Matsuo Higuchi

Development of a QMS with a ceramic single-piece quadrupole

Abstract A novel quadrupole mass spectrometer (QMS) has been developed by using a ceramic single-piece quadrupole. The quadrupole was made of silicon nitride (Si3N4). The four hyperbolic surfaces were coated with metal thin films of about 10 μm to form electrodes. Mass spectra were successfully obtained by using the conditions of the second stable zone in the mathieu diagram. It seems that there are no differences in sensitivity and resolution between the two QMSs with a ceramic quadrupole and a conventional metal one of the same dimensions.

Development of a high-strength Si3N4 sintered body☆

Due to its heat-, wear- and corrosion-resistant properties, Si3N4 ceramic is a promising material for cutting tools and other wear-resistant products, and for automotive engines, gas turbines, and other structural items. Sumitomo Electric has successfully developed sintered bodies (σ1 = 130 to 150 kg/mm2 at room temperature) with high strength by controlling grain shapes grain diameter and aspect ratio. The high strength Si3N4 materials have fracture toughnesses of KIC = 5–7 MPa/m, thermal shock resistance of ΔT = 9000°C, good acid-resistant properties, and other properties all superior to those of conventional Si3N4 materials. Highly reliable Si3N4 materials with high Weibull modulus (m > 20) have also been developed by reducing metal inclusions that would cause defect factors leading to breakup. The high strength Si3N4 is already in practical use for plastic machining tools for non-ferrous metals (Al, Cu alloys), forging tools, and other wear-resistant products and structures of steel facilities. It is also being used for automotive parts and other items requiring high reliability. The high strength Si3N4 sintered bodies fully satisfy the requirements of these products.