AEROSPACE EROSION OF DIAMOND AND DIAMOND COATINGS

The erosive hazard experienced by diamond during high velocity flight has been investigated. Impact with rain drops is simulated using a hig h-velocity jet technique (the multiple-impact jet apparatus or MIJA) w hich allows threshold velocities for damage to be accurately determine d. This technique has been used to assess natural and synthetic diamon d (both chemical vapour deposited (CVD) and high-temperature, high-pre ssure (HTHP)), as well as CVD coatings on a range of IR-transparent su bstrates. The solid particle erosion hazard is assessed using a specia lly designed sand blasting rig which is capable of achieving velocitie s up to 250 m s(-1). This apparatus has been used to study natural and CVD diamond and their erosion resistance is compared with that of cur rently used IR window materials. The results show that the superior me chanical properties of diamond make it an ideal candidate material for IR-transparent windows in an aerospace environment.