Dissolution of chromium carbide Cr3C2 in Kh17N2 steel during sintering

Abstract

The effect of sintering temperature (900-1300°C) on the interaction of Cr 3 C 2 with a Kh17N2 steel matrix is studied. It is shown that complex iron-chromium carbide of (Cr, Fe) x C y type forms during sintering. With increasing temperature, it undergoes a number of phase transformations. The following mechanism of Cr 3 C 2 dissolution in the steel matrix is established:The effectiveness of chromium carbide Cr 3 C 2 as a doping agent in producing wear-and corrosion-resistant materials was previously verified in [1][2][3]. Powder composites containing Cr 3 C 2 can be used to make tools and machine parts designed to perform in conditions of abrasive wear and in hostile environments and to deposit protective coatings on parts and mechanisms. The steel component of such materials and the proximity of linear expansion coefficients of the coating and the part promote strong and unstressed adhesion between them.The performance properties of the alloys in question are largely determined by the nature of interaction between carbides of the solid phase and the steel matrix during sintering. As a rule, this interaction leads to complex redistribution of elements between carbides and the matrix. To control the interaction of chromium carbide with the steel matrix, clear understanding of the nature and mechanism of this process is needed to limit the impact of temperature and time factors to the maximum extent.The published data on the interaction of chromium carbide with a metal matrix are incomplete [4][5][6] or mainly focus on the interaction of Cr 3 C 2 with an iron matrix [7]. The studies by Napara-Volgina and colleagues deal only with composites based on Kh18N15 austenitic steel with Cr 3 C 2 and MoS 2 additives. These data do not reflect quantitative changes in chemical composition of the carbide phase at different sintering temperatures.Our objective is to examine the variation in phase and chemical composition of chromium carbide particles in contact with a Kh17N2 chromium steel matrix and to establish the mechanism of their dissolution during heating.