Ultrasound assisted salts–metal reaction for synthesizing TiB2 particles at low temperature

• A high yield of TiB2 particles (90.4%) can be obtained via ultrasound assisted salts–metal reaction at 700 °C.
• Most of TiB2 particles (95%) are smaller than 300 nm in size.
• The effects of ultrasound on the formation of TiB2 particles at low temperature are investigated.

In situ TiB2 particles can be synthesized via salts–metal reaction by adding K2TiF6 and KBF4 mixed salts into the Al melt. In this research, a novel ultrasound assisted technique was proposed with the aim of synthesizing TiB2 particles in the Al melt at low temperature by means of introducing high-intensity ultrasound into the salts–metal reaction at 700 °C, which was at least 100 °C lower than those in the conventional methods. The effects of ultrasound on the synthesis of TiB2 particles were investigated by comparing two groups of experiments with and without ultrasound. The results showed that the yield of TiB2 particles in the ultrasonically treated sample could reach 90.4%, whereas the value of which was around 28% in the control sample without ultrasound after 10 min of reaction, indicating that ultrasound was able to promote significantly the formation of TiB2 particles at low temperature. Most of in situ formed TiB2 particles (95%) were smaller than 300 nm in size. Our research showed that significantly enhanced formation of small TiB2 particles in ultrasonic field can be attributed to faster dissolution of mixed salts powders into Al melt, accelerated mass transfer of solutes, as well as the promoted nucleation and growth of TiB2 particles due to the effects of ultrasonic cavitation.