Accession Number : AD0751259

Title :   Na2SO4-Induced Attack of Ni-20Cr-2ThO2,

Corporate Author : AEROSPACE RESEARCH LABS WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Davis,Hubert H. , Jr. ; Graham,Henry C. ; Uhlig,George F.

Report Date : JUN 1972

Pagination or Media Count : 26

Abstract : The Na2SO4-induced oxidation behavior of Ni-20Cr-2ThO2 was studied using thermogravimetric and microstructural techniques. This is of interest in gas turbine corrosion. Specimens were spraycoated with approximately 1 mg/sq cm of Na2SO4, and subsequently exposed to pure oxygen at 150 torr at 900 and 1000C. Continuous gravimetric measurements were carried out to determine oxidation kinetics, and the results have been correlated with microstructural studies. Scale morphologies were characterized by a combination of SEM, microprobe, and optical techniques. The presence of Na2SO4 on the alloy promotes a transient period of accelerated attack during which NiO is the predominant oxide formed on the specimen surface. Chromium sulfide particles precipitate internally in the alloy during the early stages of exposure and remain in the alloy throughout the duration of the experiment. (Author)

Descriptors :   (*NICKEL ALLOYS, *CORROSION), (*GAS TURBINE BLADES, CORROSION), SALT SPRAY TESTS, HEAT RESISTANT ALLOYS, HEAT RESISTANT METALS, CHROMIUM ALLOYS, THORIUM COMPOUNDS, DIOXIDES, OXIDES, OXIDATION, SULFATES, SULFIDES, MICROSTRUCTURE, SURFACE PROPERTIES

Subject Categories : Properties of Metals and Alloys
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE