The most common filter is made of Cordierite (a ceramic material) Cordierite filters provide excellent filtration efficiency and are (relatively) inexpensive. They have thermal properties that make packaging them fo r installation in the vehicle relatively simple. A coupe of major drawbacks are that cordierit e has a relatively low melting point another words goes from a solid to a liquid. (around 2000° Fahrenheit / 1100° Celsius) and cordierite substrates have been known to melt down during filter regeneration along with them being extremely fragile, thus the need for a robust good canning process. Melting is mostly an issue if the filter has become loaded more heavily than usual, such as excessive lube or fuel oil, excessive idling etc, it is more of an issue with Passive systems than with Active systems, unless there is a system break down.
Cordierite filter cores are designed simular to that of a catalytic converter cores but they have the alternate channels plugged. With the introduction of the plugs it forces the exhaust gas to flow through the wall and the particulate collects on the inlet face.