"Porous Copper Fabrication via Powder Metallurgy Approach in Combination with a Space Holder Technique"
By Mr. Shaiful Anwar Bin Ismail

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1 Question from Prof. Madya Ts. Dr. Che Nor Aiza Jaafar What is the function of binder? Why did you choose MIM techniques for producing porous copper?
Answer from presenter 1. The function of binder is purposely for MIM process. Their functions are to improve the flowability of feedstock, maintain its structure during sintering process and improve the mixing process in order to get homogeneous mixture. 2. The MIM technique is suitable for producing porous Cu because a. The MIM materials ( main metal and binder) are powder type of material. Therefore they easy to mix with space holder material (KCl) during mixing process b. Flexibility in part shape. With MIM process, the mould used in injection process can be easily designed from simple shape to more complex shape. Thus, the final product can be prepared in variety of shape. In my cases, I planned to produce different shape of Cu heatsink with porous structure c. MIM process requires 4 main stages; mixing, injection, debinding and sintering. The debinding process is purposely performed to remove the binder. Since I have appointed the water-based space holder material (KCl) in producing the pores structure, thus this material can simultaneously eliminated with binder at the same time. I can reduce the time taken to remove both binder and space holder.
2 Question from Dr. Noorshida Binti Mohd Ali Why you stop at 75% vol. of KCl? Regarding to thermal analysis, it appears that as the percentage increases, the temperature decreases.
Answer from presenter 1. With 75% vol. of KCl, I managed to obtain porosity around 77%. However once I increased the KCl vol more than 75%, the sample suddenly cannot withstand it shape and start to collapse due to extreme MIM process such as water leaching process. Thus, I conclude, with my MIM recipe, the maximum vol of KCl that suitable to produce porous Cu is around 75% KCl. 2. True, by increasing the KCl vol, the porosity percentage for the sample can also increase. With higher porosity, the structure automatically has a lot of pores and voids. With the existence of these pores, the heat generated during the thermal testing keep reducing and represented by lowering its processing temperature. This is because the porous sample has ability to dissipate more heat due to larger surface area from the pores structure