Why does customer prefer silicone free thermal grease?

One of our customer desgined thermal solution for electric motor, there are two options, one is thermal gap pad and one is thermal grease. The thermal engineer prefers a 7.9W/mK thermal pad, because its thermal conductivity is much higher than that of silicone free thermal grease.

The gap is 0.1mm between heat source and heat sink in customer’s application, so we suggested having a try on silicone free thermal grease XK-XN50. After customer went through the data sheet, he didn’t want to use this material. Why? The customer explained that the thermal conductivity of 4.6W/mK is much lower that he expected, the one of 7.9W/mK would be the right one. We showed thermal engineer the comparison data between silicone free thermal grease and thermal pad. Thermal conductivity of thermal pad is 7.9W/mK, thermal impedance is 0.13in2/W, even though thermal conductivity of silicone free thermal grease is 4.6W/mK only, the thermal impedance is just 0.006in2/W, we can see that thermal performance of silicone free thermal grease is more excellent than that of thermal pad, while thermal conductivity is very important, but it’s not the only factor that should be look at when judging thermal performance. In addition, the gap is only 0.1mm, it’s very hard to make such a thin thermal pad, but silicone free thermal grease can finish this job easily.

Siloxane volatiles must be taken care in application. the siloxane volatiles will affect the performance and service life of product, silicone free thermal grease is ideal for silicone sensetive applications.

Customer considered our suggestion carefully and decided to test silicone free thermal grease first. One week later, the engineer told us”we don’t need to test thermal pad, silicone free grease is exactly what we want, it makes tempearture rise down by 30 degree”. Now this project has been approved, production will be proceed at the end of this year.