Abstract
Relative sliding or bumping of structural elements during the operation of a very high-temperature gas-cooled reactor (VHTR), which has been developed by the Japan Atomic Energy Research Institute, are to be caused supposedly by thermal expansion, flow-induced vibration, seismic forces etc. Appropriate measures, therefore, must be taken in order to prevent abnormal wear, seizing or failure of these structural elements.
The friction and wear characteristics of Ni-based heat-resisting alloy (Hastelloy X-R), which is now thought to be one of the promising candidate materials for VHTR structures, and several ceramic materials by which the surfaces of Hastelloy X-R are to be coated, were studied in 1, 000°C and 0.2-4.1MPa He gas environment.
The followings are the conclusions derived from the present experiment:
(1) The friction coefficient of Hastelloy X-R against itself decreased with increasing O2 gas partial pressure within 3kPa in the He gas environment.
(2) The mutual transfer of material elements occurred when the material combination was Hastelloy X-R against ZrO2 coating.
(3) The friction and wear characteristics of ZrO2 and TiC coatings against themselves were stable.
