In our previous papers it was shown that introduction of spongy titanium powder particles of 10–15% by weight of fine fraction (0.1–0.16 mm) into the charge based on coarse fraction (0.63–1.0 mm) enables to increase the tensile strength of compressed and sintered permeable element samples made from such bidisperse charge under tension from 36–38 MPa to 72–75 MPa. Thus the average sample pore sizes are reduced from 220–240 μm to 143–165 μm. Ensuring its homogeneity in large volumes and thus, if possible, minimizing power consumption for mixing, drying and other possible operations become a problem in the production of permeable elements from such bidisperse charge.

The properties of porous Ti disc aerators for water treatment were investigated. It is shown that the addition of 5-15 wt-% of a finer (100-160 mm) sponge titanium powder to the coarser (630-1000 mm) base powder can increase the tensile strength of the discs obtained by a factor of two. This allows weight savings of 44% to be obtained at comparable strength levels for discs 188 mm in diameter. The discs produced from mixed powders also produce finer bubbles and have lower permeability, which can lead to energy savings through reduced pump power consumption.

A technology has been developed to obtain porous powder materials on the basis of spherecal powder particles of 12Х18Н10T сorrosion-resistant steel by technological coating deposition on them –condensate from layered and composite Si and (Si + C) or Si and (Mo + Si) nano-layers. Their deformation at points of spherical particles contact creates press forming conditions with sufficient strength rate at pressure below yield point of steel powder (below 200 MPa). The subsequent sintering occurring with an exothermic reaction in the coating ensures particle sintering in their local heating within 1100–1200 °С temperature range.

A technology has been developed to obtain porous powder materials on the basis of spherecal powder particles of 12Х18Н10T сorrosion-resistant steel by technological coating deposition on them –condensate from layered and composite Si and (Si + C) or Si and (Mo + Si) nano-layers. Their deformation at points of spherical particles contact creates press forming conditions with sufficient strength rate at pressure below yield point of steel powder (below 200 MPa). The subsequent sintering occurring with an exothermic reaction in the coating ensures particle sintering in their local heating within 1100–1200 °С temperature range.

A description is presented of a manufacturing process for large-diameter (180–300 mm) disks of sintered titanium, corrosion-resistant steel, and bronze. The properties of the initial powders and sintered disks are presented, and the dimensions of the bubbles which are formed are examined in relation to the parameters of the pore structure. Photographs of the microstructure of a disk are shown along with a scan of the disk surface. A description is given of porous disperser PA-2, which is designed for dispersing ozone and air in water. Its porous disk is made from titanium powder, while its housing and nozzle are made of corrosion-resistant steel. It is shown that replacing 1000 ceramic tube dispersers made by the German firm “Schumacher” by 2000 PA-2 dispersers in the city of Minsk's treatment system for drinking water, which has a daily capacity of 200000 m 3, made it possible to reduce the amount of ozone and gas that has to be injected for the treatment while keeping the purification level constant. None of the PA-2 dispersers had to be replaced over a 10-year period of operation.

As a result of the rapid development of power metallurgy and semiconductor technology, the nitrogen-hydrogen mixture produced by catalytic dissociation of ammonia is used on an increasing scale. Catalysts include bulk granules from powder of iron, nickel, or their oxides with promoting additions of A1203, K20, etc. [i, 2]. The common shortcoming of the bulk catalysts used at present is their low mechanical strength which results in disintegration of the particles, their mixing, friction against each other, and contamination of the gas flow. In addition to this, displacement of the particles is accompanied by the formation of continuous channels along which the main gas flow travels so that the volume of the catalyst is not used efficiently. Powder metallurgy can be used to produce porous powder materials (PPM) with the fixed structure with greatly varying composition and with the required combination of permeability and strength [3].