The disclosure discloses a NdFeB permanent magnet and a preparation method thereof. The magnet is composed of main phase I, a shell structure, a grain boundary phase adjacent to the shell structure, a main phase II, a Ga rich region and a Cu rich region. The magnet has high remanence, high coercivity, and high magnetic energy. In addition, this method can significantly reduce the production cost.

The disclosure discloses a NdFeB permanent magnet and a preparation method thereof. The magnet is composed of main phase I, a shell structure, a grain boundary phase adjacent to the shell structure, a main phase II, a Ga rich region and a Cu rich region. The magnet has high remanence, high coercivity, and high magnetic energy. In addition, this method can significantly reduce the production cost.

The present disclosure relates to a method of preparing an aluminum-containing alloy powder and an application thereof. The preparation method includes: by using the characteristic that a solidification structure of an initial alloy includes a matrix phase and a dispersed particle phase, the matrix phase is removed by reaction with an acid solution, so as to separate out the dispersed particle phase and obtain an aluminum-containing alloy powder. The preparation method is simple in process and can prepare different morphologies of aluminum-containing alloy powders of nano-level, sub-micron-level, micron-level and millimeter-level, which can be applied to the fields such as photo-electronic devices, wave absorbing materials, catalysts, 3D metal printing, metal injection molding and corrosion-resistant coating.

A multi-stage gas atomization preparation method of titanium alloy spherical powder for a 3D printing technology includes the following steps: bar preparation and machining step, multi-stage gas atomization powder preparation step through vacuum induction, and powder screening step. The collision probability of the metal droplets at the gas atomization stage is reduced by controlling the gas atomization pressure and the feeding speed of the titanium alloy electrode bar in a hierarchical manner, so that the collaborative control of the particle size and the surface quality of the titanium alloy 3D printing powder in the gas atomization preparation process is realized.

A method of producing silver fine particles includes continuously reducing silver ions contained in a silver compound to precipitate silver fine particles by introducing at least two fluids from separate flow paths and mixing the fluids, wherein one fluid of the at least two fluids contains the silver compound, and another fluid contains a reducing agent, and at least one fluid of the at least two fluids contains an amino acid. With this method, silver fine particles can be produced with sufficient continuous productivity and quality uniformity, without problems of deterioration of working environment and generation of explosive fulminating silver due to the use of a large amount of ammonia.

The present invention provides a rare-earth sintered magnet that is characterized in that: R (R indicates one or more elements selected from rare-earth elements, wherein Nd is essential), T (T indicates one or more elements selected from iron-group elements, wherein Fe is essential), X (X indicates one or two elements selected from B and C, wherein B is essential), M.sup.1 (M.sup.1 indicates one or more elements selected from Al, Si, Cr, Mn, Cu, Zn, Ga, Ge, Mo, Sn, W, Pb, and Bi), 0.1 mass % or less of O, 0.05 mass % or less of N, and 0.07 mass % or less of C are contained; the average crystal grain size is 4.0 μm or less; and relational expression (1) 0.26×D+97≤Or≤0.26×D+99 is satisfied assuming that the degree of orientation is Or [%] and that the average crystal grain size is D [μm]. With this rare-earth sintered magnet, it is possible to achieve superior magnetic characteristics in which both high Br and high H.sub.cJ are achieved.

The present disclosure discloses a preparation method of a multi-functional marine engineering alloy. Through the coupling of a multi-principal alloy structure, structural entropy, and temperature and powder metallurgy and heat treatment, mutual solubility between elements and free energy of an alloy system are regulated, Cu grain boundary segregation is eliminated, and uniform and dispersed nano-precipitation of the anti-fouling element Cu in corrosion-resistant and high-plasticity multi-principal alloys is realized. The preparation method is simple and controllable to operate, and the prepared material has plasticity higher than 75%, high yield strength, excellent corrosion resistance and anti-fouling property, and has important application prospects in the field of marine engineering.

Disclosed is a biomedical β titanium alloy and a preparation method thereof. Its composition includes: Mo: 9.20-13.50%; Fe: 1.00-3.20%; Zr: 3.50-8.20%; Ta: 0-1.00%; the balance is Ti. The β titanium alloy is suitable for the laser additive manufacturing technology, and the prepared parts have a dense equiaxed grain structure with ultra-low grain size and a small number of columnar grain structures, which produces a fine-grain strengthening effect, and greatly improve the hardness and tribocorrosion performance of the alloy material. Also provided is a method for preparing a non-toxic, low-elasticity, and tribocorrosion resistant biomedical β titanium alloy material. A powder prepared from the above alloy components is subjected to a laser additive manufacturing technology to prepare a corresponding β titanium alloy with high-hardness, good tribocorrosion resistance and extremely low cytotoxicity. Moreover, the prepared material has good weldability and is a special metal alloy powder suitable for laser additive manufacturing.

Disclosed is a biomedical β titanium alloy and a preparation method thereof. Its composition includes: Mo: 9.20-13.50%; Fe: 1.00-3.20%; Zr: 3.50-8.20%; Ta: 0-1.00%; the balance is Ti. The β titanium alloy is suitable for the laser additive manufacturing technology, and the prepared parts have a dense equiaxed grain structure with ultra-low grain size and a small number of columnar grain structures, which produces a fine-grain strengthening effect, and greatly improve the hardness and tribocorrosion performance of the alloy material. Also provided is a method for preparing a non-toxic, low-elasticity, and tribocorrosion resistant biomedical β titanium alloy material. A powder prepared from the above alloy components is subjected to a laser additive manufacturing technology to prepare a corresponding β titanium alloy with high-hardness, good tribocorrosion resistance and extremely low cytotoxicity. Moreover, the prepared material has good weldability and is a special metal alloy powder suitable for laser additive manufacturing.

The disclosure relates to a powdery filament composition for 3D printing, a 3D printer, and a method of additively manufacturing an object by the 3D printer, and more particularly to a powdery filament composition for 3D printing, which is suitable for home use because it does not produce toxic substances, a 3D printer, the size of which is suitable for home use because it does not require high power energy, high-temperature processing and the like conditions for additive manufacturing, and a method of additively manufacturing an object by the 3D printer.