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Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

Polymer Derived Ceramics↗

The CO2 mineralization potential of New Mexico basalts and associated critical element behavior and mobility.

This presentation reports on laboratory experiments assessing the carbon dioxide (CO₂) mineralization potential of New Mexico basalts, including trachybasalt and basalt lithologies. Using simulated groundwater and controlled conditions, the study evaluates the kinetics of CO₂ sequestration, mineral saturation indices, and secondary mineral formation. It also investigates the mobility of critical and trace elements such as Ni, Zn, Cu, and Li during basalt dissolution. Results indicate that New Mexico basalts can effectively sequester CO₂ through carbonate formation, with grain size and mineral composition influencing reaction rates and elemental behavior. These findings support the viability of geologic carbon storage in mafic volcanic terrains and inform strategies for critical element recovery.

36 MATERIALS SCIENCE↗

Geochemistry of Apollo 15 basalt 15555 and soil 15531.

Data are presented on major and trace element concentrations determined by atomic absorption spectrophotometry, colorimetry, and isotope dilution in Apollo 15 mare basalt 15555 from the Hadley Rille area, as well as on trace element concentrations determined in plagioclase and pyroxene separates from basalt 15555 and in soil 15531 from the same area. Most of the chemical differences between basalt 15555 and soil 15531 could be accounted for if the soil were a mixture of 88% basalt, 6% KREEP (a component, identified in other Apollo soils, rich in potassium, rare-earth elements, and phosphorus), and 6% plagioclase.

Schnetzler, C. C.↗

Petrology of basaltic and monomineralic soil fragments from the Sea of Fertility.

Basaltic and monomineralic fragments from the 150-425 micron size fractions of the Luna 16 core obtained from the Sea of Fertility were studied by optical petrographic, electron microprobe, and single-crystal X-ray diffraction techniques. Three textural varieties were identified in the basalts (intersertal, subophitic, and recrystallized). These textures, the assemblages, and individual mineral compositions (especially pyroxenes) indicate that these basalts crystallized under conditions very similar to those from Apollo 11. The pyroxenes have slightly lower Ti/Al (atomic) ratios than the Apollo 11 pyroxenes. We interpret the presence of octahedral Al as being due to the low TiO2/Al2O3 (weight %) ratio in the bulk rock. All observations made on the fine-grained basalt fragments are consistent with a rapid, near-surface, one-stage crystallization history.

Bence, A. E.↗

Some chemical features of basalts from the British Tertiary Province.

An attempt has been made to chemically characterize the basalts from four islands, Rhum, Eigg, Canna, and Muck that, together with Skye, comprise the Inner Hebrides. The basalts are shown to be chemically distinct from tertiary basalts described from the Faroes and Iceland, but have the low concentrations of Rb, Sr found in some mildly alkaline basalts dredged from the Atlantic. Possible evolution of these rocks is discussed.

Ridley, W. I.↗

Nonmare basalts. II.

Chemical characteristics of KREEP basalts from the Apollo 12 site are discussed. It is indicated that nonmare basalts are chemically distinct from mare basalts, primarily in FeO and Al2O3 concentrations and their ratios, and that the spectra of the former are closely related to the degree of partial melting. It is also noted that the chemical compositions of KREEP basalts from Apollo 12, 13, and 14 show very little chemical variation.

Hubbard, N. J.↗

Mare basalt petrogenesis in a dynamic moon

An hypothesis for mare basalt petrogenesis is presented. In the proposed model, both high- and low-Ti mare basalts are produced by partial melting and hybridization at depth accompanied by equilibrium between the hybrid liquids and the local olivine-pyroxenite residuum. The energy source for mare basalt formation is ultimately provided by radiogenic heating in the primordial lunar interior. The proposed dynamic model explains similarities in the Mg/(Mg+Fe) ratios and Cr2O3 contents of high-Ti and low-Ti basalts and avoids thermal problems inherent in previous models.

Kesson, S. E.↗

Characterization and Distribution of Lunar Mare Basalt Types Using Remote Sensing Techniques

The types of basal to be found on the moon were identified using reflectance spectra from a variety of lunar mare surfaces and craters as well as geochemical interpretations of laboratory measurements of reflectance from lunar, terrestrial, and meteoritic samples. Findings indicate that major basaltic units are not represented in lunar sample collections. The existence of late stage high titanium basalts is confirmed. All maria contain lateral variations of compositionally heterogenous basalts; some are vertically inhomogenous with distinctly different subsurface composition. Some basalt types are spectrally gradational, suggesting minor variations in composition. Mineral components of unsampled units can be defined if spectra are obtained with sufficient spectral coverage (.3 to 2.5 micron m) and spatial resolution (approximating .5 km).

Pieters, C.↗

Results of analyses performed on basalt adjacent to penetrators emplaced into volcanic rock at Amboy, California, April 1976

The physical and chemical modifications found in the basalt after impact of four penetrators were studied. Laboratory analyses show that mineralogical and elemental changes are produced in the powdered and crushed basalt immediately surrounding the penetrator. Optical microscopy studies of material next to the skin of the penetrator revealed a layer, 0-2 mm thick, of glass and abraded iron alloy mixed with fractured mineral grains of basalt. Elemental analysis of the 0-2 mm layer revealed increased concentrations of Fe, Cr, Ni, No, and Mn, and reduced concentrations of Mg, Al, Si, and Ca. The Fe, Cr, Ni, and Mo were in fragments abraded from the penetrator. Mineralogical changes occurring in the basalt sediment next to the penetrator include the introduction of micron-size grains of alpha-iron, magnetite, and hematite. The newly formed silicate minerals include metastable phases of silica (tridymite and cristobalite). An increased concentration of Fe, Cr, Ni, and Mo occurred in the 2-mm to 1-cm layer of penetrator no. 1, which impacted at the highest velocity. No elemental concentration increase was noted for penetrators nos. 2 and 3 in the 2-mm to 1-cm layer. Contaminants introduced by the penetrator occur up to 1 cm away from the penetrator's skin. Although volatile elements do migrate and new minerals are formed during the destruction of host minerals in the crushed rock, no changes were observed beyond the 1-cm distance.

Blanchard, M.↗

Lunar mare basalts - Conference summary

Compositionally, lunar mare basalts are similar to some very young subalkaline basalts from terrestrial mid-ocean ridges and to very old pods of basaltic material incorporated into ancient metamorphic rocks. Basalt flows in Mare Imbrium are considered, taking into account the results of orbital gamma ray spectroscopic studies. The results of the analyses of lunar samples obtained from the Apollo missions are evaluated and various models are discussed in connection with an interpretation of the observed conditions.

Merrill, B.↗

Regional basalt types in the Luna 24 landing area as derived from remote observations

The Soviet spacecraft Luna 24 landed in Mare Crisium and returned samples that are expected to be much like the low titanium basalts from Luna 16 and Apollo 12. This conclusion is based on earth-based spectral reflectance measurements and multispectral imagery of the Mare Crisium region and uses a background of laboratory measurements of the spectral properties of Lunar soils. These data are used to describe the regional context and composition of the Crisium basaltic units. The returned sample may also contain minor components of a high-titanium basalt and a very low titanium basalt as well as highland material.

Pieters, C.↗

Variations in chemical composition of Apollo 15 mare basalts

Chemical analyses of 30 different Apollo 15 mare basalts were examined to evaluate the effects of closure on the pearson moment correlation coefficient. It is shown possible to describe the Apollo 15 mare basalts in terms of an opaque, an olivine/pyroxene, an anorthite, and a KREEP component, if significant correlations are identified using the expected correlations as null values. Using Q-mode cluster analysis and nonlinear mapping, it is possible to recognize three groups of the mare basalts, groups 1 and 2 belonging to the olivine normative basalt cluster and group 3 to the quartz normative cluster.

Butler, J. C.↗

Sr isotopic constraints on the petrogenesis of Apollo 17 mare basalts

Sr-isotopic results are obtained for three basalt samples from Station 4, and it is shown that these basalts have Rb-Sr crystallization ages and initial Sr-87/Sr-86 ratios which are nearly identical to those of other Apollo 17 basalts. However, their Rb/Sr ratios have been increased two-to-four fold more at the time of their genesis than were those of the majority of Apollo 17 basalts. It is argued that this observation is consistent with their production by small degrees of partial melting of a source containing clinopyroxene as a residual phase.

Nyquist, L. E.↗

Basalts from Mare Crisium

The stratified core sample returned from Mare Crisium by the Luna 24 unmanned space probe is composed primarily of a variety of subophitic to ophitic basalt with very low contents of TiO2 and MgO. This consists of clinopyroxene, calcic plagioclase, olivine, and minor amounts of silica, chromite, ulvoespinel, ilmenite, troilite, apatite, and Fe-metal. Granular metabasalts have the same bulk composition, but mineral phases exhibit less compositional variation. Fine-grained impact melts have similar compositions and are apparently derived from these basalts. It is concluded that the basalts, which are chemically distinct from the very-low-titanium basalts found elsewhere on the moon, represent the local surface flows of Mare Crisium. Sparse fragments of an olivine vitrophyre that is low in TiO2 but high in MgO and approaches the composition of the Apollo 15 green glasses may be derived from patches of dark mantling materials 20 km from the landing site.

Ryder, G.↗

Oxygen fugacity of basaltic magmas and the role of gas-forming elements

It is suggested that major variations in the relative oxygen fugacity of a basaltic magma are caused primarily by gas-forming elements, especially carbon and hydrogen. According to this theory, carbon, present in the source region of a basaltic magma, reduces the host magma during ascent, as isothermally carbon becomes more reducing with decreasing pressure. For an anhydrous magma such as lunar basalts, this reduction continues through the extrusive phase and the relative oxygen fugacity decreases rapidly until buffered by the precipitation of a metallic phase. For hydrous magmas such as terrestrial basalts, reduction by carbon is eventually superceded by oxidation due to loss of H2 generated by the reaction of C with H2O and by thermal dissociation of H2O. The relative oxygen fugacity of a hydrous magma initially decreases as a magma ascends from the source region and then increases until magnetite crystallization curbs the rising trend of the relative oxygen fugacity.

Sato, M.↗

Laser Ar-39-Ar-40 study of Apollo 17 basalts

Three Apollo 17 basalts were studied by the laser Ar-39-Ar-40 method. The 70215 basalt has a normal well-behaved Ar-39-Ar-40 release pattern; the 70017 basalt has a disturbed release pattern which indicates a limited intermediate maximum age followed by a broad low-age region; and the 75035 basalt has a pattern initially similar to 70017 that is followed by a high-temperature maximum age. The laser study shows that all mineral systems in 70215 have small and uniform temperature losses, while the laser-determined ages for 70017 and 75035 are, apparently, primarily controlled by the minerals containing mesostasis inclusions. It is possible that the drop in ages observed by the conventional Ar-39-Ar-40 method was due not only to recoil of Ar-39 during neutron irradiation but also to gas loss from some minerals. It is suggested that the plagioclases are the best minerals to use for a reliable age.

Schaeffer, O. A.↗

Partitioning of Ni/2+/ between basaltic and synthetic melts and olivines An experimental study

Olivine/liquid distribution coefficients for Ni in basaltic and simple synthetic melts are found in the 1400-1070 C temperature range. The results suggest that: (1) the Ni distribution coefficients and NiO activity coefficients are strongly temperature dependent, (2) the Ni distribution coefficients are functions of melt composition and structure at a constant temperature although the dependence is small for most basaltic magmas, (3) differences in melt composition do not significantly influence generally 'basaltic' melts, (4) the Ni distribution coefficients may be used as geothermometers to predict the olivine crystallization temperatures of basaltic magmas to within plus or minus 50 C, (5) the Ni distribution coefficients are greater than one at all natural magmatic temperatures, and (6) the Ni distribution coefficients do not significantly vary as functions of the Ni content of the melt to at least one mole percent.

Leeman, W. P.↗

Mare basalts - Melting experiments and petrogenetic interpretations

Equilibrium crystallization sequences are determined in melting experiments in vacuum at Fe saturation on synthetic mare basalt compositions 70215 and 15318 Red Glass (both high-Ti) as well as 15555-15016 (low-Ti). The experiments confirm that much of the chemical variation within both the high- and low-Ti suites is controlled by near-surface fractionation processes, although the two suites cannot be related by such mechanisms. The components and crystallization products of the liquidus at various temperatures and pressures are reported. Mare basalt petrogenesis is interpreted in terms of high-pressure equilibria at Fe saturation; it is suggested that low-Ti basalts represent partial melts of a differentiated olivine-pyroxenite lunar mantle at 240 km or deeper, while cumulus clinopyroxene in the source is responsible for their REE characteristics. The formation of high-Ti basalts is considered.

Kesson, S. E.↗