The results of investigation of the thickness and microhardness of electrospark coatings (ESCs) of amorphous and nanocrystalline alloys (NCAs) are presented. It is shown that the application of amorphous and NCAs as electrode materials increases the thickness of ESCs and the produced coatings are characterized by high hardness.

No abstract

The investigations of tribo mechanical properties of coatings obtained with electrocontact welding of sintered powder materials and powderpolymer fillers of Russian manufacture are presented. It is proved that the introduction of antifriction components (powders of copper or tin) into filler material at a rate of 5-10 % increases the time to joints seizure by 1.5-2 and decreases by 1.5 the friction ratio. The application of powderpolymer and sintered fillers reinforced with metal grid produces a relief on the operating surface of the coating with the areas possessing minimum hardness. They are worn out more intensely and the forming herewith grooves help to keep lubricating oil on the friction surface. For the friction pair operating in abrasive wear conditions with adhesive wear elements, at welding it is recommended to use powder compositions (by weight): 80-90 % -PG-FBX6-2, 10-20 % of copper powder friction ratio

The results of investigations of the hardness and wear resistance of the working sections of machines, hardened using cermet materials in the form of paste, are presented. The optimum composition of the paste which greatly increases the service life of the working sections of the machines is determined.In the cultivation and the service of machines, the working sections are subjected to rapid wear as a result of the effect of abrasive particles, the cutting surfaces are blunted, and the shape, profile and working dimensions are greatly changed. Consequently, the quality of field operations is disrupted, the performance of these operations is delayed, the idle time of equipment is extended, the consumption of fuel and lubrication materials is increased and the amount of finished products is decreased [1 -3]. Therefore, the development and application of technologies capable of increasing the wear resistance of the working sections of machines is an important task and the solution of this task is of considerable importance in many areas of production.At present, a promising hardening method, which greatly increases the hardness and wear resistance of the cutting edges of the working sections of the machines, is vibroarc hardening (VAH) with cermet materials [4 -6]. In VAH, a cermet material in the form of paste is deposited on the hardened surface of the working section and burning of the direct arc results in both thermal diffusion hardening of the surface with alloying elements, including the composition of the cermet material, and VAH of the cermet coatings. A distinguishing feature of VAH is the absence of any significant heat input into the component during hardening.The cermet material developed in this study consists of a steel matrix (surfacing powder) with inclusions of alumina Al 2 O 3 , silicon SiO 3 , boron carbide B 4 C, refined to the nanosized state, and also alloying elements: nitrogen, present in the ammonium nitrate NH 4 NO 3 , and aluminium [5 -7]. Aluminium is used for deoxidation of iron and also for the formation of the ceramic phase by transformation to the aluminium oxide Al 2 O 3 and, in subsequent melting, to corundum. Corundum occupies position 9 in the mineralogical table of hardness, which is very close to the hardness of diamond. The matrix is an impact resistant, sustaining and composite frame of the cermet material. Therefore, the matrix material is produced from steelsurfacing powders with high hardness and abrasive resistance, for example PG-10N-01, PR-N70Kh17S3R4 and PG-SR4. To ensure the high impact toughness of the hardened surfaces, the content of the matrix material in the composition of the cermet material should not be less than 50%.Preliminary investigation showed that each of the components of the cermet material has a strong effect on the efficiency of hardening of the working sections of the machines. Therefore, investigations were carried out to determine the effect of the components of the cermet material on the hardness and wear resistance of hardened surfaces in orde...

No abstract