Thick Film Metallization Of Precious Metals On AlN Ceramics

The development of thick film technology was reviewed and pursued. Au-Pt powders were synthesized using HAuCl₄ and H₂PtCl₆ as precursor solution, EG as reducing agent and solvent, PVP or PEG as dispersants in polyol-process. In addition, glass formulas used in the Ag thick film metallization as binders were prepared in order to determine their performance.When different dispersants were used to synthesize Au-Pt particles, PVP showed better dispersing properties than PEG. And uniform nearly spherical Au-Pt particles in submicron size were prepared using PVP as dispersing agent by step-by-step method when the feeding rate of precursor solution was controlled at 0.04ml/s. In addition, the Au-Pt powder of high purity was successfully prepared.BaO, Al₂O₃, ZnO, Li₂O, MgO and Bi₂O₃ were added into CBS glass in order to study the glass-melting characteristics and their wetting properties on AlN substrate. The A₁, A₂, A₃ glass formulas with good wetting properties and low melting temperature were initially chosLastly, A₁, A₂, A₃ formulas were used as glass binder in Ag thick film metallization in order to study their impacts. The results showed that the paste had poor leveling property bringing about the film defects. The main reason of the defects rooted in inappropriate screen printing process. After sintering, most of the glass floated on the surface of metal layer leading to the lowering of adhesion strength.