Formation of Nanosized Lamellas of a Hardening Intermetallic Phase in the Powder Ni-based Coating Deposited by Microplasma Spraying on Steel Substrates

The Application of Transmission Electron Microscopy to the Analysis of Powder Coatings Deposited on Metal Substrates by Plasma Method

“…According to the results of TEM study of nickelchromium alloy powders, the powder does not contain the strengthening CrNi 3 phase. This is in agreement with the results of XRD analysis reported in our previous paper [13]. Figure 1 shows the TEM images of the plasma spray coating structure before its additional treatment by microplasma jet.…”

“…TEM and XRD methods confirmed a 4% increase in the volume fraction of CrNi 3 phase in the coating after additional microplasma processing (from 5 vol% to 9 vol%). It was established in our previous study that the microhardness of the coatings after additional microplasma treatment is 1.25 times higher than that of the same coatings before irradiation [13]. Thus, the structures observed in the coating before and after additional irradiation are similar (Figs.…”

“…The methods of transmission electron microscopy (TEM) is used less often for research of plasma spray powder coatings, despite the fact that it provides the opportunity of observation of dislocations and the morphology of nanoparticles [9][10][11]. The analytical transmission electron microscopy can be used to endorse the structural characteristic correlation to microhardness and electrochemical behavior of coatings [12][13][14]. The main advantage of using TEM technique/equipment is a possibility to get high resolution images on a nanometer scale.…”