Thick film silver compositions for silver terminations for reduced barium titanate capacitors
AssigneeE. I. Du Pont de Nemours and Company
InventorK. Manikantan Nair
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Abstract
Thick film silver compositions, containing silver powder, glass and certain inorganic materials, useful for silver terminations for reduced barium titanate (RBT) capacitors, are provided. The inorganic materials or their precursors contain ions capable of substituting into the BaTiO.sub.3 lattice, existing as surface layers on the RBT bodies, or grains therein, to produce (Ba.sub.1-x M.sub.x ') (Ti.sub.1-y M.sub.y ")(O.sub.3-z A.sub.z) where x<1, y<1, and z<0.1. When terminated with these thick film silver compositions, RBT capacitors have excellent dielectric properties.
Claims9
A thick film silver composition consisting essentially of a dispersion in an organic vehicle of:
- (A) 30-90 parts by weight, based on the weight of the dispersion, of silver powder;
- (B) 1-20 parts by weight, based on the weight of the dispersion, of glass having a softening point below 600.degree. C. and an absolute viscosity at the firing temperature of less than 10.sup.6 ;
- and
- (C) 0.1-30 parts by weight, based on the weight of the dispersion, of inorganic material or precursor thereof containing one or more ions (M', M" or A) capable of substituting into a BaTiO.sub.3 lattice to produce compounds of the type
- (Ba.sub.1-x M.sub.x ') (Ti.sub.1-y M.sub.y ") (O.sub.3-z A.sub.z),
- wherein
- M' is selected from the group consisting of Ca.sup.+2, Ba.sup.+2, Sr.sup.+2, Pb.sup.+2, Rb.sup.+2, Cs.sup.+2 and Fe.sup.+3 ;
- M" is selected from the group consisting of Ge.sup.+4, Ti.sup.+4, Zr.sup.+4, Zn.sup.+2 and Cr.sup.+3 ;
- A is F.sup.- ;
- and
- x<1, y<1 and z<0.1.
Dependencies are inferred from the claim text.