| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
|
|---|
| Research Abstract |
Metal phosphides have been utilized as semiconductors such as gallium phosphide and indium phosphide etc. It is interesting to investigate the formation of metal phosphides. Studies of phosphidation of metals and alloys have been undertaken to synthesize various metal phosphides and to develop a phosphorus resisting metallic material; information is provided concerning the layer structure of phosphide films, the relationship between the products and reaction conditions, kinetics, and diffusing species.
As part of a series of studies on the phosphidation of metals, at first the phosphidation of manganese has been studied at 400゜ー600゜C in phosphorus vapor at 1 atm by a sealed-tube method. Phosphide growth rates were parabolic. Hence, the rate-determining step was apparently a diffusion process. A marker experiment indicated that manganese was the component that diffused. X-ray diffraction patterns and an electron probe microanalysis of the products showed that at 450゜ー600゜C double layers composed of outer MnP and inner Mn_2P were formed. Furthermore,all the phosphidation reactions of niobium(650゜ー800゜C, 1 atm) and tungsten(800゜ー1000゜C, 1 atm) also obeyed a parabolic rate law.
In the case of molybdenum, at an initial stage the phosphidation were found to proceed according to a linear rate law and at an abvanced stage according to a parabolic rate law. The phosphidations of binary and ternary alloys of iron, chromium, and nickel with various ratios of metallic constituents in phosphorus vapor at 1 atm have been investigated. From the effect of metallic impurities on the kinetics of the phosphidation, this reaction appears to be controlled by lattice diffusion through cation vacacy in the phosphide layers. The parabolic rate constant has decreased in the sequence Ni>Mn>Fe>Cr>Ti<similar equal>Nb>W. At present the measurement of dissociation pressure of phosphides is performeer
|
