Several Aspects of Interaction between Chrome and Nanodiamond Particles in Metal Matrix Composites When Being Heated

Abstract

The paper considers the development of a technological scheme for preparing metal matrix nanocomposites based on the interaction between nanodiamond reinforcing particles and a chromium matrix when being heated, forming chromium carbide nanoparticles. These carbides are in situ synthesized ceramic reinforcing nanoparticles. The first stage of preparing composites is to obtain composites with the chromium matrix and nanodiamond reinforcing particles. For this purpose, mechanical alloying is used, i.e., processing in planetary mills. The size of a primary nanodiamond particle is 5 nm, but they are combined in agglomerates that are hundreds of micrometers in size. The time of processing in the planetary mill defines the crushing degree of the agglomerates. In this study, processing was carried out for 0.5 h, 2 h, and 4 h. The second stage for obtaining composites with reinforcing particles of chromium carbides is thermal processing. Explorations using the method of differential scanning calorimetry showed that reducing the size of nanodiamond reinforcing particles (by prolonging the time of processing in the planetary mill) leads to a decrease in the initial temperature of the reaction for developing carbides. The worked-out technique for obtaining composites was patented in the Russian Federation (the patent for invention 2772480).

Decrease in the Starting Temperature of the Reaction for Fabricating Carbides of Refractory Metals When Using Carbon Nanoparticles as Precursors

“…That is why designing methods for fabricating carbides of various metals during the direct chemical reaction between the metal and carbon is a vital task. The opportunity to decrease the carbide synthesis temperature when using carbon nanoparticles as precursors has been studied in several works: articles show that the use of carbon nanoparticles (nanodiamonds [9,32], fullerenes, carbon onions [6], globular carbon [3]) in aluminum matrix composites leads to the synthesis of aluminum carbides at significantly lower temperatures than in the case of macro-materials: when fullerenes are used, the decrease reaches 350 • C. This effect was also investigated when using chromium as a composite matrix with nanodiamond reinforcing particles [33]. The temperature was reduced to 520 • C. Studies of using this effect for the synthesis of refractory metal carbides are important, since the existing methods of producing such carbides use high temperatures.…”

“…The opportunity to decrease the carbide synthesis temperature when using carbon nanoparticles as precursors has been studied in several works: articles show that the use of carbon nanoparticles (nanodiamonds [9,32], fullerenes, carbon onions [6], globular carbon [3]) in aluminum matrix composites leads to the synthesis of aluminum carbides at significantly lower temperatures than in the case of macro-materials: when fullerenes are used, the decrease reaches 350 °C. This effect was also investigated when using chromium as a composite matrix with nanodiamond reinforcing particles [33]. The temperature was reduced to 520 °C.…”