In the fields of industrial sealing, insulation, and protection, aluminum foil fiber paper has become the preferred material for numerous critical applications due to its excellent overall performance. Faced with complex working conditions, how can one make precise selections from the many available types and thicknesses? The key lies in thoroughly understanding and comprehensively weighing three decisive parameters: temperature, pressure, and medium.
I. Temperature – Defining the Material's Survival Limit
Temperature is the primary criterion for selection, directly determining the type of base fiber and the stability of the composite structure.
• Medium to low-temperature conditions (typically -60°C to 300°C): Conventional types using ordinary glass fiber as the base material can be selected, with the aluminum foil layer effectively reflecting thermal radiation.
• High-temperature and thermal shock conditions (>300°C or even above 600°C): It is essential to select types reinforced with high-temperature-resistant specialty fibers such as basalt fiber or ceramic fiber. Additionally, the melting point limit of the aluminum foil layer itself (approximately 660°C) must be considered, and alloy foil should be used when necessary. For scenarios involving frequent rapid heating and cooling, the heat cycle resistance of the adhesive layer must be evaluated to prevent separation and failure between the aluminum foil and fiber layers.
II. Pressure – Balancing Structure and Thickness
Working pressure (including positive pressure, negative pressure, and pressure differentials) directly affects the requirements for the material's mechanical properties and thickness.
• High-pressure or pressure fluctuation environments: The material must possess higher tensile and tear resistance as well as resilience. In such cases, structurally reinforced types with coarser, tougher fibers or additional reinforcing layers, such as metal wire mesh, should be prioritized over simply increasing thickness.
• Thickness selection: Thicker gaskets can provide better compression resilience and sealing filling capabilities, making them suitable for applications with extremely high sealing requirements (e.g., high-temperature valves). However, increased thickness may reduce flexibility, requiring a balance between ensuring sealing effectiveness and ease of installation. In complex working conditions, customized designs with sandwich or corrugated structures may be necessary.
III. Medium – Testing Long-Term Stability Through Chemical Challenges
The chemical properties of the medium in contact with the material are crucial for its long-term serviceability.
• Corrosive environments: In the presence of acids, alkalis, salt spray, or specific chemical atmospheres, the natural oxide film of aluminum foil may be compromised. It is essential to select corrosion-resistant types that have undergone surface treatments such as anodization or fluorocarbon resin coating to prevent pitting or corrosion perforation.
• Special media: For liquid media, the material's porosity and hydrophobicity must be considered; for airflow containing particulate matter, its surface wear resistance should be evaluated; and in the food and pharmaceutical industries, products with food-grade coatings that meet hygiene standards must be selected.
