Applications of ferrofluids in Micro Electro Mechanical Systems (MEMS) and micropumps

V. K. Jain - R. P. Pant - Vinod Kumar

National Physical Laboratory, Dr. K.S.\,Krishanan Marg, New Delhi, India

Abstract
The micro-pump is one of the most promising micro-flow devices. At micro-level electronically controlled pumping of any fluid by a mechanical pump is not so easy and reliable. In the realm of nano-tech materials, ferrofluids have unique properties in both liquids and solids and have potential applications for MEMS/NEMS devices. This paper presents two new types of concepts, a micro-flowmeter based on a micro-turbine made using MEMS technology and the other is a micro-pump based on ferrofluidic actuation. In our first device an optical photovoltaic sensor has also been integrated with this device, and the micro-turbine rotates with a speed of 50000 rpm. We have fabricated a ferrofluid-based glass micro-pump of size 20 × 20 × 10 mm³, in which micro actuation is electrically controlled by NdFeB (N50) permanent magnets (diameter 5 × 3 mm, B_r = 1400 mT, coercive field H_c=840 ,kA/m) with a ferrofluid bearing. The device is able to pump the fluid at the rate of 10 μL/actuation. Figs 3, Refs 19.