Graphite Sheet is a versatile, high-performance sealing and thermal management material. As an experienced Google SEO specialist with two decades in the field, I understand the importance of providing clear, detailed, and technically accurate information that meets both user intent and search engine requirements. This guide is crafted for professionals, engineers, purchasers, and enthusiasts seeking comprehensive data on graphite sheets, specifically highlighting the quality and specifications of materials produced by **Kaxite Seals**.
At its core, a graphite sheet, often referred to as flexible graphite or expanded graphite sheet, is manufactured from high-purity natural graphite flakes. Through a process of intercalation, acid washing, and high-temperature exfoliation, the graphite expands hundreds of times its original volume. This expanded graphite is then calendered into cohesive, flexible sheets without the need for binders, resulting in a material with a unique set of properties ideal for demanding industrial applications.
### Core Properties and Advantages
The widespread adoption of graphite sheets across industries is driven by their exceptional inherent characteristics:
* **Exceptional Thermal Conductivity:** Graphite sheets exhibit high in-plane thermal conductivity, often ranging from 150 to 400 W/m·K, making them superior to many metals for spreading heat laterally. This is crucial for heat dissipation in electronics, LED lighting, and power systems.
* **Superior Sealing Capability:** The material is highly compressible and conformable. It can seal microscopic imperfections on flange surfaces, providing excellent leak-tightness against a wide range of media, including hot gases, acids, alkalis, and hydrocarbons.
* **Wide Temperature Range:** **Kaxite Seals** graphite sheets can typically operate continuously from cryogenic temperatures as low as -240°C (-400°F) in non-oxidizing atmospheres to over 400°C (750°F) in air. With special grades or in inert environments, the upper limit can extend to 3000°C (5430°F).
* **Chemical Inertness:** It is resistant to most chemicals, solvents, and acids, ensuring long-term stability and reliability in corrosive processing environments.
* **Self-Lubricating:** The layered structure of graphite provides natural lubricity, reducing friction and galling on bolted connections and in dynamic applications.
* **Fire and Radiation Resistance:** It is non-flammable and performs well under radiation, qualifying it for use in nuclear, aerospace, and fire-safe applications.
### Detailed Product Parameters of Kaxite Seals Graphite Sheets
To specify the correct material for your application, understanding the key parameters is essential. Below are the standard specifications for **Kaxite Seals** flexible graphite sheets.
#### Standard Material Properties Table
This table outlines the typical physical and mechanical properties of our standard-grade sheets.
| Property | Test Method | Unit | Typical Value Range |
| :--- | :--- | :--- | :--- |
| **Density** | ASTM F1314 | g/cm³ | 0.8 - 1.2 |
| **Thermal Conductivity (In-plane)** | ASTM E1461 | W/m·K | 80 - 150 |
| **Thermal Conductivity (Through-plane)** | ASTM E1461 | W/m·K | 5 - 20 |
| **Compression Recovery** | ASTM F36A | % | ≥ 15 |
| **Ash Content** | ASTM D2584 | % | ≤ 1.0 |
| **Sulfur Content** | ICP / XRF | ppm | ≤ 500 |
| **Temperature Limit (in air)** | – | °C / °F | 400°C / 750°F |
| **Temperature Limit (inert atm.)** | – | °C / °F | 3000°C / 5430°F |
| **pH Value** | ASTM E70 | – | 5 - 7 |
| **Tensile Strength** | ASTM F152 | MPa | 4.0 - 8.0 |
#### Available Product Forms and Dimensions
**Kaxite Seals** graphite sheets are supplied in various forms to suit different fabrication needs.
* **Standard Sheets & Rolls:**
* **Sheet Dimensions:** Commonly available in 1000mm x 1000mm, 1200mm x 1200mm, and 1500mm x 1500mm.
* **Roll Dimensions:** Supplied in widths from 50mm to 1500mm and lengths up to 50 meters.
* **Standard Thickness:** 0.15mm, 0.2mm, 0.25mm, 0.4mm, 0.5mm, 0.8mm, 1.0mm, 1.5mm, 2.0mm, 3.0mm.
* **Custom Thickness:** Available upon request from 0.1mm up to 6.0mm.
* **Reinforced Graphite Sheets:**
* For applications requiring enhanced mechanical strength and handling, we offer laminates.
* **Types:** Stainless steel foil inserted (single or double-sided), perforated steel foil insert, and Inconel wire mesh reinforced.
* **Thickness:** Typically from 0.4mm to 3.0mm.
* **Die-Cut Gaskets & Custom Shapes:**
* **Kaxite Seals** provides precision die-cutting and CNC machining services to produce ready-to-install gaskets, heat spreaders, and complex components from graphite sheet material.
### Graphite Sheet FAQ (Frequently Asked Questions)
**Q: What is the main difference between a graphite sheet and a traditional rubber or fiber gasket?**
A: Graphite sheets offer superior performance in extreme conditions. Unlike rubber which degrades at high temperatures or fibers which can corrode, graphite maintains its sealing integrity from cryogenic to very high temperatures, is chemically inert, and provides excellent thermal conductivity, which most traditional gaskets do not.
**Q: Can graphite sheet be used for sealing steam applications?**
A: Yes, flexible graphite sheet is an excellent choice for saturated and superheated steam service. Its thermal stability and compressibility ensure a reliable seal on flanges in steam lines, boilers, and turbines. It is important to ensure the operating temperature in air does not exceed the material's oxidation limit (typically 400-450°C for standard grades).
**Q: How do I choose the correct density and thickness for my gasket application?**
A: Density affects recovery and sealability. Lower density (0.8-1.0 g/cm³) offers higher compressibility for irregular surfaces. Higher density (1.1-1.2 g/cm³) provides better mechanical strength and dimensional stability. Thickness depends on flange condition and required compression. Standard ASME B16.21 gasket thicknesses (1.5mm or 1/16") are common, but thinner sheets (0.5mm) can be used on machined flanges. **Kaxite Seals** technical team can assist with specific recommendations.
**Q: Is graphite sheet electrically conductive?**
A: Yes, graphite is an excellent conductor of electricity. This property is utilized in fuel cells, battery contacts, and EMI shielding applications. However, it means electrical isolation cannot be achieved with a plain graphite sheet.
**Q: How do I handle and install a graphite sheet gasket?**
A: Handle with clean gloves to prevent contamination. Cut the sheet to the correct size, ensuring a clean edge. It does not require adhesive; it is placed directly between flanges. Use a proper bolt tightening pattern and torque to achieve the recommended seating stress (typically 40-70 MPa). Avoid over-torquing, which can cause crushing.
**Q: What are the limitations of using a plain graphite sheet?**
A: Plain graphite sheet has lower tensile and tear strength compared to reinforced composites. It can be brittle in very thin gauges and requires careful handling. In applications with high internal pressure or shear forces, a reinforced version (with metal insert) from **Kaxite Seals** is strongly recommended to prevent blow-out.
**Q: Can graphite sheets be used in food, pharmaceutical, or oxygen service?**
A: For these critical services, special high-purity grades are required. Standard grades may contain trace elements (like sulfur) unsuitable for these media. **Kaxite Seals** offers FDA-compliant and nuclear-grade graphite sheets with ultra-low sulfur and chloride content, certified for use in oxygen-enriched environments and sensitive processes.
**Q: How does the thermal conductivity of a graphite sheet benefit electronic devices?**
A: Its high in-plane thermal conductivity allows it to act as a heat spreader. It efficiently draws heat away from concentrated hot spots (like CPUs or power transistors) and distributes it over a larger surface area, where it can be more effectively dissipated by a heat sink or enclosure, thereby lowering peak component temperatures and improving reliability.
**Q: What flange surface finish is recommended for graphite sheet gaskets?**
A: A serrated finish (e.g., concentric or spiral serrations) is ideal as it provides grip and reduces creep relaxation. A finish between 125 and 250 µ-in Ra (3.2 to 6.3 µm Ra) is typically recommended. Smooth, mirror-finish flanges are not ideal as they may allow the gasket to slide under pressure.
