New application directions for adhesives

I. New Applications of Adhesives

1. Corrosion Protection for Mechanical Equipment
Currently, steam pipes on ships often utilize aluminum silicate insulation combined with asbestos for thermal insulation. However, leakage or condensation resulting from temperature fluctuations can cause moisture to accumulate on the outer surface of the underlying steam pipe; furthermore, prolonged exposure to high temperatures and soluble salts leads to severe corrosion of the pipe's exterior. To address this, a sodium silicate-based adhesive can be applied as a coating over the aluminum silicate layer to form an enamel-like protective coating. This coating features a coefficient of thermal expansion similar to that of the pipe material, resulting in low thermal stress and resistance to cracking. In mechanical assembly, components are frequently secured using bolts.
Components fastened with bolts are susceptible to crevice corrosion when exposed to the atmosphere for extended periods. Additionally, intense vibration during machinery operation can cause bolts to loosen. To resolve these issues, connecting components can be bonded with an inorganic adhesive prior to bolting. This approach provides both structural reinforcement and effective corrosion protection.

2. Biomedical Applications
Hydroxyapatite (Ca10(PO4)6(OH)2, or HA) bioceramic material has a composition similar to the inorganic component of human bone and exhibits excellent biocompatibility; it can form a strong chemical bond with bone, making it an ideal material for hard-tissue replacement. However, currently produced HA implants generally suffer from high elastic moduli, low strength, and suboptimal bioactivity. By using a phosphate glass adhesive to bond HA raw powder particles together at temperatures below those required for traditional sintering, the elastic modulus can be reduced.