Study on Electrochemical Formation of Neodymium-Iron Alloy

The cyclic voltammetry was used to investigate the electrode processes of Nd(III) reduced on iron electrode and Nd(III),Fe(II) reduced on molybdenum electrode in molten chlorides. The Nd-Fe and Nd-rich RE-Fe alloys contained rare earth up to 90wt% were prepared by consumable cathode and electrolytic codeposition. The mechanism of electrochemical formation of Nd-Fe alloy had been discussed.

Solidification Behavior of Laser Melting Layer of Nd_(15)Fe_(77)B_8 Sintered Magnets and Its Microstructures Evolution

To research the solidification behavior and microstructures of a laser remelting/solidification layer on anisotropic Nd_(15)Fe_(77)B_(8 )sintered magnets with their magnetization direction parallel to X, Y, Z-axis respectively, their surfaces (parallel to XOY plane) were scanned by 5 kW Roffin-Sinar 850 type of CO_(2) laser along Y axis. The rapid solidification of the molten alloy in the layer results in three distinct zones. The transition zone close to the unmolten portion of a magnet (substrate), consists of the columnar Nd_(2)Fe_(14)B phase (matrix), the 10.0%~15.1% dendrite primary iron phase dispersing in the matrix, and the Nd-rich phase along Nd_(2)Fe_(14)B grain boundaries. The columnar crystal zone in the middle of the layer consists of the long columnar Nd_(2)Fe_(14)B grains and their grain boundary Nd-rich phase. And the dendrite crystal zone near the free surface of the layer consists of dendrite Nd_(2)Fe_(14)B grains and their grain boundary Nd-rich phase. When the laser scanning velocity is lower, the growing direction of the microstructures in the layer tends to the laser scanning direction step by step. When the velocity is not lower than 25 mm·s^(-1), the laser remelting/solidification layer thins and the columnar crystal zone comprises almost the whole layer. Under this condition, on the substrate with its magnetization direction along X or Y-axis respectively, the columnar Nd_(2)Fe_(14)B grains in the layer grow in the direction of Z-axis (that is their long-axis along Z-axis), their alignment of the easy magnetization axis [001] is parallel to the magnetization direction of the substrate correspondingly; but on the substrate with its magnetization direction along Z-axis, the columnar Nd_(2)Fe_(14)B grains in the transition zone grow at an angle of 30°~50° between Z-axis and their long-axis. And the columnar Nd_(2)Fe_(14)B grains in the columnar crystal zone gradually tend to the Z-axis,and their easy magnetization axis [001] arrange in the range of 0°~360° of the plane perpendicular to their long-axis.

Effect of Pd doping on the acetone-sensing properties of NdFeO_3

The acetone-sensing properties of the undoped and Pd doped perovskite-type oxides NdFeO3 were investigated from room temperature to 400°C. The perovskite-type NdFeO3 was synthesized by a sol-gel method, and the dopants Pd with the content from 1wt% to 5wt% were implanted into NdFeO3 nanoparticles by thermal diffusion. X-ray diffraction （XRD） and scanning electron microscopy （SEM） techniques show that NdFeO3 is an orthorhombic structure with the average particle size of about 40 nm. A giant acetone-sensing response of 675.7 is observed when the Pd content in NdFeO3 powders is about 3wt%. The response and recovery time of the sensor to the 5×10–4 acetone gas are 16 and 1 s, respectively. At the same time, it performs a good selectivity to acetone gas and may be a new promising material candidate for the acetone-sensor development.

High-power and high-efficiency operation of an all-solid-state, quasi-continuous-wave, titanium sapphire laser system

High-power and high-efficiency operation of an all-solid-state, quasi-continuous-wave, titanium sapphire laser is obtained with a diode-laser-pumped frequency-doubled Nd:YAG laser as the pump source. A maximum output power of 2.5 W is obtained for 16-W power of 532-nm pump light. A much higher conversion efficiency of 15.7% is obtained when at the maximum output power.