Comparison of the texture functions describing the grain alignment in NdFeB magnets

Two types of Gaussian distribution function ('theta type' and 'tan theta ty pe') describing the degree of grain alignment in sintered NdFeB magnets hav e been compared in the distribution coefficient sigma (or sigma(g)), the di stribution probability P(theta) and the grain alignment dependence of coerc ivity. The results show that when the grain alignment is good (the ratio of remanence-to-saturation polarization J(r)/J(s) greater than or equal to 0. 90), sigma(sigma(g)) and P(theta) for the two types of Gaussian functions h ave similar variation-tendencies, the calculated values of normalized coerc ivity based on the starting field theory are basically the same and are con sistent with experiments. When the grain alignment is not good (J(r)/J(s) g reater than or equal to 0.80), the variation tendencies of sigma and P(thet a) are different. In addition, according to 'tan theta type' Gaussian funct ion? the theoretical values of the normalized coercivity based on the start ing field theory are still consistent with the experiments, but according t o 'theta type' Gaussian function, the theoretical values seriously deviate from the experiments. This means that the 'tan theta type' Gaussian functio n is a better texture function for describing the grain alignment (C) 1999 Elsevier Science B.V. All rights reserved.