These high quality ceramic parts are made by HIP, hot isostatic press. This Chinese company just made worlds 2nd largest HIP press and supplies to all major aero engine companies. Naura also uses their equipment for its ceramic parts.
Another Chinese company of AVIC is making the worlds largest HIP press right now!
They provide HIP presses to Jiangfeng, China’s largest PVD sputtering target manufacturer
Here is another company that’s making ceramic and steel balls/rollers for HSR and machine tool bearings. Interestingly, bearings are the last component to be indigenized for HSR and high end machine tools. In fact bearings for all commercial 350km HSR are imported now (probably the only imported component today), and domestic ones are still under testing. Mass producing high quality bearings is way harder than it sounds