Cast-in-place, ambiently-dried, silica-based, high-temperature insulation

Abstract

A novel sol-gel chemistry approach was developed to enable the simple integration of a cast-inplace, ambiently-dried insulation into high temperature applications. The insulation was silicabased and synthesized using methyltrimethoxysilane (MTMS) as the precursor. MTMS created a unique silica microstructure that was mechanically robust, macroporous, and superhydrophobic.To allow for casting into and around small, orthogonal features, zirconia fibers were added to increase stiffness and minimize contraction that could otherwise cause cracking during drying.Nano-sized titania powder was incorporated as an opacifier to reduce radiative heat transport. To assess relevance to high temperature thermoelectric generator technology, a comprehensive set of materials characterization experiments were conducted. The silica gel was thermally stable, retained superhydrophobicity with a water contact angle >150°, and showed a high electrical resistance >1 G ohm, regardless of heating temperature (up to 600 °C in Ar for 4 h). In addition,The silica-based thermal insulation exhibited a Young's modulus ~3.7 MPa and a low thermal conductivity < 0.08 W/(m.K) at room temperature before and after heat treatment (up to 600 °C in Ar for 4 h). Thus, based on the simplicity of the manufacturing process and the optimized material properties, we believe this technology can act as an effective cast-in-place thermal

Basalt/Polyacrylamide‐Ammonium Polyphosphate Hydrogel Composites for Fire‐Resistant Materials

“…[ 13,15,16 ] They have been extensively used as the fillers in fire‐resistant materials for the last 30 years, but not been used in hydrogel to the best of our knowledge. Besides, the silica‐based materials, for example, basalt fibers, [ 17–20 ] with high temperature resistance [ 21 ] have been widely used as the low‐cost alternative to aramid fireproof fibers such as Kavlar, Nomex, Teflon, etc. Introducing the intumescent flame retardants and silica‐based fibers into hydrogel is promising to protect the gel network from burning and extending the fireproof time.…”

Facile Preparation of High Strength Silica Aerogel Composites via a Water Solvent System and Ambient Pressure Drying without Surface Modification or Solvent Replacement

“…However, early APD includes solvent replacement and surface modification, and the waste liquid produced in this process is difficult to be recycled and utilized, resulting in great waste and environmental pollution [ 8 , 9 , 10 ]. Since then, researchers have prepared silica aerogels using methyltrimethoxysilane (MTMS) as a precursor by APD without solvent replacement [ 11 , 12 , 13 , 14 , 15 , 16 ], but aerogels have poor mechanical properties and are prone to brittle fracture during use [ 17 , 18 , 19 ]. Our research group [ 20 ] used MTMS as the precursor and mullite fiber as the reinforcing phase to prepare an aerogel insulation composite material in the early stage, which has a low thermal conductivity (0.0403 W/m·K at room temperature and 0.101 W/m·K at 1100 °C), but its strength is not strong enough to resist external vibration and compression during use (0.108 MPa at 10% strain).…”

Analysis of Heat Insulation for Coil in the Electromagnetic Induction Controlled Automated Steel-Teeming System

“…Although arranging 40 mm vermiculite can achieve a better heat insulation effect, the thickness of 40 mm cannot meet the actual production requirements, and the safety has not been tested and analyzed. Currently, in order to meet the severe heat protection requirements, high temperature heat insulation material has achieved great development [15][16][17][18][19][20], new heat insulation materials represented by aerogel [21], nano heat insulation material [22], fiber heat insulation material [23] and heat insulation coating [24] are lighter and thinner, their heat insulation performances are better, which may be provide new method to reduce the coil ambient temperature and to ensure the feasibility of the EICAST technology.…”