Carbon Rods for Carbon Evaporation

Overview

Rave Scientific offers Ultra high purity carbon rods which are used for carbon evaporation in EM applications, either to coat non-conductive samples with a thin layer of carbon or to produce support films for TEM samples.  The structure of the carbon rods is in reality high purity graphite which is formed during the purification process of the rods. The maximum level of impurity for the high-purity carbon rods is 2ppm with none of the elements exceeding 1ppm. See typical statements of purity. The typical level of impurity is 1ppm or less. This makes the ultra-high purity carbon rods ideal for SEM/EDS, EBSD, WDS and EPMA applications. Currently two grades of ultra-high purity carbon rods are offered:

• Grade F-S which is the high-purity standard grade. This is the most common grade of carbon rods. The rods tend to be stronger and more brittle. Stepped points of this grade are best made with an electrical carbon rod shaper. Available in Ø3.05mm (Ø0.120”) and Ø6.15mm (Ø0.242”) with a length of 305mm (12”). Compatible with carbon coaters from Cressington, AGAR, JEOL, Quorum, Leica, Edwards , Anatech (Hummer) and Denton.
• Grade F-A which is a high purity softer grade. This is a softer grade and stepped points are somewhat easier to make from this grade, when using a hand carbon rod shaper.  Compatible with coaters from Cressington (50Hz), AGAR (50Hz), JEOL (50Hz), Edwards and Denton.

Specifications of the ultra-high purity carbon rod grades.

The carbon rods are furnace purified; this changes the carbon into graphite and removes impurities. A statistical sample of each production batch of the ultra high purity carbon rods is analysed. (ETV-ICP Electro Thermal Evaporation – Inductively Coupled Plasma) is used for elemental analysis of the carbon rods. For each element there is 1ppm maximum allowable spot impurity.

Typical analytical results for the statement of purity in ppm for the carbon rods are: