We studied the influence of uniaxial anisotropy on the magnetization curves of a Co10Cu90 alloy by means of a model that is developed taking into account correction terms for the partition function in the limit of large anisotropy and aligned grains. This result is a sum of terms where the first term is the Brillouin function of quantum paramagnetism. Fitting of our curves to the discussed model was compared with another model that considers the influence of the distribution of magnetic moments and we observe a good agreement. We show that the uniaxial anisotropy is enough to consider its effects on the system.