ساخت نانوکامپوزیت MoSi2-TiB2 به‌وسیله آلیاژسازی مکانیکی و مقایسه خواص آن‌ها برای استفاده در فرایند پاشش گرمایی

this study, MoSi2-TiB2 nanocomposites with 10 and 20 wt.% of TiB2 were synthesized by mechanical alloying through two different methods. In the first method, elemental powders of molybdenum, silicon, titanium and boron were milled together for 60 hours. In the second method, MoSi2 was made by 30-hours milling of Mo and Si. Then, commercial TiB2 was added to the matrix and milling was continued for another 30 hours. Heat treatment was carried out on the resultant specimens at 1000˚C for 60 min. The effect of mechanical alloying on grain size and lattice strain was investigated by Williamson-Hall method using XRD patterns. The mechanical properties of the samples were determined by hardness test. It was found that TiB2 added to MoSi2 increased hardness considerably. Agglomeration process was carried out on the powders to be used in thermal spray process. The morphology and microstructure of the milled powders before and after agglomeration process were studied by SEM. The sphericity and particle size distribution of agglomerated particles were evaluated using Clemex software. The results showed that the nanocomposite powder produced by the first method had a higher quality for thermal spray process due to its higher hardness compared to the second one. It also had adequate particles sphericity.