The development of miniaturization, lightness, high integration and high power of electronic technology has put forward new requirements for substrate and packaging materials. Aluminum nitride ceramics possess intriguing properties, such as high thermal conductivity, insulation and thermal expansion coefficient being similar to semiconductor silicon, high mechanical strength, good chemical stability and non-toxic, have a good prospect as ideal substrate materials. The preparation of high quality aluminum nitride powder is the key to synthesize high quality aluminum nitride ceramics. In this paper, the traditional methods of micrometer aluminum nitride powder preparation and the new technologies and methods of aluminum nitride nanopowder preparation are introduced, and the research direction and development trend of aluminum nitride powder preparation are prospected.

In this study, fine aluminum oxynitride (γ-AlON) powder was synthesized from a solid-state hydrolysis byproduct for the first time through in-depth research on the hydrolysis of metal Al powder. Hydrolysis begins on the surface of the Al particles, the initial solid-state hydrolysis byproduct is AlOOH and then Al(OH)₃, and during the reaction stage, a unique core‒shell structure with a hollow outer core composite precursor is formed. Pure-phase AlON powder can be synthesized by utilizing a composite precursor with an appropriate Al₂O₃/Al ratio (Al₂O₃/Al = 10.27) under a flowing N₂ atmosphere. The core‒shell structure decreases the diffusion distance between raw materials and reduces the nitridation temperature (1700 °C). Furthermore, the unique hollow structure of the composite precursor results in some of the synthesized AlON powder also having a hollow structure, which is conducive to powder crushing, and fine nanoscale (D₅₀ = 292 nm) powder can be obtained only via a grinding process. The combination of Al–H₂O reaction and direct nitridation (DN) methods has led to the development of a new synthesis method for AlON powder and provides a new method for the recovery of the solid-state hydrolysis byproduct of metal Al powder.

A series of YAG:Ce,Mn transparent ceramics were prepared via a solid-state reaction-vacuum sintering method. The effects of various Mn²⁺–Si⁴⁺ pair doping levels on the structure, transmittance, and luminescence properties were systematically investigated. These transparent ceramics have average grain sizes of 10–16 μm, clean grain boundaries, and excellent transmittance up to 83.4% at 800 nm. Under the excitation of 460 nm, three obvious emission peaks appear at 533, 590, and 745 nm, which can be assigned to the transition 5d→4f of Ce³⁺ and ⁴T₁→⁶A₁ of Mn²⁺. Thus, the Mn²⁺–Si⁴⁺ pairs can effectively modulate the emission spectrum by compensating broad orange-red and red spectrum component to yield high quality warm white light. After the optimized YAG:Ce,Mn transparent ceramic packaged with blue light-emitting diode (LED) chips, correlated color temperature (CCT) as low as 3723 K and luminous efficiency (LE) as high as 96.54 lm/W were achieved, implying a very promising candidate for application in white light-emitting diodes (WLEDs) industry.