Focus in this work was to investigate a commercially available basalt fiber under thermal and mechanical load.
According to EU regulation 443/2009 car manufacturers have to reduce CO2 fleet emissions to 95 g/km until 2020. Two main strategies for reduction of CO2 emissions and fleet consumption are lightweight design and alternative drives.
In this context natural gas and fuel cell vehicles are promising candidates to reach these goals. For this purpose compressed natural gas (CNG) and compressed hydrogen (CHG) are stored in filament wound high pressure vessels. As carbon fibers stand for at least 70% of pressure vessel cost, one possible way is the investigation of alternative reinforcing fibers.
During the last years basalt fibers came into focus of researchers as a cost competitive fiber with slightly higher mechanical properties and thermal and chemical stability than E-glass fibers.
As basalt fibers are a natural product, chemical composition and thus fiber properties vary with the mining region. For example high amounts of silicon oxide (SiO2) and aluminum oxide (Al2O3) lead to better mechanical properties.
Different oxides affect other properties like thermal and chemical resistance. According to higher amounts of iron oxide lead to a better heat resistance of basalt fibers compared to E-glass fibers.
The chemical composition of the investigated basalt fiber is shown in Table 1 and compared to the composition of an E-glass fiber. Basalt fibers were obtained from ASA.TEC (Austria) and compared to a standard E-glass fiber and the carbon-HT fiber T700 by Toray Industries, which is often used for pressure vessels.
Nominal properties of the fibers under investigation are shown in Table 2, as given by the fiber manufacturers.
In conclusion it has to be stated that in contrast to former view basalt fibers and basalt-epoxy composites seem to have lower thermal resistance than glass fibers and glass-epoxy composites.
Compared to carbon fibers basalt and glass fibers withstand higher maximum temperatures without decomposition, which can be considered favorable for use for composite pressure vessels.
Eduard Kessler 1,
Rainer Gadow 2
Jona Straub 2
1 NuCellSys GmbH, Germany
2 Institute for Manufacturing Technologies of Ceramic Components and Composites (IFKB), University of Stuttgart, Germany.