Investigation of production opportunities magnesium boron compoundsby self propagating high temperature synthesis method

In this thesis, production conditions of magnesium boron compounds by self-propagated high temperature synthesis method (SHS), are investigated. Experimental studies are carried out in two steps: Reduction and leaching. Boron oxide is preferred as boron source, high purity and various particle sized magnesium metal powders are used as magnesium source. In reduction step, magnesium and aluminum metal powders are used as reductant. Reduction processes are carried out by SHS method, effects of using various amount of boron oxide and metal powders was investigated. Increase in Mg powder ratio in green mixture is resulted increase in MgO phase as by-product. Also decrease in B2O3 phase in green mixture is caused decreased reaction yield or failed SHS reactions. In leaching process, SHS products were used, processes were made in different acid solutions and various time and temperature. Raw materials midproducts and products are characterized by AAS, ICP-MS and XRD techniques. In first step, aluminum and magnesiım powders are used as reductant in SHS reactions. Various particle sized magnesium powders are reacted with boron oxide powder and particle size effect on magnesium diboride powder production by shs method is analyzed. DTA (Differantial Thermal Analysis) device is used for if reactions exothermic and reaction temperature increases proportionally with particle size of magnesium powder. In second step, effects of various stoichiometries magnesium and boron oxide powder mixtures on SHS reactions. Afterwards, SHS products are dissolved in hydrochloric acid, nitric acid and sulphuric acid for removal of by products of SHS reactions. In dissolving procceses, SHS products are dissolved in each acids, at 20 degree celcious, 40 degree celcious and 60 degree celcious at 400 round per minute seperately to analyze effects for removing by products. The highest boron oxide to magnesium oxide solubility was reached by using nitric acid solutions and the lowest one was reached by sulphuric acid solutions. Leaching by using a sulphuric acid solution is assumed the most efficient process. After SHS and dissolving process, products are characterized by XRD (X-Ray Diffractometer). Afterwards, amount of dissolved magnesium and boron are determined by ICP-MS (Atomic Absoption Spectroscopy).