[Experience in plasma-detonation coating of the working parts of medical instruments with nickel-aluminide-based alloys]. / Opyt naneseniia plazmenno-detonatsionnykh pokrytii iz splavov na osnove aliuminida nikelia na rabochie chasti meditsinskikh instrumentov.

The composition, the structure, and basic physical and mechanical properties of coatings composed of the nickel aluminide-based alloys HA-67, BKHA are examined. They are obtained by the detonation and plasma methods and by the combined detonation-plasma method as well. Because of the increased binder-base strength, a great and more uniform hardness, plasma-detonation coatings have been shown to be optimal as compared to the detonation and plasma methods. The greater hardness is directly related to the increased content of nickel aluminide in the plasma-detonation coatings.

[Change in the composition and structure of the metal in the zone of the welded seam of dental drill blanks]. / Zakonomernost' izmeneniia sostava i struktury metalla v zone svarnogo shva zagotovok zubnykh borov.

Composition and structure of metals in the meld zone connecting a dental burr handpiece made of hard alloy BK-6 with a shank made of steel 20X13 are examined by the X-ary microanalyzer MS-46 and the X-ray diffractometer "dPOH-2". Representative interdiffusion processes of alloy components into steel and, converserly, iron from steel into hard alloy are found. After melding, the transition layer has been shown to represent the cobalt-iron solid solution with variable concentration of the components through the layer, tungsten carbid particles being uniformly spread all over the metallic matrix. The phasic composition change is analysed in the course of material welding. The enrichment of stell melt with carbon of tungsten carbid results in the formation of gamma-Fe phase in the meld zone. The failure of burr blanks is noted to occur at the interface of the second (10-20 micrometer) and the first (130-140 micrometer) zones. The increase in the concentration of both iron and iron-containing phases--alpha-Fe, gamma-Fe, Fe3W3C--at the surface of steel fracture is responsible for the failures.