Ievdokymova O. Regularities of formation of structure and properties of highly efficient tribotechnical composites from super coarse-grained high-modulus carbide powders

The dissertation is devoted to solving important scientific and technical problem in obtaining highly efficient tribotechnical composites from super coarse-grained high-modulus carbide powders by identification of structure and properties of porous composites from super coarse-grained carbides WC, SiC powders with relations of plastic metals and alloys, which allowed to develop an effective manufacturing technology of the friction pairs parts and identify effective conditions of their work. It was found that covering the super coarse-grained WC and SiC by cobalt or nickel can provide pressing of pressed samples without destroying of the WC and SiC particles at 30 to 250 MPa and get pressed samples with porosity between 45 and 20 % respectively. To eliminate chemical interaction of molten metal the links with WC the particles of SiC should be covered with a thin (5 mkm) layer of WC and to increase strengthof bonds between the particles the bunch TN65 in amount of 5 to 10 % (by weight) must be added in. The first time the phenomenon of spontaneous structuring of composite at the liquid phase sintering of super coarse-grained WC, coated with Co or Ni, in which the porous strong skeletal structure is formed suitable for use as an effective high-loaded antifriction material. Tests of friction pairs parts from the developed material based on SiC (WC) 5 % (by weight) TN65 was carried out at the conditions of SE "Plant number CA 410" which have shown that the wear resistance of parts of the developed material exceeds the wear resistance of serial bearing made from tin bronze in 3-3.5 times which is used in the fuel pump unit 934 of the motor D36.