40 results about "Nitrogen partial pressure" patented technology

An sintered iron-based powder metal body with outstandingly lower re-compacting load and having a high density and a method of manufacturing an iron-based sintered component with fewer pores of a sharp shape and having high strength and high density, the method comprising mixing,an iron-based metal powder containingat most about 0.05% of carbon,at most about 0.3% of oxygen,at most about 0.010% of nitrogen,with at least about 0.03% and at most about 0.5% of graphite powder and a lubricant, preliminarily compacting the mixture into a preform, the density of which is about 7.3 Mg / m3 or more, and preliminarily sintering the preform in a non-oxidizing atmosphere in which a partial pressure of nitrogen is about 30 kPa or less at a temperature of about 1000° C. or higher and about 1300° C. or lower, thereby forming a sintered iron-based powder metal body with outstandingly lower re-compacting load and having high deformability, the density of which is about 7.3 Mg / m3 or more and which contains at least about 0.10% and at most about 0.50 of carbon, at most about 0.010% of oxygen and at most about 0.010% of nitrogen, and which comprises at most about 0.02% of free carbon, and, further applying re-compaction and re-sintering and / or heat treatment thereby forming a sintered component, as well as the method alternatively comprising applying preliminary sintering in an atmosphere with no restriction of the nitrogen partial pressure and then annealing instead of the sintering step, thereby obtaining a sintered iron-based powder metal body with the nitrogen content of at most about 0.010%.

A hexagonal boron nitride (h-BN) powder is disclosed in which primary particles of the powder exhibit a ratio (D / d) of long diameter (D) to thickness (d) in a range of 5 to 10. Agglomerated particle bodies made of the primary particles have an average particle diameter (D50) in a range of 2 μm to 200 μm, inclusive, and the powder has a bulk density in a range of 0.5 g / cm3 to 1.0 g / cm3. In an exemplary method for producing the h-BN, boron carbide is nitridizated in a nitrogen partial pressure of at least 5 kPa at 1800° C. to 2200° C., inclusive. B2O3 (or precursor thereof) is added to the nitridization product to produce a mixture. The mixture is decarbonized in a non-oxidizing atmosphere at a 1500° C. to 2200° C., inclusive. The decarbonization product is pulverized and subject to particle-size classification, yielding H-BN powder. The method includes a depressurizing step, performed at 100 kPa or less either during nitridization or after decarbonization.

The invention provides a design of a novel dynamic nitrogen adsorption instrument and achieves the purpose of greatly raising test speed and operational reliability of the nitrogen adsorption instrument. By the adoption of a four-way solenoid valve, gas flowing path is subtly controlled. Therefore, rapid and reliable test of sample cell in a liquid nitrogen cup is always maintained only through changing gas flow. Through switch of the solenoid valve, rapid conversion of two working conditions from nitrogen adsorption test to nitrogen partial pressure adjustment and vice verse is realized, and the sample cell is in the liquid nitrogen cup from beginning to end without the need of up-and-down motion of the liquid nitrogen cup. The invention has the advantages of simple structure, low cost, accurate control and the like.