High-temperature resistant nano-copper produced by laser direct writing, preparation method and application thereof

A preparation method for a high-temperature resistant nano-copper produced by laser direct writing, comprising the following steps:

• (1) uniformly heating and stirring an alcohol solvent, an organic dispersant, an organic auxiliary agent and an appropriate amount of formate to obtain a precursor solution;
• (2) adding an appropriate amount of nano-copper oxide into the precursor solution and thoroughly dispersing the mixture via ultrasonication to obtain a nano-copper oxide ink, comprising 43.0-50.4 wt % of nano-copper oxide, 37.1-50.4 wt % of alcohol solvent, 3.4-5.3 wt % of organic dispersant, 0.0-9.5 wt % of organic auxiliary agent and 1.3-2.0 wt % of formate, and the nano-copper oxide being a copper oxide nanowire;
• (3) coating a pretreated substrate with the nano-copper oxide ink, followed by heating and drying to obtain a nano-copper oxide film;
• (4) applying one-step laser direct writing-induced passivation/photothermal reduction sintering to the nano-copper oxide film to obtain a high-temperature resistant nano-copper, wherein the laser is a continuous green light with a wavelength of 532 nm, a laser power is 100-400 mW, a laser speed is 20-200 mm/s and a laser scanning period is 20-40 μm;
• and the laser-induced passivation involves comprising a passivation reaction of HCOO− on a surface of the nano-copper, causing copper ions on the surface of the nano-copper to form a copper formate dimer complex with HCOO−, forming an oxidation-resistant coordination passivation layer;
• wherein the high-temperature is 170° C., wherein a temperature of the heating and stirring in step (1) is 50-70° C., a rotation speed is 600-1500 rpm, and a duration is 2-20 h;
• a real-time temperature during the ultrasonic dispersion in step (2) is 50-60° C., an ultrasonic pulse width is 0.1 s, and an ultrasonic duration is 0.1-2 h;
• and a temperature of the heating and drying in step (3) is 50-80° C., and a duration is 2-12 h.