2results about How to "High ignition point" patented technology

The invention discloses a micro-alloying rapid extrusion flame-retardant magnesium alloy and a preparation method thereof, and belongs to the technical field of metal materials. The microalloying fast extrusion flame-retardant magnesium alloy is prepared from the following components in percentage by mass: 1.0 to 1.8 percent of aluminum, 0.3 to 0.4 percent of calcium, 0.4 to 0.6 percent of manganese, 0 to 0.08 percent of nano particles, less than or equal to 0.02 percent of inevitable impurities and the balance of magnesium. Calcium is preferentially oxidized at high temperature to form a compact CaO layer to block oxygen, so that the ignition point of the alloy is obviously improved; a high-density nanophase is dynamically separated out from aluminum and manganese in the rapid extrusion process, the grain boundary is effectively pinned, grain coarsening is inhibited, and the stability of a microstructure below an oxidation film is enhanced; nanoparticles are combined with ultrasonic melt treatment to refine the structure, surface oxidation film microdefects are filled at the same time, and the self-repairing capacity and compactness are improved. According to the design, through microalloying design (the total element content is smaller than or equal to 2.8%), nanoparticle reinforcement and a rapid extrusion process are cooperated, collaborative optimization of low production cost, good flame retardant property and efficient extrusion capacity of the alloy is achieved, and the industrial prospect is wide.

This invention relates to the field of sealing grease technology, and more particularly to a high-performance, flame-retardant water-based shield tail sealing grease, its preparation method, and its application. The sealing grease comprises, by mass percentage: 10%–25% polyalphaolefin, 15%–30% polyisobutylene, 10%–25% sodium poly(isobutylene-alt-succinate), 10%–18% deionized water, 20%–30% filler, 1%–15% thickener, and 1%–3% reinforcing fibers. Specifically, the polyalphaolefin and polyisobutylene constitute a continuous oil phase, while the sodium poly(isobutylene-alt-succinate) dissolves or disperses in the deionized water and accumulates at the oil-water interface, allowing the deionized water to be stably dispersed as an internal phase, forming a water-in-oil structure. The sealing grease of this invention has moderate zero-point penetration, excellent pumpability, reliable sealing under 3.5MPa water pressure, good erosion resistance under both fresh and seawater conditions, and an ignition point of not less than 295℃. It also has excellent flame retardancy and environmental friendliness, and is suitable for shield tail sealing in long-distance, deep-buried and high-water-pressure shield tunnel construction.