Magnesium oxide nano powders were prepared by precipitation method using anhydrous sodium carbonate and magnesium chloride hexahydrate as raw materials, and the influence of chloride ions in the synthesis of the powders was investigated. It was shown that the precipitation process with the addition of chloride ions could change the phase composition of the precursors, and the precursors with alkaline magnesium carbonate and hydrated magnesium carbonate as the main components were obtained, and the magnesium oxide powder with a primary particle size of 40 nm could be obtained after calcination at 900 ℃. The addition of chloride ions in the powder preparation has the effect of promoting the sintering densification and grain growth of magnesium oxide during sintering, and also helps to obtain the microstructure with uniform grain size distribution. The density of the powder doped with 5% (mass fraction) chloride ions was 96.4% when sintered at 1200°C for 3 h in air atmosphere, while the density of the sample without chloride ions was only 52.4% under the same conditions.
The present invention relates to a method of preparing MgAlON transparent ceramic powder, which belongs to the field of synthesis and preparation of ceramic materials. A rapid preparation method of MgAlON transparent ceramic powder, characterized in that it includes the following steps:
1) Mixing α-alumina powder, aluminum nitride powder and magnesium oxide powder to obtain mixed powder; ball milling, to obtain slurry;
2) Drying the slurry of step 1) to obtain the mixture; 3) Putting the dried mixture in the crucible, which is placed in the graphite reactor, and applying high current directly to the graphite reactor, heating to 1400°C-1700°C with a heating rate of 100°C-400°C, holding time of 0-20min, and then cooling naturally to obtain MgAlON transparent ceramic powder.
The method is characterized by simple process, fast synthesis speed and high efficiency, and the obtained MgAlON ceramic powder has high purity (≥98wt%), uniform and fine particle size (average particle size ≤700nm), and is especially suitable for making transparent ceramics.