TANTALUM AS A MATERIAL OF CONSTRUCTION FOR THE CHEMICAL-PROCESSING INDUSTRY - A CRITICAL SURVEY

Materials selection is based on safety and economic considerations; th e least expensive material securely withstanding service conditions fo r a required service time is chosen. For the integrity of equipment in the CPI chemical resistance is an essential factor. Of all metallic m aterials used for CPI equipment, tantalum is second to none regarding chemical inertness, comparing only to resistance properties of the non metals glass, fluoropolymers, and graphite. The price of tantalum, how ever, prohibits its broad application for construction. There are only two ways by which the demand for tantalum in this field can be promot ed significantly. First, a major increase in the aggressivity of servi ce conditions in process engineering caused by process development or modification. Second, cost reduction via tantalum price dilution by me ans of duplex systems application, utilizing the advantages of a less expensive base metal and a thin tantalum lining or coating. The more i mportant systems of this type are discussed and evaluated regarding th eir potential of development.