Overfilling the crucible will cause the material to spill over and create an electrical short between the liner and the hearth. We find that the melt level of a material in the crucible directly affects the success of the crucible liner. Because not using a crucible liner is not always an option, especially in shared systems, some customers will use a copper crucible liner and place the starter source in the copper crucible liner instead of placing directly in the hearth.Ī key process note is to consider the fill volume of the crucible liner. We also recommend using a FABMATE® or graphite crucible liner or running tantalum directly from the hearth of the e-gun. Contact us byĬlicking here with your e-gun manufacturer, pocket size, and number of pockets in order for us to produce a quote. Tantalum will still require high power for evaporation even when using a starter source or rod, but less so than when using pellets. This allows higher temperatures to be achieved at lower powers and eliminates the problem of partially melted pellets. We machine a rod such that the outer diameter of the rod is not in contact with the cooled walls of the crucible liner. We have also found that using a rod for high temperature materials like tantalum helps to reduce the amount of power required for deposition. The two main benefits of using a starter source are ease of use and handling as well as superior packing density. We recommend using a pre-machined slug (or starter source) instead of pellets. Great care should be taken during the entire evaporation cycle due to the high degree of difficulty and risk of equipment damage. For these reasons, the e-beam evaporation of tantalum should be closely monitored through welder's shade 9 glass. It is then possible for the e-beam to drill a hole through the crucible liner and into the e-gun hearth.

This can be evidenced by a sudden and steep fall-off of the deposition rate. In other words, if the starting material is in pellet form, there is a high risk that even at high powers (>5kW), the pellets will not melt together uniformly which will increase the likelihood of the e-beam burning through the pellets and hitting the crucible. Typically, tantalum does not melt well to form a solid slug for evaporation. However, the process can be difficult and should be monitored very closely.ĭue to its high melting point (3,017☌), tantalum requires high powers in order to achieve an effective deposition rate. Tantalum is rated 'excellent' for e-beam evaporation. Tantalum, along with its alloys and compounds, is evaporated under vacuum to make semiconductors, optical coatings, magnetic storage media, and wear and corrosion resistant coatings. It is also used as a capacitor for electronics and may be alloyed with other metals to add strength and durability. It is mainly used to make surgical implants due to its non-toxic nature. It is metallic grey-blue in color with strikingly similar chemical properties to niobium. Tantalum has a melting point of 3,017☌, a density of 16.6 g/cc, and a vapor pressure of 10 -4 Torr at 2,590☌. Tantalum is classified as a transition metal on the Periodic Table and is considered to be one of the refractory metals which are highly resistant to corrosion. To speak to someone directly about current pricing, please Actual prices can vary and may be higher or lower, as determined by availability and market fluctuations. These approximate materials prices are published to provide budgetary guidelines. We sell these pellets and pieces by unit weight for evaporation use in deposition processes.

Tantalum pentoxide vapor pressure