IMPROVING THE EFFICIENCY OF NITROCEMENTATION TECHNOLOGY WITH ELECTROSPARK ALLOYING

Abstract

A new process for the nitro cementation of steel surfaces based on electrospark alloying (ESA) is proposed, which consists in the pretreatment of the surface with an aluminium electrode, followed by the application of a nitrogen-containing paste and subsequent alloying with a graphite electrode. This process is an innovative approach to increasing the wear resistance and strength of metallic materials of the coating-substrate type. The main goal of the investigation was to determine the effect of the energy parameters of the alloying process on the key quality indicators of the obtained coatings. The effect of discharge energy on layer thickness, microhardness, continuity and surface roughness was investigated. The results of metallographic and durometric tests indicate that nitrogen-containing coatings consist of a hardened «white» layer that gradually transitions to the diffusion zone and the substrate metal. The coatings obtained have a «white layer» thickness of 100-110 μm. The durometric tests show an increase in microhardness to 6800-10380 MPa. The phase composition of the coatings is represented by cubic iron nitride and iron carbide alloyed with ferrite. The use of ESA allows a reduction in energy consumption and processing time compared to traditional chemical heat treatment methods. The absence of the need for full heating of the part reduces the risk of thermal deformation and preserves the original mechanical properties of the base metal. The proposed method of nitro-cementation based on electrospark alloying is a promising technology for strengthening the surfaces of steel parts. The use of a combined approach involving pre-treatment with an aluminium electrode, application of a nitrogen-containing paste and alloying with a graphite electrode allows high microhardness, thickness and continuity of the coatings to be achieved. This gives new possibilities for increasing the wear resistance and durability of important parts and components of pumping and compressor equipment, contributing to the development of modern technologies in the field of materials science and surface engineering. Further research in this area could be aimed at optimising the technological parameters of the electrospark alloying process to improve the efficiency and quality of the coatings obtained. This may include studying the effect of different types of electrodes, alloying modes and processing conditions on the structural and mechanical properties of coatings.