Air Permeability (w187,189, 302, 304, 310)
Below are results for air permeability tests I took on wafers w302, w304, w187, w189, w310. The X axis is the position of a sample on the wafer (from inside to outside).
Samples form wafer 189 passed no air and the permeability of wafer 187 is extremely low.
Permeability of other wafers increases closer to the outer diameter of the wafer what proves that membranes have more and bigger pores in that area.
All these results were taken from samples with no pinholes or very few. Most of them are multiple data points.
Samples form wafer 189 passed no air and the permeability of wafer 187 is extremely low.
Permeability of other wafers increases closer to the outer diameter of the wafer what proves that membranes have more and bigger pores in that area.
All these results were taken from samples with no pinholes or very few. Most of them are multiple data points.
Thanks. Any burst pressures for these?
It looks like data is starting to make sense. Given all the problems that we’ve had with anything involving liquid flow, I think these air tests will prove to be quite useful. Can any quantitative comparisons be made to the TEM images?
Also, please explain what the lowest measurable flow is. I assume that you are limited by the leak rate – please give some type of number, so we can understand what “no flow” really means.
We do need burst tests ASAP, on each new set of wafers, so the others know how to choose their testing parameters.
I test the setup for leaks before starting experiments. There is no measurable leaks comparing with the times at which I measure the flow as far I know.
So the “no flow” basically means that the sample was left under pressure for more then 15 min and no air passed through (the water column didn’t move).
I will talk about all data that I think can be taken form TEM images and air permeability comparison tomorrow at the meeting. But it is mostly taking pore distributions and pore diameters form TEM images and fitting them to the formulas to get the flow, which then can be compared with experimental data. I’ve done few preliminary calculations (didn’t use the MatLAB code for TEM yet) and they seem to agree. I will tell more tomorrow.