Compatibility of graphite with primary platinum group metals industrial matte

Wettability of SGL's RN-graphite by synthetic and industrial PGM (Platinum Group Metal)-furnace matte (CuFeNiS) was investigated using a sessile drop configuration. This work was done to determine the compatibility of a graphite refractory with liquid PGM-furnace matte. Direct measurements of interfacial contact angles were used to determine wettability. In inert conditions, graphite was poorly wetted by synthetic and industrial PGMfurnace matte (CuFeNiS), the contact angles were > 90° for all tested matte types. No correlation was observed between the sulphur content of the matte and its wetting behaviour. The granulated matte expanded by up to 25 volume % during melting.

Journal of Composites Science, 2019

Copper–graphite composites with 0–4 wt % graphite were fabricated by field-assisted hot pressing with the aim of studying the effect of graphite content on microhardness and tribological properties. Experimental results reveal that hardness decreases with the graphite content. Wear testing was carried out using a ball-on-disc tribometer with a normal load of 8 N at a constant sliding velocity of 0.16 m/s. The friction coefficient of composites decreases significantly from 0.92 to 0.29 with the increase in graphite content, resulting in a friction coefficient for the 4 wt % graphite composite that is 68.5% lower than pure copper. The wear rate first increases when the graphite content is 1 wt %; it then decreases as the graphite content is further increased until a certain critical threshold concentration of graphite, which seems to be around 3 wt %. Plastic deformation in conjunction with some oxidative wear is the wear mechanism observed in pure copper, while abrasive wear is the m...

SVOA Materials Science and Technology, 2019

Based on the results previously obtained for cast alloy structural steels, the influence of isothermal holding at heating or cooling on graphite morphology and impact strength in industrial grey and ductile pearlitic irons were investigated. Some novel microstructure features were revealed in the irons after their optimal heat treatment, namely: ferrite matrix formation instead of pearlitic one in both irons; partial or full solving the original networked graphite plate-like inclusions; branched interfaces of originally spheroid graphite inclusions surrounded by probably nano-structured matrix areas etc. The microstructure features revealed were assumed to be responsible for the obtained unprecedented increase of impact strength up to KCU  550 kJ/m 2 for each iron grade. The phenomena observed were attributed to a number of the known processes development during the proposed heat treatment, but require additional precise investigations in view of their general importance for metallic materials: composites, deposited, 3-D printed, powder sintered etc.

Tikrit Journal of Engineering Sciences, 2017

Coppergraphite composites are widely used in sliding bearings and brushes due to their excellent thermal and electrical conductivities and high wear resistance. The aim of this research is to study the Influence of the graphite content and milling time on hardness, compressive strength, wear volume and friction coefficient of copper-graphite composites that prepared via powder metallurgy. A powder mixture containing 0,5,10,15,20 and 25 vol% graphite was milled for 1,3,5,7 and 9 hours. The milled mixture was cold pressed at 700 MPa for 30 second, followed by sintering at 900 ℃ for one hour. It was found through this work that increasing milling time results an appreciate increase in hardness and radial compressive strength. Slight reduction in wear volume and slight increase in the coefficient of friction for all compositions except that for pure copper in which a considerable increase in wear volume and decrease in the coefficient of friction was observed. On the other hand, increasing the graphite volume fraction increases the composite hardness, to reach an optimum value, and decreases the radial compressive strength. A great decrease in both wear volume and coefficient of friction was observed due to increasing the graphite content up to 25 vol%. Finally, a graphite, cast iron chips and fireclay sintering configuration was found to be an effective procedure which minimizes oxidation to levels comparative with those observed previously by sintering in argon or hydrogen atmospheres.

Copper – graphite composites found many applications such as sliding bearings and electric brushes due to their high wear resistance and excellent electrical and thermal conductivity.Current research aims to study the effect of graphite content and milling time on physical properties of copper – graphite composites made by powder metallurgy route. Copper and graphite powders with 0,5,10,15,20 and 25vol% graphite, were milled mechanically using ball mill for 1,3,5,7 and 9 hours. The milled mixture was cold pressed at 700 MPa for 30 second, followed by sintering at 900 o C for one hour. In the present work it was found that increasing both milling time and graphite content results in a decrease in the bulk density, the apparent density and the thermal conductivity. It was found that the bulk density ranges between (8.47-5.25) g/cm 3 , the apparent density ranges between (8.55-5.7) g/cm 3 and the thermal conductivity ranges between (226.5-89.5) W/m.k. On the other hand both total and apparent porosity were increased with increasing graphite content and milling time. It was also found that water absorption is directly proportional with the apparent porosity and is ranges between (0.1-1.5)%. Microscopic examinations were used to consolidate and interpret the results. © 2013 AENSI Publisher All rights reserved. To Cite This Article: Farouk M.Mahdi, Raed N.Razooqi, Saif S. Irhayyim. Effect of Graphite Content and Milling Time on Physical Properties of Copper-Graphite Composites Prepared by Powder Metallurgy Route. Aust. J. Basic & Appl. Sci., 7(12): 245-255, 2013

The upper-sidewall of a typical PGM smelter is lined with synthetic graphite at the hot-face.

Global Journal of Research In Engineering, 2014

The present paper investigates the effect of sintering temperature and graphite content on the microstructure and effect on wear and frictional properties of Fe+C powder metallurgy preforms. For the present work the specimens were prepared with graphite content 0.5%, 1%, 1.5% and 2% by weight and were sintered at three sintering temperature 800°C, 900°C and 1050°C. Microstructural properties were evaluated using scanning electron microscopy. The wear and friction property of the powder preforms were tested on Pin-On-Disc apparatus. The powder specimen was used as pins and the disc was of AISI 51200 steel. The experiments was carried out under load of 40 N, speed 1000 rpm, time 1500 seconds and relative humidity 60% 65%. The result was 2% graphite content specimen with sintering temperature 1050°C showed good wear resistance. The wear rate decreased with the increase in sintering temperature and increase in graphite content of the specimen.

Graphite is one form of Carbon. The graphite was coated with silicon carbide to increase the wear properties. The coating improves the oxidation resistances of the base material. The silicon carbide was coated on the graphite using plasma spray for a thickness of 50µm and 100µm. Various tests were carried out such as porosity test, surface roughness test, thermal shock test and adhesion test to find the strength and quality of the coating.

Journal of Materials Science, 2008

The Dynamic Chemical Plating (DCP) technique allows production of 2-lm copper films containing particles of graphite or PTFE in 18 and 15 min, respectively, at ambient temperature. DCP yields composites with particle-incorporation fractions of 12% for graphite microparticles and 22% for PTFE nano-particles. The composite films show excellent tribological properties, acting as selflubricating coatings with friction coefficients as low as 0.18.

Advances in Materials Science and Engineering, 2013

It has been shown repeatedly that many elements present as traces or at low level can affect graphite shape in cast irons. As part of a long term project aimed at clarifying the growth and the alteration of spheroidal graphite, a study on the effect of a few elements (Cu, Sn, Sb, and Ti) on primary graphite growth was undertaken and analysed with reference to an alloy without any such additions. This work was performed by remelting alloys in graphite crucibles thus saturating the melt in carbon and enabling primary graphite to grow by controlled cooling of the melt above the eutectic temperature. Primary graphite growth in the reference alloy was observed to be lamellar, while the added elements were found to affect bulk graphite and to modify its outer shape, with Sb leading eventually to rounded agglomerates together with wavy lamellae. Secondary ion mass spectrometry was used to analyze the distribution of elements, and no build-up of trace elements at the graphite surface could ...