Silicone coatings have excellent chemical resistance in acid and alkali environments, but the specific performance is affected by factors such as formulation, concentration and temperature. The following is a comprehensive analysis from three aspects: core characteristics, application performance and limitations:

1. Alkali resistance (strong stability)
High concentration alkali solution tolerance
After immersion in 3% NaOH solution at 100°C for 100 hours, the silicone coating film remains intact without blistering or shedding. The silicon-oxygen bond (Si-O) in its molecular structure is inert to alkaline media and can effectively resist the corrosion of OH⁻ ions.

‌Typical application‌: Inner wall coating of chemical alkali storage tanks, which can extend equipment life and reduce maintenance costs.

‌Salt spray and hot and humid environment resistance
The coating shows no signs of corrosion in 5% salt water immersion for 70 hours or salt spray tests (such as ISO 9227 standard). The low surface tension (lotus effect) of silicone makes it difficult for alkali to penetrate the substrate.

2. Acid resistance (selective tolerance)
‌Good performance in weak acid environment‌
It has good protection against dilute acetic acid and low-concentration organic acids (such as acidic substances in contact with food processing equipment). For example, water-based modified silicone topcoat can resist acidic environments with a pH of ≥ 4.

‌Limitations of strong acid environments‌
‌Not resistant to dilute hydrochloric acid/dilute sulfuric acid: The coating is easily softened or even dissolved after contact, especially in high temperature environments.
‌Failure in high-concentration acid: Strong acids (such as concentrated nitric acid) will cause hydrolysis of silicon-oxygen bonds and destroy the coating structure.
‌Improvement plan‌: Acid resistance can be improved by adding special nanofillers (such as flaky mica powder) or using silicon-epoxy composite coatings (such as GS-9080 coatings resistant to pH 4-9 range).

3. Key influencing factors and limitations ‌Temperature and concentration thresholds ‌Alkalinity limit‌: Alkali resistance is stable below 100°C, and corrosion may be accelerated if the temperature exceeds this.
‌Acid sensitivity‌: even weak acid.
Solvent compatibility issues ‌ Silicone coatings are less oil-resistant and tend to soften after contact with gasoline and ester solvents. They should be avoided in fuel pipelines and other scenarios].

Advances in composite coating technology ‌ Silicone-acrylic composites: improve acid resistance while enhancing adhesion (such as anti-ion corrosion)].
‌ Water-based modification process ‌: reduce VOC emissions and maintain comprehensive protection against acid, alkali and salt spray (such as building exterior wall applications)].