Edward J. Lamby

The inhibition of graphite oxidation by phosphorus additives

Abstract Impregnation of graphite with organic phosphate and phosphite esters has been found to result in increased resistance to air oxidation at elevated temperatures. Thermal decomposition of the phosphorus compounds at 200–600°C leaves a hydrophilic residue strongly adsorbed on the graphite surface at active sites where oxidation normally occurs.

The effects of boron additives on the oxidation behavior of carbons

Abstract Impregnation of graphite with aqueous solutions of boric oxide or with organo-borates has been found to result in marked reduction in the rate of oxidation of the graphite in dry or moist air between 600 and 1000°C. At these temperatures, the additives probably form a glassy oxide residue which blocks active sites on the graphite surface.

Catalysis of coal char gasification by alkali metal salts

Abstract A study has been made of the gasification behaviour, in carbon dioxide and steam, of a number of coal chars doped with small amounts of alkali metal carbonates. For a given additive, the magnitude of the catalytic effect increased with the rank of the parent coal. A progressive loss in catalytic activity on thermal cycling during steam gasification was associated with reaction of the alkali salts with mineral matter in the chars. The kinetic data were consistent with catalytic mechanisms involving oxidation/reduction cycles on the char substrates.

Eutectic salt catalysts for graphite and coal char gasification

Low melting binary and ternary eutectics of the alkali metal halides, carbonates and sulphates have been found to be more effective low temperature catalysts for the CO2 and steam gasification of graphite and coal chars than the pure salt components. The reduced melting points of the eutectic phase facilitate contact between the catalyst and the carbonaceous substrate.

Catalytic CO2-gasification of graphite versus coal char

Abstract The effects of alkali carbonate catalysts on the C0 2 -gasification of Illinois No. 6 hvB bituminous coal char, demineralized Illinois No. 6 coal char, Pittsburgh No. 8 hvA coal char, Navajo subbituminous coal char, Reading anthracite coal char, North Dakota A lignite char and spectroscopic grade highest purity graphite are reported. Alkali carbonate salts are effective Boudouard catalysts for all these substrates, but salient differences between coal char and graphite reactivity are observed. To account for these differences, a redox mechanism based on alkali hydride intermediates is proposed.

Significant parameters in the catalysed CO2 gasification of coal chars

Abstract Alkali and alkaline earth carbonates have been used to catalyse the C02 gasification of coal chars prepared by pyrolysis of Illinois No.6 coal. This study found that alkaline earth carbonates are fair gasification catalysts, though throughputs are insensitive to loadings in the range of 5–20 wt%. The order of efficacy is Ba > Sr > Ca. Alkali carbonates are excellent catalysts, with throughputs showing a dependence on loadings and atomic number. In particular, at high loadings (20 wt%) the order is Cs > K > Na > Li. As kinetic parameters for the alkali carbonate catalysed Boudouard reaction with coal chars differ significantly from those for graphites, an alternative redox cycle mechanism has been proposed involving an alkali hydride intermediate.

Observation of alkali catalyst particles during gasification of carbonaceous materials in CO2 and steam

Results of a microscopical examination of catalysed carbon gasification are reported. Both in CO2 and steam, alkali catalysts show evidence of mobility. In the steam gasification of coal chars, the catalysts irreversibly combine with indigenous mineral matter. This is less pronounced in C02. The catalysed CO2 gasification was observed by hot stage microscopy, where alkali carbonate catalysts achieve an apparently molten state during incipient gasification. For single crystal graphite, circular pitting, hexagonal pitting and channelling were observed. For coal chars, irregular morphologies tend to obscure direct observation of surface/catalyst interactions, though subsequent scanning electron micrographs reveal the consequences of extensive catalyst mobility.

Aqueous pretreatments of polyetherimide to facilitate the bonding of electrolessly deposited copper

A chemical method for pretreating polyetherimide substrates to promote adhesion to copper is described. The process consists of cleaning the polymer surface followed by surface normalization, debris solubilization, and adhesion promotion via chemical modification of the polymer surface. Classes of candidates for each of the major steps are described and the optimal agents assembled into a recommended procedure. Peel strengths between 150-210 g mm-1 for copper to polyetherimide were achieved utilizing the suggested scheme. Scanning electron microscopic and X-ray photoelectron spectroscopic analyses were employed to investigate changes in the polymer surface and chemistry during processing. Metallized specimens were examined after 90° peel testing and the failure locus found to be within the polymer layer.

Photo‐Selective Electroless Metal Deposition Following Light Absorption by Titanate Ceramics

Light absorption by titanate ceramics which have been pretreated with a Sn +2 containing solution can deactivate and electroless plating catalyst providing that photo-exposure occurs in an O 2 containing ambient. Conditions are described whereby a lead zirconate-titanate ceramic can be photopatterned by a brief exposure to a 365 nm wavelength lamp using a Mylar photomask and electroless Ni plated to yield a Ni pattern on the ceramic. Line/space resolution exceeding 0.05 mm is attainable

Comparison of effects of adding Boudouard catalysts before and after coal charring

Abstract The gasification behaviour of coal to which Boudouard catalysts were added before and after charring was compared. For Illinois coal and for Navajo subbituminous coal, experiments showed that it is not of significance if alkali carbonate catalyst is added before or after charring. The results suggest that Boudouard catalysts must be highly mobile under gasification conditions, and their activity dominates the gasification process at these conditions compared to mass transfer constraints.