Abstract
Results are reported from studies in which several monolithic ceramic materials in the form of modulus-of-rupture bars were exposed for 100 h to the combustion conditions found in either a small single- or two-cylinder diesel engine. Fuels included a standard Phillips D-2 diesel or synthetic mixture of the Phillips D-2 and an aromatic blend. The ceramics included two commercial grades of partially stabilized zirconia (PSZ-TS and PSZ-MS), silicon nitride (GTE WESGO SNW-1000 and Norton NT-154), and (Hexoloy SA) silicon carbide. Significant reductions in postexposure four-point bend fracture strength occurred in the PSZ-TS material irrespective of whether it was exposed in the single- or two-cylinder engine. Only a small decrease in fracture strength occurred in the PSZ-MS material, and essentially no decrease in fracture strength occurred in the silicon nitride (GTE WESGO SNW-1000) when tested at room temperature. The Norton NT-154 silicon nitride was tested at both room temperature and at 700°C over several strain rates ranging from 1 × 10-4 to 1 × 10-7 s-1. Room temperature tests indicated that the engine exposed bars actually showed a slight increase in average strength, 830 MPa, versus 771 MPa for the unexposed material. Elevated temperature strength comparisons showed no reduction in strength due to previous engine exposure. Hexology SA silicon carbide showed no reduction in fracture strength when tested at 700°C.
Original language | English |
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Pages (from-to) | 301-308 |
Number of pages | 8 |
Journal | Proceedings - Society of Automotive Engineers |
Issue number | P-243 |
State | Published - 1991 |
Event | Proceedings of the Annual Automotive Technology Development Contractors' Meeting - Dearborn, MI, USA Duration: Oct 22 1990 → Oct 25 1990 |