Influence Of Phosphorus Additions Research Articles

Influence of Phosphorus Addition on the Stress Rupture Properties of Direct Aged IN706 Superalloy

This study investigated the influence of phosphorus (P) addition on the stress rupture properties of direct aged IN706 superalloy. The results showed that P slightly improved the stress rupture life of the superalloy when added in the range between 0.002% and 0.008%; however, it significantly reduced the stress rupture life when added in the range between 0.013% and 0.017%. Microstructure characterization indicated that the precipitation of γ′, γ″, and η phases was not significantly affected by the addition of P. Phosphides precipitated in the alloy containing 0.017% P after aging at 980 °C for 10 min. Compared to a similar study previously made on IN706 superalloy, it was found that the optimum P concentration in the as-solutioned state for improving the stress rupture properties was not definite. Furthermore, the relationship between the amount of P segregated at the grain boundary and the role of P on the stress rupture properties was discussed.

Phosphorus in Sintered Steels: Interaction of Phosphorus with Mo

Abstract Phosphorus as an alloy element is quite common in powder metallurgy, the contents industrially used being markedly higher than those present in wrought steels. However, embrittlement effects are reported also for sintered steels, in part depending on the alloy elements present. In this study, the influence of phosphorus addition on the mechanical properties of PM steels alloyed with Mo, as the most common VI group element in sintered steels, was investigated. PM steels of the type Fe-x%Mo-0.7%Cy% P were manufactured with varying contents of Mo and P, respectively. It showed that P activates sintering also in these materials and enhances Mo homogenization, but there is in fact a risk of embrittlement in these steels that however strongly depends on the combination of Mo and P in the materials: If a critical level is exceeded, embrittlement is observed. At low Mo contents, higher P concentrations are acceptable and vice versa, but e.g. in a material Fe-1.5%Mo-0.7%C-0.45%P, pronounced intergranular embrittlement occurs, further enhanced by sinter hardening effects. This undesirable phenomenon is more pronounced at higher sintering temperatures and in case of faster heating/cooling; it was observed both in materials prepared from mixed and prealloyed powders, respectively. This typical intergranular failure observed with embrittled specimens, in particular after impact testing, indicates the precipitation of brittle phases at the grain boundaries, apparently when exceeding the solubility product between Mo and P.

Phosphorus in Sintered Steels: Effect of Phosphorus Content and P Carrier in Sintered Steel Fe-C-P

Abstract Phosphorus as an alloy element is quite common in powder metallurgy, the contents industrially used being markedly higher than those present in wrought steels. In this study, the influence of phosphorus addition through different P carriers was investigated. PM steels of the type Fe-0.7%C-x%P (x = 0.0 … 0.8%) were manufactured by pressing and sintering in H2. It showed that Fe3P is the best phosphorus carrier, resulting in fine and regular microstructure and in high impact energy data at 0.3 … 0.45%P while red P and also Fe2P showed a tendency to agglomeration, with resulting secondary porosity. At high P levels the mechanical properties tend to drop, for the tensile strength at P > 0.60%P while for the impact energy the threshold is 0.45%P. The dimensional behaviour of Fe-C-P can be related to PM aluminium alloys, expansion by transient liquid phase being followed by shrinkage by persistent liquid phase, at least at higher temperatures. In contrast to the dimensional behaviour, degassing and reduction is hardly affected by the phosphorus content.

Size Distribution of Retained Austenite in Phosphorus-Containing TRIP Steels

The present work investigates the influence of phosphorus addition on the size distribution of retained austenite in TRIP steels containing 0.01%, 0.09% and 0.14% phosphorus. The size of retained austenite is measured by means of neutron depolarization technique and optical microscopy. It is found that the addition of phosphorous increases the size of the larger intergranular and inter-ferritic austenite grains and therefore also increases the volume fraction of retained austenite due to the strengthening effect of phosphorous on the surrounding ferrite and bainite grains. For all phosphorous additions the most frequently observed austenite size is around 0.2 μm, which is probably corresponds to the interlath film-type retained austenite. The average grain size from the neutron depolarization technique agrees in general with that from the optical microscopy and it is suggested that the accuracy can be improved by further development of the data analysis by taking into account the preferred shape and orientation of the austenite grains.

Influence of nutrient solution on Al-tolerance of Pseudomonas sp.

Using a soil bacterium ( Pseudomonas sp.), the influence of different levels of aluminium included in nutrient solutions before and after autoclaving and the influence of phosphorus addition on growth of the bacterium were investigated. Both phosphorus addition (350 μM) and Al-application before autoclaving caused a distinct decrease in Al-availability and thus an apparent increase in Al-tolerance, both effects adding up in a linear fashion. The Weibull function was shown to be well suited to describe toxic effects of Al on the microorganism under investigation.

Influence of nutrient solution on Al-tolerance ofPseudomonassp.

Using a soil bacterium (Pseudomonas sp.), the influence of different levels of aluminium included in nutrient solutions before and after autoclaving and the influence of phosphorus addition on growth of the bacterium were investigated. Both phosphorus addition (350 μM) and Al-application before autoclaving caused a distinct decrease in Al-availability and thus an apparent increase in Al-tolerance, both effects adding up in a linear fashion. The Weibull function was shown to be well suited to describe toxic effects of Al on the microorganism under investigation.

Influence of phosphorus addition on the surface tension of liquid iron and segregation of phosphorus on the surface of Fe-P alloy

This article presents a study of the surface tension and phosphorus surface segregation in Fe-P alloys. The surface tension was measured by the sessile drop technique. The result of the dynamic surface tension for the low phosphorus content alloys shows that the alloy surface vaporization has a clear effect on the surface tension and causes a positive surface tension temperature coefficient. However, from this article, it is evident that phosphorus in liquid iron acts as a surface active element similar to arsenic. The surface segregation was determined using Auger electron spectroscopy. The result on the surface analysis of as-solidified sample indicates that the adsorption of impurity elements, such as oxygen, carbon, and nitrogen, can conceal phosphorus segregation on the free surface. Phosphorus segregation was also examined in the samples as-cleaned by Ar+ and then treated 30 minutes at 650°C. Phosphorus was found to segregate extensively on the surface of the alloys. On the basis of the analysis of the published data, the surface active intensity sequence of some nonmetallic elements was arrayed, and the surface active intensity of fluorine and boron in liquid iron was estimated.

Influence of phosphorus addition on diamond CVD

Abstract Phosphorus-containing diamond films were deposited on Si(100) by hot-filament CVD using a Ta filament and mixtures of hydrogen, methane and phosphine. The phosphorus concentration in the gas phase was varied between 330 and 5280 ppm PH 3 CH 4 . The P additions led to important modifications in the diamond morphology, growth rate, growth orientation, film quality and homogeneity. These modifications were similar to those which are observed in a growth environment leading away from optimal growth conditions for diamond. The P additions, however, seemed to influence the growth kinetics due primarily to surface reactions rather than to changes in the gas activation (i.e. atomic hydrogen and carbon growth species). A comparison between experimental results and thermodynamic calculations suggested that methinophosphide (HCP) — an unstable and highly reactive phosphorus species — is probably responsible for the deleterious P influences. Qualitative secondaryion mass spectrometry measurements showed the presence of P in all diamond films prepared with PH3 added to the reaction gases.

Influence of phosphorus additions on the mechanical properties of stainless steel: M. Nakamura et al, (Iwate University, Ueda Morioka, Japan), J. Japan Soc. Powder and Powder Metallurgy, Vol 39, No 1, 1992, 24–27. (In Japanese)

Influence of phosphorus additions on the mechanical properties of stainless steel: M. Nakamura et al, (Iwate University, Ueda Morioka, Japan), J. Japan Soc. Powder and Powder Metallurgy, Vol 39, No 1, 1992, 24–27. (In Japanese)

Influence of phosphorus addition on the properties of VMoTiO 2 catalysts

The effect of the addition of phosphoric acid at different stages of the preparation on the properties of VMoTiO 2 catalysts has been studied by ESR. The evolution of the V 4+ and Mo 5+ signals after different reduction treatments indicates that, depending on the procedure followed, either only the surface or the whole catalyst can be affected. By impregnating with H 3PO 4 after calcination, a surface layer of chemisorbed phosphates is formed, protecting the sample bulk against reduction. If the impregnation takes place before calcination of the precursor material, the dispersion of the vanadium and molybdenum ions is observed and is ascribed to the formation of mixed phosphate phases.

Influence of phosphorus additions on annealing behaviour of cold-worked copper

Abstract High-purity copper and two alloys containing 0.16 and 0.76 wt-% phosphorus have been examined after 95% cold-rolling and subsequent annealing treatments. In the cold-rolled state the pure copper and the dilute alloy are similar in almost every respect but differ significantly from the more concentrated alloy in structure and texture. On annealing, the two alloys behave similarly showing a marked retardation in recovery and recrystallization when compared to the pure copper. The growth rate of recrystallized grains is more strongly inhibited by phosphorus than is their nucleation, and this leads to substantial modification in the as-recrystallized structures and textures. Evidence for segregation of phosphorus atoms to the dislocation substructure is found in the recovery kinetics, the release of stored energy at low temperatures, and in strain-ageing effects during mechanical testing. Modification of annealing behaviour in the alloys may be attributed to segregation of phosphorus atoms at lattice...

Influence of phosphorus on the phytotoxicity of alachlor

Abstract The effects of different levels of phosphorus on the initial and residual activity of alachlor (2-chloro-2, 6-diethyl-N-methoxymethylacetanilide) were studied in glasshouse experiments using German millet (Setaria italica (L.) Beauv.), a species susceptible to alachlor. Results showed that the initial phytotoxicity of alachlor decreased with the increasing rates of phosphorus. As the concentration of the herbicide was increased, higher levels of phosphorus were required to alter its phytotoxicity. The phosphorus concentration in plant tops increased with increments in the phosphorus level of the soil and was unaffected by alachlor at low rates. At high concentrations of the herbicide the phosphorus level of some plant shoots increased significantly, although such increases tended to vary with the size of the shoot. Bioassay data showed no significant influence of phosphorus additions to the soil on the residual activity of alachlor.