After alkali washing, the surface of molybdenum bar is gray metallic luster and smooth. Alkali washing, also known as "alkali boiling", is a chemical cleaning method. A method of adding alkali liquor into the boiler water to remove the scale in the boiler under a certain pressure. First make the scale soft, then use mechanical method to remove the scale, the scale removal rate is generally up to 80%. It is a high-strength alkaline solution made up of sodium hydroxide and sodium carbonate or trisodium phosphate, and then softens, loosens, emulsifies and disperses the deposits of molybdenum rod, making the surface of rod appear metallic luster and relatively smooth. In alkaline washing, some surfactants are often added to increase the cleaning effect. Alkali washing can make the alkali liquid circulate at a certain temperature, the time is generally 6-12h, and the time can also be extended according to the situation
Polished molybdenum rod has good properties of molybdenum, such as high temperature resistance, high strength, good thermal conductivity and low thermal expansion, etc. it is often made into high temperature products and used in various high temperature fields. Molybdenum rod can be divided into different types according to different surface states, including polished molybdenum rod, alkali washed molybdenum rod, polished molybdenum rod and forged molybdenum rod. The polishing molybdenum bar has the deepest processing degree, bright and smooth color on the surface, dense internal and external density of the product, and no cracks. The surface of polished molybdenum rod is silver gray metallic luster with smooth surface and small size error. The surface of alkali washed molybdenum rod is gray metallic luster, and the surface is smooth. The surface of polished molybdenum bar has metallic luster and is flat and rough. There is a layer of oxide on the surface of forged molybdenum bar, which is dark black. The surface of sintered molybdenum bar is gray metallic luster, but compared with the surface smoothness of the above molybdenum bar, its surface is the roughest.
Molybdenum rod is mainly prepared by powder metallurgy. The preparation process is as follows: powder mixing, ball milling, forming, sintering, forging and machining. Because of its good high temperature characteristics, it can be made into electrode materials and used in glass kilns to produce glass, refractory fiber and other products.
