Liquid infiltration property of micro-porous stainless steel produced by powder space holder method
Kazuaki Nishiyabu*, Satoru Matsuzaki**,  Shigeo Tanaka**
* Osaka Prefectural College of Technology
26-12 Saiwai, Neyagawa,
Osaka 572-8572, Japan
** Taisei Kogyo Co., Ltd.
26-1 Ikeda-kita, Neyagawa,
Osaka 572-0073, Japan

A production method for micro-porous metal components has been developed by applying the powder space holder (PSH) method to metal powder injection moulding (MIM) process. This paper deals with the liquid infiltration property of micro-porous metals produced by the PSH method. The material used is high-corrosion resistant austenitic stainless steel 316L, and the samples have micro-sized open porous structures with high specific surface area. The test apparatus for evaluating a liquid infiltration performance of the porous specimens was developed using analytical balance. From the weight change in a liquid infiltration test, the effecting factors on water absorption behaviour of the porous specimens were revealed. The results of the infiltration rate were compared to some important characteristics of the porous specimens such as mean pore diameter, liquid and gas permeability and specific surface area measured by capillary flow porometry. The effects of pore size on the infiltration rate were seen between porous specimens with a single digit µm and 15µm in mean constricted pore diameter.
More information/purchase paper

Cooling performance of tube X-COOLER shaped by MIM technology
B. S. Zlatkov1, H. Danninger2, O.S.Aleksic3.
1. FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan-Strasse 2, 2700 Wiener Neustadt, Austria
2. Institute of Chemical Technologies and Analytics, Getreidemarkt 9/164, 1060 Wien, Austria
3. Institute for Multidisciplinary Studies of the University of Belgrade, Kneza Viseslava 1a, 11000 Belgrade, Serbia

An advanced X-COOLER was produced by MIM (metal injection moulding) technology as a regular array of thin Cu tubes on a carrier copper plate used as motherboard plate. This cooler was designed to serve as a CPU active and passive heat sink. Its thermal properties were measured and compared to those of Cu heat sinks produced by precision forging technology of copper and Al heat sinks produced by the cold forging technology of aluminium, with pins arranged in a similar matrix array. Measurements were done for input heat generated on a heater placed at the bottom side of the motherboard plate and conducted by two dissipation modes: natural air convection and forced air flow cooling by a CPU ventilator (axial fan). Ventilator RPMs and volume air flow or “wind” velocities were varied through the input voltage and calibrated by an additional wind meter. Two variations of the fan-generated air flow in the cooler were tested, siphoning or upward and blowing or downward. Thermal resistance [Rth], thermal conductivity [λeff] and the heat transfer value W/tT for all three cooler types were determined and compared. All results were normalised by the heat sink outer volume, active surface and material volume to show the advantage of the novel MIM shaped heat sink in the volume-specific thermal conductivity.
More information/purchase paper

Micro-channelled heat exchanger manufactured by Ceramic Injection Moulding and co-firing
Luc Federzoni, Pascal Revirand
CEA Grenoble LITEN 17 rue des Martyrs
F-38054 Grenoble cedex 9
France

This work concerns the development of an innovative processing route for manufacturing a new design of ceramics micro-channelled heat exchanger.  The manufacture is based principally on the Ceramic Injection Moulding process of the different elements of the micro-channelled heat exchanger. Furthermore, the different elements are co-fired in order to produce the part. The micro-channelled heat exchanger is characterised by a complex network of inner channels. The paper focuses on the alumina feedstock based on ultrafine alumina powders and on conditions of injection, debinding and co-firing, developed essentially for this study. Moreover, interfaces between the co-fired elements have been characterised by optical microscopy.  This process may be applied to design complex and precise microstructures for mass produced micro-channelled heat exchangers, cold plates and micro reactors than can be used for various large scale applications in the field of energy and electronic cooling.
More information/purchase paper