Page 8 - Дисертація_Борух

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It is shown that the alloying of the SmCo 5Zr, V or Ti alloy also causes a

reduction in the grain size of the CaCu 5 phase after treatment by the solid-HDDR

method at low hydrogen pressure.

The Nd 11,7Fe 82,3B 6 and Nd 16Fe 76B 8 materials and the materials alloyed with

zirconium, up to 2.1 at. % as an additional factor of grinding the microstructure

(Nd 11,7Fe 81,1Zr 1,2B 6 and Nd 16Fe 73,9Zr 2,1B 8,), are studied. The stoichiometric

Nd 2Fe 14B (or Nd 11,7Fe 82,3B 6) alloy due to the peritectic reaction of the formation of

the Nd 2Fe 14B phase, consists of Nd 2Fe 14B phase rich in Nd and α-Fe. It is shown

that the introduction of only 1.2 at. % Zr completely prevents the release of iron.

That is, alloying with zirconium is a means of controlling the phase composition of

this type of ferromagnetic materials. This is especially important for permanent

magnets, because the higher the content of Nd 2Fe 14B phase in them, the better their

properties. Alloys alloying with zirconium with excess of neodymium (to

stoichiometric) leads to the change in their morphology.

The grinding conditions of Nd 16Fe 73,9Zr 2,1B 8 alloy under which the Nd 2(Fe,

Zr) 14B phase is preserved, are established. It is shown by the expansion of the

peaks on the diffraction patterns that with increasing frequency and duration of

grinding, the residual stresses are formed in the alloy and the microstructure is

crushed. As the rotation frequency of the mill chamber as well as the duration of

the process increase, these effects are more noticeable. The particles of powder

obtained at the mill chamber rotation frequency of ν = 100 rpm for τ = 12 h, are

anisotropic, as evidenced by the change of the peaks of the Nd 2(Fe, Zr) 14B phase.

Conditions of hydrogenation-disproportionation (HD) in ground

Nd 16Fe 73,9Zr 2,1B 8 materials are investigated taking into account the mechanism of

texture memory - incomplete disproportionation of Nd 2Fe 14B phase. It is

established that after HD under hydrogen pressure of 0.05 MPa at temperature

700°C in Nd 16Fe 73,9Zr 2,1B 8 alloy there are remains of the Nd 2Fe 14B phase. After

recombination of such an alloy, a powder with magnetocrystallographically

anisotropic particles is obtained.