Thermal Management


Taking inspiration from nature


VersarienCu thermal management material


With the heat that systems designs are exposed to increasing so more effective thermal management is needed. Based on structures found in nature Will Battrick looks at an advanced heat transer mechanism for next generation electronic designs


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cross a broad range of industry sectors, there is an increasing need for more sophisticated thermal management technology. Data centres are becoming packed with greater numbers of servers and countless high performance processors, in attempt to satisfy our hunger for bandwidth. Likewise, further features and functionality are being integrated into consumer electronic devices, such as gaming machines, smartphones, laptop and tablet computers, while the form factor of these products is shrinking, offering customers more streamlined and attractive products. Within the automotive world, mechanical systems are being supplanted by electronic ones, as x-by-wire technology grows in popularity. Lighting is also going through huge changes, as incandescent, fluorescent and high intensity discharge (HID) lamps are replaced by LED based lamps, which have superior energy efficiency and flexibility. If the long term reliability of these systems is to be assured then the large quantities of heat they generate needs to be dissipated in an efficient manner.


Engineers serving all of the sectors 10 March 2013


mentioned are now searching for thermal management mechanisms that are markedly more effective. The traditional heat sinking techniques that have been employed until now simply don’t provide the heat transfer levels necessary, as well as being too large and cumbersome for system designs where space is limited.


Turning to nature Structures found in nature have proved to be highly successful at maximising surface area, so that biochemical processes can take place efficiently. Micro-porous metallic materials, similar in form to natural structures such as bone and coral have, by applying similar principles, the potential to dramatically improve thermal management performance. However, until now the problem has been fabricating such materials in a cost-effective manner. Notable progress has been made in the field of micro-porous metals in recent times with the advent of the Lost Carbonate Sintering (LCS) process. Developed at the University of Liverpool, this allows production of a copper-based material which has a homogeneous distribution of micro-fine open cell pores.


Components in Electronics


The process has four basic phases. To begin with, the copper particles are mixed together with non-metal particles (see Figure 1). The proportion of copper particles to non-metal particles and the size of particle used will directly influence the fabricated material’s pore diameter and its pore density. The mixture is then compacted into net or near-net shape forms (see Figure 2). Following this, the


morphology that is highly effective at transferring heat, while being inexpensive to produce. Its open cell pores maximise surface area, allowing the flow of a fluid through the material that can remove the high levels of heat present. By partnering with Versarien the LCS


process developed at the University of Liverpool has now been transformed into a commercially-viable thermal interface


Figure 1: Copper & Non-Metallic Particles are Mixed Together


mixture is subjected to temperatures of approximately 1000 °C while being held in a vacuum (see Figure 3). This causes the copper particles within the mixture to adhere to together without melting, as well as removing the non-metal particles. Finally quality assurance and customisation is carried out (see Figure 4).


The copper based material fabricated using this process has an optimised


product that can be fabricated on an industrial scale – VersarienCu. Employing the LCS process, the company can deliver a permeable metallic foam material in large unit volumes that can be easily implemented into a wide range of different application environments, such as data centres/server farms, automobile electronics, gaming, computing and solid state lighting. It has been found to be up


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