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NiAl intermetallic coating thickness of about 50 μm was fabricated on hypo-eutectoid steel by mechanical alloying using pre-activated Ni–Al composite granules as coating material. First, Ni and Al powders were mixed with the composition of Ni-50 at.% Al and mechanically activated in a planetary ball mill, until the composite granules of this powder mixture, having maximum activity (9 cm sec−1), were formed after 120 min of milling at 200 rpm. The composite granules were then taken out from the planetary ball mill just before the critical time, i. e. the time at which these granules synthesize and convert to an intermetallic NiAl compound. The highly activated composite granules of Ni–Al were then put into the vial of a vibratory ball mill with the substrate on top of the chamber. After mechanical alloying for 60 min in the vibratory ball mill, the composite granules were synthesized fully and heat was produced during the synthesis which helped producing a thick and strong adhesive coating of NiAl intermetallic on the steel substrate. The main advantage of this technique is that not only is time saved but also there is no need for any post mechanical alloying process such as annealing or laser treatment etc. to get homogeneous, strongly bonded intermetallic coatings. X-ray diffraction analysis clearly indicates the formation of NiAl phase. Micro-hardness of the coating and substrate was also measured. The cross-sectional microstructure of the composite granules and the final coating were studied by scanning electron microscopy.

In this work, we proposed a novel mechanical alloying method to deposit Ni x-Ti x intermetallic coating on various metallic substrates using laser treatment. Three different substrates (Al-based alloy, Ti-based alloy, and hypoeutectoid steel) were used, and 50-70 µm thick Ni x Ti x coating was deposited during the process. For mechanical alloying, we used a self-constructed vibratory ball mill (single chamber) and for laser treatment, we used a "TrumpfTruDisk 1000" machine equipped with a four-dimensional control system "Servokon" designed specifically for experimental studies. Different laser beam intensities were used for laser operation. The cross-sectional microstructures of coatings were studied using a scanning electron microscope equipped with a Bruker energy-dispersive X-ray Spectrometer (EDS). Additional investigation of a cross-sectional area of one of the Ni x Ti x-coated samples was performed with field emission high-performance SEM and focused ion beam (FIB). Phase compositions of the obtained coatings, before and after laser treatment, were analyzed using X-Ray diffraction method. After the deposition process, the micro-hardness of the coatings was measured using a Vickers hardness tester. The structure and morphology of the obtained coatings were investigated.