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Submicron grain size violet tungsten oxide’s morphology is the most special one among tungsten oxides including yellow tungsten oxide, violet tungsten oxide, blue tungsten oxide and brown tungsten oxide. The morphology of VTO is a needle-shaped crystal like APT crystal form. The quality of submicron violet tungsten oxide directly affects the production and quality of tungsten powder and tungsten carbide powder. Therefore, how to judge the quality of violet tungsten oxide is becoming the emphasis of studying. Determining the quality…

Violet tungsten oxide nano powder may be produced by adopting tungstic acid mWO3?nH2O (m≥1, n≥1) as raw material. 1. Tungstic acid heated above 100°C: mWO3?nH2O=mWO3+nH2O (1) Introduce NH3, the introduced NH3 reacts in the formula (2) under the catalytic action of tungsten oxide WOx (2≤x≤3): 2NH3=N2+3H2 (2) 2. When the reaction temperature rises above 500°C, the reaction product WO3 in formula (1) and the reaction product H2 in formula (2) undergo the reduction reaction in formula (3): WO3+0.1H2=WO2.9+0.1H2O (3) If…

95% violet tungsten oxide refers to a violet tungsten oxide powder with W18O49 purity of 95% and WO3 content of 5%. Chinatungsten Online provides this kind of violet tungsten oxide with grain size of 10~18μm and density of 1.75g/cm3. Chinatungsten Online provides 95% violet tungsten oxide, that is, grade A1 of violet tungsten oxide. The impurity content (%) is as follows: Sn≤0.00005; S≤0.0005; Cu≤0.0010; Mo≤0.00005; Bi≤0.0005; As≤0.0005; P≤0.0005; Si≤0.0005; Ca≤0.0001; Mn≤0.00005; Ti≤0.0002; Mg≤0.0002; Na≤0.0004; K≤0.0006; Cr≤0.0002; Sb≤0.0001; V≤0.0002; Co≤0.0002; Ni≤0.0002;…

Nano violet tungsten oxide may be prepared by using ammonium paratungstate 5(NH4)2O?12WO3?5H2O as raw material. 1. Ammonium paratungstate heated above 400°C, the reaction in formula (1) occurs: 5(NH4)2O?12WO3?5H2O=12WO3+10NH3+10H2O (1) The reaction product NH3 in the formula (1) or NH3 introduced in other ways reacts in the formula (2) under the catalytic action of tungsten oxide WOx (2≤x≤3) to generate reducing gas hydrogen H2. 2NH3=N2+3H2 (2) 2. When the reaction temperature rises above 500°C, the reaction product WO3 in formula (1)…

Grade 1 violet tungsten oxide is classified according to national standard with grade of WO2.72-1. Certainly, there are different grades of violet tungsten oxide in line with different classification criteria. Moreover, during the actual production process, manufacturers may adopt different raw materials, processing equipment, and processing technology so that they may produce a variety of violet tungsten oxide with different specifications. In accordance with national standard, the component of grade 1 violet tungsten oxide should satisfy the following requirements: More…

Super grade violet tungsten oxide is a type of violet tungsten oxide classified in accordance with national standard with grade of WO2.72-0. The other type of violet tungsten oxide is grade 1 violet tungsten oxide. However, in fact, different manufacturers are producing a variety of violet tungsten oxide with different specifications. That is because raw materials, processing equipment and processing technology adopted by the manufacturers may vary during the actual production process. According to national standards, the component of super…

High-purity high density violet tungsten oxide’s color can reflect its quality. Moreover, the color of violet tungsten oxide is related to its oxygen index, tightness of particles and aspect ratio of needle. The purple-colored violet tungsten oxide has a slightly higher oxygen index, slightly thinner and longer needles; And the mauve-colored violet tungsten has slightly coarser and shorter needles. The quality of violet tungsten oxide can be determined by colorimetry. This method is more intuitive and effective, which saves time…

Coarse grain size violet tungsten oxide is insoluble in water, so its solubility in water is almost zero. Violet tungsten oxide is also insoluble in ethanol. However, it is soluble in alkali liquor as tungsten oxides are all acidic oxides. What is solubility? Solubility refers to the mass of solutes dissolved in a 100g solvent to a saturated state at a certain temperature. The solubility of a substance fundamentally depends on the physical and chemical properties of the solute and…

Fine grain size violet tungsten oxide can be used to produce ultrafine tungsten powder (W powder) and ultrafine tungsten carbide powder (WC powder). Ultrafine W powder and WC powder prepared by using fine violet tungsten oxide as raw material have better performance. The phase composition of the violet tungsten oxide has a great influence on the properties of the prepared W powder and WC powder. In addition, the content of NH3 in violet tungsten oxide can also greatly affect the…

Nano-needle violet tungsten oxide has a diameter of 20-200nm, a length of 0.5-10μm, and a length-diameter ratio of 5-300. This type of violet tungsten oxide may be synthesized in one step by a solution process. Therefore, the reaction time is short, and the reaction initiation temperature is low. A large quantity of gases are produced in the reaction course, and sufficient contact with air is impeded, so that the generated product, namely, the violet tungsten oxide, is relatively single, favorable…