Hohai University

Wenmin Guo

Jianfeng Zhang

Yuping Wu

Gaiye Li

Sheng Hong

Xin Zhang

Huiyang Cao

The present invention discloses a preparation method of an alumina supported cerium oxide powder material. A cerium organometallic precursor is effectively decomposed into CeOnanoparticles at 500-700&#xb0; C. in an oxygen atmosphere condition by using a chemical vapor deposition method, and the CeOnanoparticles are evenly dispersed on an AlOsupport. The decomposition of the CeOprecursor is accelerated by changing experimental parameters of reaction between organic materials and oxygen, so as to control the size and microstructure of powder, thereby achieving the preparation and even dispersion of cerium oxide nanoparticles, and avoiding the problem of generation of toxic waste liquor during reaction. The method of the present invention is simple, has a short preparation period, and the cerium oxide nanoparticles prepared are evenly dispersed, can be used as catalytic materials and functional materials, and have a broad application prospect in multiple fields.

Preparation method of alumina supported cerium oxide powder material

A tungsten carbide-cubic boron nitride composite material and preparation method thereof mainly includes WC and cBN, wherein the WC powder is coated with Co nano-layer and the cBN powder is coated with SiOnano-layer, and hardness and toughness of the composition material can be improved by coating. The method for preparing a tungsten carbide-cubic boron nitride composite material adopts chemical vapor deposition method and high temperature sintering method. First nano-layers were coated on the surface of WC and cBN, and then the bulk materials can be obtained via high-temperature sintering.

Tungsten carbide-cubic boron nitride composite material and preparation method thereof

The present invention discloses a method for uniformly coating metal nanoparticles without a carbon impurity on an oxide ceramic powder surface, which includes the steps of putting grinded and mixed a metal organic material and oxide ceramic powder into a rotational reaction chamber, then bubbling oxidizing gas under a rotational and heating condition to oxidize the metal organic material into a metal oxide, and finally bubbling reducing gas to reduce the metal oxide into nanoparticles in a metallic state, so as to implement the uniform coating of the nanoparticles in the metallic state, and avoid coarsening and growing problems of nanoparticles led by a long-term coating reaction under a high temperature. The present invention has a simple method and a short preparation period, and the metal nanoparticles prepared are uniformly dispersed and have wide application prospects in multiple fields like catalytic materials and conductive ceramics.

Method for coating metal nanoparticles on oxide ceramic powder surface

A method for preparation of a high-density hexagonal boron nitride (hBN) ceramic material is disclosed. According to the method, the surface of hBN powder is coated with an evenly-dispersed SiOnanoparticle layer using tetraethyl orthosilicate as a precursor, and then the high-density hBN ceramic material is obtained by pressureless sintering. The relative density of the prepared hBN ceramic material is over 80%.

Method for preparing high-density hexagonal boron nitride ceramic material

A method for preparing a titanium nitride-titanium diboride-cubic boron nitride composite material is disclosed. Titanium powder and cubic boron nitride raw powders are mixed by a planetary ball milling method, and then the titanium nitride-titanium diboride-cubic boron nitride composite material is prepared through the steps of wet mixing, drying, sieving, pre-sintering through a high-temperature vacuum furnace, cold isostatic press molding and high-temperature sintering.

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Jiangsu, China

Wenmin Guo