What is the effect of molybdenum on ceramic properties?
2021 06/19
The oxidation effect of molybdenum on ceramics is not significant. Therefore, when the chromium-nickel austenitic stainless steel maintains a single austenite structure and no intermetallic precipitation, the addition of molybdenum has little effect on its room temperature mechanical properties, but, as the content of molybdenum increases Increase, the high-temperature strength of steel is improved, such as Boron Nitride Ceramic Shaft durability, creep and other properties are greatly improved, so molybdenum-containing stainless steel is often used at high temperatures, however, the addition of molybdenum increases the high-temperature deformation resistance of steel, and the steel often There is a small amount of δ ferrite, so the hot workability of molybdenum-containing stainless steel is worse than that of molybdenum-free steel, and the higher the molybdenum content, the worse the hot workability. In addition, the molybdenum-containing austenitic stainless steel is prone to κ (σ) phase Precipitation, which will significantly deteriorate the plasticity and toughness of steel. Therefore, in the production, equipment manufacturing and application of molybdenum-containing austenitic stainless steel, attention should be paid to prevent the formation of intermetallic phases in ceramics, although molybdenum acts as an alloying element to austenite The Boron Nitride Ceramic Shaft reasons for the resistance of bulk stainless steel to reducing media, surface pitting corrosion and crevice corrosion are not fully understood, but a large number of experiments have pointed out that the corrosion resistance of molybdenum is only effective when the steel contains a relatively high amount of chromium. Molybdenum is mainly strengthened steel. The corrosion resistance of medium chromium. At the same time, the corrosion inhibition effect of molybdenum after the formation of acid salt has also been confirmed by experiments. In terms of resistance to stress corrosion of high-concentration chloride solutions, molybdenum is resistant to austenitic stainless steel as an alloying element. The reasons for reducing medium, resistance to pitting and crevice corrosion are not fully understood, but a large number of experiments have pointed out that the role of molybdenum is only effective when the ceramic contains a higher amount of chromium, and molybdenum is mainly used to strengthen the corrosion resistance of chromium in steel. At the same time, the buffering effect of molybdenum after the formation of molybdate has also been confirmed by Boron Nitride Ceramic Shaft experiments, although this experiment refers to the same in terms of resistance to stress corrosion caused by high concentration of chloride. Molybdenum below 3# is harmful to the stress corrosion resistance of austenitic stainless steel, but because common chromium-nickel austenitic stainless steels are mostly used in aqueous media containing trace chlorides and saturated oxygen, their stress corrosion is also originated from pitting corrosion Therefore, chromium-nickel-molybdenum austenitic stainless steel containing molybdenum has higher resistance to pitting corrosion, so in practical applications it often has better resistance to chloride stress corrosion than steel without molybdenum.