Ceramic shafts are formed by isostatic pressing. Ceramic raw materials have the advantages of high toughness, high flexural strength and high wear resistance, excellent thermal insulation, and a coefficient of thermal expansion close to that of steel, so ceramic shafts are gradually replacing the work of traditional metal shafts.
Ceramic shafts have the following advantages:
First, because ceramics are hardly afraid of corrosion, ceramic shafts are suitable for operation in harsh conditions covered with corrosive media.
Second, because the density of the ceramic bearing rolling ball is lower than steel, the weight is much lighter, so the centrifugal effect on the outer ring during rotation can be reduced by 40%, and thus the service life is greatly extended.
Third, ceramics are less affected by thermal expansion and contraction than steel, thus allowing the shaft to work in environments with more drastic temperature changes when the shaft clearance is certain.
Fourth, because ceramic has a higher modulus of elasticity than steel, it is less prone to deformation when subjected to force, thus facilitating higher working speeds and achieving higher accuracy.
Overall, the performance and price ratio of ceramic shafts is far better than that of all-steel shafts, saving a lot of downtime for maintenance, reducing the scrap rate, and reducing the number of spare parts for shafts in stock.
The advantage of ceramic shafts over metal shafts is their "high temperature resistance, high temperature strength" and "corrosion resistance".
In the case of gas turbines, for example, the choice of materials is similar to that of aircraft turbines and turbofan engines.
Nickel-titanium high-temperature alloy is the rotor shaft and blade of the basic material. However, high-temperature strength reduction, high-temperature creep, high-temperature corrosion, is the main factor to reduce its service life.
The disadvantages of high-temperature alloys are overcome if silicon nitride ceramic material rotors are used. At present, the rotor of small gas turbine is manufactured with silicon nitride ceramic material and the experimental results are encouraging.