MAGNETO RHEOLOGICAL FLUID AND MANUFACTURING METHOD THEREOF

The present invention relates to a magnetorheological fluid and a manufacturing method thereof. The magnetorheological fluid comprises: a dispersion medium; magnetic particles; and a thixotropic agent. The magnetorheological fluid has viscoelasticity. When the shear stress (τ) of the viscoelasticity of the magnetorheological fluid is τ=τ_0sin(wt) and the shear strain (γ) is γ=γ_0>sin(wt+δ)=G'sin(wt)+G"cos(wt), where G' is referred to as storage modulus and G" is referred to as loss modulus, and when a magnetic field is applied thereto, the slope of G" is less than or equal to 0 in the section where the shear strain applied to the magnetorheological fluid has a value satisfying tan δ=G"/G'=1. Therefore, the magnetorheological fluid can reduce the degree of sedimentation of the magnetic particles in the dispersion medium. 본 발명은 자기유변유체 및 자기유변유체의 제조 방법에 관한 것이다. 본 발명에 따른 자기유변유체는, 분산매체, 자성입자 및 요변제(Thixotropic Agent)를 포함하는 자기유변유체(Magnetic Rheological Fluid)로서, 자기유변유체는 점탄성(Viscoelasticity)을 가지며, 자기유변유체의 점탄성의 전단응력(Shear Stress; τ)을 τ=τ0sin(wt), 전단변형(Shear Strain; γ)을 γ=γ0sin(wt+δ)=G'sin(wt)+G"cos(wt)라고 할 때[G'는 스토리지 모듈러스(Storage modulus), G"는 로스 모듈러스(Loss modulus)라 함], 자기장 인가시, 자기유변유체에 가해지는 전단변형 0.01% 내지 tan δ = G" / G' = 1을 만족하는 전단변형 값에 이르는 구간에 대하여 G"의 기울기는 0과 동일하거나 작은 것을 특징으로 한다.