A preparation method for a W—Cu composite plate with a Cu phase in finger-shaped gradient distribution is provided. The method includes adding WO.sub.X powder obtained with ammonium metatungstate as a raw material into W powder through a combustion synthesis method, adding a binder and a pore-forming agent to prepare a slurry, then performing tape casting, soaking in water and sintering to obtain a W framework with pores in finger-shaped distribution, and then infiltrating Cu to obtain a target product. The Cu phase in the W—Cu composite material prepared by the present method is distributed in a finger-shaped gradient manner from an infiltration surface to the interior of a specimen, the Cu phase and the W phase are mutually pinned, and the W—Cu interface has good bonding strength. The present method has the characteristics of adjustable material component performance, simple process, low cost, suitability for large-scale production and the like.

To provide a metal particle composition having excellent oxidation resistance, which does not require a transition metal catalyst and can be applied to existing metal particles, a method for producing the metal particle composition, and a paste. The metal particle composition contains, with respect to 100 parts by mass of metal particles, 0.1 to 5 parts by mass of a compound (A) having a structure represented by the following general formula (I):

##STR00001## in which R.sup.1 and R.sup.2 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group, R.sup.3 and R.sup.4 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group, an aryl group, or an aralkyl group.

To provide a metal particle composition having excellent oxidation resistance, which does not require a transition metal catalyst and can be applied to existing metal particles, a method for producing the metal particle composition, and a paste. The metal particle composition contains, with respect to 100 parts by mass of metal particles, 0.1 to 5 parts by mass of a compound (A) having a structure represented by the following general formula (I):

##STR00001## in which R.sup.1 and R.sup.2 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group, R.sup.3 and R.sup.4 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group, an aryl group, or an aralkyl group.

Provided is a three-dimensional object formation method for forming a three-dimensional object by at least repeating: forming a powder material layer using a powder material for three-dimensional object formation containing a base material coated with an organic material; and hardening a predetermined region of the powder material layer by delivering a hardening liquid to the powder material layer formed in the formation of a powder material layer, where the hardening liquid contains a cross-linking agent cross-linkable with the organic material.

Provided is a three-dimensional object formation method for forming a three-dimensional object by at least repeating: forming a powder material layer using a powder material for three-dimensional object formation containing a base material coated with an organic material; and hardening a predetermined region of the powder material layer by delivering a hardening liquid to the powder material layer formed in the formation of a powder material layer, where the hardening liquid contains a cross-linking agent cross-linkable with the organic material.

A silver sintering preparation in the form of a silver sintering paste comprising 70 to 95 wt.-% of coated silver particles (A) and 5 to 30 wt.-% of organic solvent (B) or in the form of a silver sintering preform comprising 74.5 to 100 wt.-% of coated silver particles (A) and 0 to 0.5 wt.-% of organic solvent (B), wherein the coating of the coated silver particles (A) comprises silver acetylacetonate (silver 2,4-pentanedionate) and/or at least one silver salt of the formula C.sub.nH.sub.2n+1COOAg with n being an integer in the range of 7 to 10, and wherein the at least one silver salt is thermally decomposable at >160° C.

A composition including a three-dimensional metal printing powder; an organic polymeric additive on at least a portion of an external surface of the three-dimensional metal printing powder; and optionally, an inorganic additive on at least a portion of an external surface of the three-dimensional metal printing powder. A process for preparing a three-dimensional metal printing powder having an organic polymeric additive disposed thereon. A process for employing the three-dimensional metal printing powder including selective laser sintering.

A composition including a three-dimensional metal printing powder; an organic polymeric additive on at least a portion of an external surface of the three-dimensional metal printing powder; and optionally, an inorganic additive on at least a portion of an external surface of the three-dimensional metal printing powder. A process for preparing a three-dimensional metal printing powder having an organic polymeric additive disposed thereon. A process for employing the three-dimensional metal printing powder including selective laser sintering.

A mixed powder for powder metallurgy comprises: an iron-based powder; and a lubricant, wherein the lubricant consists of a low-melting-point lubricant having a melting point of 86° C. or less and a high-melting-point lubricant having a melting point of more than 86° C., the low-melting-point lubricant has at least one of an amide group, an ester group, an amino group, and a carboxyl group, a ratio R1 of the low-melting-point lubricant to whole of the lubricant is 5 mass % or more and less than 90 mass %, a ratio R2 of a mass of a free lubricant to a mass of a binding lubricant is 0 or more and 15 or less, and an amount R3 of the low-melting-point lubricant contained as the free lubricant is less than 0.10 parts by mass with respect to 100 parts by mass of the iron-based powder.

A nanoparticle of a decomposition product of a transition metal aluminum hydride compound, a transition metal borohydride compound, or a transition metal gallium hydride compound. A process of: reacting a transition metal salt with an aluminum hydride compound, a borohydride compound, or a gallium hydride compound to produce one or more of the nanoparticles. The reaction occurs in solution while being sonicated at a temperature at which the metal hydride compound decomposes. A process of: reacting a nanoparticle with a compound containing at least two hydroxyl groups to form a coating having multi-dentate metal-alkoxides.