High temperature measurements of rates of uptake of molybdenum oxide, tellurium oxide, and rubidium oxide vapors by selected oxide substrates

The rates of uptake of molybdenum, tellurium, and rubidium oxide vapors by substrates of calcium ferrite and a clay loam have been measured in air over a temperature range of 900° to 1500°C. and a partial pressure range of about 10-7 to 10-4 atm. The measured rates of uptake of molybdenum and tellurium oxide vapors by molten calcium ferrite and of rubidium oxide vapor by both molten clay loam and calcium ferrite were controlled by the rates of diffusion of the oxide vapors through the air. The measured rates of uptake of molybdenum and tellurium oxide vapors by molten clay loam were controlled by a combination of a slow surface reaction and slow diffusion of the condensate into the substrate.