Abstract: The invention discloses an AlCrVTiSiON nano-gradient coating with surface pre-oxidation and a preparation method thereof, belonging to the technical field of coatings. The AlCrVTiSiON nano gradient coating is prepared by arc ion plating technology, wherein the target materials are selected from metal Cr target, V target, AlCrSi target and AlTiSi target. In order to further improve the heat resistance of the coating and increase the cutting amount during service, the AlCrVTiSiON nano-gradient coating with O element content increasing from inside to outside was formed. The prepared coating has good heat resistance, which is suitable for high-speed cutting and improves processing efficiency.

Abstract: The present invention relates to an orthogonal-phase compound and its nonlinear optical (NLO) crystal of BaGa7Se7, its producing method and uses thereof. Polycrystalline orthogonal-phase BaGa4Se7 was prepared by a high-temperature solid-phase reaction in a sealed silica tube. Large size single crystals of orthogonal-phase BaGa4Se7 could be prepared by the flux method or Bridgman method. BaGa4Se7 crystallizes in the point group mm2. Orthogonal-phase BaGa4Se7 has a powder second harmonic generation (SHG) efficiency of about 5 times that of AgGaS2 and is phase-matchable. The orthogonal-phase BaGa4Se7 is non-hygroscopic and has good mechanical properties, which makes it easy to cut, polish, and coat by normal processing. The orthogonal-phase BaGa4Se7 crystal has never been cracked during cutting and polishing. The orthogonal-phase compound and NLO crystal of BaGa4Se7 can be used as NLO devices.

Abstract: A method for preparing a boron-containing low-carbon steel oxide film includes performing micro-arc oxidation on boron-containing low-carbon steel in an electrolyte by using the boron-containing low-carbon steel as an anode, to obtain a boron-containing low-carbon steel oxide film. The electrolyte contains sodium meta aluminate of 5 g/L to 25 g/L, sodium dihydrogen phosphate of 2 g/L to 10 g/L, sodium carbonate of 2 g/L to 15 g/L, and glycerol of 2 g/L to 8 g/L. The preparation method provided by the present invention has a simple and controllable process, and the obtained boron-containing low-carbon steel oxide film has a secure bond with the substrate, thus effectively avoiding occurrence of galvanic corrosion.

Abstract: The present invention provides a preparation method for a nitrogen-doped carbon-loaded metal monatomic catalyst, including: mixing a soluble metallic salt, a hydroxylamine hydrochloride, a soluble carbon source, water, and ethanol, to obtain a mixed solution, then performing drying and precipitation, to obtain a catalyst precursor, and finally performing calcination, to obtain a nitrogen-doped carbon-loaded metal monatomic catalyst. In the present invention, the metallic salt, the hydroxylamine hydrochloride, and the carbon source are fully mixed in the solution, and after being dried, are calcined, to carbonize the carbon source, so that ammonium ions are decomposed into nitrogen-doped carbon, and meanwhile, metal atoms are loaded onto the nitrogen-doped carbon. The method is simple, and costs are low.