The present invention provides a silver coating composition that develops excellent conductivity (low resistance value) by low-temperature and short-time calcining and that has excellent printability. A silver particle coating composition including: silver nano-particles whose surfaces are coated with a protective agent including an aliphatic hydrocarbon amine; and a dispersion solvent, wherein the dispersion solvent includes a solvent selected from the group consisting of a glycol ether-based solvent and a glycol ester-based solvent. The silver particle coating composition is suitable for various printing methods such as intaglio offset printing and screen printing.

There is a problem that when a silver powder sintering paste that is substantially free from resin is used, an organic solvent used as a dispersion medium bleeds, which results in contamination and wire bonding defects. In order to solve the problem, provided is a metal powder sintering paste that contains, as a principal component, silver particles having an average particle diameter (a median diameter) of 0.3 μm to 5 μm and further contains an anionic surfactant but is substantially free from resin.

There is a problem that when a silver powder sintering paste that is substantially free from resin is used, an organic solvent used as a dispersion medium bleeds, which results in contamination and wire bonding defects. In order to solve the problem, provided is a metal powder sintering paste that contains, as a principal component, silver particles having an average particle diameter (a median diameter) of 0.3 μm to 5 μm and further contains an anionic surfactant but is substantially free from resin.

A method of preparing shape-controlled alloy particles includes dissolving a solvent in a surfactant selected to inhibit particle growth; adding a noble metal precursor and a transition metal precursor to form a mixture; irradiating the mixture with a microwave under reflux for about thirty minutes or less at an irradiation temperature of between 185° C. and 195° C.; cooling the mixture; and drying the mixture at a temperature of between 55° C. and 65° C. to obtain shape-controlled alloy particles having a uniform shape, the shape dependent upon the surfactant used.

A method for the manufacturing a representative homotop of a binary metallic nanoparticle (A.sub.xB.sub.1-x).sub.N with a given composition A.sub.xB.sub.1-x, number of atoms N and shape, and at a given temperature, including generating a plurality of homotops, calculating an energy of the generate homotops using formula:

[00001]$\begin{array}{cc}{E}_{\mathrm{TOP}}=E_0\left(x,N\right)+{\mathrm{.Math.}}_{\mathrm{BOND}}^{A.Math.\text{-}.Math.B}\left(x\right).Math.N_{\mathrm{BOND}}^{A.Math.\text{-}.Math.B}+\underset{i}{.Math.}.Math..Math.{\mathrm{.Math.}}_{\mathrm{CORNER},i}^A\left(x\right).Math.N_{\mathrm{CORNER},i}^A+\underset{j}{.Math.}.Math..Math.{\mathrm{.Math.}}_{\mathrm{EDGE},j}^A\left(x\right).Math.N_{\mathrm{EDGE},j}^A+{.Math.}_{\left\{\mathrm{LMN}\right\}}.Math.{\mathrm{.Math.}}_{\left\{\mathrm{LMN}\right\}}^A\left(x\right).Math.N_{\left\{\mathrm{LMN}\right\}}^A& \left(1\right)\end{array}$

where E.sub.0(x, N) is constant for a given particle, ε.sub.BOND.sup.A-B(x) is related to an energy gain caused by the mixing of both metals, N.sub.BOND.sup.A-B is a number of heteroatomic

A method for the manufacturing a representative homotop of a binary metallic nanoparticle (A.sub.xB.sub.1-x).sub.N with a given composition A.sub.xB.sub.1-x, number of atoms N and shape, and at a given temperature, including generating a plurality of homotops, calculating an energy of the generate homotops using formula:

[00001]$\begin{array}{cc}{E}_{\mathrm{TOP}}=E_0\left(x,N\right)+{\mathrm{.Math.}}_{\mathrm{BOND}}^{A.Math.\text{-}.Math.B}\left(x\right).Math.N_{\mathrm{BOND}}^{A.Math.\text{-}.Math.B}+\underset{i}{.Math.}.Math..Math.{\mathrm{.Math.}}_{\mathrm{CORNER},i}^A\left(x\right).Math.N_{\mathrm{CORNER},i}^A+\underset{j}{.Math.}.Math..Math.{\mathrm{.Math.}}_{\mathrm{EDGE},j}^A\left(x\right).Math.N_{\mathrm{EDGE},j}^A+{.Math.}_{\left\{\mathrm{LMN}\right\}}.Math.{\mathrm{.Math.}}_{\left\{\mathrm{LMN}\right\}}^A\left(x\right).Math.N_{\left\{\mathrm{LMN}\right\}}^A& \left(1\right)\end{array}$

where E.sub.0(x, N) is constant for a given particle, ε.sub.BOND.sup.A-B(x) is related to an energy gain caused by the mixing of both metals, N.sub.BOND.sup.A-B is a number of heteroatomic

The present invention provides a silver nano-particle production method which is safe and simple also in terms of scaled-up industrial-level production, in a so-called thermal decomposition method in which a silver-amine complex compound is thermally decomposed to form silver nano-particles. A method for producing silver nano-particles comprising: mixing an aliphatic hydrocarbon amine and a silver compound in the presence of an alcohol solvent having 3 or more carbon atoms to form a complex compound comprising the silver compound and the amine; and thermally decomposing the complex compound by heating to form silver nano-particles.

The present invention provides a silver nano-particle production method which is safe and simple also in terms of scaled-up industrial-level production, in a so-called thermal decomposition method in which a silver-amine complex compound is thermally decomposed to form silver nano-particles. A method for producing silver nano-particles comprising: mixing an aliphatic hydrocarbon amine and a silver compound in the presence of an alcohol solvent having 3 or more carbon atoms to form a complex compound comprising the silver compound and the amine; and thermally decomposing the complex compound by heating to form silver nano-particles.

A method for producing a metal powder provided on the surface thereof with a glassy thin film, wherein a glassy substance is produced in the vicinity of the surface of the metal powder by spray pyrolysis from a solution that contains a thermally decomposable metal compound and a glass precursor that produces a glassy substance that does not form a solid solution with the metal produced from the metal compound by thermal decomposition, so as to form the metal powder provided on the surface thereof with the glassy thin film. The glass precursor is prepared such that the melting temperature Tm.sub.M of the metal and the liquid phase temperature Tm.sub.G of the mixed oxide of the glassy substance satisfy the following formula (1):
−100 [° C.]≤(Tm.sub.M−Tm.sub.G)≤500 [° C.]  (1).

A method for producing a metal powder provided on the surface thereof with a glassy thin film, wherein a glassy substance is produced in the vicinity of the surface of the metal powder by spray pyrolysis from a solution that contains a thermally decomposable metal compound and a glass precursor that produces a glassy substance that does not form a solid solution with the metal produced from the metal compound by thermal decomposition, so as to form the metal powder provided on the surface thereof with the glassy thin film. The glass precursor is prepared such that the melting temperature Tm.sub.M of the metal and the liquid phase temperature Tm.sub.G of the mixed oxide of the glassy substance satisfy the following formula (1):
−100 [° C.]≤(Tm.sub.M−Tm.sub.G)≤500 [° C.]  (1).