Either an electr-plating or wet chemical deposition process is used to put chrome or nickel on a sleeve. Nikosil sounds like an alloy (nickel/silicon/moly) that would require cladding or perhaps the entire sleeve is cast of this alloy. Some of the best engines are now ABN. OS, Webra, Thunder Tiger, and YS. I have OS, Webra, and one TT and have always used all synthetic fuel they all have hundreds of flights on them. I also fly Enya, Rossi, and Super Tigre and they are good engines but none have lasted longer than my OS 46FX or Webra 50 Speed.