A silver powder containing: silver particles; and an adherent that is attached to surfaces of the silver particles and contains a metal oxide that has a melting point lower than a melting point of silver.

A method for prepares low melting point metal particles, a conductive paste and a method for preparing the conductive paste, and relates to the technical field of functional materials. The method for preparing low melting point metal particles includes providing an organic resin carrier having fluidity, adding a low melting point metal material and the organic resin carrier into a sealed container for a vacuuming operation or filling a protective gas, making a temperature in the sealed container higher than the melting point of the low melting point metal and performing dispersion by stirring, and lowering the temperature, after performing the dispersion, to be below the melting point of the low melting point metal with continuous stirring during a cooling process to obtain low melting point metal particles dispersed in the organic resin carrier. Low melting point metal particles can be effectively prepared.

A method for prepares low melting point metal particles, a conductive paste and a method for preparing the conductive paste, and relates to the technical field of functional materials. The method for preparing low melting point metal particles includes providing an organic resin carrier having fluidity, adding a low melting point metal material and the organic resin carrier into a sealed container for a vacuuming operation or filling a protective gas, making a temperature in the sealed container higher than the melting point of the low melting point metal and performing dispersion by stirring, and lowering the temperature, after performing the dispersion, to be below the melting point of the low melting point metal with continuous stirring during a cooling process to obtain low melting point metal particles dispersed in the organic resin carrier. Low melting point metal particles can be effectively prepared.

Provided is a mixed powder for powder metallurgy that contains a readily available compound as a lubricant, does not need to contain a stain-causing metal soap, has excellent ejection properties, and can exhibit excellent fluidity without deteriorating the ejection properties even in the case of further containing carbon black. The mixed powder for powder metallurgy contains (a) an iron-based powder and (b) a lubricant, where the lubricant (b) contains a specific aliphatic amine.

Provided is a mixed powder for powder metallurgy that contains a readily available compound as a lubricant, does not need to contain a stain-causing metal soap, has excellent ejection properties, and can exhibit excellent fluidity without deteriorating the ejection properties even in the case of further containing carbon black. The mixed powder for powder metallurgy contains (a) an iron-based powder and (b) a lubricant, where the lubricant (b) contains a specific aliphatic amine.

A graphene modifying method of metal having following steps of providing metal powders, graphene powders and a binder, the metal powder has metal particles, and the graphene powder has graphene micro pieces, each graphene micro piece is formed by 6-atom unit cells connected with each other, each 6-atom unit cell is connected to a stearic acid functional group by a sp3 bond; mixing the metal powder, the graphene powder, and the binder to generate heat by a friction, each sp3 bond connected with the stearic acid functional group is thereby heated and broken, each 6-atom unit cell is connected with other 6-atom unit cells via the broken sp3 bond, and the metal particles are thereby wrapped by the 6-atom unit cells; and sintering the metal particles into a metal body to transform the plurality of graphene micro pieces into a three-dimensional mash embedded in the metal body.

A graphene modifying method of metal having following steps of providing metal powders, graphene powders and a binder, the metal powder has metal particles, and the graphene powder has graphene micro pieces, each graphene micro piece is formed by 6-atom unit cells connected with each other, each 6-atom unit cell is connected to a stearic acid functional group by a sp3 bond; mixing the metal powder, the graphene powder, and the binder to generate heat by a friction, each sp3 bond connected with the stearic acid functional group is thereby heated and broken, each 6-atom unit cell is connected with other 6-atom unit cells via the broken sp3 bond, and the metal particles are thereby wrapped by the 6-atom unit cells; and sintering the metal particles into a metal body to transform the plurality of graphene micro pieces into a three-dimensional mash embedded in the metal body.

According to an example, a composition may include a high melt temperature build material in the form of a powder; a first low melt temperature binder in the form of a powder; and a second low melt temperature binder in the form of a powder; and in which the first low melt temperature binder melts at a temperature that is different from the second low melt temperature binder.

Provided is a raw material powder for powder metallurgy, capable of preventing stains, surface defects and decarburization of a sintered body, improving strength and density thereof. The raw material powder for powder metallurgy is for use in the production of a sintered body that is sintered at a temperature of not lower than 500° C., composed of a mixture of a metal powder and a lubricant, in which the lubricant is melamine cyanurate or terephthalic acid. Alternatively, the raw material powder for powder metallurgy is for use in the production of a sintered body that is sintered at a temperature of not lower than 500° C, composed of a mixture of a metal powder, a first lubricant and a second lubricant, in which the first lubricant is melamine cyanurate or terephthalic acid, while the second lubricant is preferably erucic acid amide or stearic acid amide.

The metal ceramic powder with a particle size of 15-45 .Math.m and suitable for thermal spraying is prepared through a combination of mechanical ball milling, spray granulation, and vacuum sintering. The metal ceramic powder is sprayed on a surface of a steel substrate adopting the high velocity oxygen fuel (HVOF) technology with oxygen-propane as fuel and taking oxygen as a combustion improver, propane as fuel, nitrogen as powder feeding carrier gas, and air as a cooling medium to prepare and form the NiCrBSi—ZrB2 composite coating. The present disclosure solves the problem that ZrB.sub.2 ceramic is difficult to compact during sintering and improves powder bonding strength and fluidity. The preparation method is simple, has advantages of high coating deposition efficiency and convenient equipment operation, and is cost-effective. The preparation method can improve thermal corrosion resistance and high-temperature wear resistance of a surface of boiler, and prolonging lifetime of the boiler.