A DC high-voltage relay with at least one contact pair including a movable contact and a fixed contact, the contact pair having a contact force and/or an opening force of 100 gf or more, having a rated voltage of 48 V or more, the movable contact and/or the fixed contact includes a Ag oxide-based contact material. Metal components contain at least one metal M essentially containing Zn, and a balance being Ag and inevitable impurity metals, and the contact material has a content of the metal M of 0.2% by mass or more and 8% by mass or less based on a total mass. The contact material has a material structure in which one or more oxides of the metal M having an average particle size of 0.01 μm or more and 0.4 μm or less are dispersed in a matrix including Ag or a Ag alloy.

Disclosed are a method of manufacturing an aluminum-based clad heat sink, and an aluminum-based clad heat sink manufactured by the method. The method includes ball-milling (i) aluminum or aluminum alloy powder and (ii) carbon nanotubes (CNT) to prepare a composite powder, preparing a multi-layered billet using the composite billet, and directly extruding the multi-layered billet using an extrusion die to produce a heat sink. The method has an advantage of producing a light high-strength high-conductivity aluminum-based clad heat sink having an competitive advantage in terms of price by using direct extrusion that is suitable for mass production due to its simplicity in process procedure and equipment required.

Provided is a method for manufacturing a three-dimensional shaped object. The method for manufacturing the three-dimensional shaped object includes: a first step of receiving designation of a shaping mode of the three-dimensional shaped object; a second step of shaping, based on shaping data for shaping the three-dimensional shaped object, the three-dimensional shaped object by discharging a shaping material from a nozzle; and a third step of controlling cleaning of the nozzle in accordance with the shaping mode received in the first step.

Provided is a method for manufacturing a three-dimensional shaped object. The method for manufacturing the three-dimensional shaped object includes: a first step of receiving designation of a shaping mode of the three-dimensional shaped object; a second step of shaping, based on shaping data for shaping the three-dimensional shaped object, the three-dimensional shaped object by discharging a shaping material from a nozzle; and a third step of controlling cleaning of the nozzle in accordance with the shaping mode received in the first step.

In a method for manufacturing a three-dimensional shaped object, when an amount of a shaping material discharged toward a shaping surface per unit movement amount of a discharging unit is defined as a discharged shaping amount, in a layer forming step of forming a layer on the shaping surface, in a case in which a second partial shaped object to be shaped is not adjacent to a first partial shaped object that is shaped previously and is shaped with a gap between the first partial shaped object and the second partial shaped object, the second partial shaped object is shaped by setting the discharged shaping amount to a first discharged shaping amount, and in a case in which the second partial shaped object is adjacent to the first partial shaped object, the second partial shaped object is shaped by setting the discharged shaping amount to a second discharged shaping amount that is greater than the first discharged shaping amount.

In a method for manufacturing a three-dimensional shaped object, when an amount of a shaping material discharged toward a shaping surface per unit movement amount of a discharging unit is defined as a discharged shaping amount, in a layer forming step of forming a layer on the shaping surface, in a case in which a second partial shaped object to be shaped is not adjacent to a first partial shaped object that is shaped previously and is shaped with a gap between the first partial shaped object and the second partial shaped object, the second partial shaped object is shaped by setting the discharged shaping amount to a first discharged shaping amount, and in a case in which the second partial shaped object is adjacent to the first partial shaped object, the second partial shaped object is shaped by setting the discharged shaping amount to a second discharged shaping amount that is greater than the first discharged shaping amount.

Disclosed is a nano dispersion copper alloy with high air-tightness and low free oxygen content and a brief manufacturing process thereof, wherein alloy comprises the following components: Al.sub.2O.sub.3, Ca and La. The manufacturing process comprises the following steps of: preparing Cu—Al.sub.2O.sub.3 alloy powder by an internal oxidation method; mixing the Cu—Al.sub.2O.sub.3 alloy powder with Cu—Ca—La alloy powder; sheathing the mixed powder under protection of argon; performing hot extrusion and then rotary forging; vacuumizing the sheath after the rotary forging; and sealing and placing the sheath in a nitrogen atmosphere with a temperature of 450° C. to 550° C. and a pressure intensity of 40 Mpa to 60 Mpa for 3 hours to 5 hours. The dispersion copper prepared by the present disclosure has the advantages of low free oxygen content (≤15 ppm), high dimensional stability, good air-tightness and an air leakage rate≤1.0×10.sup.−10 Pa m.sup.3/s after hydrogen annealing.

Disclosed is a nano dispersion copper alloy with high air-tightness and low free oxygen content and a brief manufacturing process thereof, wherein alloy comprises the following components: Al.sub.2O.sub.3, Ca and La. The manufacturing process comprises the following steps of: preparing Cu—Al.sub.2O.sub.3 alloy powder by an internal oxidation method; mixing the Cu—Al.sub.2O.sub.3 alloy powder with Cu—Ca—La alloy powder; sheathing the mixed powder under protection of argon; performing hot extrusion and then rotary forging; vacuumizing the sheath after the rotary forging; and sealing and placing the sheath in a nitrogen atmosphere with a temperature of 450° C. to 550° C. and a pressure intensity of 40 Mpa to 60 Mpa for 3 hours to 5 hours. The dispersion copper prepared by the present disclosure has the advantages of low free oxygen content (≤15 ppm), high dimensional stability, good air-tightness and an air leakage rate≤1.0×10.sup.−10 Pa m.sup.3/s after hydrogen annealing.

A method for obtaining a lead-free or low lead content brass billet subjects a mixture of lead-free or low lead content brass chips and graphite powder to extrusion, either direct or inverted. The method obtains lead-free or low lead content brass billets.

A method for obtaining a lead-free or low lead content brass billet subjects a mixture of lead-free or low lead content brass chips and graphite powder to extrusion, either direct or inverted. The method obtains lead-free or low lead content brass billets.