Which type of properties you want to improve? As there are many type of particles which have different applications like improving abrasion and corrosion resistance of metals

We want to improve strength and wear resistance.

Sir,

You can go for nano-SiC/Si3N4 for improving hardness and wear resistance, chk

ISRN Nanomaterials, Vol. 2012, Article ID 169850, doi:10.5402/2012/169850.

Journal of Composite Materials, Vol. 44, pp. 313-326, 2010.

Or Nanosized TiC/Al2O3 for better mechanical properties. Chk,

Journal of Minerals & Materials Characterization & Engineering, Vol. 10, No.14, pp.1293-1306, 2011.

Powder Metallurgy, Vol. 54, No. 2, pp. 148-152, 2011.

Materials Science & Engineering A, Vol. 558, pp. 485–491, 2012

Or Nano-ZrO2/SiO2/MgO for improving mechanical properties, Chk

Key Engineering Materials, Vol. 351, pp. 114-119, 2007

Journal of Mechanical Science and Technology, Vol 26, pp. 367-372, 2012.

TiO2 and SiC may be added as nano powders

ZrO2/SiO2/MgO, TiO2, SIC may be added

1.oxides (Al2O3, Y2O3),

2.nitrides (Si3N4, AlN)

3.carbides (TiC, SiC)

4.hydrates (TiH2)

5.borides

Above thesr five nano powder will improve the mechanical properties 

You may refer the following article. A full list of nano reinforcement particles is given.

C. Suryanarayana, Nasser Al-Aqeeli, Mechanically alloyed nanocomposites, Progress in Materials Science 58 (2013) 383–502.