Monthly Archives - September 2020

To verify the microstructure and properties of laser cladding tungsten carbide nanometer layer

In tungsten carbide, carbon atoms embedded in the gap of the tungsten metal lattice do not destroy the original metal lattice and form interstitial solid solution, so it is also called interstitial compound. Tungsten carbide can be prepared by heating a mixture of tungsten and carbon at high temperatures, and the presence of hydrogen or warp accelerates the reaction. If the oxygen-containing compound of tungsten is used for preparation, the product must eventually be vacuumed at 1500℃ to remove [...]

Preparation of nanometer tungsten carbide composite powder

Tungsten carbide is a black gray crystalline powder. Relative density 15.6(18/4℃), melting point 2600℃, boiling point 6000℃, Mohs hardness 9. Tungsten carbide insoluble in water, hydrochloric acid or sulfuric acid, soluble in nitric acid and hydrofluoric acid mixture. Tungsten carbide reacts strongly with fluorine at room temperature and is oxidized to tungsten oxide when heated in air. At 1550 ~ 1650℃, the metal tungsten powder can be directly combined with carbon black, or at 1150℃, the tungsten powder can [...]

The high precision isotope ratio analysis of ultramicro strontium samples can be realized by using silicotungstic acid as the emitter

Strontium isotope ratio (87Sr/86Sr) has been widely used in earth science, astrochemistry, environmental chemistry, food origin tracing, archaeology and other fields. Since the 1960s, the Thermoelectric ionization mass spectrometer (TIMS) has been regarded as the benchmark technique for ratio analysis of 87Sr/86Sr with excellent accuracy and high sensitivity. Excellent sensitivity is the prerequisite for the analysis of high precision 87Sr/86Sr ratio in ultramicro samples. The key to improve the sensitivity lies in the selection of suitable emitters to improve [...]