Adhesion of Colloidal SiO(2) Particles on ZnS-Type Phosphor Surfaces

Area of Science:

• Materials Science
• Surface Chemistry
• Colloid Science

Background:

• ZnS:Cu,Al,Au phosphors are vital for green emission in color television tubes.
• Understanding particle interactions on phosphor surfaces is key to improving display technology.
• Surface treatments can significantly alter the properties of phosphor particles.

Purpose of the Study:

• To investigate the adhesion of colloidal SiO2 particles onto ZnS phosphor surfaces.
• To determine the role of surface pre-treatments, including ZnO precoating, on SiO2 adhesion.
• To elucidate the attractive interactions within the ZnS-ZnO-SiO2 system.

Main Methods:

• Surface treatment of ZnS phosphor particles (washing, ZnO precoating).
• Addition of colloidal SiO2 particles and analysis of adhered amounts using SEM and ESCA.
• Electrophoretic adsorption (ESA) measurements to assess surface charges.

Main Results:

• Colloidal SiO2 particles adhere effectively to ZnS surfaces only when precoated with ZnO.
• SiO2 particles are observed to form a layer on top of the ZnO precoating.
• Surface charge analysis using ESA provided insights into the interaction mechanisms.

Conclusions:

• The presence of ZnO is essential for significant adhesion of SiO2 particles to ZnS phosphors.
• The ZnS-ZnO-SiO2 system exhibits specific attractive interactions that govern particle adhesion.
• This finding has implications for the design and manufacturing of advanced phosphors.