Microwave method for synthesis of micro- and nanostructures with controllable composition during gyrotron discharge

Synthesis of oxide and nitride ceramics in high-power gyrotron discharge

“…Previously it was shown that in order to transform the initial mixture of powders into a new material the gyrotron discharge parameters should be chosen so that the microwave discharge was followed by an afterglow phase [11]. Only under this condition almost complete absorption of microwave radiation of gyrotron in the powder mixture and initiation of chemical reactions of synthesis of substances was possible [13].…”

“…The plasma-chemical experiments were carried out in a specially constructed reactor [8] using gyrotron with a power up to 0.55 MW, frequency of 75 GHz, and microwave pulse duration between 0.1 and 15 ms. An actual gyrotron power was measured with a calorimeter [9]. The discharge was initiated in Ti + B, Mo + B, W + B, Mo + W + B, Mo + BN, Ti + KBF 4 , and Mg + CB 4 mixtures in the air and nitrogen atmospheres [8,10,11]. It was found that the surface temperature of the powder mixture in the breakdown phase for these discharges was 2000 to 5000 K, while the temperature in the plasma-gas layer reached 10000 K [11].…”

“…The discharge was initiated in Ti + B, Mo + B, W + B, Mo + W + B, Mo + BN, Ti + KBF 4 , and Mg + CB 4 mixtures in the air and nitrogen atmospheres [8,10,11]. It was found that the surface temperature of the powder mixture in the breakdown phase for these discharges was 2000 to 5000 K, while the temperature in the plasma-gas layer reached 10000 K [11]. The main products of the process were metal and boron oxides and metal borides [10,11].…”

“…It was found that the surface temperature of the powder mixture in the breakdown phase for these discharges was 2000 to 5000 K, while the temperature in the plasma-gas layer reached 10000 K [11]. The main products of the process were metal and boron oxides and metal borides [10,11]. Also formation of BN was found in some cases.…”

Synthesis of micro- and nanostructures with controllable composition in the chain plasma-chemical reactions initiated by the radiation of a powerful gyrotron in the mixtures of metal-dielectric powders

“…The report presents a new type of exothermic chain reactions initiated by powerful microwave radiation of gyrotron in mixtures of metal-dielectric powders. In this microwave-plasma-chemical process new substances are synthesized with controlled composition [1]. Chain selfsustaining reactions in which initially appearing products take part in the formation of new products are the basis of many technological processes of synthesis of substances.…”