Graphite purification equipment

Selection considerations

Why graphite needs purifying

Graphite and carbon felt line the hot zones of crystal growth furnaces and appear as boats and fixtures in cell-making tools. At high temperature, metal and other impurities in these parts can migrate into silicon, so producers bake them at very high temperature in a controlled gas atmosphere to drive impurities out. A purification furnace treats parts, not wafers.

The parts come from several neighbouring classes: hot-zone items under process graphite parts, insulation and other furnace parts under crystal growth components including Huaxin's PAN sandwich rigid felt (Huaxin), and graphite boats used in PECVD on deposition systems, for example NAURA's tube PECVD system in cell production. Purified parts then serve in crystal growth furnaces like the Czochralski silicon growth furnace during wafer processing. Some parts also receive a protective surface layer afterwards on component coating furnaces, such as the CVD component coating furnace.

The furnace listed here

The class lists the CONAL VH continuous graphite purification furnace from NAURA. It moves graphite structural parts and felt through continuously at high temperature, rather than treating them in fixed batches. That suits a producer with a steady flow of similar parts; a shop with very mixed part sizes should ask how loading and fixtures handle that mix.

Writing the purchase order

Ask NAURA for a current written specification of temperature range and process gases for the configuration you order. Describe your incoming material, its typical impurity profile and the purity level your customers need, and send sample parts for a trial run at NAURA before shipment and again after installation, following the equipment trials guide. Agree how purity is measured after treatment, which lab runs the analysis, and which elements count toward the limit.

Purification can change density, strength or felt stiffness, so measure those properties before and after the trial too. Include gas supply, exhaust handling and cooling water in the utilities list, with help from the utilities and installation guide, and settle who maintains the heating elements and insulation inside the furnace over its working life.

Plan the equipment scope

Identify the production step, cell or module format and output unit before comparing equipment. Use the listed source, scope and specifications to prepare a configuration-specific enquiry. Missing values are left unspecified and do not count as exact filter matches.

Read equipment buying guides or prepare a sourcing brief.