Study On The Preparation Of Boron Powder And ZrB₂ Powder By Combustion Synthesis And Formation Mechanisms Of Them

In this thesis, the preparation and application of B powder and ZrB₂ powder is introduced. By means of experiment and theory the preparation of B and ZrB₂ in the combustion synthesis is summarized. Optimum processing parameters and the influencing rule of product are identified. The enlargement of preparation is studied, and these researches supply theoretical guidance for the optimization of process.In the combustion synthesis B powder is prepared under different processing parameters, such as the reactant amount, reaction ratio, the pressure of tablets. Through EM and EDS these samples were studied. The minimum particle size and the supreme purity of product is prepared when the reactant amount is 100 g. The same samples are prepared when the reaction ratio is 1. With the pressure of 5 MPa, the particle size is minimum and with the pressure of 10 MPa, the purity is supreme. The reaction mechanism of B powder in the combustion synthesis is researched through the analysis of different parameters and thermodynamics.By comparion of preparation Laboratory circumstance with enlargement, the volatile matter of enlargement is researched. Thus, the purity of Mg excess 10 % by 94.08% which is higher than other samples. Enlargement of preparation can be feasible.In the combustion synthesis ZrB₂ powder is prepared under different Mg mass. SEM, EDS and XRD were used to study these samples. The minimum particle size and the supreme purity of product is prepared when the Mg excess by 5 %. The reaction mechanism of ZrB₂ powder in the combustion synthesis is researched through the analysis of different Mg mass and thermodynamics, dynamics. The particle size of product of enlargement is between 3 and 5μm. The purity and impurity content are the same as those in laboratory circumstance.