분말사출성형체에서 Sr-페라이트 자성분말의 배향도에 미치는 첨가제의 영향

조태식; 정원용; Tae Sik Cho; Won Young Jeung

Polymer(Korea), Vol.25, No.2, 240-245, March, 2001

Export Citation

분말사출성형체에서 Sr-페라이트 자성분말의 배향도에 미치는 첨가제의 영향

Effect of Additives on the Orientation of Magnetic Sr-Ferrite Powders in Powder Injection Molded Compacts

조태식^†, 정원용¹

국립상주대학교 신소재공학과
¹한국과학기술연구원 금속공정연구센터

Tae Sik Cho^†, and Won Young Jeung¹

Department of Materials Science and Engineering, Sangju National Univerisity, Sangju 742-711, Korea
¹Meal Processing Research Center, KIST, Seoul 130-650, Korea

E-mail:

초록

다극 이방성 Sr-페라이트 소결자석을 제조하기 위한 자장중 분말사출성형공정에서 Sr-페라이트 자성분말의 배향도에 미치는 결합제의 첨가제 영향이 연구되었다. 외부자기장의 방향에 대한 Sr-페라이트 자성분말의 배향도는 첨가제의 종류, 사출성형온도와 관련한 사출성형체의 유동성과 외부자기장의 세기에 크게 의존하였다. Paraffin wax/carnauba wax/HDPE 3성분계 결합제에 stearic acid를 첨가하면 분말사출성형체의 유동성이 향상되어 Sr-페라이트 자성분말의 배향도가 증가되었으나, silane계 커플링제를 첨가하면 성형체의 유동성이 오히려 감소되어 Sr-페라이트의 배향도가 감소되었다. 80% 이상의 Sr-페라이트 자성분말의 배향도는 사출성형체의 겉보기점도가 2500 poise(1000 sec^-1)이하이고 외부자기장의 세기가 4 kOe 이상인 유용한 조건에서 얻어졌다.

The effect of additives on the orientation of magnetic Sr-ferrite powders has been studied during powder injection molding under applied magnetic field for fabricating multi-pole anisotropic sintered Sr-ferrite magnets. The orientation of the Sr-ferrite powders depends sensitively on the fluidity of powder-binder mixture, related to the binder additives and the injection molding temperature, and the magnetic field intensity. The orientation of Sr-ferrite powders is good for the compacts with stearic acid added in the binder system of paraffin wax/carnauba wax/HDPE, but it is poor for the compacts with silane coupling agent added. The orientation of Sr-ferrites higher than 80% is achieved at the following useful conditions; apparent viscosity lower than 2500 poise in 1000 sec(-1) shear rate and applied magnetic field higher than 4 kOe.

Keywords:powder injection molding;orientation of Sr-ferrites;fluidity;stearic acid;coupling agent

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[1] Jeung WY, Cho TS, Moon TJ, J. Korean Magn. Soc., 4, 219 (1994)

[2] Cho TS, Jeung WY, Moon TJ, Polym.(Korea), 19(1), 87 (1995)

[3] Murillo N, Gonzalez J, Guraya C, Gutierrez M, Seco FJ, J. Magn. Magn. Mater., 203, 165 (1999)

[4] German RM, "Powder Injection Molding", p. 5, MPIF, NJ (1990)

[5] Messler RW, Metal Powder Report, 5, 363 (1990)

[6] Lin ST, German RM, Powder Metall. Intern., 21, 19 (1989)

[7] Wiech RE, U.S. Patent, 4,305,756 (1981)

[8] Rivers RD, U.S. Patent, 4,113,480 (1978)

[9] Denes PA, Ceram. Bull., 41, 509 (1962)

[10] Cullity BD, "Introduction to Magnetic Materials", p. 212, Addison-Wesley Publishing Co., Massachusetts (1972)

[11] Chung CI, Rhee BO, Cao MY, Liu CX, Advances Powder Technol., 3, 67 (1986)

[12] Calvert PD, Tormey ES, Pober RL, Ceram. Bull., 65, 669 (1986)

[13] Han CD, Weghe TVD, Shete P, Haw JR, Polym. Eng. Sci., 21, 196 (1981)

[14] Seymour RB, "Additives for Plastics", p. 123, Academic Press, NY (1978)

[15] Han CD, Sandford C, Yoo HJ, Polym. Eng. Sci., 18, 849 (1978)