Quartz fiber, with its high purity, high temperature resistance, ablation resistance, low thermal conductivity, thermal shock resistance, wave transmission, excellent dielectric properties, and good chemical stability, plays an irreplaceable role in high-end manufacturing fields such as aerospace, electronic communications, and optics. However, the preparation process, from natural high-purity quartz ore to high-performance quartz fiber products, is a demanding pursuit of overall craftsmanship and is influenced by a variety of factors.
1. Raw Materials
The focus on raw materials mainly includes purity, particle size, and gas inclusions. Regarding purity, metallic impurities are a significant influencing factor. Even alkali metal, alkaline earth metal, or transition metal ions present in concentrations of only a few parts per million can have a substantial impact on quartz fiber products: reducing temperature resistance, making them prone to deformation and failure at high temperatures; inducing crystallization, accelerating the transformation of quartz glass from an amorphous state to a cristobalite crystalline state at high temperatures, leading to fiber brittleness and a sharp decrease in strength; and affecting dielectric properties, as impurity ions increase dielectric loss, hindering its application in high-frequency electronics.
The particle size and gas inclusions of the raw materials determine the bubble content of the produced quartz rods. Quartz glass rods with high bubble content are prone to fraying during melt drawing and lead to an increase in micro-defects on the quartz fiber surface, which to some extent affects the quality and performance of the finished quartz fiber products.
2. Melt Drawing
Converting solid quartz material into continuous and uniform fibers is a crucial step in determining its microstructure and mechanical properties. Taking the drawing of quartz rods using an oxyhydrogen flame as an example, the purity, pressure, and flow rate of hydrogen and oxygen, temperature control and adjustment, drawing process route, and equipment are all direct determinants of the quartz fiber product quality.
The melting temperature is mainly controlled by the flow rate and pressure of the combustion gases. If the melting temperature is too high, the fibers are prone to melting and breaking; if the temperature is too low, the forming tension increases, making fraying and breakage more likely. Furthermore, environmental cleanliness is also very important, as the entire drawing process must be carried out in an ultra-clean environment. Any dust particles in the air adhering to the fiber surface will become stress concentration points, significantly reducing its mechanical strength.
3. Microstructure
The stability of quartz fibers under long-term high-temperature environments directly depends on their resistance to crystallization. As mentioned earlier, crystallization is the primary failure mechanism of quartz fibers at high temperatures. The crystallization rate has an exponential relationship with temperature. Key factors affecting crystallization include:
* Surface condition: Microcracks, contamination, and wear on the fiber surface can all become the starting point for crystallization. Therefore, surface treatment and protective coating are crucial.
* Micro-defects: For brittle materials like quartz fibers, their strength is extremely sensitive to defects such as surface and internal microcracks, bubbles, and inclusions. Post-treatment processes such as flame polishing and acid pickling can effectively heal surface microcracks and improve strength.
4. Sizing Agent
During the quartz fiber drawing process, a special surface treatment agent needs to be coated on the fiber surface. This effectively lubricates the fiber surface, effectively integrates the fiber monofilaments into a bundle, and changes the fiber surface condition. This not only meets the requirements of subsequent processing of the fiber precursor but also promotes the bonding between the quartz fiber and the reinforced polymer in composite materials.
The quality of quartz fiber products is not determined by a single step, but by a precise engineering process that involves the entire chain of raw material purity, melt drawing process, microstructure control and post-processing technology.
Post time: Nov-20-2025
