COMBINATIONS OF WOOD AND SILICATE .1. IMPREGNATION BY WATER GLASS AND APPLICATIONS OF ALUMINUM SULFATE AND CALCIUM-CHLORIDE AS REACTANTS

To make a composite material from wood and a mineral by utilizing silicate, inorganic substances were produced by the impregnation of water glass (sodium silicate) into the wood followed by precipitation with an aluminum sulfate or a calcium chloride solution. The weight percent gains were sufficient with a small concentration of 5% water glass, and there was little difference in them between the vacuum-impregnating and the diffusion-penetrating processes. Inorganic substances were observed to be deposited in the lumina of tracheids, vessels, and other components. They proved to be the compounds, aluminum silicate or calcium silicate, produced by replacing natrium ions in the water glass with aluminum or calcium ions from the same distribution of both elements, silicon and either aluminum or calcium by electron probe X-ray microanalysis. The composites obviously have a fire-resisting effect. When exposed to fungal attack, the weight losses were reduced for the aluminum sulfate-treated specimens, but the composites were greatly hygroscopic.