_4$ smo študirali tako, da smo odvzeli vzorce pri različnih časovnih intervalih po dodatku baze in ustavili kemijske reakcije. Analize vzorcev s presevno elektronsko mikroskopijo (TEM) v kombinaciji z EDXS spektroskopijo in rentgensko praškovno difrakcijo (XRD) so pokazale nastanek amorfne Co deficitne faze in $Co(OH)_2$, ki hitro reagirata in nastanejo majhni $CoFe_2O_4$ nanodelci. Med staranjem na povišani temperaturi nanodelci rastejo. Koloidne suspenzije nanodelcev v vodnem in organskem ne- polarnem mediju smo pripravili z adsorpcijo citronske ozirom ricinolejske kisline. Meritve magnetnih lastnosti na sobni temperaturi so pokazale ferimagnetne lastnosti nanodelcev $CoFe_2O_4$ medtem, ko so suspenzije kazale superparamagnetno obnašanje. cobalt ferrite nanoparticles co-precipitation colloidal suspensions magnetic properties kobaltov ferit nanotehnologija magnetne lastnosti koprecipitacija true false true Angleški jezik Slovenski jezik Znanstveno delo 2017-08-30 08:39:04 2017-08-30 08:40:06 2022-08-01 14:25:00 2019-07-11 16:30:27 2014 0 0 str. 488-496 št. 3 Letn. 61 2014 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1318-0207 546.732:620.3 14086149 28006183 1318-0207 URN:SI:UM:DK:RGJT7DDJ Acta_Chimica_Slovenica_2014_Gyergyek,_Drofenik,_Makovec_The_magnetic_and_colloidal_properties_of_CoFe2O4_nanoparticles_synthesized_by_co.pdf Acta_Chimica_Slovenica_2014_Gyergyek,_Drofenik,_Makovec_The_magnetic_and_colloidal_properties_of_CoFe2O4_nanoparticles_synthesized_by_co.pdf 1 4CD2FE84F0567E81FD02DC2497FDF3DB 9e6ea3ecc26c676f137dce0102ce65773e9b7780de17cc43d791be86c5469cf6 951f78d3-7c0e-11eb-bb7a-00155d0001ca 20.500.12556/dkum/bab3e4c8-1afe-4374-886e-53d67e216664 https://dk.um.si/Dokument.php?lang=slv&id=116383 https://journals.matheo.si/index.php/ACSi/article/view/982 1 https://dk.um.si/Dokument.php?lang=slv&id=116382 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0