The objective of this program was to provide an experimental basis for specifying materials for heat exchangers and gas turbines exposed to a pressurized fluidized bed combustor environment. A 1000 hour test was completed which: (1) exposed heat exchanger materials both within the fluidized bed and in the freeboard of a pressurized fluidized bed combustor at temperatures ranging from 1050 to 1600/sup 0/F for up to 1117 hours; and (2) provided the first successful long term exposure of turbine blade materials subjected to PFBC flue gas where the particulates were removed solely by cyclones. This report describes the operating conditions and major observations during this test period. Operating conditions varied sufficiently to significantly alter the particulate loading and mean particle diameter of the particulate entering the turbine section. This permitted several observations to be made: most of the turbine blade specimens appeared to be in satisfactory condition showing little, if any, erosion; particulate loading and/or particle size had a profound effect on the degree of deposition and erosion on the turbine blades; and in general, erosion was not visually apparent when 3 stages of conventional cyclones were used to clean the PFBC flue gas (however, upsets could cause marked erosion if the grain loading and particulate size increased only by small amounts). The heat exchanger specimens appeared to be in satisfactory condition both in bed and above the fluidized bed. These tests indicated the possibility that conventional cyclones alone may be sufficient to protect gas turbine blade materials exposed to PFBC flue gas. Also, there seems to be satisfactory heat exchanger materials for above-bed use and probably in-bed use.