High-temperature resistant glass fiber pipes must withstand drastic temperature fluctuations in high-temperature environments, and their thermal shock resistance directly determines their service life and safety. Surface treatment technology, through the synergistic effect of physical and chemical processes, constructs a thermal stress buffer layer, optimizes interfacial bonding strength, and introduces high-temperature resistant functional groups, thereby significantly improving the structural stability of the material under extreme temperature differences.
Acid-base etching is one of the fundamental methods to enhance thermal shock resistance. By controlling the concentration and reaction time of acid or alkali solutions, a micron-level uneven structure can be formed on the glass fiber surface. This "locking effect" not only increases surface roughness but also forms mechanical anchoring points at the fiber-matrix interface. When the material experiences a sudden temperature change, the etched layer disperses concentrated thermal stress, preventing localized crack propagation. Simultaneously, the silanol groups (Si-OH) activated during the etching process can chemically bond with active groups in subsequent coatings, forming a composite interface that combines physical intercalation and chemical bonding, further enhancing thermal shock resistance.
Silane coupling agent treatment is a core technology for improving interfacial thermal stability. The alkoxy groups (such as methoxy and ethoxy) in silane molecules hydrolyze to form silanol groups, which condense with the silanol groups on the glass fiber surface to form Si-O-Si bonds, constructing a "molecular bridge" structure. Its organic functional groups (such as amino and vinyl groups) then form covalent or hydrogen bonds with the resin matrix, tightly binding the inorganic fiber to the organic matrix. This chemical bonding effectively transfers thermal stress, preventing crack initiation caused by interfacial debonding. Furthermore, the silane coating can seal microcracks on the fiber surface, reducing the pathways for crack propagation under thermal shock, thereby enhancing the overall thermal shock resistance of the material.
Surface coating technology achieves thermal stress buffering by introducing high-temperature resistant functional layers. For example, ceramic coatings such as alumina and zirconium oxide have low coefficients of thermal expansion and high thermal conductivity, forming a thermal gradient transition layer on the fiber surface. When the material is heated, the coating rapidly conducts heat to balance the temperature difference between the fiber and the matrix, reducing thermal stress accumulation. Meanwhile, the hardness of the ceramic coating inhibits crack propagation, and the difference in thermal expansion coefficients between it and glass fiber can be gradually transitioned through gradient coating design, avoiding coating peeling due to thermal mismatch.
Plasma treatment activates the fiber surface through high-energy particle bombardment, introducing oxygen- and nitrogen-containing polar groups. These active groups not only enhance the chemical bond between the fiber and the matrix but also form a nanoscale rough structure on the surface, improving mechanical interlocking force. Plasma treatment also removes impurities and water films adsorbed on the fiber surface, reducing localized stress concentration caused by moisture vaporization under thermal shock. High-temperature resistant glass fiber pipes modified by plasma exhibit significantly reduced interfacial bonding strength attenuation rates during repeated thermal shock cycles, demonstrating superior thermal shock resistance.
Composite surface treatment technology achieves performance synergy through multi-process collaboration. For example, acid-base etching is first used to increase surface roughness, then a silane coupling agent is used to form chemical bonds, and finally a ceramic coating is applied to construct a thermal stress buffer layer. This layered treatment method utilizes the mechanical anchoring effect of the etched layer, leverages the chemical bonding effect of the silane coating, and simultaneously disperses thermal stress through the ceramic coating. The three-layer structure works synergistically, enabling high-temperature resistant glass fiber pipes to maintain structural integrity under extreme temperature differences, and improving thermal shock resistance several times over compared to single treatments.
Surface treatment technology has a multi-dimensional synergistic effect on improving the thermal shock resistance of high-temperature resistant glass fiber pipes. Through the combined effects of physical anchoring, chemical bonding, thermal stress buffering, and crack suppression mechanisms, surface treatment technology can significantly extend the service life of materials under extreme temperature environments, providing key material support for high-temperature fields such as aerospace and industrial furnaces.
