Annealing effects on the anisotropy fields and coercivities of (Y1-x2Cox)Co5

Anisotropy fields B
A
and intrinsic coercive fields H
c
have been measured at room temperature for polycrystalline samples of the alloy series (Y
1-x
2Co
x
)Co
5
where
0 \leq x \leq 0.129
. Measurements were made on as-cast, argon-arc melted samples and on the same samples after annealing for 5 days at 950°C. The singular point detection technique was employed to measure anisotropy fields directly using pulsed fields up to 20 Tesla. For the as-cast samples the anisotropy field deereases monotonically at approximately 3% per 1% of Y substituted. For annealed samples the anisotropy field increases at approximately the same rate. The intrinsic coercivity shows the same trends although the increase of H
c
with B
A
is non-linear for annealed samples. The results can-be generally accounted for in terms of the phase segregation in the annealed samples which has been observed using electron microprobe analysis.