Influence of contamination and the process of ageing
There are two main factors that have an influence on worsening the reaction of conversion. The first factor is a chemical contamination of a noble metal of a catalyst character due to fuel contamination with lead, magnesium or other elements. The second factor is linked with thermal ageing of an active layer. This phenomenon takes place at the temperature of about 800 Celsius degrees and causes burning of components of an active layer. However, the chemical contamination takes place at lower temperature ranging from 400 to 600 Celsius degrees.