3results about How to "Avoid sintering and agglomeration" patented technology

This application relates to a silicon nitride magnesium powder, its preparation method, and its applications, belonging to the technical field of structural ceramic powder materials. The preparation method includes: embedding silicon nitride powder into magnesium powder to form a magnesium-based composite powder with a micro / nano composite structure on its surface; mixing the magnesium-based composite powder with a dispersant to obtain a reaction precursor; subjecting the reaction precursor to a self-propagating synthesis reaction to obtain the silicon nitride magnesium composite powder; and sequentially subjecting the silicon nitride magnesium composite powder to acid washing and calcination treatments to obtain the silicon nitride magnesium powder. The prepared silicon nitride magnesium has a yield of over 95%, an oxygen content of less than 0.15 wt.%, and a particle size controlled between 1 μm and 2 μm with uniform distribution; it is suitable for applications such as a sintering aid for high-performance ceramics, a component of refractory materials, and a reinforcing phase in metal matrix composites.

This invention discloses a spherical powder of tantalum-tungsten alloy and its preparation method and additive manufacturing method, belonging to the field of refractory metal material preparation technology. The preparation method includes: subjecting a homogeneous tantalum-tungsten alloy ingot to a three-stage hydrogenation treatment, sequentially holding at 0.01~0.04 MPa and 300~500℃ for 1~3 h, at 0.04~0.08 MPa and 900~1000℃ for 0.5~1 h, and at 0.02~0.05 MPa and 300~400℃ for 0.5~1.5 h. This segmented hydrogenation process controls the diffusion behavior of hydrogen in the alloy, achieving controlled embrittlement and avoiding over-hydrogenation. Further, multi-cycle crushing and dynamic sieving based on the target particle size range are performed to obtain hydride precursor powder, significantly reducing ineffective fine powder and improving the yield and production efficiency of the plasma spheroidization process. The resulting tantalum-tungsten alloy spherical powder has a sphericity of not less than 99%, an oxygen content of not more than 150 ppm, and a concentrated particle size distribution. It is suitable for additive manufacturing processes such as laser selective melting and electron beam selective melting, providing a reliable raw material for the forming of high-performance tantalum-tungsten alloy components.

The invention discloses a cerium-zirconium solid solution / manganese-based oxide honeycomb catalyst as well as a preparation method and application thereof, and relates to the technical field of novel materials for environmental catalysis. The catalyst disclosed by the invention is formed by mixing cerium-zirconium solid solution loaded silicate clay and natural manganese ore and then carrying out high-temperature calcination; the mass ratio of the cerium-zirconium solid solution to the silicate clay is (0.5-2): 1, and the molar ratio of zirconium to cerium is (0.15-0.35): 1; and the mass of the manganese-based oxide accounts for 25-77% of the total mass of the catalyst. An alkaline ureido silane coupling agent is grafted to the surface of silicate clay, cerium and zirconium hydroxide precursors are generated on the surface of a silicate clay carrier through in-situ precipitation, then a cerium-zirconium solid solution precursor / silicate clay compound and a manganese ore mixture are subjected to high-temperature calcination forming, and the non-noble metal monolithic honeycomb catalyst is prepared. The honeycomb catalyst prepared by the invention has excellent chlorine poisoning resistance and low-temperature catalytic activity.