Experimental Study of Electroless Composite Coated HSS Drilling Tool on Mild Steel

The development of project is investigation of electroless composite coating on high speed steel drilling tool with help of an optimizing process parameter. For purpose of increasing hardness, wear resistance, surface lubricity, oxidation temperature and tool life. Nickel-Phosphorous-Titanium nitride (Ni-P-TiN) is coated by electroless coating technique. Normally high expensive CVD and PVD coating techniques are used for tool coating. But in our project for the first time less expensive electroless coating technique is used. A comprehensive experimental study of electroless composite coating on high speed steel drilling tool under specific condition for studied. Electroless coating is an autocatalytic coating process in which the metal to be coated undergoes catalytic reaction and deposit over the substrate. The coating bath consists of different concentrations on Nickel-Phosphorous-Titanium (20g/1). And then sodium hypo-phosphite (23g/1) as reducing agent, sodium acetate (13g/1) as stabilizer and ammonium hydrogen difluroide (7g/1) as the complexing agent. The surfactant SLS (1.2g/1) was added into solution before coating deposition. The stabilizer thiourea (1ppm) was added into the bath to make the reaction stable. The output parameters such as surface roughness, microhardness, optical was measured. . Surface morphology was studied by using scanning electron microscope (SEM). The results showed that the proposed methods resulted in significant improvement on the quality of the coating produced.