Effect of nano-TiC dopant size on magnetic properties and corrosion resistance of hot-deformed NdFeB

Effects of dopant size on the magnetic properties and corrosion behavior of hot-deformed NdFeB with the intergranular additions of nano-TiC were investigated using X-ray diffraction(XRD),X-ray photoelectron spectrometer(XPS),scanning electron microscopy(SEM),electrochemical and magnetic measurement technologies.Additions of 50 nm-TiC,unlike 30 nm- and 40 nm-TiC,are found to increase the magnetic energy product and comprehensive magnetic properties,due in main to the improvement of magnet orientation by more strip-shaped Nd-rich phases.Nano-TiC dopants especially with a size of40 nm can increase the electrochemical corrosion resistance of magnets.It is attributed to the hindrance of additives on the reaction channel formation and their barrier effect on the oxidations of Nd and Fe.For 40 nm-TiC doped magnet,the charge transfer resistance in electric double layer structure reaches 15000 Ω·cm^(2) that is one order of magnitude higher than other cases,which is responsible for the lowe st corrosion current density and accordingly the best anti-corrosion properties.

Large electrostrictive effect and strong photoluminescence properties in Sm_(2)O_(3)-modified lead-free potassium sodium niobate-based piezoelectric ceramics

In this work,the phase transition behavior and electrostrictive and photoluminescence properties of Sm_(2)O_(3)-modified 0.965(K_(0.48)Na_(0.52))(Nb_(0.95)Sb_(0.05))e_(0.035)Bi_(0.5)(Na_(0.82)K_(0.18))_(0.5)HfO_(3)(KNNSe0.035BNKH)ceramics were investigated.Results showed that the phase structure of the Sm2O3-modified ceramics evolved from coexisting orthogonal and tetragonal ferroelectric phases to a relaxor pseudocubic phase along with the strong destruction of the long-range ferroelectric order.Domain switching in Smmodified ceramics with a relaxor pseudocubic phase became difficult,evident from the PFM images.Consequently,large electrostrictive effect with an electrostrictive coefficient of 0.022 m4/C2 was obtained in 1.0 mol%Sm-modified samples.With regard to long-term stability,the materials exhibited temperature-independent(20-100℃)and fatiguefree(up to 105 cycles)behavior,which guarantees their application in various devices.The KNNSe0.035BNKHexSm ceramics have the advantages of photoluminescence performance with bright orange emission under 407 nm visible light excitation.Overall,KNNS0.035BNKHxSm ceramics have broad application prospects in multifunction devices due to their large electrostrictive effect,excellent photoluminescence performance,and long-term stability.