Increase of the purity of metal products surfaces with application of nanotechnologies

It is known that the quality of the surface of metal products machinery and equipment measured at the value of the roughness significantly affects their performance. This also applies to the impellers turbopump units (TNA) of liquid rocket engines (LRE), the cast of superalloys, because this figure significantly affects the volumetric flow of the fuel components. However, due to the difficulties of conducting full-scale experiment on LRE, in that article the data from the cast steel ship propellers (SP) were used. There is a certain similarity between geometries of SP and functions of TNA. The similarity of the features and technologies of their production, both of which, firstly, produce a casting: impellers TNA - investment casting process, SP - casting in sand-clay molds, secondly, there is the similarity in the materials of the molds - in both cases, their basis is the sand, and the second component is a liquid binder. At the same time when molding in sand-clay parts often affects the penetration, firmly linked with the body of the casting crust, formed as a result of penetration of liquid metal into the pores between the grains of sand form, which is subsequently removed in a variety of ways, usually with the deterioration of surface cleanliness. To reduce metal penetration work surfaces forms are coated with fireproof paint, representing a suspension of the powder filler (graphite, powdered quartz, etc.). However, the use of such paints does not prevent the formation in castings of metal penetration due to the particle size of the fillers. In this paper a nonstick paint containing nanopowders of refractory chemical compounds is used, the use of such coatings is almost completely prevents the formation of burnt-on steel castings, including the one described in the work of the ship propeller, and, as a result, increased clarity and improved surface quality. The obtained results can be used in the manufacture of molds for the casting of the impellers TNA.