Laws of Formation of Electrospark Coatings from Alloys of the Ni – Cr – Al – Y System

The main parameters of electrospark alloying of steel 45 with anodes made from Ni – Cr – Al – Y alloys have been investigated. The anodes were fabricated by casting and hot pressing. The highest values of the mass transfer coefficient were observed in the case of electrospark alloying with hot-pressed alloys. Microstructure and x-ray phase analyses of electrospark coatings revealed the presence of solid solutions based on nickel, iron, chromium as well as intermetallic compounds. Coatings obtained by electrospark alloying with hot-pressed alloy are more wear-resistant than are coatings obtained by alloying with cast alloys.     

Formation of Electric-Spark Coatings of Ni-Cr-Al-Y Eutectic Alloys

We studied the main parameters of the kinetics of electric-spark alloying of 45 steel with anodes cast and hot-pressed from alloys of the Ni-Cr-Al-Y system. The highest mass transfer coefficient was obtained in the case of alloying with hot-pressed alloys. A uniform distribution of nickel-, chrome-, and iron-base phases as well as of intermetallic ones was detected in the electric-spark coatings by means of microstructural, X-ray phase, and X-ray spectral investigations, which provides evidence of the formation of a structure in the form of a conglomerate of fine phases. The wear resistance of the coatings obtained from hot-pressed anodes is higher than that from cast alloys.     

Phase equilibrium in alloys of the system Cr-Hf-N

Translated from Poroshkovaya Metallurgiya, No. 8(308), pp. 76–81, August, 1988.