gray, hexagonal, crystal(s) solid, a=0.3141 nm, c=0.3470nm; can be prepared by heating HfO2+C+B2O3; hardness 2900 kgf/mm2; resistivity 8.8μohm· cm; used as a refractory material and as a sputtering target with 99.5% purity to produce films, which may be wear-resistant and semiconducting [HAW93] [KIR80] [CER91]
Hafnium boride is used in wear resistant coatings. It is also employed as a nuclear reactor control rod. Furthermore, it is used in hypervelocity re-entry vehicles like ICBM heat shields or aerodynamic leading-edges. It is useful in the preparation of high temperature composites in conjunction with silicon carbide (SiC).
A method of combustion synthesis of high purity hafnium diboride micropowder. The technical solution of the present invention is: the present invention is realized according to the following steps: First, the basic raw materials and diluent for dosing, the basic raw materials contain hafnium dioxide, boronic anhydride and magnesium powder, according to the weight percentage of: hafnium dioxide: 30% to 60%, boronic anhydride: 10% to 40%, magnesium powder: 15% to 50%, the diluent hafnium diboride added weight of the basic raw materials of 0 to 3 times; Second, drying, mixing; Third, the mixed raw material powder into the graphite boat, and then into the closed pressure vessel, closed pressure vessel using circulating water cooling, and keep the reaction under the pressure of 0 ~ 5Mpa protective atmosphere or vacuum conditions, ignition so that the raw material is self-propagating combustion and transformed into a product; Fourth, cooled to take out the product, the product is hafnium diboride and magnesium oxide mixture, acid washing to remove magnesium oxide, and then the hafnium diboride Water washing, filtration, drying, to get hafnium diboride powder.
