Study of physical characteristics of nickel wicks developed by metal injection moulding

Abstract

The present research is focused on porous, grooved and tubular wick development. The basic purpose of a wick is to generate capillary pumping pressure for circulation of a working fluid within the loop heat pipe, which is used in spacecrafts and satellites. The present work establishes metal injection moulding as a potential route for wick development in the near net shape form. Nickel powder, polypropylene powder and thermoplastic binder have been used to produce green compacts of the wicks before sintering. Experiments have been performed at three levels of sintering temperature (900, 930 and 950uC) and sintering dwell time (30, 60 and 90 min). Optimum sintering condition has been found in this work as 900uC temperature and 60 min time, which gives optimal values of porosity (55 vol.-%), average pore diameter (2?6 mm), permeability (1?94610 212 m 2 ), effective thermal conductivity (9?37 W m 21 K 21 ) and average capillary pumping pressure (54 kPa) in the wick.

A novel approach of manufacturing Nickel Wicks for loop heat pipes using Metal Injection Moulding (MIM)

“…Structural integrity of the compact is developed in this stage. The debound compacts are heated to 900 • C, 930 • C, 950 • C for 30, 60, 90 min, respectively in pure hydrogen atmosphere to avoid oxidation (Samanta et al 2013). Due to application of heat, strong particle to particle bonding occurs at the contact points among the particles by formation of neck similar to that in conventional powder metallurgy (German & Bose 1997;German 1998).…”

Nickel Wick by Continuous Freeze-Casting: Influences of the Particle Size on the Capillarity and Mechanical Properties

“…Wicks are the main component of loop heat pipe (LHP) systems, highly efficient heat transfer devices quite appreciated in the aerospace and electronics industries [ 8 , 9 , 10 ]. The wicks allow the coolant to flow self-propelled through its porous structure without the need for an external pump.…”