Synthesis Advantages and Disadvantages

Several chemical routes are known for the synthesis of h-BN powders. Two of them (i, ii) are used on the industrial scale  

The material obtained is heat treated at temperatures up to 2000 °C under nitrogen. This leads to well-formed boron nitride platelets with a thickness of 0.1 -0.5 pm and a maximum diameter of 5 pm. 

Reaction of boric oxide with organic nitrogen compounds. In this process, boric oxide or boric acid is made to react with nitrogen compounds such as melamine, urea, dicyanamide, or guanidine  

These reactions are carried out at temperatures between 1000 and 2100 °C in N2 atmosphere. Before final thermal treatment, the product can be washed with methanol or diluted acids in order to remove all non-reacted products. For removing oxygen impurities, a thermal treatment at 1500 °C in inert N2 or Ar atmosphere is used. The process leads to crystal lattices with a less pronounced three-dimensional order, that is, BN with tur-bostratic structure (t-BN) is obtained, which is characterized by partial or complete absence of three-dimensional order in the stacking of its atomic planes. 

Although above routes can yield cheap product, the reaction kinetics and the state of art is not given in the scientific literature. Among other conventional methods, let us outline the following  

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