Influence of Spray Drying Conditions on Particle Size and Morphology of Al2O3/ZrO2(3Y) Composite Particles

Zirconia toughened alumina materials are frequently used in biomedical applications due to their enhanced toughness, strength and wear resistance compared to monolithic alumina. In this work, the influence of spray drying conditions is studied on the characteristics of spray-dried Al2O3/ZrO2(3Y) composite particles. The SEM images of composite particles confirm the formation of dense composite particles of round shape without internal holes. The particles of the best morphology of the median diameter of 44 µm were produced by drying the slurry of 70 wt.% solid content with feed rate of 15 ml/min using the drying air with inlet temperature of 210 °C and spraying air with flow rate of 357 l/h.

Synthesis of high strength monolithic alumina aerogels at ambient pressure

Mechanically strong monolithic alumina aerogels were obtained via ambient pressure drying by incorporating attapulgite (ATP) and alumina sol.

Graphene Covered Alumina Nanofibers as Toughening Agent in Alumina Ceramics

Graphene is a promising component for next-generation high-performance structural and multifunctional composite materials. Graphene deposited onto nanofibers of high aspect ratio can serve as reinforcement agent for improving ceramic fracture toughness and electroconductivity. It was found that quality and quantity of graphene sheets on the fiber surface essentially depends on the pyrolysis of carbon source conditions such as gas flow, duration, temperature and the composition of the gas mixture. The alumina/graphene composites of 10 and 15 wt% of nanofibers covered by graphene were produced by spark plasma sintering (SPS) at 1380 °C. Both composites show improvement in mechanical and electrical properties as compared to the monolithic alumina. The main advantage of the graphene growth on the fibers surface is a lack of complicated step of constituents mixing. Graphene platelets are believed to act as toughening agents prevailing crack propagation under loading.