Metal Dusting: Kinetically or Thermodynamically Controlled?

Metal Dusting is a high temperature corrosion process (400°C to 800°C) upon which carbon ingress from the gas phase in alloys leads eventually to the loss of integrity of materials: a powdery mixture of carbon, carbides and metal is left. This corrosion process occurs in for instance ammonia plants, petro-chemical plants, and in syngas atmospheres where the carbon activity is a_c more than 1. During the last two decades quite some research has been performed all over the world to control and understand this phenomenon. However, up till now a break through has not been achieved yet.

A continuing Joint Industrial Programme is performed at TNO, mainly aiming towards defining the aggressivity parameter of gases responsible for the degradation mechanism Metal Dusting in austenitic materials. The industrial partners in this programme (20 in total) range from material suppliers, via engineering companies to petrochemical companies. The current talk will discuss and compare several measures used to estimate the aggressiveness of a gas.