KeywordsPreservative penetration Preservative microdistribution Copper-Chrome-Arsenic Electron probe X-ray analysis Scanning electron microscope hardwoods softwoods Schlüsselwörter (Sachgebiete) Schutzmittelaufnahme Mikroverteilung Kupfer-Chrom-Arsen Elektronen-Sonden-Röntgenanalyse Raster-Elektronenmikroskop Nadelhölzer LaubhölzcrThe Microdistr.bution of Copper-Chrome-Arsenic in Preservative Treated Sapwoods using X-ray Microanalysis in Scanning Electron Microscopy
SummaryThe microdistribution of copper-chrome-arsenic preservative in sapwoods of Pinus radiata, P. syhestris, Picea abies s Fagus sylvatica, Eucalyptus regnans and E. maculata has been examined, both before and after leaching. The technique employed was energy dispersion X-ray analysis in conjunction with scanning electron microscopy. The results show that CCA distribution in softwoods is relatively even, while in the hardwoods, especially E. maculata, there are large pockets of unprotected cells between the main treatment pathways. Ray cells play a significant role in the penetration of softwoods and beech, while vessels in the eucalypts are important. The pit membranes in all wood species retain high levels of CCA. In addition to the preservative distributed in cell walls, gross cellular inclusions, both amorphous and crystalline, are frequently encountered in cell lumina. With the exception of E. maculata these deposits are removed by leaching, which also produces a redistribution of preservative elements within the wood specimens, particularly the softwoods. Different levels of Cu, Cr, and As occur at different locations within and between wood species, the softwoods tending to have higher preservative concentrations than the hardwoods. It was also found that different ratios of the three elements exist in softwoods and hardwoods, and that the preservative undergoes disproportionation and recombination within the wood. The results further indicated that fixation mechanisms are not the same in softwoods and hardwoods, and this may lead to the more uniform distribution and higher cell wall loadings in the former, thus producing a better preserved substrate.Nachweis der Mikroverteilung von KCA-Salzen im geschützten Splintholz mit Hilfe der Röntgen-Mikroanalyse bei der Raster-Elektronenmikroskopie Zusammenfassung Die Mikroverteilung von KCA-Salzen im Splintholz von Pinus radiata, P. sylvestris, Picea abies, Fagus sylvatica, Eucalyptus regnans und E. maculata wurde vor und nach Auslaugung untersucht. Die Untersuchung basieite auf der Messung der Energiestreuung der Röntgenstrahlen in Verbindung mit der Raster-Elektronenmikroskopie. Die Ergebnisse zeigen, daß die Verteilung der KCA-Salze in Nadelhölzern relativ gleichmäßig ist, während sich in Laubhölzern, speziell in E. maculata, große Bereiche von ungeschütztem Gewebe zwischen den Haupttränkungswegen befinden. Während bei der Tränkung sowohl der Nadelhölzer als auch des Buchenholzes die Holzstrahlen eine wichtige Rolle spielen, sind bei Eucalyptus besonders die Gefäße wichtig. Die Tüpfelmembranen bes...