1. Introduction

PHPS (Perhydropolysilazane) is an inorganic polymer precursor characterized by a Si–N backbone structure with reactive Si–H and N–H functional groups.

Under exposure to moisture or air, PHPS undergoes hydrolysis and oxidation, converting into a dense silicon dioxide (SiO₂) network.

In practical applications, PHPS acts as a liquid precursor coating that transforms into a glass-like inorganic protective layer after curing at room or low temperature.

2. Molecular Structure and Conversion Mechanism

PHPS belongs to the polysilazane family. Its molecular backbone consists primarily of Si–N–Si linkages.

During exposure to humidity:

• Si–N bonds gradually convert to Si–O bonds

• Si–H reacts with water to form Si–OH

• Si–OH further condenses into Si–O–Si three-dimensional networks

The final structure is a dense silica (SiO₂) film.

This conversion can occur at room temperature and can be accelerated by heating or catalytic methods.

3. Key Advantages

• Room-temperature or low-temperature curing

• Formation of highly dense inorganic films

• Excellent barrier performance

• Outstanding corrosion resistance

• Superior UV and weather resistance

• High optical transparency

• Strong adhesion to metals, glass, ceramics, concrete, and certain plastics

4. Typical Applications

• Electronics protection coatings

• Semiconductor passivation layers

• Optical transparent coatings

• Metal anti-corrosion systems

• Concrete and stone waterproofing

• Ceramic precursor materials (Si₃N₄ / SiON under high-temperature pyrolysis)

5. Comparison with Traditional Silicone Resins

Compared with conventional silicone resins:

• PHPS features a Si–N backbone rather than Si–O.

• After curing, PHPS forms inorganic SiO₂ instead of an organic silicone network.

• It offers superior heat resistance and barrier performance.

• It is positioned as a functional inorganic coating material.

6. Future Outlook

With growing demand in flexible electronics, advanced corrosion protection, and high-performance surface engineering, PHPS is becoming an increasingly important material in next-generation inorganic coating technologies.

Its ability to convert into dense silica at low temperature makes it highly valuable for advanced material applications.