The aim of this work was to obtain a protective ZrO2 coating on diamond particles, which protect from oxidation and graphitization, enabling sintering at higher temperatures lower pressures than its thermodynamic stability in atmospheric conditions. coatings were obtained by mixing with zirconium oxidizing air or oxygen. Mixtures 80 wt% sintered SPS method 1250 °C 1450 °C. To stabilize the tetragonal structure ZrO2, 3 mol% Y2O3 added before milling process. composition powder phases,...

Six different commercial subsieve powders were used for examining the effects of particle characteristics on mean size and specific surface area. The measurements carried out using air permeability laser light diffraction techniques. experimental data indicate that both methods give similar results spherical powders. advantage systems over gas permeameters is ability to provide additional information distribution. Irregularly-shaped should be analysed by techniques relying permeametry area...

The objective of the present work was to determine suitability a new iron-based Mn–Cu–Sn matrix alloy for manufacture diamond-impregnated tool components. A number specimens were consolidated by hot press route from ball-milled powders. Density, microstructural features, phase composition, bending properties and hardness evaluated. results revealed excellent mechanical properties, including σ0.2 > 850 MPa in 3-point HK0.5 300. commercial Co-WC reference also produced comparison purposes....

Six different commercial powders, finer than 45 μm, were used for examining the effects of particle characteristics on mean size and specific surface area. The measurements carried out using most commonly air permeability- laser light diffraction (scattering) techniques. As permeability method has been as a benchmark decades in powder metallurgy (P/M) industry, physical phenomena that govern passage gas through bed under laminar flow conditions also presented. experimental data indicate both...

Abstract The possibility of the use inexpensive iron-base powders in production sintered diamond tools is again explored. Ball-milled Fe-Ni-Cu-Sn-C and Fe-Mn-Cu-Sn-C were consolidated to a virtually pore-free condition by hot pressing at 900°C. resultant materials are characterised combination high Knoop hardness, 260-440 yield strength, 780-1350 MPa, resistance abrasion. These properties can be significantly modified changing milling time.

Abstract The effect of yttrium additions on the glass formation Zr 50 Cu 40 Al 10 alloy with high oxygen content was investigated. Unlike other reports showing positive alloying Zr-based alloys a few percent rare earth elements, we examined Y-to-oxygen ratios. As calculated, stoichiometric amount (2808 at ppm) is required to bind all (4212 form Y 2 O 3 . Additionally, influence half (1404 and double (5616 levels yttrium, respect measured be bound evaluated. Y-doped were synthesized by arc...

Abstract The main objective of this paper was to perform sinterability studies ball-milled Fe-12%Ni-6.4%Cu-1.6%Sn-0.6%C powders. A mixture precisely weighed amounts elemental iron, nickel and graphite, pre-alloyed 80/20 bronze powders for 8, 30 120 hours. After cold-pressing at 400 MPa the specimens were sintered 900 o C minutes in a reducing atmosphere subsequently tested density hardness as well subjected structural using scanning electron microscopy (SEM) X-ray diffraction (XRD) analysis....

Abstract Premature corrosion in the form of longitudinal cracking a high-frequency (HF) induction seam-welded steel pipe occurred after just 24 months service. The failed was investigated to reveal main cause its failure, and results microstructural examinations (light optical microscopy, scanning electron microscopy with energy-dispersive spectrometry) suggest that failure resulted from an HF welding process defect—a so-called cast weld , is, huge number iron oxides line caused by...

Abstract A premature corrosion failure in seam-welded galvanized steel cold water pipes was reported to occur after just 18–24 months service. The aim of the present work investigate causes this pipes, through metallographic investigations. This comprised chemical analyses, visual examination internal surfaces and microstructural examinations perforation regions (pitting areas) using optical scanning electron microscopy with energy-dispersive x-ray analysis. investigations showed that...

The work presents the possibility of application inexpensive iron-base powders in production sintered diamond tools. It has been shown that ball-milled Fe-Ni-Cu-Sn-C and Fe-Mn-Cu-Sn-C can be consolidated to a virtually pore-free condition by hot pressing at 900°C. as-consolidated materials are characterised combination high hardness, mechanical strength resistance abrasion. Their properties widely modified changing milling time.

The work presents a possibility of fabrication inexpensive iron-based powders intended to form the matrix in sintered diamond-impregnated tool components. In this study, finely dispersed, pre-alloyed steel powder, containing over 95 wt.% Fe, has been designed and fabricated by means proprietary process developed at AGH-University Science & Technology. It shown that experimental powder can be consolidated closed porosity condition (>95% theoretical density) pressure-less sintering...

The work presents the design and fabrication procedures used to manufacture inexpensive iron-base powders employed as a matrix in diamond-impregnated tool components. Three newly developed low alloy steel powders, containing from 94.4 99.4 wt.% Fe, have been formulated with assistance of ThermoCalc software produced by means proprietary process patented AGH-UST. It has shown that are readily pressureless sintered closed porosity condition (>95% theoretical density) at temperature range...

Abstract A premature pitting corrosion in seam-welded 3-inch L235 steel pipe was reported to occur after 8 years service. This part of a closed ice water cooling system, where the inlet temperature 6 °C and outlet 11 °C. The present work aimed investigate causes this through metallographic investigations. comprised visual examination internal surfaces microstructural examinations perforation regions (pitting areas) using optical scanning electron microscopy (SEM) with energy dispersive X-ray...

Abstract Zr-based bulk metallic glasses (BMGs) are characterized by excellent glass-forming ability, combined with superior mechanical properties. However, oxygen impurities degrade both these aspects as oxides serve heterogeneous nucleation sites during solidification. Rare-earth elements (REEs) known to be good scavengers, binding less harmful forms. The most stable rare-earth oxide (REO) is M 2 O 3 , which occurs in three polymorphic forms, depending on the radius of metal cation: cubic,...