Thermark and Cermark sound similar...because they are similar. 

Both are permanent solutions for marking on metals, though there are two different formulations for each.  One is for metals and the other is for glass and ceramics. The solution for glass and ceramic can also work on some plastics.  

The process is called laser bonding because the laser "bonds" propietary Thermark/Cermark material ON TOP of the metal surface.  The process does not remove material and engrave.  

This non-intrusive process is many times the preferred method for marking labels especially those that will be used for marking UID tags and exposed to the outside elements.  The UV rays from the sunlight will not fade the Thermark/Cermark material.  

Also, Thermark tape applied to anodized aluminum will bond to the surface of the anodized layer.  It will not remove the anodized protective layer.   

Recently, the people that make Cermark (Ferro) purchased Thermark and now they are one company.  The two products remain and for good reason.  We will explain later in this section.  

Thermark and Cermark come as a paste, a tape or a spray.  

All will work great on bare metals.  That is the key, bare metals.  Often I hear people having issues with this process and see posts on forums asking for help. 

It boils down to this:

1.  If the laser is not hot enough, the Thermark/Cermark will wipe off when cleaning the part post laser

2.  If the laser settings are correct, then Thermark/ Cermark is permanent and will be a black color on top of the metal surface

3.  If the laser settings are too hot, then Thermark/Cermark is permanent and will be a brown color on top of the metal surface

If the metal has a coating, the laser bonding will not work.  

Here are some difference between Thermark and Cermark:

1.  Thermark spray can seems never to clog.  Cermark can clog and people will turn the Cermark spray can upside down to spray until Cermark does not come out.  In this case Thermark can go farther.

2.  Thermark is easy to wipe off.  Cermark has a hardener and is thicker and more difficult to wipe off after the laser process.

3.  Thermark is a thinner coating compared to cermark, so laser settings can be faster. 

4.  Thermark tape is thicker and requires slower laser speed