US Air Force funds Waikato tech project

20 July 2017

Fei Yang for web

Dr Fei Yang is researching the heat transfer properties of diamond-copper composites.

The US Air Force has awarded a University of Waikato engineer more than $250,000 to research the heat transfer qualities of copper-diamond composites.

Dr Fei Yang, a materials and processing engineer, says copper and diamond can enable very high rates of heat transfer, which would make them ideal for computers and all devices that have graphic and central processing units (GPUs and CPUs).

Today we are asking our devices to do more and more and those machines are power hungry. “That’s the challenge,” says Dr Yang. “High-end units might need a 1000 or 2000 watt power supply, and that energy is released as heat while doing powerful computations. High-powered, high density machines can’t work to their full potential if the units expand and overheat.”

There are two issues being addressed here – one is matching the thermal expansion coefficient of a copper-diamond mixture to that of the substrate material and the other is increasing the thermal conductivity to more than that of copper.

The materials GPUs and CPUs are traditionally made from change their physical shape when heated which prevents them transferring heat efficiently. And, while diamond and copper composites have good conductivity, they naturally repel each other when heat is applied.

Dr Yang thinks he has come up with a way to make the mineral and metal stick – called “wettability”, and the US Air Force funding will allow him to develop his idea that’s been stewing for about three years. He received some initial funding from the University of Waikato’s Strategic Investment Fund.

“I will be working towards advancing the fundamental understanding in heat transfer of advanced heat sink materials and collaborating with industry partner(s) to develop the manufacturing technology to produce the qualified copper-diamond heat sink products for use in high-power ICs and high-density electronic devices in the electronics and communication engineering industry,” says Dr Yang.

The US Air Force has a history of supporting new and innovative ideas, and Dr Yang says he applied to them after one of their representatives came to Waikato University and made a presentation about the sorts of research they fund and what funding was available.

“I made an initial application then had to produce a white-paper about my research,” says Dr Yang, a senior research fellow in Waikato’s School of Engineering. “They got their technical staff to review my idea and I then had to make a final detailed proposal. What they required got more and more detailed as the process went through.”

The interface microstructure and thermal transfer and expansion of the designed copper/diamond composite will be analysed and tested to obtain more understanding on how the heat transfer would be affected, enabling increased control over interface quality.

The American funding is for two years with Dr Yang required to report at the end of each funding year.