The relatively new Type N thermocouple represents the single greatest advance in thermocouple thermometry in recent years. The dominant, well established Type K thermocouple has, for many years been the industry standard general purpose, high temperature (up to 1100oC) sensor world-wide.
In fact, type N offers superior performance and reliability to Type K in all applications and should be considered as an alternative when specifying new installations. Type N has very good thermoelectric stability which is much better than that of other base metal types; it also has an excellent resistance to high temperature oxidation.
The Nicrosil-Nisil thermoelement (Nickel-Chromium – Silicon / Nickel Silicon) is typically sheathed in an Inconel which offers good protection against corrosive atmospheres. The assemblies are ideally suited for accurate measurements in air up to 1200oC. In vacuum or controlled atmosphere, they can withstand temperatures in excess of 1200oC. The sensitivity of 39µV/oC at 900oC is only slightly lower than that of Type K (41µV/oC). Interchangeability tolerances are the same as for Type K.
The extension cable insulation for Type N is IEC-584 colour coded as pink outer, pink positive and white negative. Labfacility offers a wide range of Type N thermocouple assemblies and cables from stock on the Farnell website.