Ramesh and Prabhu Nanoscale Research Letters 2011, 6:334 http://www.nanoscalereslett.com/content/6/1/334 Page 9 of 15 evaporation with subsequent settlement of the nanoparti- cles initially contained in it. The nanoparticles deposition improves the wettability of the surface considerably [95]. During quenching, the local boiling phenomenon of quenchant leads to occurrence of a wetting front which ascends the cooling surface with a significant velocity during nucleate boiling and descends in the fluid direc- tion during film boiling. A wetting process that occurs over a long time period of time is called non-Newtonian wetting, whereas a wetting process that occurs in a short time period or an explosion-like wetting process is termed as Newtonian wetting. A Newtonian type of wet- ting usually promotes uniform heat transfer and mini- mizes the distortion and residual stress development. In extreme cases of non-Newtonian wetting, because of large temperature differences, considerable variations in the microstructure and residual stresses are expected, resulting in distortion and the presence of soft spots [1]. Tensi has shown that the measured values indicate con- gruent curves for calculated hardness sample quenched in the distilled water and the total wetting time mea- sured at the top of the sample was more than 60 s, Figure 3 Cooling curves superimposed on the hypothetical I-T diagram. nano-dispersions could exhibit improved spreading/wet- ting capabilities at a confined space [109]. The pool boil- ing studies on nanofluid shows deposition of porous layer of nanoparticle on the heater surface. The reason for this porous layer formation could be microlayer Figure 4 Effect of alloying elements on TTT diagram.