Investigating the effect of size and distribution diamond nanoparticles on hardness and light transmission of Zinc Sulphide/diamond nanocomposite

Z​inc ​sulfide / diamond nanocomposite samples ​containing one volume ​percent diamond nanoparticles with meanaverage particles​ size​ of about 10 nm and 500 nm were sintered using hot pressing technique. The effect of size and distribution of nanodiamond particles on hardness and light transmission were studied. The addition of nanodiamond particles led to an increase in hardness in all sintered specimens, although the hardness increase depended on the size and distribution of diamond nanoparticles. In other words, the hardness of samples with smaller particle size and more uniform distribution was more. so that those samples that contained smaller diamond nanoparticles of about 10 nm with a more uniform distribution in the matrix had the highest hardness value of about 475 Vickers. The scattering phenomenon is due to the presence of diamond nano particles and their agglomerations, as well as the presence of the pore. Although there are scattering effects due to the presence of diamond nanoparticles and their agglomerates, it can be discarded. Although the presence of a pore in sintered specimens can have effect on reducing the light transmission but according to the results, it can be concluded that in this study, absorption is the dominant phenomenon in the drop of light transmission in all sintered specimens. The main cause of absorption in sintered specimens containing nano sized particles of less than 10 nm is the presence of impurities such as nitrogen due to the conditions for the synthesis of primary diamond nanoparticles and their surface changes during sintering. Also, in sintered specimens containing less than 500 nm in size diamond nanoparticles, absorption is due to the change surface in during time sintering.The maximum light transmission (35%) was achieved for sample containing nanodiamond particles with mean size of 500 nm.