Expandable graphite sheet

Buyers must prioritize expansion ratio (typically ranging from 100 to 300 times) and carbon content (ideally ≥99%). For thermal management, verify the thermal conductivity (horizontal vs. vertical) and density (usually 0.7 to 1.5 g/cm³). Ensure the sheet maintains high-temperature resistance up to 600°C in oxidizing atmospheres and up to 3000°C in non-oxidizing environments.

The product must comply with RoHS (Restriction of Hazardous Substances) and REACH regulations to ensure it is free from toxic heavy metals. For electronics applications, check for UL 94V-0 flammability ratings. Suppliers should ideally hold ISO 9001:2015 for quality management and ISO 14001 for environmental standards.

Expandable graphite is primarily used for thermal interface materials (TIMs) in smartphones and laptops, fire-retardant seals in construction, and chemical-resistant gaskets in the petroleum industry. The material must demonstrate excellent electromagnetic shielding (EMI) capabilities and flexible compressibility to fill gaps between heat sources and heat sinks effectively.

Request a Scanning Electron Microscope (SEM) analysis to check the flake structure and a Thermogravimetric Analysis (TGA) to confirm the expansion temperature. Conduct a sulfur content test, as low sulfur (<800 ppm) is critical to prevent corrosion on contacted metal surfaces like copper or aluminum.

The most significant risk is moisture absorption during sea transit, which can degrade the expansion properties. Ensure the supplier uses vacuum-sealed moisture-proof packaging. Another risk is specification mismatch; always request a pre-shipment sample from the actual production batch to verify the expansion volume matches the TDS (Technical Data Sheet).

Focus on tiered pricing based on carbon purity rather than just total volume. Negotiate for customized slitting and die-cutting services to be included in the unit price to reduce secondary processing costs. Ask for a long-term price stability agreement, as raw graphite prices can fluctuate due to mining regulations.

Expandable graphite is often classified under HS Code 3801.90. While not always classified as dangerous goods, some high-expansion variants may require a Material Safety Data Sheet (MSDS) and a Non-Hazardous Goods Declaration for air freight. For shipping to the US or EU, ensure the Palletization meets ISPM 15 heat-treatment standards to avoid customs delays.

Utilize Secured Trading Services provided by Made-in-China.com to ensure payment is only released upon confirmation of receipt. For large orders, insist on a Third-Party Inspection (such as SGS or Intertek) at the supplier's warehouse before the final balance payment is made.