Consultancy Service - Electron Miscroscopy (Materials Characterisation)

The CREST laboratory is equipped with various sample preparation techniques which are utilised prior to inspection with the appropriate microscope. Since the SEM uses electrons to image the specimen this requires that the sample be electrically conductive. Metals require no sample preparation, however non-conductive samples must be coated with a thin layer of conductive material. Various methods for making the sample conductive are available at CREST including a dedicated coating facility incorporating:

Polaron sputter coater unit (E500): The sputter coater coats the sample with gold atoms by utilizing argon gas and a small electric field to create positively charged argon ions. The positive charged ions act like sand in a sandblaster and knock gold atoms from gold sputter coating target onto the specimen.

Edwards Auto 306 vacuum evaporator: The Edwards Auto is a thermal evaporator that can take up to four samples at a time and includes a film thickness monitor. The metals that can be evaporated within the system are largely unrestricted. A digital display allows provides vacuum and system information at all times.

Jeol vacuum evaporator (JEE-4B): Jeol JEE-4B is used for coating of samples for SEM work. There is in addition a wide selection of adhesives and paints for mounting of samples prior to analysis. These include:

• Double sided carbon tape that is conductive.
• Carbon, silver paint.
• Epoxy resin (non-conductive and will need to be coated).

The CREST facility also houses a dedicated sample preparation room that includes both a mounting and polishing section containing the following equipment:

• Motopol 2000 grinder polisher.
• Pneumet 3 mounting press.
• Struers polisher.
• Metaserv universal polisher.

The sample preparation room in addition incorporates a Telstar AV-100 laminar flow unit enabling extremely clean conditions for sample preparation.