What are the signs of aging in color-changing silica gel?

Ageing of color-changing silica gel is mostly seen in incomplete colour return, physical structural degradation and functional deterioration. Such alterations signal a considerable reduction in its adsorption capability and need to be replaced in time.

1. Unnatural Colour: The Most Obvious Sign of Ageing

Incomplete regeneration: The blue silica gel after heat regeneration still maintains greyish white, dark red or local black, and does not recover to uniform deep blue.

Dull Colour: The colour does not look as bright as a new silica gel and looks murky and dull.

Uneven Colour Change: Some particles change colour, others stay pink, with slow or stagnant reaction.

Note: The colour change function of cobalt chloride indicator may deteriorate due to long-term temperature cycling and oxidation, and eventually the indicator will become inactive.

2. Signs of Structural Damage: Physical Deterioration

Performance Ageing Signs at State Normal

Particle integrity: Hard, unbroken Slightly fractured, powders readily

Looseness Particles run loose Clumping, hard, hard to spread

Touch Dry, not sticky Residual dampness or too heavy

The appearance of a substantial volume of powder means the destruction of silica microporous structure and the great loss of its adsorption ability.

3. Functional degradation: Poorer performance in real-world conditions

Slow response to moisture absorption: When it is placed in a humid environment, the colour change is very slow or non-existent;

Less Regeneration Efficiency: Partial recovery takes more baking time, and the colour recovery declines over time;

Failure to maintain sealing and dryness: Colour changes in a short period in a desiccator, unable to maintain a low humidity environment.

Special Reminder: The device has to be updated immediately as soon as the indicators of ageing are identified to provide reliable protection (especially for precision moisture protection of cameras, pharmaceuticals etc. ).